10 Problems That Can Cause Led Driver Failure (Part 3)

5. The test results are different with different loadsNon waterproof LED driver with LED lamp test, it is normal, with electronic load test, the result is likely to be abnormal. Usually this happens for the following reasons:(1) the output instantaneous voltage or power of the driver is beyond the working range of the electronic load meter. (especially in CV mode, the maximum test power should not exceed 70% of the maximum load power, otherwise the load may overpower during loading, resulting in the drive not working properly or loading.

)(2) the characteristics of the electronic load meter used are not suitable for measuring constant current source, and the load voltage tap position jumps, resulting in the driver not working normally or loading.(3) because the input of the electronic load meter will have a large capacitor in it, the test is equivalent to connecting a large capacitor in the output of the driver, which may cause instability in the current sampling of the driver.Because the LED driver is designed to meet the working characteristics of LED lamps, the closest to the actual and real application of the test method should be to use LED beads as load, ammeter and voltmeter series to test.

Non Waterproof Led Driver6. Outdoor LED driver may be damaged due to the following common conditions:· connect AC to the DC output of the drive, resulting in the failure of the drive;· connect AC to input or output of DC/DC drive, resulting in drive failure;· connect the constant current output end with the dimmer, resulting in the failure of the actuator;· connect the phase line to the ground line, resulting in no output of the driver and live enclosure;7. Wrong phase connectionGenerally, outdoor engineering applications are three-phase four-wire system. Taking the national standard as an example, the rated working voltage between each phase line and the zero line is 220Vac, and the voltage between the phase line and the phase line is 380Vac. If the construction worker connects the driver input end to two phase lines, the product will fail due to excessive input voltage of LED driver after energizing.Because of the difference in the input resistance, when one driver is charged to start, the internal resistance decreases and the voltage may be mostly applied to the other driver, resulting in its over-voltage damage and failure. Therefore, it is recommended that the same distribution branch, switch or circuit breaker to break together, can not only disconnect the zero line.

Do not put distribution fuse on the zero line, the line to avoid the zero line bad contact.8. The fluctuation range of the power grid exceeds a reasonable rangeWhen the distribution line of the same transformer power grid branch is too long and there are large power equipment in the branch, when the large equipment starts and stops, the power grid voltage will fluctuate violently, even causing the power grid instability. When the instantaneous voltage of the grid exceeds 310Vac, it is possible to damage the driver (even with the lightning protection device is not effective, because the lightning protection device is to deal with a few tens of us-level pulse spikes, and the power grid fluctuations may reach tens of mS, or even hundreds of mS). Therefore, the street lighting branch power grid has a large power machinery to pay special attention to, it is best to monitor the fluctuation of the power grid, or a separate power transformer power supply.9. The line trips frequentlyToo many lights on the same road lead to overload of the load on one phase of the electricity and uneven power distribution between the phases, resulting in frequent trip lines.10. Drive heat dissipationWhen the actuator is installed in a non-ventilated environment, the actuator shell should be in contact with the lamp shell as far as possible. If conditions permit, the contact surface between the shell and the lamp shell should be coated with thermal adhesive or thermal pad to improve the heat dissipation performance of the actuator, so as to ensure the life and reliability of the actuator.To sum up, there are many details of LED driver in practical application that need to be paid attention to, and many problems need to be analyzed and adjusted in advance to avoid unnecessary failure and loss!China OEM LED Driver, LED Power, LED Adaptor SupplierWe are a worldwide supplier of LED Driver established in 2006. Our products such as LED Driver, LED Power and LEDwww.




Home solar system - COB LED Drive

Assuming there are pure LED, or perhaps just led with a resistance, you can use a current controlled step down buck converter. It will give you more efficiency than going through the 220V, in theory.Product examplePrinciple

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LED Driver Design Skills and Application Scheme Collection
LED Driver Design Skills and Application Scheme Collection
For novices, LED drive design is not an easy task. In view of this problem, Xiaobian specially summarizes some problems that designers need to pay attention to in their work and shares their own design experience.Do not use bipolar power devicesSince bipolar power devices are cheaper than, usually about 2 cents each, some designers use bipolar power devices in order to reduce the LED driving cost, which will seriously affect the reliability of the circuit, because with the increase of the LED driving circuit board temperature, the effective working range of bipolar devices will be rapidly reduced, This will lead to device failure when the temperature rises, thus affecting the reliability of LED lamps. The correct way is to select MOSFET devices. The service life of MOSFET devices is much longer than that of bipolar devices.Try not to use electrolysisShould electrolytic capacitors be used in LED driving circuits? At present, there are supporters and opponents. Supporters believe that if the temperature of the circuit board can be controlled well, the purpose of prolonging the service life of electrolytic capacitors can be achieved in turn. For example, a high-temperature electrolytic capacitor with a service life of 8000 hours at 105 ° C is selected. According to the current electrolytic capacitor service life estimation formula, "the service life is doubled for every 10 ° C reduction in temperature", Then its working life is 16000 hours at 95 degrees, 32000 hours at 85 degrees and 64000 hours at 75 degrees. If the actual working temperature is lower, the service life will be longer! From this point of view, as long as the selection of high-quality electrolytic capacitors has no impact on the service life of the driving power supply!Some supporters believe that the low-frequency flicker caused by the high ripple current brought by no electrolytic capacitor will cause physiological discomfort to some human eyes, and the large low-frequency ripple will also lead to the bright dark grid of differential frequency flicker in some digital camera equipment. Therefore, high-quality light source lamps still need electrolytic capacitors. However, opponents believe that the electrolytic capacitor will age naturally. In addition, the temperature of LED lamps is very difficult to control, so the service life of electrolytic capacitor will be reduced, which will affect the service life of LED lamps.In this regard, senior engineers believe that electrolytic capacitors can not be considered in the input part of LED drive circuit. In fact, electrolytic capacitors can be omitted by using PI linkswitch pH. the single-stage PFC / constant current design of PI can save designers from large capacity capacitors. In the output circuit, high voltage withstand ceramic capacitors can be used to replace electrolytic capacitors, so as to improve reliability, When designing the two-stage circuit, the output adopts a 400V electrolytic capacitor, which will seriously affect the reliability of the circuit. It is recommended to use ceramic capacitor for single-stage circuit. For industrial applications that do not pay much attention to dimming function, high temperature environment and need high reliability, it is recommended not to use electrolytic capacitor for design.The withstand voltage of MOSFET shall not be lower than 700V600V MOSFET is relatively cheap. Many people think that the input voltage of LED lamps is generally 220V, so 600V is enough, but the circuit voltage often reaches 340v. Sometimes, 600V MOSFET is easy to be broken down, which affects the service life of LED lamps. In fact, selecting 600vmosfet may save some costs, but it pays the price of the whole circuit board, Therefore, do not choose a 600V withstand voltage MOSFET, and it is best to choose a MOSFET with a withstand voltage of more than 700V.Try to use single-stage architecture circuitsSome led circuits adopt a two-stage architecture, namely PFC (power factor correction) isolated DC / DC converter, which will reduce the efficiency of the circuit. For example, if the efficiency of PFC is 95% and the efficiency of DC / DC part is 88%, the efficiency of the whole circuit will be reduced to 83.6%! "Pi's linkswitch pH device integrates PFC / cc controller, a 725vmosfet and MOSFET Driver into a single package at the same time, which improves the efficiency of the driving circuit to 87%. Such a device can greatly simplify the layout design of the circuit board and can save up to 25 elements used in the traditional isolated flyback design! The omitted elements include high-voltage high-capacity electrolytic capacitor and optocoupler. Led two The stage architecture is suitable for old drivers that must use a second constant current drive circuit to make PFC drive LED constant current. These designs are outdated and no longer cost-effective, so it is best to adopt single-stage design in most cases.Try to use MOSFET devicesIf the power of the designed LED lamp is not very high, it is recommended to use the LED driver product with integrated MOSFET, because the advantage of this is that the integrated MOSFET has less conduction and generates less heat than the discrete one. In addition, the integrated MOSFET is a controller and FET together, and generally has the function of overheating shutdown. When the MOSFET is overheated, it will automatically turn off the circuit to protect the LED lamp , this is very important for LED lamps because they are generally small and difficult to air.
Technology Trend of LED Driver Chip for Lighting
Technology Trend of LED Driver Chip for Lighting
With the further development of LED, its utility or the ability to generate light output from power supply will only continue to improve. Secondly, LED lighting has the characteristics of environmental protection and does not need to deal with, expose and dispose of the common toxic mercury vapor in cold cathode fluorescent lamps (CCFL). Finally, incandescent bulbs often need to be replaced after about 1000 hours of use, while fluorescent lamps can last up to 10000 hours. However, these figures are dwarfed by the fact that led lighting can provide more than 100000 hours of life.Heat dissipation, reliability and safety regulations need to be consideredAs we all know, the working environment temperature of the LED drive module is high and the heat dissipation condition of the module is poor, resulting in the LED drive circuit working at a high temperature all the time, which will lead to a series of problems such as reduced LED application reliability and shortened service life, so the heat dissipation has to be considered emphatically; Reliability and safety regulations are easily neglected, especially before the enforcement of relevant regulations, in order to reduce costs, some LED lighting manufacturers will omit circuits in terms of reliability and safety regulations; However, this is precisely the basis for the long-term development of the LED lighting industry and the embodiment of the design ability of LED driver chip manufacturers. The cost of increasing this part of the circuit varies greatly according to the schemes provided by different chip manufacturers.Yu Zhongwei, product director of Taiwan's Jiji Technology Co., Ltd., believes that we should pay attention to the trend of standardized forming, such as American energy star and Japanese PSE specification. In addition, the dimming function has attracted more and more attention, such as traditional thyristor dimming, 1 10V dimming, and Dali dimming. Finally, for the requirements of the driving scheme derived from solving the heat dissipation problem, in addition to the consideration of cost and the requirement of lighter weight, we must also take into account better electrical characteristics (efficiency, power factor, electromagnetic interference, output ripple, etc.).Led needs rich power conversion and driving schemesLin Zhiyan, technical marketing manager of ansenmey semiconductor lighting market, said that LEDs are essentially low-voltage devices. According to different colors and currents, their forward voltage drop may vary between 2 4.5 V, and LEDs need to be driven by constant current to ensure the required luminous intensity and color. At the same time, LED applications are diverse, and different power supplies need to be used to supply power, such as high-voltage AC-DC, medium voltage DC-DC and low-voltage DC-DC.This requires appropriate power conversion and led driving schemes to drive LEDs according to specific application requirements, such as switching driver, linear driver, linear constant current regulator (CCR), high-voltage switching power supply scheme, power factor correction (PFC) controller, and even novel lighting management integrated circuit (LMIC) to meet specific application requirements, Provide high energy efficiency and high reliability to help give full play to the long-life advantages of LED.Jiji technology also believes that the market has not blindly pursued the "one-time satisfaction" scheme, but learned that there are conflicts between various characteristics. For example, under the traditional single-stage output architecture, the power factor and output ripple cannot be optimized at the same time and must be compromised. Therefore, the strategy of accumulation technology is to propose different solutions for different needs of customers. In terms of architecture, when the market is one-sided towards isolated solutions in recent years, Jiji believes that the irreplaceable advantages of non isolated architecture in specific applications can not be ignored, so it continues to develop a variety of products. At present, in addition to the successful service of active power factor correction products, thyristor dimming and four-stage dimming products, Jiji is also actively working towards higher cost-effective solutions.Off line power drive promotes applicationTony Armstrong, product marketing director of power products Department of linglilte company, said that especially in the occasion of driving HB (high brightness) led, linglilte's LED Driver IC can provide sufficient current and voltage suitable for many different types of LED configurations by using a conversion topology that meets the input voltage range and the required output voltage and current requirements.Specifically, only using off-line power supply to drive LED can make the application grow exponentially, because this form of power supply can be easily obtained in both commercial buildings and residential buildings. Although the replacement accessories of LED lamps are relatively simple and easy for end users to install, the new requirements for LED Driver IC have been greatly improved. Because LEDs need a well regulated constant current source to provide constant light output, using AC input power supply to supply power to LEDs requires some special design methods to meet some very special design requirements. To this end, linglilte recently launched an innovative off-line single-stage active power factor correction (PFC) isolated flyback LED controller, lt3799.Compatibility and integrated control become highlightsLance Zheng, marketing director of Marvell green energy department, pointed out that in 2011, the growth of the whole lighting market exceeded 40%, and 2012 became a key year for the take-off of the LED market. Compatibility and integrated control will become two highlights of technological development.The first is compatibility. The existing lighting architecture is based on traditional lighting technologies, such as incandescent lamp technology. Due to space constraints, to replace these bulbs and configurations, LED lamps need to use bulbs of the same specification to match lighting control equipment (such as triac dimmer already configured). In order to deal with this problem, the area of the driving circuit board in the bulb needs to be reduced and compatible with various dimmers.The second is the integrated control function. By adding wireless control technology to the LED driving circuit at a very low cost, it can bring new features, such as color temperature adjustment, mode lighting, scene control, etc. These cool features are based on LED technology and help increase users' acceptance of LED lighting technology.The era of perceptual lighting is comingSajol Ghoshal, director of microelectronic sensing driven Lighting Department in Austria, pointed out that the main factor promoting the continuous development of LED lighting technology is regulations. At present, the construction of new power plants has become very expensive, so governments around the world are looking for ways to significantly reduce energy consumption in the next decade. In a building, a high proportion of energy consumption comes from lighting. Therefore, the new regulations that force the reduction of energy consumption will affect the design, installation and application of lighting systems. The EU is planning to phase out inefficient light bulbs and has developed regulations for commercial lighting.Historically, lighting is a roughly controlled electrical load, which can be further refined by manual control with a simple switch. For example, the California Parliament Act 32 requires buildings to reduce energy consumption by half by 2018. Other building regulations, such as Title 24 in California, even put forward more specific requirements, such as requiring sunlight capture through windows and skylights to reduce energy consumption, and requiring buildings to be equipped with automatic lighting control systems. At present, low-cost passive infrared detectors are rarely used in rooms. Controlling lighting through the building system can greatly reduce energy consumption and bring highly optimized lighting to users, so as to improve the comfort experience. In this regard, it is obvious that there is still a long way to go.Therefore, using the advantages of LED power supply and flexibility to realize lighting control in the next generation lighting system will be the main trend. This scheme can enable the lighting system to adjust the brightness and color of the LED according to the environmental changes to meet the environmental requirements. For example, when there is enough sunlight in the room or there is no person in the room for a long time, this method can automatically reduce a lot of energy consumption.Intelligent dimming schemeNXP semiconductor is also an active promoter of intelligent dimming. Zhang Weichao, marketing manager of lighting products in Greater China, said that for LED lighting driver manufacturers, the design scheme needs to improve the performance to a greater extent, including key performance such as PFC, thd, efficiency and output constant current accuracy, reduce the space demand of circuit board and reduce the design complexity and system cost. At the same time, with the development of LED residential and commercial lighting applications, the demand for dimming increases, but the thyristor dimming used in incandescent lamps will still exist, so the architecture design of driving IC needs to face a wider dimming compatibility problem.At the same time, the future lighting scheme tends to be more intelligent dimming. Considering the factors of energy saving, the biggest breakthrough in the lighting field is to improve the application mode of lighting, that is, intelligent, wireless lighting control, or "intelligent lighting". Intelligent lighting marks a fundamental change in our relationship with light - at home, in the office, and even outdoors. Connecting wireless IP with energy-efficient lighting technology in a safe, small and low-cost solution can transform the way we design, control and manage lighting. For each bulb with IP address, this complete hardware / software scheme can realize the connection between IP, so as to establish an advanced lighting system that can be easily controlled through smart phones, tablets and personal computers.Intelligent lighting network includes lights, switches, sensors, remote control, and optional IP control mode realized through network management of smart phones, tablets and personal computers. These lights can realize network IP control through the Jennet IP stack protocol based on 6LoWPAN.Compared with the traditional control scheme, the Jennet IP SW stack allows the system to be controlled through smart phones, tablets and personal computers. These functions can be realized through low-cost gateway, which can be controlled through Internet or local area network (LAN). The solution of chip icfl or ISSL is suitable for home users to professional users with management system.
Analysis of Main Characteristics of LED Driver
Analysis of Main Characteristics of LED Driver
Based on the rate of change characteristics of voltage current, LED drivers need a satisfactory design, so it is very important to understand their characteristics and select the appropriate driving circuit based on specific applications. In this way, the special driving circuit can provide the rated voltage and current for these LEDs and create a good condition for their normal operation.To achieve the purpose of lighting, the LED needs a forward voltage to let the current flow. Therefore, the LED driver shall provide a forward bias for the led to make it emit light. The luminous level or brightness of the LED is usually proportional to the magnitude of the forward current. In addition, the current through the LED should not exceed the rated current specified by the equipment, otherwise permanent injury may be caused. Therefore, the constant current driving circuit is an ideal scheme to control the current at the correct level of driving LED. In other words, the LED drive circuit is a power conversion circuit that provides a constant current rather than a constant voltage. The LED driving circuit shall at least include a voltage detection circuit and a current switching circuit.When the voltage detection circuit detects different voltage levels of the power supply, it will send a signal to the current switching circuit, and then the current switching circuit will be started automatically. The predetermined current value is used to readjust the electrical setting of the LED, so as to effectively light up as many LEDs as possible.Linear driverThe linear regulator can provide a simple method of generating constant current by connecting a current sampling resistor between the output of the regulator and the grounding node. The constant output voltage of the regulator generates a constant current through the feedback resistance. The power supply reference voltage and current sampling resistance determine the current of the LED. Linear regulators are often used to drive low-power LEDs, such as backlights for portable devices such as PDAs. Typical current values for these LEDs are between 15 mA and 25 mA, and VF is between 3.0 V and 3.4 v. If the linear driver is used to power multiple LEDs, these LEDs should be connected in series to ensure that the current through all LEDs is the same, so that the amount of light emitted is approximately equal.The advantage of the linear driver is that the cost and electromagnetic interference of the scheme are low, because the linear regulator only needs to place a few resistors around the driving IC and does not use switching elements. Since the linear driver needs to output a high voltage to provide LED current, the disadvantage of this scheme is low efficiency, that is, the ratio of LED voltage to power supply voltage is low. The main limitation of linear voltage regulator is that the power supply voltage is always higher than the LED voltage, so the linear voltage source can not improve the output voltage, but can only reduce the voltage to a certain extent. This inefficiency can cause heating problems.Switch driverFor high current applications with a wide input range, simple driver schemes such as those mentioned above will produce higher heat generation and lower efficiency. The switch driver with constant current output is the first choice to drive high-power LED. The driver is usually used to switch the inductor and LED load in series or the capacitor in parallel and the supply voltage on the LED. The inductor or capacitor is used to save electric energy when the switch is turned on; Then supply current to the LED when the switch is off. Unlike linear drivers, switching drivers can be configured to realize the functions of voltage buck, boost or both. Therefore, it is obvious that the switch driver allows the led to operate over a wide input voltage range. In addition to the current adjustment function with constant luminous amount, they can also minimize power loss. There is no doubt that switching regulator is more efficient than linear regulator. However, compared with linear regulators, switching drivers are more expensive and require careful design for EMI problems. In order to drive LEDs in an appropriate way, we need to find the most satisfactory performance price ratio.PWM dimmingMany LED applications require dimming functions, such as LED backlight or building lighting dimming. The dimming function can be realized by adjusting the brightness and contrast of the LED. Simply reducing the current of the device may be able to adjust the light emission of the LED. However, allowing the led to work below the rated current will cause many adverse consequences, such as color difference.Instead of simple current regulation, a pulse width modulation (PWM) controller is integrated into the LED driver. The PWM signal is not directly used to control the LED, but to control a switch, such as a MOSFET, to provide the required current to the LED. PWM controller usually works at a fixed frequency and adjusts the pulse width to match the required duty cycle. At present, most LED chips use PWM to control LED lighting. In order to ensure that people do not feel obvious flicker, the frequency of PWM pulse must be greater than 100 Hz.The main advantage of PWM control is that the dimming current through PWM is more accurate, which reduces the color difference of LED lighting to the greatest extent.Other features of LED driverBecause it can emit more light than traditional lighting sources, high brightness LEDs occupy a place in many lighting applications. But these LEDs generate more heat than traditional LEDs. Therefore, the LED driver needs the overheat protection function to avoid being damaged by the heat emitted during continuous operation.
Strange Behavior of the DALI Controlled Luminaires
DALI requires less than 2V maximum difference between the highest and lowest points on the line. To achieve that you must use sufficient cable gauge and a power supply with sufficient current limit. The luminaires will go on "spontaneously" if they see a system failure condition, which is less than minimum DALI voltage for more than 500ms. For up to 150m you need to use 0.75mm squared CSA.You may be overloading the PSU in the 905 router. Although it has a current limit at 250mA, which is the maximum allowed by DALI, you have 48 luminaires plus 3 control panels. The luminaires (assuming one DALI driver per luminaire) are restricted to 2mA each by the standard, but the control panels do not have the same restriction; they are allowed to be up to 250mA each (although not a good idea to go that high). So measure with a current meter in series at the router end what you are drawing during non transmit times, and look at the DALI signal with a scope to see if the high levels are dipping below 9.5VI faced a strange behavior of a DALI controlled LED luminaires circuit. I have 48 LED luimianires with a MeanWell ELG150-C700-DA drivers connaected according to the scheme below:I commissioned the system and it works OK but sometimes I can't switch some luminaires OFF via the DALI commands. When I send DAPC 0 or OFF command this luminaire go OFF, but in a second the go back to 100% of their output. Besides that this problem is floating, because in a different days different luminaires start to work in a such way. Moreover sometimes ALL luminaires go ON spontaneously.I doubt that the problem is in LED drivers because when I tested some other drivers from the same bunch, everything was OK. I think that something is wrong with the DALI bus installation quality, but I don't know from where to start the thoubleshooting.I am a novice in a DALI theme, could you advice me what parameters I should check to find the root of the problem?Here is a DALI signal at the beginning of the DALI bus near the 905 routerBy the way why the signal amplitude for 2 DALI packets is different?·OTHER ANSWER:I faced a strange behavior of a DALI controlled LED luminaires circuit. I have 48 LED luimianires with a MeanWell ELG150-C700-DA drivers connaected according to the scheme below:I commissioned the system and it works OK but sometimes I can't switch some luminaires OFF via the DALI commands. When I send DAPC 0 or OFF command this luminaire go OFF, but in a second the go back to 100% of their output. Besides that this problem is floating, because in a different days different luminaires start to work in a such way. Moreover sometimes ALL luminaires go ON spontaneously.I doubt that the problem is in LED drivers because when I tested some other drivers from the same bunch, everything was OK. I think that something is wrong with the DALI bus installation quality, but I don't know from where to start the thoubleshooting.I am a novice in a DALI theme, could you advice me what parameters I should check to find the root of the problem?Here is a DALI signal at the beginning of the DALI bus near the 905 routerBy the way why the signal amplitude for 2 DALI packets is different?
How to Know If Graphics Card Is Supported on Unity?
According to this Romanian Website, you should be good!EDIT: Model number on the laptop itself is slightly different, but the graphics card is the same model so laptop model shouldn't make any difference.EDIT 2: So, it was clarified that this is a certified (pre-installed) rather than a certified installation, meaning there could have been modifications done the standard Ubuntu image, such as custom drivers. So, you should be okay, but as the comments on the original question indicated, it would be best to try with a LiveUSB first because one of those modifications could have been a custom driver for the graphics.I am looking to purchase a computer and put Ubuntu / Unity on it. I am not a hardware expert but I do know how to navigate around Ubuntu. I am having trouble finding whether or not the computers graphic card is supported or not. I am not looking to maximize the use of the graphics card but want to make sure it will support external monitors (hopefully 2). here are the specifications on the computer:Inspiron 15 7000 Series16GB, DDR3L, 2 DIMM, 1600MHz256GB Solid State Drive**AMD Radeon R7 M270 4GB DDR3**15.6-inch 4K Ultra HD (3840 x 2160) Truelife LED-Backlit Touch Display with Wide Viewing Angle (IPS)802.11ac Bluetooth 4.0, Dual Band 2.4&5GHz, 2x2MUI DocumentationBacklit Keyboard, US EnglishUS Power CordBRAD15BDW1601_5208/US/CA/BTO58WHr, 4-C (rem) 58 WHr, 4-Cell Battery (removable)802.11ac Bluetooth 4.0, Dual Band 2.4&5GHz, 2x2 Wireless DriverThanks in advanceEDITHere is the link to the computer: ·OTHER ANSWER:I am looking to purchase a computer and put Ubuntu / Unity on it. I am not a hardware expert but I do know how to navigate around Ubuntu. I am having trouble finding whether or not the computers graphic card is supported or not. I am not looking to maximize the use of the graphics card but want to make sure it will support external monitors (hopefully 2). here are the specifications on the computer:Inspiron 15 7000 Series16GB, DDR3L, 2 DIMM, 1600MHz256GB Solid State Drive**AMD Radeon R7 M270 4GB DDR3**15.6-inch 4K Ultra HD (3840 x 2160) Truelife LED-Backlit Touch Display with Wide Viewing Angle (IPS)802.11ac Bluetooth 4.0, Dual Band 2.4&5GHz, 2x2MUI DocumentationBacklit Keyboard, US EnglishUS Power CordBRAD15BDW1601_5208/US/CA/BTO58WHr, 4-C (rem) 58 WHr, 4-Cell Battery (removable)802.11ac Bluetooth 4.0, Dual Band 2.4&5GHz, 2x2 Wireless DriverThanks in advanceEDITHere is the link to the computer:
Can I Use the TLC5940 LED Driver If I'm Already Using Other SPI Devices on My Arduino Mega?
Can I just include this in the standard daisy chaining and assign a new slave select? SPI is normally used as a parallel bus and requires MISO to be tri-state (disconnected when not selected). In some forums online some people seem to indicate you can't use the TLC5940 on the same SPI bus as other devices. The device does not have a chip select which gives a challenge. No direct wiring is possible but can be solved. Are there different forms of SPI? I'm quite confused, can I use the TLC5940 with other SPI devices?It is possible to connect the TLC5940 but it requires some extra logic. You can for instance block the clock signal when it is not selected. This can be done with a MOSFET or 74HC125 and a pull-low resistor. Cheers!• Related QuestionsZigbee RGB control using XbeeLooking at the Shiftbrite LED module page and xBee datasheet, it would seem you can do this without a microcontroller. The Shiftbrite LED module uses 4 lines (3 if enable always active) which are:Data, Clock, Latch and Enable (both input and output pins, so 8 pins in total)This means modules can be chained together easily, so you can add more Shiftbrite LED modules later on if desired. The xBee has 8 pins which can be used as digital I/Os, and configured in "virtual wire" mode, where whatever logic level appears at the Tx input pin will be output on the corresponding Rx output pin.So, with a bit of reading to setup the xBee for virtual wire mode, you should be able to write your code as if the LED module was connected directly to the R-Pi------How to install multiple individual led strips?I have used these inexpensive LED tape lights from Amazon.com with very good success.You can cut them down to as small as 4" pieces, and use connectors to get wire leads to connect to a driver. You'll need some low-voltage wiring to go between the tape ends and the driver. You have to calculate how much wattage you are putting on each driver, but they do come in several sizes so you can potentially put a lot on a one driver.Links:------Is it a good idea to refresh a display (8x8 LED matrix in this case) inside an interrupt handler?Normally interrupt handlers are indeed used for short actions. The reason is that the main program blocks.However, if the main handler does not do any time critical actions, it is a lesser problem.Make sure that the interrupt handler does not take longer than the next interrupt call. Than you get an interrupt call within an interrupt call, etc.In your case your refresh function is probably always taking the same time. You can measure it (do a test with 1000 iterations and divide the time by 1000, or 1M is you cannot measure it). And you know the refresh rate. Than you know how many percent (minus some overhead) is left for your main program.Personally I think writing 64 GPIO pins, even with shift registers should be done very quickly, but testing is better than assuming.------How to tell if a chip's heat sink can be groundedYes it is really unclear on the spec sheet and the app-note does not help either.Without more information or calling the manufacturer you would need the part in hand to test it. If you plan on going ahead before you get the parts, you really don't want to leave a big copper pad like that floating. Which is why it may be grounded on that schematic, but not shown on the part info, it may not be internally connected at all but just a thermal pad. If in doubt it would be better to route it out through a small cap or resistor you can short out later when you have the parts in hand. Adding the extra pin to the symbol will also make life a lot less confusing for the PCB designer later too.------Is there anyway to unlock hibernated NTFS partition?use ntfs-3g command with remove_hiberfile option .You need to mount the partition in read-write mode and are not able to or willing to boot into Windows. so, it is not included here because it completely deletes hiberfil.sys and will cause you to lose all unsaved information in the hibernated Windows programs.The following is a quotation from man ntfs-3g about the remove_hiberfile option that would be used to do this.remove_hiberfileUnlike in case of read-only mount, the read-write mount is denied if the NTFS volume is hibernated. One needs either to resume Windows and shutdown it properly, or use this option which will remove the Windows hibernation file. Please note, this means that the saved Windows session will be completely lost. Use this option under your own responsibility.------Dimming multiple LED panels without PWM to LEDs; modified DMX control or something else?Is this possible, Yesis the DMX to Meanwell architecture the way to go?Use multiple Mean Well HLG-240-48A or HLG-240-48B (cheapest cost per watt)The type A has a pot to vary the current between 50% and 100%.Type B uses 0-10v, or a resistance to set the current. Use strings of 16 LEDs (white, blue, green) or 21 red in series (45v Vf). Connect as many of the strings in parallel as each HLG can support. Try to match forward voltages of the strings when connecting in parallel.The parallel wiring will cause some current imbalance between strings. If the forward voltages are not matched well enough you will need to add current balance circuits. The easy way is to use an LM3466 with each string. Keep the temperature down with good thermal management.------Wireless wont show up on Dell Latitude D620, I am New to LUBUNTU and never used Linux duplicate URL gave me the commands I needed in Terminal to make this work for me:sudo apt-get updatesudo apt-get install firmware-b43-installersudo apt-get remove bcmwl-kernel-sourcesudo rebootThe remove seemed to be the key I needed for my 1490 a/b/g card.CTRLShiftC works on Mint so here is what I got on my D520... (Yes I have both a D520 and a D620... not a typo)owner@Latit-D520 $ uname -a Linux Latit-D520 3.13.0-24-generic #47-Ubuntu SMP Fri May 2 23:31:42 UTC 2014 i686 i686 i686 GNU/Linux owner@Latit-D520 $ lspci -vnn | grep 14e4 02:00.0 Ethernet controller 0200: Broadcom Corporation BCM4401-B0 100Base-TX 14e4:170c (rev 02) 0c:00.0 Network controller 0280: Broadcom Corporation BCM4311 802.11a/b/g 14e4:4312 (rev 01) owner@Latit-D520 $ I then compared my model at------What rating of constant current LED driver do I need? closedA constant voltage supply will output its rated voltage at any current up to the maximum it is built to supply. If overloaded, it should shut down. They come in standardised voltages, such as 12V or 24V.A constant current supply will deliver whatever voltage it needs to, in order to push its rated current through the LEDs. So a 1500mA supply will keep ramping up the voltage until 1500mA flows. This will be subject to a maximum voltage that the power supply can deliver, such as 30V.Selecting the wrong sort of power supply is liable to either overload the power supply or blow the LEDs.If you're using 12V LED strips, then you need a 12V constant voltage supply, with a wattage rating high enough for the sum of the wattages of all the strips------Recessed Lighting Junction Box CordYou are likely to have issues and I would strongly recommend replacing at least the LED driver box ("junction box"), if not the entire light.The white cable that connects to the driver box contains at least two low-voltage wires, and is secured to the grounded metal driver box by a plastic collar. Contact between the metal box and the internal wires likely caused your issue, pulling on the cable probably caused further exposure of the internal wires, and if your wire nuts aren't well-secured inside the box due to some of this punching and pulling, you could have a real mess on your hands from low voltage high voltage ground contact.Rather than punching holes in the ceiling, try to pull the light downward out of the hole and the driver box should follow------AMD Radeon outputs only 1080i (1920x1080@30hz) on Full HD TVYou may be running into an issue with the color format.You should have a choice between YCbCr 4:4:2, YCbCr 4:4:4 and RGB (HDMI Limited/Full Range) if you look really closely under the panel settings in Catalyst Control Center.Generally TVs are guaranteed to support the Luma/Chroma (YCbCr) formats for all refresh rates but not RGB. It is the opposite story for general purpose monitors, most of them only support RGB.I would suggest you try using YCbCr 4:4:2 and see if that changes anything. I prefer Luma/Chroma for TVs personally because even when configured in the menus to use full-range RGB many TVs still clip full black/white over HDMI. You probably would never notice this unless you have your TV properly calibrated, but RGB is more trouble than it is worth for TVs------Wattage of DC device is not equal to AC closedThis is a constant current driver that regulates its output voltage in order to generate the specified current.30V is the maximum that your driver can output in order to drive 700mA through the LEDs. In practice, it will usually output a lower voltage depending on what sort of LEDs you have connected.However, 5.6W would suggest an output voltage of just 8V, which is well short of what you'd expect to see across ten LEDs wired in series, so I suspect that either your device is not measuring what you think it is or your LEDs are not wired in series.Use your multimeter to measure the output voltage across the LEDs and see what you get. Assuming you are still getting 700mA through the LEDs the actual power will be 0.7 times the actual voltage.------What does this WIFI sound mean?There are two sounds audible, both are two tones. One is a bee-boop, and the other is a boo-beep.The "bee-boop" (first sound) indicates the discovery of a new device and the attempt to initialize it. That sound is heard any time a hot-pluggable device is added to the system or enabled. You will hear it if you, for example, connect a USB flash drive.The "boo-beep" indicate the loss of a hot-pluggable device. You will hear that sound if you remove a USB flash drive.As for explaining your issue, it seems that the computer tries to initialize the device and then the device disconnects. This could be caused by any number of things including a defective device, a defective port, an incorrect driver, or a port with insufficient power to run the device.------Thoughts on this 3-way wiring jobOz wiring looks kinda weird to folk in the top half of the planet.This seems to be an Oz equivalent of what Brits would call 2-way switches and what Americans would call 3-way switchesThe "loop" connector is presumably not wired to the switch but is a provided as a convenience to save having a floating connector-block (or wire-nut).In your case it looks like the three blacks shown at right in the diagram above have, in your photo, been connected using a "loop" terminal rather than by using a floating connector block.It isn't clear from your photos if the rest of the your wiring's connections are consistent with this diagram.It might be that the triple reds and triple blacks in your first photo are where some parallel (separately switched) lights branch off
Global Linear LED Drivers Market 2017 Texas Instruments,NS,Mcroblock,AnalogicTech
In this report, the global Linear LED Drivers market is valued at USD XX million in 2016 and is expected to reach USD XX million by the end of 2022, growing at a CAGR of XX% between 2016 and 2022.Geographically, this report is segmented into several key Regions, with production, consumption, revenue (million USD), market share and growth rate of Linear LED Drivers in these regions, from 2012 to 2022 (forecast), coveringUnited StatesEUChinaJapanSouth KoreaTaiwanTo get more details about report visit @ Linear LED Drivers market competition by top manufacturers, with production, price, revenue (value) and market share for each manufacturer; the top players includingTexas InstrumentsNSMcroblockMaximAnalogicTechLinearNXPInfineonToshibaOnsemiEnquiry about report: invantresearch.com/report-enquiry/4413On the basis of product, this report displays the production, revenue, price, market share and growth rate of each type, primarily split intoType A-LampsT-LampsDecorative LampsOtherOn the basis on the end users/applications, this report focuses on the status and outlook for major applications/end users, consumption (sales), market share and growth rate of Linear LED Drivers for each application, includingTransportationIndustrialOtherIf you have any special requirements, please let us know at ·RELATED QUESTIONIs Amazon's Great Indian Sale a scam?I decided to figure it out because amazon's 2019 great Indian sale has just started today (Sep 29th - Oct 4th) and if it is a scam, amazon must have already increased prices 'exorbitantly'. Because I've a deals &price history tracking websiteI regularly keep track of millions of amazon product prices, so lets see how the price changed in last 20 days for these most popular products:1) Philips QT 4011: The highest selling trimmer in India. Price is never below Rs.2099 during normal days. Price dropped to Rs.1749 today.2) JBL GO Wireless Speaker: The most top rated & top selling wireless speaker on amazon. Price dropped by 17%.3) Mi 32″ LED TV: The most popular budget smart tv right now. Price dropped by 12%.4) Haier Fully Automatic Top Load Washing Machine: The top selling affordable washing machine. Price dropped by 16%.5) Canon 1500D DSLR: The successor of the hugely popular 1300D & best selling DSLR right now. An impressive 18% price cut.6) F Gear Luxur Backpack: The super popular & top rated backpack on amazon. Got 17% price cut.7) WD My Passport 2 TB Hard Drive: The #1 selling external hard disk on Amazon. Got 8% price cut.8) Mattel Hot Wheels Car Set: The World's single most popular toy set earning billions of dollars revenue for Mattel. Got 31% price cut.9) Black & Decker Drill: The budget alternative to Bosch drill set offering almost similar quality. Got a very impressive 27% price cut.10) Steelbird Full face Helmet: The top selling budget helmet from otherwise expensive Steelbird. 24% price cut.And of-course, Amazon's own brands including echo, solimo etc will always always get impressive price cuts during every great Indian sale.Not just these, today I observed last 30 days price trend of numerous popular amazon products & I can honestly conclude "There is no such practice as price alteration by amazon India before big sales"."There may be NO deals, Bad deals, Great deals, Good deals, Not so good deals.....But NO scam deals"All the data and price history's are from my website -Buzzguide.in: Amazon's Best Deals, Price History, Product Rankings
Do I Have Other Options but Shorting Out Those Diodes?
This type of "amplifier" is designed to accept a 12-24V control voltage from another LED driver. The 5.1V zeners give it a bit of a threshold voltage (6V or so). They have no other function at all. You can safely short those diodes if using a 5V logic-level drive.• Related QuestionsConnecting smartphone to raspberry pi via usbAccording to: if your phone supports tethering on raspbian, your phone will be visible as usb0 network device via ifconfig command. Then you may add the line:to /etc/network/interfaces file and finally run the command ifup usb0 to start the connection------PWM Red LED on Stellaris LaunchpadI was writing to GPTMTAMR where I should be writing to GPTMTBMR (bullet #3 in the comments). In other words I was writing a value to a timerA register where I should be using timerB. Added the final code as a simple proof of concept for PWM the red LED on Stellaris LaunchPad.------How to control a common-cathode RGB LED matrix with Arduino?The maximum continuous current you can source from a Q is 35 mA, but the max you can source from the whole chip is 70 mA so, depending on what your array looks like and how hard you want to drive the LEDs, this excerpt from TI's HC595 data sheet says you may be SOL. :(------CPU Usage at 100% with Hardware InterruptsAll I had to do was update BIOS. I was previously still using the initial version that came with my motherboard. In my case I just had to go to the Asus support site, download the latest BIOS, and then follow instructions that I found here to update it from a USB stick------PWM dimmer for off-the-shelf 12v LED bulbsif you add an inductor in series with each lamp assembly that will stop the inrush current from immediately charging the capacitor and make them respond to PWM controlyou could alternatively use resistors instead at a lower efficiencysimulate this circuit Schematic created using CircuitLabThis means you'll need to modify each light socket------I/O on SSD hosting a DB periodically hangs with queue length peaks of 800How full is the disk?If the disk is nearly full (80-90%) the disk has to work extra hard doing garbage collection.I saw this situation recently where the queue depth and transaction time on one particular box were much worse than the rest and that particular disk was at 90%------BCR402R - what is the purpose of Rext in this LED driver?It allows you to increase the current.To do so, you need to know the value of the internal R : it's about 0.6(V)/0.01(I) 60 ohms. Rext60 ohms would double the current to 20ma.Leave the pin open; connecting it to Vs is the same as asking for infinite current; not a good idea...------Asus laptop wifi led not lightingLooking at this model, there is no WiFi light (A WiFi LED indicator isn't very common on laptops now, it featured before WiFi was a near certainty to appear on a laptop).The light you're referring to indicates that you are in airplane mode. As such, it is function exactly as intended.------What type of plug do I need to switch on a VL-CSH07G LED?It appears from the specs listed on that website that you need a low voltage constant current supply - that LED needs 700 mA at 3.2 volts (as with any other LED, you must control the current, and let the LED determine the voltage - you can't run it from a fixed 3.2 volt supply.)------Using Arduino-UNO to control LED pins Greater than the Number of I/O PinsTake a look at this LED driver16 bits wide, so you'll only need five of them, outputs are constant current, and each output can sink 120 mA.Plus, the thing is a shift register with an output latch, so you'll only need to use 3 of your Arduino's I/Os to talk to it------i need to control rgb leds brightness using phototransistor plus transistor and at the same time send light value to analog pin on ArduinoYou need to have the Arduino read the photo transistor.You need an RGB LED driver, like the On-Semi NCP5623 or something like a WS2812 with RGB LED and driver.You can probably do without the photo transistor because you will know how bright each LED is when you set the brightness.------TI TM4C1294XL Programming IssueThis is because of the way how driverlib GPIOPinWrite function works.The ui8Val is the value that will be written to the port pins that are selected by the ui8Pins, not to the one specific pin. Thus your code will work if you rewrite it in the following way:.------How do I control several individual LEDs with Arduino?The quickest way I know to throw together a quick prototype with dozens/hundreds/thousands of individually-controllable LEDs is to use a Digital LED Strip with an Arduino and an appropriate power supply and a few wires.(These 2 kinds of LED strips already have the shift register chips built into the strip)------limit LED current only with transistor and base resistorThis design would rely on transistor hFE wich is not consistant between transistors. As stated in The art of electronics : a design that imply a specific value for hFE is generally a bad design.You might want to add resistors in series with your LEDs and use the transistors as switches (in saturated mode).------PWM to analog 1-10V converter: help to understand how it worksA few points; the 10v goes nowhere on the board, bad layout.The opto isolator is not isolating, the grounds are common.Solution is to separate the grounds, still works.The op amp really needs a 12v supply to get full range 0 to 10 volts.This does actually work on the simulator.------Wifi disabled by hardware switch, but hardware switch doesn't helpApparently this is part of a bigger problem with certain Broadcom chips, see use the driver brcmsmac, that actually works with BCM4313Also, there's loads of info here, but I haven't looked through it all, may be you find something relevant------Computer doesn't wake from sleep modeI fixed it. Here are the instructions:1. I didn't have the swap - as I had 4 Gb of RAM. But swap is necessary for suspend mode. So I had to create a swap file of 4 Gb, using the instructions here:www.cyberciti.biz/faq/linux-add-a-swap-file-howto/2. Removed nomodeset kernel param from lilo.conf------Lower power version of ULN2803?ULN2003A are usually quite a bit cheaper, but only 7 channels. BTW, they're not really good for 500mA, if you read the datasheet critically, you'll see it's more like 50 or 60mA per channel with all channels active, assuming a reasonable temperature range. From the Toshiba datasheet, the lower graph is for Ta 85C.------Constant-Current for a 20W LEDIf you want a simple constant current LED driver, on All About Circuits we've been designing one.However, it's only rated to 1W. You'd probably need to upgrade the fet and driver to get it to run at 20W, the fet would also need heatsinking and you'd probably need a bigger inductor------RGB LED flickering with PWMHere's a quick schematic of an LED driver, using part numbers for the LEDs found in the schematic editor. And I thought my handwriting was bad.simulate this circuit Schematic created using CircuitLabAnd I still don't understand the flickering, since I don't see how they get turned on in the first place------Alternating LEDs through n-MOSFETsWhen V2 goes high it turns M2 on.Then drain of M2 becomes ground and 9v actually divide across R2 and R1,so gate of M4 is now 4.5 volt which is greater than threshold voltage.so M4 turns on and D1 glows.To solve try a voltage divider like R1220,R222k.------What do I need in order to install under cabinet lights?"Gx53 LED Light Bulb 110 Volts 5 Watts Warm White with Lamp Base for Ceiling Downlight Under Counter Lighting (5 Watts)"These are available through Amazon and can be hard wired directly into your existing wiring with individual switches if necessary.Voltage transformers are only another unnecessary weak link you can do without.------Can I have multiple outside LED strip lights coming from one driver?If your strips are intended for "12VDC" then they require a constant voltage supply. This is the usual arrangement for strips. In this case:If your strips are not specified for 12V but instead should be driven by constant current then you will need a constant current driver per strip. This would be uncommon.------Boost LED driver output spikesYour spike is common on hard switched power supplies .It is probably the mosfet ,PCB,coil ,diode capacitance resonating with parasitic inductance in the PCB and in the semiconducter bonding wires .Try gate resistance ,Try better PCB layout,Try DS RC snubber .If you do not improve things you will fail radiated EMC------Communication between state machines with hidden transitionsUnless you can actually prevent the button from being pressed at the application, you will always have a window open for the gadget to have it's state changed in-between the control messages. This window will always exist if you have no means of applying a semaphore between A and G operations------Windows 10 boot slow Pre Session Init 40 seconds Aggressive LPMVarious attempts to disconnect devices from motherboard pointed at DVD drive, diconnecting it reduced Pre Session Init from 40 to 10 seconds. Next, I attempted to tweak BIOS settings for SATA controller, particularly Aggressive Link Power Management, when it is off then there was no delays in boot. I hope this research would help someone------Laptop screen resolution stuck in 1280x800 - Ideapad Z580If the graphics issue is showing up in bios, then it is not a problem with Windows. Have you tried changing display modes using keyboard shortcuts or BIOS settings? If neither of those work, I would try connecting your laptop to another display, and see if that doesn't fix the resolution problem------Weird Behaviour with Bootstrapping CircuitCapacitive bootstrap circuits on gate driver chips depend on the fact that the control signals are switching continuously at a relatively high rate (10s of kHz, typically). Otherwise, the bootstrap charge (voltage) leaks away.A static test like what you have set up isn't going to demonstrate the bootstrap effect at all.------Arduino Nano uploading gives error: avrdude: stk500_recv(): programmer is not respondingI was having the same problem and got the same error message. Turns out these boards don't come with a bootloader preinstalled. If you have some jumper wires and another working arduino you can use this tutorial to install the bootloader and it should work great, mine did at least! :).------R-EXT connection on the STP16CP05MTR LED sink driverThe R-EXT resistor in figures 17-18 of the datasheet is shown connected to the R-EXT pin at one end, and a not-very-commonly-used symbol for Ground, at the other end. Thus, the resistor does need to be connected to ground. Notice also that the GND pin connects to the same symbol, such as in Figure 17.------Less noise when not following LED Driver datasheetI was going to bark up the same tree as Photon did. What connection is made to the DIM- pin nominally? Is it a trace run back to the ground pin of the DAC?Is this noise present directly at the DAC output with respect to its immediate ground as well?------No WiFi on HP Netbook 2133You might be affected by this bug : it suggests that you use Synaptic to turn on "Proposed Updates". The last update on that report was only a few hours ago (at the time of writing), so I'd give it a day before trying this.------Why this current regulator won't regulates?The same circuit, with an BUZ70 will work perfect.There is still a little reduction on current at high voltages (from 15 to 24V). I don't know if it is a reduction of the gain of the MOS at higher voltages between gate and drain (doesn't should be ah higher gain)?------How to detect if LED is switched on in external circuit using Arduino NANO?The answer depends on your definition of "on".An led is on ifThere is voltage across I th orThere insufficient voltage across it, orThere is current through it, orIt generates light output, orIt generates sufficient light output....Based on each of the above, there is an answer to your question.------Using an LED torch as a helmet light, will I blind oncoming drivers?Not necessarily blind, but annoy and distract.For oncoming traffic, the best lights are ones mounted below eye level and that limit the upper beam. The easiest way to check for this online is to see if a light is sold by a German mail order store and whether it passes StVZO regulations.------Samsung Monitor Bx2450 resolutionI just wanted to do it a bit more specificreference:Setting up the resolution to 1280x1024 (this is enable GPU funtion in catalyst control center):Manually scaling the resolution in Catalyst Control Center: Set up the resolution to 1920x1080:Note: A computer restart must be done to apply changes.------Issues booting Debian on a Dell laptop closedIt appears that either the physical flash drive or the way it was configured was the issue. Creating an image with Rufus on a new flash drive fixed the issue. However, poor support for network, trackpad, and graphics drivers led me to just install Ubuntu with a much smoother experience.
Can a Few Inexpensive Components Light a White Led From 2 AAA Alkaline Batteries? Closed
(1) Processor pin or similar driveIf a processor or other device was available with enough current drive and a rail to rail square wave (which some 6th sense tm suggests to me may be the case in this case) then a simple diode pump from a single pin may suffice. This could be driven from any point with a rail to rail rectangular wave present with a suitable mark space ratio range plus drive capability as above. simulate this circuit Schematic created using CircuitLabVLED max 2 x V - 2 x Vdiode_drop.At V 2V, VLED max 2 x 2 - 2 x 0.3 3.4V.Many modern White LEDs could be operated from this voltage.As an indication of what could be achieved, an LED rated at say 150 lumen/Watt and with 1 mA LED current would make about 3V x 0.001A x 150 lumen/Watt 0.5 lumen.If this light was distributed evenly over an A4 sheet (hard to do evenly) then light level 0.5 Lumen (0.21 m x 0.3m) 8 lux.At 2.5 mA LED current illumination level rises to 20 lux over an A4 sheet and text and colour pictures would be easily read by most (despite what many text books say.)LED current can come in pulses as long as the frequency was high enough to avoid LED flicker and as long as peaks of capacitor discharge current does not over-stress the LED. (2) Asian (or other) IC.This circuit meets your spec rather well.The main qualification is availability of the IC in Western markets. The IC is available as aQX5252F (TO94 pkg (similar to TO92 but with 4 leads)) andQX5252E in a DIP pkg.The 5252x operates from a single NimH or NiCd cell and the 5253x is the same but operates from 2 cells. The latter would be best suited to your spec. The DIP version adds variable light level sensitivity when used as a solar lamp controller. The IC costs around 10 cents in modest volume in China and probably a few tens of cents in 1's. Features includeLED driver.Brightness level set by inductor valueInternal PV isolation diode and switch MOSFET so ...Total circuit comprises IC, LED, inductor, battery.The IC goes into shutdown mode when Vin is above a preset voltage and drives the LED when Vin is below a preset level. This feature is used to provide auto turn-on turn-off lawn light control. SBAT can instead be used as an enable line or tied low for permanent operation. From memory efficiency is in the 85% region - better than many informal circuits. (3) From the archives ... from this stack exchange question is a good start.This circuit will flash an LED of any colour and forward voltage (or potentially even several LEDs in series) or will pulse a load using one cell - probably about 1 volt will be enough to operate it. I "designed" this circuit but it is based on a design that has not only long been used in transistor form but existed in pre-transistor thermionic valve days and, while I have never seen it used elsewhere, I would be surprised if it has not been independently "developed" by many other people.As shown Q1 collector is driven negative below ground when Q1 turns off until energy in L1 is dissipated. Swap ground and supply and transistor types for ve supply. Add diode from output to use as a DC supply. L1 - small potted "resistor like" inductor or many others - experiment. Q1 Q2 - almost any "jellybean" small pnp & npn transistors. C1 polarised only to get high capacitance per size.Can be eg ceramic if capacitance high enough for needs. Use only either LED2 (best) or LED1 at one time.Use either LED2 (most efficient) or LED1Time constant R2 x C1.Long time constant leads to discrete flashes.Short time constant produce apparently permanently on LED.Use resistor between Q1b-Q2c for higher supply voltages.Resistor in series with C1 will extend pulse length.More soon ...Closed. This question is off-topic. It is not currently accepting answers. Want to improve this question? Update the question so it's on-topic for Electrical Engineering Stack Exchange. Closed 5 years ago. Improve this questionPlease help with finding an energy-efficient LED driver circuit for 2 AAAs(all the way down to 2V), for example for this LED: It has to be:1. Cheap2. As few parts as possible3. Energy-efficient·OTHER ANSWER:Closed. This question is off-topic. It is not currently accepting answers. Want to improve this question? Update the question so it's on-topic for Electrical Engineering Stack Exchange. Closed 5 years ago. Improve this questionPlease help with finding an energy-efficient LED driver circuit for 2 AAAs(all the way down to 2V), for example for this LED: It has to be:1. Cheap2. As few parts as possible3. Energy-efficient
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