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Control a 20V Led



I’m starting playing with gadgeteer modules, and I have several LEDs of 20v ( 1A ) that I want to dim ( using PWM ).
What kind of gadgeteer module should I use to manage this ?

Thanks in advance.


That’s pretty high voltage for most modules. The Load module might help. You’ll need to see if it can switch fast enough for your needs.


Treat it like AC. Give it a separate power source and tie an optocoupler to the PWM to control it.


I concur.

The BCP55s on the Load module should be able to handle the switching fine. Just use a low frequency when you’re PWMing – it doesn’t need to be more than 200 Hz.

I’d recommend ignoring @ Skewworks advice about using optocouplers. Most optocouplers aren’t designed to directly drive loads like that, and, as @ ianlee74 already noted, there’s a perfectly good off-the-shelf solution (the Load module) that will work perfectly for your application.

The bigger issue is the constant-current-source power supply that you’ll need to power the LEDs. Even if they’re labeled “20V”, you can’t drive them directly with a voltage source; you’ll need a current source to drive them, as LEDs are rated for a specific amount of current.


I just wanted to note here that the Load module page says “The 3A 50V transistors…”

According to the schematic the part#'s listed there are actually 1.5A, 60v

So either the devices page text is in error, or the schematic part# list there are wrong.


@ VersaModule - The schematic part# is wrong. The right part# is PBSS4350Z, which is a 3A 50V transistor. We will be correcting the schematic. Thank you for pointing this out.