PWM to manufactured LED housings?

I'm looking at some manufactured units that has circuitry in them.

Here are the lights.

If you say I can send PWM power into their circuitry for dimming, is a TIP122 fine and reliable? How many amps without stressing the transistor?

Thx

If the units just have series resistors this should be possible.

If they have active electronics (such as constant current drive) its less clear. The 10--30V
rating suggests these have constant current drive or a switch-mode converter internally
(which would not be compatible with PWM).

Do you have one to take apart and examine?

TIP122 is not a sensible choice, a logic level power MOSFET is the way to go.

Thanks Mark.

I don’t have one yet. I’ll see what I can find out.

I think most these housed units have their own chip that’s up to something, I’m not sure what.

For the MOSFET, that’s sort of what I’ve been reading. Why is that the case with modest current? If it’s <2a?

Just learning here… thx for the help.

TIP122 will likely need heatsinking, even with 1.5A, and wastes a volt or more. The right MOSFET will
run cool without heatsink.

MarkT:
The 10–30V rating suggests these have constant current drive or a switch-mode converter internally (which would not be compatible with PWM).

In fact given that specification, not just “suggests” but it is absolutely certain they have constant current drive and a switch-mode driver is the only practical way to achieve this.

Which will strenuously resist any of your efforts to PWM then. For a start, a switch-mode driver must have an input capacitor.