I have a street lamp with a led and simple driver in it, I don't know the exact led voltage but the driver (image attached) says 27-36V DC output, MODEL: 50W.

Is there a part I could place between this driver and the led, so I can control dimming by Arduino via PWM ?

The led driver specs (large image below) says: INPUT; AC 85-285V and OUTPUT: DC 27-36V 1500mA, MODEL: 50W

I thought it would work to put this "PWM power module" between the driver output and the led, but (I tested months ago) I remember it started to blink, I think only when decreasing power but not on full power (controlled by PWM with arduino).

  • Should it work with this module or I am trying something very wrong ?
  • Are there any other parts that should work for sure in this situation ?

The specs on the PWM module are these:

Voltage: 5 V - 36 V DC;
Power: 400 W;
Current: 30 A;
PWM Voltage: 3.3-20V;
PWM frequency: 0-20kHz ;

PWM power module

Led driver

  • your question is unrelated to the arduino ... why are you asking here? – jsotola Nov 15 '20 at 23:33
  • because I need it to work with Arduino, otherwise I can find parts that control dimming with a rotating knob, but this is an Arduino project. – adrianTNT Nov 15 '20 at 23:43
  • your question is about the LED power supply, not anything that controls it ... you would have the same question if you used a 555 timer for dimming ... technically, you are actually asking if you can use a rotating knob to dim the LEDs ... and it has been answered that no, you cannot – jsotola Nov 16 '20 at 0:39
  • No, that is not what I asked, it is an Arduino project, I used arduino board, software and modules to connect to this driver. I needed to know where the problem is. – adrianTNT Nov 17 '20 at 2:34
  • it makes no difference how you generate a PWM control signal, software or hardware, the result is the same ... that makes arduino irrelevant to the question ... if you cannot control the power supply with a 555 timer, then you cannot control it with an arduino either – jsotola Nov 17 '20 at 3:40

It will not be possible for you to PWM dim your LED with that LED driver (power supply).

That is a constant current driver with under/over-voltage protection. It delivers a specific amount of current (1.5A) and varies the voltage to allow that to happen.

If the voltage rises too high or falls too low then there must be a fault, so it shuts the power off. This is usually because there is either a short (LEDs tend to "fail short") or an open circuit. The former causes the voltage to drop too low and the latter for it to be too high.

When you insert PWM control you alternate between driving the LEDs and an open circuit. If that open circuit persists too long (low duty cycles) the driver will shut off.

You will need to replace the LED driver (the power supply) with one which includes PWM control internally to it.

  • Can you give me more info on what kind of power supply I should look for ? I tried looking for pwm led driver 220v module but closest I could find was controllers with knob for PWM control. – adrianTNT Nov 15 '20 at 23:07
  • No, I can't. I don't know what is available. All I know is that you can't PWM the output of that power supply and you need to find one that you can. – Majenko Nov 15 '20 at 23:07

If you buy a 30V current-limiting power supply set to limit the current to 1.5A, you should be able to use it to power your LED light through a high power logic level MOSFET. You could control the MOSFET with a PWM signal from an Arduino and use that to vary the brightness of your light. With a little googling I found an adjustable power supply with an output ranging from 0-30V and a power rating of 0 - 1.5A https://www.canakit.com/r182-0-30v-0-1.5a-adjustable-regulated-power-supply.html

It does not look to be weather-proofed like the one you show however, and you'd need to make sure the heat-sink was able to dump enough heat to prevent it from overheating.

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