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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152 votes
4 answers
74k views

How can I efficiently drive an LED?

I understand that I can not connect an LED directly to a battery because it will draw too much current. Thus, there must be something else in the circuit to limit the current. What options are there? ...
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28 votes
3 answers
2k views

The mysterious case of the random leakage current

Disclaimer: I already know the solution of this circuit debugging conundrum (and it is not trivial), and I'll post it after some time, so that other people could give their contribution to this ...
15 votes
3 answers
2k views

LM2586 - Inductor Heats Then Burns

I'm designing a step-up constant current source to drive LED strips (nominal load voltage is about 54 VDC). Requirements: Vin: 18..32 VDC Iout = 0.2 A Vout = 54 VDC (nominal) - 57 VDC (maximum) ...
12 votes
2 answers
2k views

Why do most flyback converters / LED drivers operate under 100 kHz?

Most of the LED drivers and flyback converters I have come across operate in the 60-100 kHz range. Is there any particular reason behind this - example - ferrite cores not being able to handle higher ...
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11 votes
4 answers
2k views

How to drive 700mA LED cheaply?

I'm new to electronics and am trying to make a night vision circuit. A similar question has been asked before, but with priority on efficiency. I want to control a 700mA-1000mA IR LED using a 5v input ...
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11 votes
3 answers
2k views

Why did my LED drivers blow up?

I recently designed my first PCB, which houses LED driver circuitry for some custom lighting. I fastidiously followed the driver's datasheet (Diodes Inc AL8862QSP-13) in designing the circuit: making ...
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11 votes
4 answers
4k views

Are LEDs in modern streetlights usually pulsed? If so, roughly what frequency?

I can think of some reasons why modern LED streetlights would likely be pulsed; Efficient voltage conversion starting from line voltage would likely include an AC or switching step higher than 60 Hz....
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9 votes
1 answer
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Explanation of LED driver circuit

I've been reading up on LED drivers and found some common connection schemes. Yet, I recently came across the following LED driver circuit at this URL: I tried to find out what exactely was going on ...
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9 votes
2 answers
13k views

Hacking a cheap DC-DC buck converter module (LM2596 chip) into a CC LED driver

On the Internet you can find plenty of dirty cheap DC-DC buck converter modules like the following: which is based on an LM2596-ADJ SMPS IC and follows the schematic in the application notes of the ...
8 votes
4 answers
3k views

Can I send PWM through 1 meter cable?

I am working on a project where I need to drive two LEDs on a PCB (= PCB_LED) which is 1 meter away from another PCB (= PCB_MCU). The PCB_MCU includes a microcontroller with two LED drivers. Each LED ...
7 votes
3 answers
208 views

High power (up to 400W) LED DC/DC power supply design considerations

I am designing a power supply for a high power COB LED requiring 360W @ ~75V from a variable ~60-80V DC input. I have noticed that it is difficult to find switching controller ICs that advertise being ...
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7 votes
1 answer
1k views

Microcontroller Adjustable 2A 24V Constant Current Source

I need to come up with a method to provide a microcontroller-adjustable, regulated current ranging from 0-2A at ~24V to a load in a closed-loop fashion. I have been researching this issue for awhile ...
6 votes
4 answers
511 views

Will a current mirror prevent thermal runaway of these LEDs in parallel

The source is a constant current LED driver. I found that connecting the LEDs in parallel caused thermal runaway with one LED consuming nearly all of the current with its temperature constantly ...
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6 votes
3 answers
841 views

Reduce output current ripple on hysteretic buck converters

I am learning to use a new type of regulator: a buck with hysteretic control, therefore with no fixed frequency and no output capacitor. As example, I was trying out the ILD4001 for an LED driver. ...
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6 votes
1 answer
376 views

Where can I find the datasheet for this LED driver IC?

This IC (in the middle of the board, has seven terminals) is from a LED driver circuit: And here is a closer look: It has the text "9504DB 6C70Y" on it. I need help finding its datasheet. ...
5 votes
3 answers
728 views

How can a DC18V ~ 36V LED driver work with DC3.6V LEDs without burning them out?

I bought some slightly more powerful leds to build a hobby project and grow some herbs. The kit has 10 LEDs that have the following spec: ...
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5 votes
4 answers
6k views

Zener Diode + fuse overvoltage protection for LEDs with constant current driver- fast or slow blow fuse?

I am working with a 6-axis robot (UR5) with a smart camera mounted on the end of arm, and I want to add a ring light to the camera lens which I will power using tool outputs from the robot interface. ...
5 votes
5 answers
832 views

Dynamically dimming individual LEDs in a lighting system [duplicate]

I'm planning to build an aquarium lightning system with individually controllable LED's, I don't have much experience with electronics except from the irregular tinkering, but I'm a programmer and I ...
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5 votes
1 answer
252 views

Understanding a sub-nanosecond pulse generator

I have been reading a couple of papers (1,2) that use a Step-Recovery Diode to generate sub-nanosecond electrical pulses, for the purposes of pulsing an LED. I am simply trying to understand the ...
4 votes
4 answers
2k views

LED current driver

I am trying to regulate the current across an LED so that I can tightly control its intensity since I will be using this light as a source of illumination for a sensor. I am using a CAT4002A-D LED ...
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4 votes
5 answers
1k views

Is my LED driver fundamentally incorrect, or can I compensate it somehow?

I'm driving 3 tricolor LEDs from 3 PWM pins. They can't source enough current to drive them directly so I have them switching on some 2n7000s. Works great when each PWM corresponds to one color but... ...
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4 votes
3 answers
666 views

Matching number of LEDs to power supply

I have an LED power supply - constant current with output 1.4A/96W/23-69VDC. I want to buy a number of LEDs and connect these in series. What do I need to calculate to know how many of the following ...
4 votes
2 answers
718 views

How to reduce LED flash rate (frequency) [closed]

I have purchased an LED flasher circuit from Ebay (see jpg) for use on a model plane, but the flash rate on the circuit is much too fast, about 4 flashes a second. I am trying to achieve 1 or 2 ...
4 votes
3 answers
380 views

Pulse oximeter design: How to drive a bi-polar LED having two different forward voltages?

My lab partner and I are building a pulse oximeter for our capstone project and could use some help. I have an ELM-4002 which is a bipolar LED with the following specifications. The two LEDs are ...
4 votes
3 answers
789 views

Is a current mirror necessary if LEDs are binned?

I have a 20VDC input with a buck CC LED driver, driving 48 LED strings of 6 x 3V LEDs in series. I am underdriving the LEDs at 60% of rated power. Each LED string consumes ~33mA. The LEDs are ...
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4 votes
2 answers
583 views

LED Driver Design

I'm trying to make a transformer-less LED driver with some high power LEDs and found I this circuit with a 130 mA output: Can someone explain for this circuit: Do the voltage changes depend on the ...
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4 votes
2 answers
448 views

Understanding the characteristics of a LED driver

I would like to understand the characteristics of a LED driver I have at home. Here is a photo of the label: I never studied LED drivers before. This post, this article, and this document helped a ...
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4 votes
2 answers
2k views

DIY LED lamp is less powerful than expected

I am making an LED lamp using an LED strip. The LED strip I am using is a 240 LED/m SMD2835 strip, which operates at DC12V, and is supposed to use 18W of power per meter. My lamp is constructed as ...
4 votes
2 answers
157 views

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 ...
4 votes
4 answers
450 views

Multiple switching LED drivers on single PCB

I am working on a high power LED board project. It requires to have 100 LEDs, of different types and colors. There will need to be 17 individual strands (need to be able to dim them separate.) Max ...
4 votes
2 answers
305 views

Tuning a constant-current LED driver, per channel

So, I am using a constant-current LED driver from the TLC592x series. This driver allows you to tune the current for all of its channels with a resistor RIREF. The outputs are used to drive a LED bar ...
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4 votes
2 answers
650 views

Reduce coil whine in LED driver

I have designed a PCB to control RGB LEDs at various intensities using the PWM input to an ALW8808WT-7 driver from an STM32RCT MCU. The 33 uH inductors in my prototype board let off an awful whine ...
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4 votes
2 answers
382 views

0 - 70mA led driver

For a project, I want to detect the red part on the moving disk of Ferraris electricity meter. I want to do this with an Infrared LED and a phototransistor that receives the reflected light. The ...
4 votes
4 answers
7k views

Driving LED with an N-channel MOSFET

I am driving a red LED with a forward voltage of approx. 2 V as shown in the picture. The driving signal comes from a microcontroller with a logic HIGH of 1.8 V. The LED is being sourced from an ...
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4 votes
2 answers
493 views

Is advisable to drive an LED matrix using a Shift Register+FET on High side and an LED driver on the low side?

Trying to find the most economical way to drive 60 leds (~20mA) for volume production. Our main MCU doesn't have enough pins, so I2C or similar set up is needed and total budget of driving LEDS ...
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4 votes
2 answers
356 views

Open-loop Buck LED dimming

About this buck LED driver... TL/DR the questions: 1) I intend to drive the FET from a microcontroller PWM via a suitable FET driver. This open loop control scheme seems too simple. Is it a trap? I ...
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4 votes
2 answers
3k views

LED Driver for 300mA LEDs

I'm trying to put together a project with some bright LEDs but I'm not sure how to control them. Ideally I'd like to drive about 64 of these LEDs that have a forward current of 300mA and voltage drop ...
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4 votes
1 answer
2k views

MeanWell 3-in-1 dimming

I've got a constant current MeanWell LED driver that has 3-in-1 dimming (100k potentiometer, 0-10V signal or 10V PWM), and would like to control the dimming with a microcontroller. I found a few ...
4 votes
2 answers
714 views

Can overshoot current from DC/DC converter damage LED lamp?

I'm building buck converter to drive led lamps. It consists of microcontroller, PWM generator, buck-circuit and current sensor. Microcontroller knows what target current should be and sets duty cycle ...
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4 votes
3 answers
223 views

Why does this MOSFET heat up?

Does anyone have an idea why this MOSFET warms up in this circuit? In simulation everything looks good, but the real MOSFET heats up to around 60°C. I am designing this circuit for 1.2A. Measured ...
4 votes
2 answers
745 views

Very weak LED dimming with combined PWM signals using 555 timers

First of all, here's the circuit: What I'm doing here is using 2 PWM signals generated by 555 timers to control the warmth of the LEDs and the brightness. The top 555 is the brightness control and ...
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4 votes
1 answer
430 views

36x LED 5730 in series: diodes burnt when LED driver (based on BP9833A or MT7854BD) powered up

Background: I have 18W, 36 LED lamp fixture which I cannot change. Originally it has 2x parallel 18off 5730 LEDs and 300mA driver. It works for some time, but diodes starts burning. I thought that ...
4 votes
1 answer
3k views

LED-driver board with WS2818/WS2811 and PT4115

I want to develop a board with a WS2818 IC and three PT4115 as high current LED drivers. Input voltage shall be 12-18V. You can easily mount a Wemos D1 Mini ESP8266 board on the top edge, as the pins ...
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3 votes
3 answers
2k views

Parallel resistor in series with LEDs

I have seen two parallel resistors used in series with LEDs in several LED bulbs. Why are parallel resistors used instead of series one?
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3 votes
1 answer
3k views

Will this circuit work ? 100 Leds project

I am new to electronics. I have been given 100 Leds project by my teacher at college . Can anyone here validate this circuit. Thanks in advance.
3 votes
5 answers
22k views

Full Spectrum LED(400nm~840nm) vs Grow Light LED (RED+BLUE)

I'm planning to buy lights for my planted aquarium tank. After a small research I found that regular lights are not suited for growing plants. Beacuse they need BLUE for Leaf Growth and RED for Stem ...
3 votes
3 answers
3k views

Making an efficient constant current source

I need help making an efficient constant current driver. I want to power my home with LED light strips for lighting and decorative purposes. I need to be able to turn each strip on and off ...
3 votes
2 answers
679 views

MAX6966 a suitable sink driver for nixie tubes?

I recieved some IN-14 nixie tubes for Christmas, and was hoping to implement them in a project i have been considering for some time. The details are unimportant, except that each nixie tube should ...
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3 votes
2 answers
2k views

Mixed forward voltage LEDs in series with constant current driver

I've been looking for answers for a few weeks, so now I'll actually voice my question! My plan is to power 109 LEDs in series off of one constant current driver. The goal is to create supplemental ...
3 votes
3 answers
156 views

Best way to power a single LED from a battery

I'm looking for a good way to power a single LED with a coin battery (CR2032). Here are some of the requirements/characteristics of the system I'm trying to add this LED to: I don't need full ...
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