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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2 answers
74 views

Preventing power LED runaway with voltage and PWM [closed]

Using near-minimum voltage for the LEDs to light up, and PWM to control brightness by not allowing the frequency/brightness to go above a certain point. Comments are telling me its not okay to not to ...
2 votes
2 answers
146 views

Driving different number of LEDs in series with a constant current driver

After two days of searching, I'm a bit lost when trying to design an LED with a constant current driver IC. In my circuit, I have LED indicators I want to control independently and an LED backlight ...
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Workings of single constant-current source with four MOSFET-switched LEDs

Background I have several hundred RGB+White LED lights which are controlled by a driver circuit which is no longer manufactured, and trying to plan some maintenance and possible replacement of the ...
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Sanity checking an LM2596-ADJ constant current supply design for driving LEDs

I've designed, in simulation, an adjustable constant-current supply based on an LM2596-ADJ buck converter IC. I chose STW8B12C LEDs for simulation because three of them in series roughly matches up ...
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COB LED unwanted blinking

I'm testing a Cree CXB1304 powered by a constant current driver Meanwell LPV-35-36 This setup makes the LED blink regularly every 2 secs, as I've read this occurs when the driver has insufficient ...
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LED driver circuit works only when I touch it with my finger

I'm trying to convert an E14 RGB LED bulb to be able to power it from a lithium battery. Inside the bulb are 2 PCBs - a transformer and a LED driver - which are connected by 3 wires. Black and red are ...
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1 vote
1 answer
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How to set outputs on a Toshiba TC62D722CFNG shift register LED driver IC

I want to use the TC62D722CFNG shift-register LED driver IC to toggle some LEDs, however, I am having trouble getting the outputs to turn on at all. The IC is capable of controlling the LED current ...
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3 votes
3 answers
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Using long button presses to vary duty cycle of 555 (instead of potentiometer)

Apologies for poor phrasing and structure, this is my first post. I am trying to learn how to implement 555 to create a PWM with variable duty cycle (for control of LED brightness) Rather than the ...
3 votes
3 answers
158 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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How do I build an LED driver, where the input is a current source?

I'm designing a driver to interface four 7-segment digits (8V, 20 mA per segment) with an AS1115 driver (5V supply, constant current outputs). Following an internet source, I have the circuit shown ...
2 votes
2 answers
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Powering long LED strip, injecting power. Correct way to fuse?

Recently I asked an opinion based question regarding LED strips. I have learned my lesson and now I have an actual question regarding "how power flows". I'll explain: I have a lighting ...
1 vote
1 answer
46 views

How to choose suitable LED power supply

Can I replace an LED power supply with this output: DC 50~57 V, 280~300 mA with a new supply with this output: DC 45~85 V, 300 mA ±5% ? In other words, does it matter that the output voltage has a ...
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High Bay LED light rebuild

I've got a 200 W High Bay LED light from a friend. Its circuitry is blown up; it was connected to 380 V instead of 220 V, but it also had flickering issues before that. I would like to build it a ...
2 votes
1 answer
59 views

Can I use an external MOSFET to dim this high-power LED driver?

I want to use the PAM2861 LED driver. It can handle my intended load (1 A and two LEDs around 3 V per channel) and I know this because someone with a similar project used it. It's also available at ...
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3 answers
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Picking the right boost/buck converter to power LEDs from 12 V battery

I'm looking to run four 3 W high-intensity LEDs in a series circuit using a 12 V battery, for an outdoor lighting setup. My intention was to use an adjustable buck/boost converter, as I've used to run ...
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LED strip multi segmented WS28xx wire gauge

Given the following "circuit", I'm trying to find out what the correct wires gauge should be for the points: A,B and C. I have 15 LED strips (WS2815, DC 12V / 60 LEDs per meter). Each ...
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How can I use a 5 V LED driver with an 8 V display?

I'm using a Raspberry Pi Pico to make an enormous countdown timer. The LED driver will be the AMS AS1115 and the digits are Kingbright SC40-19SYKWA. My problem is that the digits want 8 V but the ...
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1 answer
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How do I search for multi-output relay/driver chip for negative voltages?

I have a strip of RGB LEDs. If I attach a multimeter between the common pins and another pin like the red power, I measure -2.4V . I think this is what is described as common anode. I have an L293D ...
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Are my calculations correct? 5050 LED strip 96 LEDs/m and Gledopto thin controller

So I bought Gledopto mini LED controller 5in1 and now I want to buy compatible strip. I bought a 5050 LED strip: 5 meters with 96 LED per meter. From what I found power consumption per LED is 0.24 W ...
4 votes
3 answers
790 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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0-10V LED driver dimming with Raspberry Pi and FET

I'm a beginner, so please be gentle! I'm trying to dim the linked LED light fixture driver using a Raspberry Pi (RPi). I want to dim using PWM in conjunction with a FET. Before dimming I am trying to ...
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2 votes
2 answers
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Derive voltage of LED array?

I'm trying to diagnose a faulty builder's worklight. It has a single board, a 8.4V battery, an external 8.4V DC input, and a LED Panel. What voltage would you expect at the LED panel? I'm measuring 8....
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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. ...
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RGB matrix connection to IS31FL3731 LED driver

Can anyone help me connect RGB LEDs to an IS31FL3731 LED driver from ISSI? I can not wrap my head around how to make the connection. According to the datasheet, figure 8, it should be connected like ...
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LED - Downlights/Recessed Lights - Quality, Safety [closed]

I been looking to upgrade old recessed can lights with "modern" LED slim potlights, Market is flooded with different brands. I went out and purchased a bunch of LED lights, removed the ...
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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1 vote
1 answer
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LED8102S Driver Circuit

I have what I thought was a pretty simple low-side LED driver circuit based on the STLED8102S IC. The supply voltage to the circuit is 12VAC nominal (15VAC measured), rectified & smoothed to ...
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2 votes
1 answer
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Trying to use opamp to buffer BuckPuck control input - but it keeps blowing up

I'm trying to make a fairly simple circuit, which powers a few LEDs in series using a single BuckPuck 3021 (https://www.ledsupply.com/content/pdf/led-driver-luxdrive-buckpuck_documentation.pdf) The ...
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Trying to recreate calculation results from datasheet for ZXCS440 LED driver

I am trying to design an LED driver based on the Typical Applications Circuit of this ZXCS440 datasheet (page 13), but when applying the calculations shown on pages 6-8 I am struggling to find the ...
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Using USB-C PD 12V to power LED strip?

My Philips Hue light strip 30W / 12V power supply died, and I'm looking to replace it. The OEM replacement is big and heavy; meanwhile there are GaN-based USB-C wall plugs, that can deliver 30W / 12V,...
-1 votes
1 answer
50 views

DALI DAPC Control not working [closed]

I am using Osram constant current LED power supply to dimm led lights using DALI. I have functional program with dimming using DALI DAPC commands. Dimming in range 100-255 is okay and works as it ...
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What is constant current LED driver output voltage?

Does Mean Well LLD-L driver output same voltage as the input? Is it possible to limit the maximum output voltage for use as a lab bench supply? I want to use it to charge a lithium battery, if it is ...
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TLC5946 no output when BLANK is LOW

I'm testing the TLC5946 LED driver and I'm trying to bitbang into it's registers with this bit of code: ...
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2 answers
88 views

Lower voltage limit of constant current driver

I am looking for a constant current driver with rather low current (100-200mA) to drive COB LEDs (approx 34V). I found several which give an output voltage range, e.g. 12 W input: 220 Vac 50 Hz output:...
2 votes
1 answer
56 views

How to interpret LED driver output labels?

I am looking to drive an LED panel with an alternative driver to better suit my application, but first need to understand the existing one which does not seem to match the same labelling convention as ...
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1 answer
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BQXX marking code IC part number

I have an IC in hand which its marking is BQDDVB. could you help me find its part number?
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1 answer
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How to calculate components values for LM3421 in SEPIC mode

How can I calculate the components values for LM3421 in SEPIC mode? In the LM3421 datasheet, there is not much information about SEPIC topology. (Section 9.2.9.2 is labelled "Detailed Design ...
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Significance of LED number in selecting inductor and capacitor values in backlight driver circuit

I am looking to configure an LED backlight driver circuit and had a couple questions I was hoping I could find some answers for. My application is a TFT LCD screen with a single anode/cathode input ...
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1 answer
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Driving parallel channels with 1 PWM signal [closed]

I am currently developing a protoboard for an LED driver having PWM control for dimming using a microcontroller. I plan to drive a number of parallel channels of LEDs ('n' number of RGB channels) and ...
0 votes
1 answer
67 views

Is there anything to limit LED output dimming 50% while the wall dimmer controls 50% to 0%?

We got a project for a client but our lights are too bright for the space, we still want to sell the the lights because we have extra inventory and need a way to dim the LED output to 25W instead of ...
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LED driver short output & single LED issues LT3477

I'm using the LT3477 IC for operating up to 6 LEDs in series. The LED that I'm using has Vf = 2.9 V and has maximum current of 350 mA. Circuit input power is 5 V@2 A (J1 and J4 on schematic). There is ...
1 vote
2 answers
42 views

Improve thermal effeciency of buck LED driver with fixed supply rail

I have this driver circuit that uses an ILD8150: There are two identical sections of this module on my PCB. One powers 6 LEDs the other powers only 2 LED. The Vf of the LEDs is 2.85V @ 350 mA. So the ...
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Transformer humming after replacing halogen bulbs with LEDs

I replaced the IKEA 10W G4 halogen bulbs in my under-cabinet lights with 1.5W G4 disc LEDs and the 120-12V AC transformer started buzzing, but not if I kept one halogen bulb in. I recall reading ...
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Power hundereds of LEDs using shift register

I have 400 LEDs I need to drive with a bank of 75hc595s. My problem is that the controller is a raspberry pi zero and the max input for it is 5 V at 1 A, however my LEDs are 3.0-3.2 V at 20 mA or 8 A. ...
1 vote
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Understanding why Meanwell LDD-350H outputs > 350mA current

I built a LED light for my aquarium. I used 140 various 1 W power LEDs, driven by 14 constant current Meanwell LDD-350H drivers. Each driver is handling between 8 and 11 LEDs. I use 36 V power supply. ...
1 vote
1 answer
160 views

How to drive multiple floating N-channel MOSFETs

I want drive a RGBW-LED (CREE XLamp XM-L) using a synchronous constant current buck. To control the brightness and color, the LED of each color channel is controlled by a shunt transistor using PWM. ...
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2 votes
1 answer
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Relay contact sticks-Led driver

I m using relay 230vac/10amp to switch on/off LED driver. But sometimes relay sticks. Loads are nowhere close to 230v*10amp=2300watts. I cant understand what is causing this. i tried connecting an NTC ...
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Current in inductors of emi filter

I am currently working on an EMI filter for a led driver (constant current). Here you can find the according schematic: My question now is, which (if any) current is going through the inductors/have ...
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EMI Filter - current in inductors / part selection

I want to use a NLDD-1400H LED Driver as constant current source with 1.4A ouput. On the last page of the datasheet there are information about an EMI Filter, I want to use. Here is the schematic: ...
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When running a wireless charging circuit, my power supply whines and the transistor gets super hot even though everything works, is anything wrong?

I created a wireless LED power circuit to drive adafruit wireless LEDs.The circuit works great, LEDs are fully lit but my desktop power supply lets out an awful whine whenever its running (it normally ...

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