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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28
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3answers
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 ...
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3answers
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) ...
11
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2answers
1k 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 ...
11
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4answers
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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....
9
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1answer
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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 ...
6
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1answer
940 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 ...
5
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3answers
609 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: ...
5
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4answers
5k 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
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3answers
649 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. ...
5
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2answers
8k 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 ...
5
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5answers
771 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 ...
4
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4answers
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 ...
4
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2answers
571 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
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2answers
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
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4answers
373 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
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2answers
171 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
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2answers
310 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 ...
4
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2answers
195 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 ...
4
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2answers
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 ...
4
votes
1answer
618 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
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2answers
549 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 ...
4
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2answers
421 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 ...
4
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1answer
69 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 ...
3
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3answers
1k 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?
3
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1answer
2k 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
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2answers
531 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 ...
3
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2answers
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
1answer
416 views

What will happen if I connect a resistor to a constant current LED driver?

What will happen if I connect a 120 Ohm resistor to the outputs of a constant current LED driver designed to provide 0.600mA (24 - 38 volts)? According to Ohm's law this resistor will allow a current ...
3
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2answers
1k views

Optocoupler driving 300mA continously (or use darlington topology?)

Looking at driving two LED strings with a DC/DC constant current LED driver module. The constant current side can't be referenced to ground of the control circuit, so I need to have an isolated ...
3
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3answers
4k views

Is it OK to PWM a current source?

I want to control power RGB LEDs, for efficiency and safety they are better to be driven by a current source. I can use either linear or buck converters. I made a linear current source using ...
3
votes
1answer
66 views

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 ...
3
votes
1answer
67 views

Using LED driver as PWM digital outputs

I'm building a robotics project where I need to control a lot of DC motors. I picked the DRV8870DDAR H-bridge motor driver chip which needs 2 PWM input signals to control the speed and direction. ...
3
votes
2answers
690 views

TLC5940 - with 200LEDs from car battery

I'm working on project that involves 100 white and 100 RGB leds, controlled with 25 TLC5940. I've managed to connect three TLCs to Arduino MEGAv3 and so far so good. I've found out that I have to add ...
3
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2answers
377 views

LED Power Supply Design Recommendation

I have a power supply based on VIPer22a. It is an isolated supply with output 17V, 400mA. The input voltage ranges from 100-240V, 47-63Hz. It drives the LED Array module perfectly. I have attached the ...
3
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2answers
644 views

Advantage of using an op-amp connected emitter follower for LED driving?

I came across the following circuit used to set a microcontroller-controlled fixed current in an LED to around 100mA (target current): As far as I understand, the voltage reference at the IN+ (1.2V) ...
3
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3answers
120 views

Boost LED driver output spikes

I designed a boost LED driver based on TPS92691. It drives 56V 5A COB LED from 22-50V input. It works ok. Oscilloscope shows small spikes on input (100mV), but large spikes on output (3V). The spikes ...
3
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3answers
274 views

Driving a 12v LED, substituting a PWM chip for a linear regulator?

I'm trying to reverse engineer a broken control box for some dual intensity motorcycle LED spotlights, and I note on the circuit board there is an AX 3007-50 12V ...
3
votes
1answer
280 views

Why are constant current drivers 10% less efficient than constant voltage drivers?

I want to drive a CREE XP-G3 LED with 2.73V, 350mA. My power supply is a car battery (10.5-14.5V). I went to the Texas Instruments website and inputted the above specs into their WEBENCH designer, ...
3
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1answer
2k 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 ...
2
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5answers
21k 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 ...
2
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3answers
554 views

Do COB LEDs usually need electrically insulating from the heatsink?

I have some Vero series LEDs from Bridgelux. I want to put multiple LEDs on 1 heatsink. I was planning to use thermal epoxy, so there is the possibility of the aluminium base of the LED touching the ...
2
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3answers
409 views

Disadvantages of dimming LEDs via current regulation as opposed to via pulse frequency?

I bought an LED stripe from näve (very similar to this model), but found that it created flicker in video recordings. The flicker got less visible with lower frame rates, but even at 24 fps it was ...
2
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3answers
457 views

Zener diode selection in a led boost ic circuit

I'm wondering how to select a correct zener diode value for this led driver I am using RT4533AGJ6 (link to datasheet). My understanding of boost converters is limited, although I understand that there ...
2
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3answers
2k views

Understanding constant current LED drivers (ac to DC)

I am trying to understand the way constant current LED drivers work. Lets say I have a driver with these specs: Description: Power: 18W Output Voltage: DC 36-63V Output Current; 300mA Input ...
2
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1answer
749 views

How do I make the LM3914 (LED) Bar-graph driver IC make the LEDs light up brighter?

Like I said in the title, I am using the LM3914 IC to drive a 10 segment LED Bar-graph. The actual subsystem has the signal pin on the IC connected to a capacitor, thus displays the amount of charge ...
2
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3answers
2k views

Avoid leakage current

I use an opamp driver to pump several amps through an LED. My circuit is below. simulate this circuit – Schematic created using CircuitLab When the input is low, I see a small leakage which I ...
2
votes
1answer
217 views

Linear current driver with several BJTs in parallel

With the circuit setup shown below, if I have available a type of Q2 transistor with a certain maximum dissipated power and need that D1 withstands a large current that would lead Q2 in trouble, it is ...
2
votes
1answer
222 views

Why is my RGB LED strip passing current through the transistor?

I am following this schematic: http://www.electronoobs.com/eng_arduino_tut13_sch2.php It uses a BD140 PNP transistor. I checked the wiring was correct. Basically, the transistor boosts the current ...
2
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2answers
2k views

Inductor & Led, In series or in (reverse) parallel?

I am using a YX8018 IC. It's a basic switching boost design meant to boost a single AA rechargeable (1.2V) to a white led (3.3V), with solar panel charging. According to the data sheet (Chinese, not ...
2
votes
1answer
65 views

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 ...

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