Electrical Engineering Stack Exchange
Electrical Engineering Stack Exchange

Questions tagged [led-driver]

An LED driver is a self-contained power supply that controls the amount of current and voltage supplied to an LED light. An LED constant current driver monitors the loop current of each LED and automatically adjusts the generated DC voltage output to the minimum value needed to produce the highest forward voltage. As mains power is AC and Light Emitting Diodes run on DC, this current needs to be converted by a rectifier

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How to achieve constant current around 325mA for a 1W power LED with low headroom voltage

I built the circuit suggested by @MicroservicesOnDDD in their answer to this question: Low Overhead Constant Current LED Driver and had a play. Here's the circuit in the linked question: The most LED current I could get by adjusting R9 was 100mA.…
Mark Highton Ridley
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How do I get a sharper off time curve on my Led driver output?

I designed a pcb with the following dual led circuit based around the TPS92518: I would like to turn on and off the Powerleds in the <1ms range. At the moment our camera stills sees the leds a bit glowing. When I measure on the scope, my output…
user3411864
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LM3914 Bar/Dot display driver

I would like to try out the LM3914, but I could use some help in understanding how to calculate the current limiting resistor. I am referring to page 9 of the datasheet: Do I need to modify the reference output voltage with a voltage divider in…
Status Re
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LED driver identification needed

Can someone identify IC "U1" in the below LED lamp PCB? I've tried to google the identifiers but didn't find anything :-( It's an 18 W lamp for 240 V AC, and according to the customer it's the second lamp within a few weeks that blew up (obviously…
mic
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Controlling 2-lead, 2-colour LEDs

An open appeal for a simple way to control 2-colour, 2-lead LEDs. I am using these LEDs as the 'mimic' lights for my model train layout point control. Working on 12v DC, the point motor is wired to provide a +12v feed to either of 2 connections when…
GSSR
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Design example for LED driver output that support 0-10V sinking dimmer

I am trying to come up with a device that can connect to 0-10V wall dimmer(sinking) and convert it to corresponding PWM signal. I have trouble understanding how the 0-10V interface has to be designed on the device to support 0-10V sinking dimmers.…
Sudeep Dodda
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How can I disable LED cycling?

I havean LED ceiling light with a S4523B chip for cycling. Would it be OK to disable cycling by shorting pin 1 and 3? I would like both outputs to be on when the PCB gets power. UPDATE2 (input part of the circuit):
Pablo
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Oscilloscope probe affects operation of the circuit

I'm working on an LED driver for a fairly powerful LED array. I'm using one of TI's chips, the TPS92691. I'll start by providing the schematic: The array can sink up to 10 A. I'm using both analog dimming and PWM dimming for this application. The…
AMacDonald
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Maximum number of LEDs in series for AP5724 LED driver

For a small project, I would like to use 8 LEDs in series. Each LED has a Vf of 3.3 V. My input voltage is 3.3 VDC. I plan to use the AP5724 LED driver. The datasheet has an example of a circuit using 6 LEDs. I tried asking the manufacturer but I…
Ariel Narboada
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Driving 6 LEDs in series with current control

I'm looking at driving an LEDs, maximum 6 LEDs in series (can be less.) I have used the LT3465ES6 for this job. I have calculated the needed current limit resistor and didn't get the needed results (tested with 4 LEDs 50 mA.) The calculation…
Gal Magen
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Constant current LED driver - lowering brightness with dip switches

Having a 28W LED lamp with constant current LED driver which has some dip switches where I can change the current, is it safe to lower the current to reduce the brightness of the LED?
Twan Manders
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How to make a proportional current output on a constant current driver with PWM dimming

I'm making a constant current LED driver out of 2 2N2222 transistors and a couple of resistors. Works great. I added a PWM signal to the input so I could dim the LED, also works great. The problem is, I'm using this LED driver for a video camera, as…
0x3333
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Using the ULN2803A

I'm so confused. How does this chip drive 8 LED's when there is no apparent power source? What am I missing? New design based on comments.
Kevin McQuown
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A DIY Power supply system for a 150w high power led engine

I have this SST-300 High-power LED which requires 10A and 12-14V as described in the product characteristics. The product is suggesting with its own power supply as well as its own constant current led driver which comes as a separate unit from the…
meowcat
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Constant current buck led driver

I've calculated everything up and came up with the following. Vin,max – 4.2v , Vfb = 0.1v , 1.8 <= Vf <= 2.4V, Vout – Vf + Vfb fsw = 1.5MHz, 30mA <= I_led <= 250mA, I_led = Vfb / Rs I set I_led to be 160mA and I_ripple is 40% of I_led (…
Noah Da
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