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DIY 3W constant current LED driver

This is quick post about 3W constant current LED driver which I was design to combine with some homemade furniture piece. The main components of this system is LM311 voltage comparator and IRF9540 P-Channel MOSFET.


Schematic of 3W LED driver module

This module is design to drive maximum of two 3W high power LEDs and it requires 8V - 10V DC (500mA) power source. In this given configuration this module may not need any heat-sink (for IRF9540) and consume maximum of 500mA of power.

Breadboard version of 3W LED driver

At prototyping stages we test this module using 9V DC (1A) power supply with two 3W LEDs (EDEX-3LA1-E1). I developed final version of this module using piece of strip-board and PCB design is not done.
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Comments

Anonymous said…
nice, and no choke...
1 question though. 3w power leds are rated at 700 ma. why go for 500 ma?
December 27, 2013 at 7:54 PM
Dilshan Jayakody said…
During our tests this system draw 450mA with two 3W LEDs, so we keep minimum current as 500mA.
December 27, 2013 at 8:48 PM
Dilshan Jayakody said…
Schematic is updated to fix some errors:

1. Fix IRF9540 source and drain connections.

2. Add buck switcher output
circuit to IRF9540.
December 29, 2013 at 8:29 AM
Jerome Demers said…
To limit current for my LEDs, I use the LM317 in a "current regulator" mode. It's pretty darn simple! Decoupling cap, a resistor and the LM317.
December 29, 2013 at 10:29 AM
Ben said…
Any thoughts on an led driver for a battery powered applications?

In the past, I've used TI's LM3410 sepic led driver with a aaa (1.5v), but the maximum constant current is about 700ma. I'm hoping to find something that gets closer to 1A.

December 29, 2013 at 11:29 PM
Dilshan Jayakody said…
For high current LED projects I’m using NCL30100 or HV9911 (both are available at eBay).

Liner Technology developed several high current LED drivers (ex: LT3743, LT3476, etc.) but I never used them because these ICs are bit difficult to find in local market place (and even in eBay also).
December 30, 2013 at 7:36 AM
Selvam said…
Hi Dilshan, I am building a battery powered LED torch with 4X1.2V 1200mA batteries, and 3X3W LEDs I am trying hard to find a driver which could do the job of connecting them together
the LEDs I have are,
LED, HIGH POWER, 5000K, 70CRI, 275LM
Series: LUXEON TX
LED Colour: White
Luminous Flux @ Test: 369lm
Forward Current @ Test: 1A
Forward Current If Max: 1.2A
Forward Voltage @ Test: 2.86V.

could you please help me what should be the specifications of the driver??
March 10, 2014 at 6:12 PM
Anonymous said…
Ijust recently came across this web log after doing a google seach for "constant current mosfet and lm311 circuit" hence I have these. and finding this is the most inspirational thing I have found so far! thanks to ALL contributers, I have to go carefuly design, I already made a similar circuit for my 1.8 to 2 watt blue laser, but as the laser still works but the circuit is now getting temprimental, I need to go make some kind of new, and hopefully better circuit. Thanks for this!
June 1, 2020 at 6:46 AM
JeffreyEdwards said…
I really liked your Information. Keep up the good work. Constant Voltage LED Driver
March 25, 2021 at 10:27 PM
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