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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16 views

Addressable Latch IC to control single output

I am trying to implement a circuit using simple addressable ICs. The one I tried was WS2811 RGB Led Driver (Neopixel). But my requirement is not that complex. In my case there is only one LED needs to ...
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Questions regarding choosing the best OLED display module for series production [closed]

I am designing a product that hopefully there will be some volume to (hopefully at least 1000 and up to 5000 per month. Can´t go into details). This product needs a simple graphical display (for ...
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55 views

Correct "correlated" voltage tuning for (multiple) LED

I need to tune the voltage between 6 LED drivers (Meanwell hlg-320h-36ab) that delivers 36Vdc and a LED that can take 30-41Vdc 250w for each of its 6 strips (total 1500w). This will change the color ...
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276 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 ...
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48 views

Buck-boost LED driver returning to Vin

I am working on a design involving driving a string of 22 LEDs in series using a constant current. The relatively high voltage required (~66V) has lead me to look into buck-boost LED drivers. I have ...
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48 views

What is "SW current limit" on Led Driver?

I am trying to understand the maximum current capability of this LED driver IC. I am pretty sure its on page 4 labeled as "SW current limit": But I want to be sure, as I cannot find and ...
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53 views

How to maintain a stable DC current in case of intermittent disconnections

Aplogies if the question sounds very basic. I have a set of LED strips which are powered by a 12v 5A LED driver (which is plugged to my wall socket 220V AC). As the intermidiate connection between the ...
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3answers
83 views

Driving 3v LED at 4.5 volts to get higher Luminosity [closed]

I have a 3V 700mA LED (Datasheet). I am operating it with LR1130 cells. There are 3 cells connected in series to give 4.5V. Now as I am driving the LED at higher voltage, it becomes hotter and it also ...
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28 views

Simple (variable) PWM generator for led driver that accepts PWM input

I have a cc(constt. current) led driver that accepts pwm input in the range of 2v-8v for led dimming.Can I provide this pwm signal from a 555 based pwm generator? If so how can I keep o/p pwm(from 555)...
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103 views

What is the best LED driver to use for this setup - Help with WS2815 data amp over long lines

Currently have 5 m WS2815 strips installed running from 18 AWG wiring connected to 12 VDC Meanwell power supplies and our controllers (SP108,SP102,SP608), power injection on all lines. When we tested ...
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61 views

Transistor with PWM vs LED driver for LCD backlight

I'd like to design a circuit that utilizes a small 1.3" LCD display with maximum LED backlight forward current of 40 mA. Since I'd like to use brightness control, I am hesitating between using a ...
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65 views

Understanding LED Forward Voltage in a Constant Current Boost Driver

I am wishing to control different clusters of LEDs. Each cluster can have a different number of LEDs in its string, for example, one cluster might have 8 in series and another only 4. I was thinking ...
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114 views

When to switch to 4 layer PCB

I'm currently designing my own 60% per-key RGB mechanical keyboard. (60% means the keyboard only contains 60% of the keys of a regular keyboard.) I've laid out the components, routed the switch scan ...
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95 views

Constant current source (aka "LED driver"): Behaviour with halogen light bulb

I wanted to ask a quick question. When running (power) LEDs, they mostly require an adequate constant current source / LED-driver IC. Most of the time you connect multiple LEDs in series, so that the ...
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282 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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DIY LED Fixture/Panel Design Questions - 1. How to control each RGB channel (COB) or 2. How to cool a panel of 40 meters of LED strips

I'm looking to build a 1kW LED light fixture for an experimental photographic process. I need 1kW fixture or around 100,000 lumens because of the low sensitivity of an emulsion. I'm wondering if ...
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1answer
80 views

In Chinese Led torch how does the LED automatically light down when recharging? [closed]

I repaired some led rechargeable torches which work under 230 V. When we plug it to main socket for charging even with the switch on, the LED goes off. What mechanism in these torches to off the LED ...
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2answers
314 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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52 views

Turn on led with p channel mosfet when voltage drops?

I have a project where, without a microcontroller, I am trying to trigger an led when voltage drops by an amount, and increase brightness of that LED steadily as the voltage continues dropping from ...
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28 views

How to choose supply capacitor for RGB LED with LED Driver

I'm designing a circuit with an RGB LED. I'm controlling the brightness of each color using the Texas Instruments TLC59731 LED Driver: TLC59731 Datasheet I noticed that it includes a supply capacitor ...
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1answer
33 views

LED Driver - Luminaire still lights up

Guys I'm having difficulties regarding a light drive, I'll report the problem and what I did to try to solve this situation. The light driver is being placed in an LED fixture, when you clear a phase (...
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2answers
54 views

Demultiplexer 1 to 4 - high specification

I'm working on a power stage (LED driver) that could manage 4 different LEDs color string. Each string is composed by 6 LEDs in serie. See the image to have a better idea: The schematic is composed ...
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1answer
36 views

Voltage deviation on the bootstrap capacitor

In the application note for ILD8150 at chapter 2.2.7 I read: The high-side MOSFET gate driver is supplied by the bootstrap circuit. Capacitor CBOOT is charged when the high-side MOSFET is switched ...
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52 views

Flicker-free LED driver at low DC: how to select driver

I tried several LED drivers and some of them have an undesirable behavior: at low duty-cycle levels you can notice flickering. This is not due to the actual PWM of course, but due to the driver itself....
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99 views

How much voltage is too much for an LED?

I have an amplitude modulation LED driver (a dimmable constant current reduction LED driver.) It can power an LED up to 30W, 750mA, 6-40V. The LED I am connecting is good for 750mA, 12V. Will it be ...
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48 views

powering a series LED with a battery

I am working on what you could call a brake light for a car but I was having a little bit of trouble understanding how it should be powered. So, I plan to have 3 high power LEDs in series connection. ...
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3answers
138 views

Selecting base resistor on op-amp controlled constant current LED driver

How do I calculate the appropriate value for R1 and R8 so I don't get extra current flowing through my transistor bases at low voltage? simulate this circuit – Schematic created using ...
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1answer
83 views

How does amplitude dimming (CCR) work?

When a LED driver dims using constant current reduction (CCR), what voltage and current is sent to the LED chip at the various dimming levels? Say I have a CCR-compatible LED chip which takes 500mA ...
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2answers
102 views

MOSFET to drive LED, never turns fully off

I have the following circuit (see attached) where I am using a SI2302 MOSFET to switch an LED using a micro-controller (internal pull down.) The problem I am seeing: Upon switching between 3.3V (HIGH)...
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27 views

How to calculate BCR421U LED driver external resistor to my specified current

I am using a BCR420U as a constant current for an LED indicator, the datasheet does not mention a formula for calculating the external resistor needed for a given current output, all I have is this ...
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1answer
85 views

Why don't mass-produced LED chips burn out right away?

In a previous post, I was trying to determine if one of the pre-assembled 300mA LED chips shown below could be rigged up with parallel and series resistors to be correctly powered by a 350mA CC power ...
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123 views

How could I build an amplifier circuit that can take an input voltage of 0-0.7V and amplify to 0-32V, 1 ampere, that works for 100 MHz?

A little background first. I am trying to build a pretty dumb project where I try to take a VGA input and display it in a manner similar to a Nipkow disk. The high frequency RGB signals need to be ...
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1answer
49 views

What is the difference between buck and step-down converter

I always thought "buck" and "step-down" are synonyms. But now I'm looking at two datasheets: CAT4201 CAV4201 They seem very similar, but the first is described as "350 mA ...
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1answer
71 views

Bridge rectifier and phantom voltage

I have a constant current LED driver which keeps the LEDs at about 5% glow when the AC side when the driver has its phase terminal connected to live power and its neutral terminal not connected to ...
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113 views

Ammeter (DSN-VC288) showing wrong values

I am building my own RGB-LED-Strip (WS1812B) controller, including an Ammeter bought at my local electronics store to monitor the current consumed by the LEDs. On the back it can be identified as a &...
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1answer
106 views

What are these soldering lines in following pcb?

I have a switch mode power supply (flyback) LED driver. I just wanted to extract its schematic but some straight parallel lines of soldering made me confused. Both layers of this pcb is presented in ...
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207 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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36 views

How do LED drivers with current control work

I'm reading the datasheets of this two LED drivers: FL7760 STCS1A The main obvious difference is the first driver requires an external MOSFET, while the second one has the transistor built-in. But I'...
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86 views

How does AC LED Driver provide power to LED when input circuit is open?

Over on the Home Improvement Stack Exchange there have been several questions noting that an LED light bulb or lamp glows dimly when only one of its AC supply wires is connected. Here, here, and here ...
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1answer
54 views

Fast circuit breaker on low side of mosfet driven led circuit

I have some high power CREE COB LED's CXA1304-0000-000C00A20E8, which I turn on for 0.5 ms using a MOSFET on the low side. The signal comes from an optocoupler. I experienced some burned MOSFETs from ...
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69 views

Schmitt trigger VS transistor [closed]

Can you please explain for me what is the difference between Schmitt trigger and transistor, especially in driving LEDs and in current consumption. EDIT: There's answers and comments which seem to be ...
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1answer
14 views

Is "Peak NMOS current limit" the continuous output current limit of this LED driver?

I am trying to find the maximum current the DIO5661CD6 can supply to the LED(s.) I do not see the usual "continuous current" parameter anywhere in the datasheet. Is the "Peak NMOS ...
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1answer
32 views

Understanding Meanwell CV+CC driver characteristics

I have an LED fixture that can take 2 to 2.5 amps. Vf is around 36 volts. I am planning to use Meanwell ELG series driver to power it up. [Datasheet here] This particular model can work in CV+CC mode ...
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1answer
41 views

Is 4x7+dp LED segment display wired the same as 4x8 LED dot matrix?

I'm currently working on a project that need a 4x7+dp common cathode LED segments display. I have found two drivers for it that I like. #1 https://www.issi.com/WW/pdf/31FL3731.pdf #2 https://ams.com/...
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2answers
64 views

Are pull-up resistors needed for shift registers (constant current sink drivers)?

I'm wondering if pull-up resistors are strictly necessary when using shift registers to control motor drivers or LEDs. I have two STP16DPPS05 low voltage 16-bit constant current sink drivers, one ...
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2answers
69 views

LED driver does not give constant current with a load

I'm working with an AL5810Q, which is a linear LED driver where the current can be set with only one external resistor following $$I_{LED}=\frac{750}{R_{SET}}.$$ With that, since I need a current of ...
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80 views

Using emitter follower as voltage source [closed]

I have an open-drain IC and I need to connect it to another device, avr, which is 3.3V, additionally information leds are needed. Avr should read digital signal from that open-drain device. Avr is ...
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1answer
141 views

MeanWell PWM dimming

I have similar situation, described here: MeanWell 3-in-1 dimming So, I need to control MeanWell power by PWM signal from Arduino. I tried to simulate scematics, given as answer in that topic, but it ...
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1answer
71 views

Help identifying component (LED matrix PCB)

I have a led matrix PCB without a driver and I'm trying to figure out how to control it. I'm having trouble identifying one of the components on the PCB. Here is a scheme of a part of the PCB: These ...
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2answers
244 views

Identify LED driver IC / manufacturer logo

I am interested in an LED driver IC. It drives a 40W E27 LED with a 12V fan. The logo looks kind of like "JD." The IC number is difficult to read: something "960?S" (see picture.) ...

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