A small, cheap, CC LED driver module that is worth a look... (5/5)

The CN5711 chip is the heart of a neat little module that solves a lot of LED management problems in 10mm*20mm for just a couple of bucks.

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An update on the thermal stuff. Extended operation at 1.5A definitely takes a thermal toll, but not beyond the operating parameters. The chip runs at about 98℃ is it might be a good idea to attach a small heatsink to the flood on the reverse of the board to reduce this a bit if you intend to push it to the limit like that.

 

Nice module! Already purchased one for my next project.
One question though.
You said:
"The chip is perfectly happy with parallel LEDs so long as they are within the current limits. The application note advises "in order to make sure the current is evenly distributed among the LEDs, a robust resistor in series with each LED is recommended", the same advice so often given by members here."

What value should be used for these resistors?

 

The value of the Resistors will depend upon how much "Voltage-Overhead" your Power-Supply provides.

A Schematic, with all specific values of Components used,
and the Data-Sheet for the LEDs is required.

Then, a calculation of all of the estimated Voltage-losses
between the Power-Supply, and the LEDs, can be done.
( including estimated Power-Supply-Voltage-Sag, if not actively Regulated ).
.
.
.

 

Thanks for the review! I think you meant the CN5711 chip, not CN7511. I plan on using a similar chip, the CN5710, that has a max current of 1A instead of 1.5A. It's cheaper, too.

Purchase from JLCPCB here.
English data sheet here.

 

Another chip of my preference is the SM2082. Handles LEDs from mains. Sort of a goofy bridge rectifier on application notes, but hey! Good chip.

----> https://datasheetspdf.com/pdf-file/934677/SUNMOON/SM2082/1

 

Hi, thanks for your review of this chip and the little board (LD06AJSA). I am new to this forum, hence I thank for your understanding the way I formulate my questions.

Here are my imediate questions:
1. Trimpot: According to the instructions of the board the little trimpot in the corner of the board should be adjusted to 0 Ohm. At what points should the resistance measured?

2. Test 1: I used this board with success using a CR2450 battery as power source and an white indicator LED. This LED consumes a current of about 2 mA when brightly lit. I used an Arduino Uno R3 board to control the LED's intensity via the CE input of the board using a PWM pin (3). The intensity could be controlled within a range of intensities that I measured with an ambient light intensity sensor.

3. Test 2: I tested PWM controlling of this LED in another arrangement, too, using a DPS5005-CC/CV Power Supply and a PWM-capable Pulse Generator. The advantage of this setup was that I could control the range of light intensities across PWM control worked the best by adjusting the voltage output of the Power Supply. Within this range where both intensities and dynamic range could be optimized the power supply worked in CC mode.

4. Test 3: Then I returned to using the LD06AJSA board with PS5005-CC/CV Power Supply as power source and PWM-control by Arduino Uno R3 via the CE PWM control pin of the LD06AJSA board. Unfortunately, the intensity control of the LED could not be worked out. At this point I would much appreciate any advice in trouble shooting of this problem.

 

Hi, thanks for your review of this chip and the little board (LD06AJSA). I am new to this forum, hence I thank for your understanding the way I formulate my questions.

I’m glad you found it useful, it’s the reason I spend time on these things.

1. Trimpot: According to the instructions of the board the little trimpot in the corner of the board should be adjusted to 0 Ohm. At what points should the resistance measured?

This should be with the wiper rotated all the way counterclockwise. The 0Ω would be from the wiper pin (center) to the left pin (pin 1).

2. Test 1: I used this board with success using a CR2450 battery as power source and an white indicator LED. This LED consumes a current of about 2 mA when brightly lit. I used an Arduino Uno R3 board to control the LED's intensity via the CE input of the board using a PWM pin (3). The intensity could be controlled within a range of intensities that I measured with an ambient light intensity sensor.

This isn’t pushing the 1500mA limit very far, but it would certainly work.

3. Test 2: I tested PWM controlling of this LED in another arrangement, too, using a DPS5005-CC/CV Power Supply and a PWM-capable Pulse Generator. The advantage of this setup was that I could control the range of light intensities across PWM control worked the best by adjusting the voltage output of the Power Supply. Within this range where both intensities and dynamic range could be optimized the power supply worked in CC mode.

But of course it’s a lot more complex and costly.

4. Test 3: Then I returned to using the LD06AJSA board with PS5005-CC/CV Power Supply as power source and PWM-control by Arduino Uno R3 via the CE PWM control pin of the LD06AJSA board. Unfortunately, the intensity control of the LED could not be worked out. At this point I would much appreciate any advice in trouble shooting of this problem.

It’s hard to say what the problem was with so little information. My first impulse would be to check that the 0V (ground) pin on the driver board has a connection to the Arduino. But aside from that, I need an as built schematic or wiring diagram—or better yet a clear photo—to even start to troubleshoot things.

 

Thanks for the review! I think you meant the CN5711 chip, not CN7511. I plan on using a similar chip, the CN5710, that has a max current of 1A instead of 1.5A. It's cheaper, too.

Purchase from JLCPCB here.
English data sheet here.

Thanks for noting the transposition. It’s fixed.