# "Amplify" LED-Controller to handle higher currents

I have a bunch of LED controllers which I am currently controlling over WiFi. Unfortunately, they are all rated for very small currents of about 2 Amp (ish).

Each LED Color gets driven with a simple N-Channel Mosfet as a low-side switch.

My question is: Assuming my N-Channel mosfet is properly rated, can I drive a load which is much larger with this setup? The PWM Generator symbolizes my LED-Controller, which should pull the Base of the PNP Transistor to Ground since it is just a low-side mosfet. The values of the resistors are all default, I am aware that I have to tweak them properly. The LED on the right hand side of the schematic is basically an entire LED-Strip with three LEDs in series and a huge amount of those three LED Groups in parallel.

The maximum current the LEDs should draw is about 6 Amps. I'm planning to use an IRLZ34N with heatsinks. Probably way overkill but I have plenty of those so... why not.

The default PWM Frequency of the controller is 1kHz but I'm thinking about patching that to a higher frequency. I know the chip supports it and right now my power supply gives of annoying high pitched noises even though it is a name brand. The accuracy of the PWM signal isn't critical at all, it's just for some ambient lights. Since I want to dimm them properly, the dynamic range of the duty cycle is very high, so basically 0-100%ish. Usually I won't run them close to 0%. The brightness isn't linear so everything below 40% is almost like switching them off completely.

Will the PWM dimming still work properly?

Everything has a common ground.

simulate this circuit – Schematic created using CircuitLab

• "Huge amount" isn't a specification. How much current do you want to switch and what's the PWM frequency and dynamic range of the duty cycle? What accuracy do you require? Stuff like that. More stuff is better. $\frac{\text{d}I}{\text{d}t}$ raises inductance questions. $\frac{\text{d}V}{\text{d}t}$ raises capacitance questions. Stuff matters.
– jonk
Feb 11, 2018 at 17:12
• I'm sorry, you are absolutely right. I added more details. Feb 13, 2018 at 21:07
• Much better. +1 for that. I may get time or someone else may. But you've added important details that really do help. Thanks.
– jonk
Feb 13, 2018 at 22:11
• I would recommend a resistor from the base of the transistor to the 12v positive rail in the same way you have done for the MOSFET. That will help turn the transistor off quickly and avoid issues if there is any leakage. Nov 2, 2019 at 23:14
• You can delete R4. Mar 7, 2021 at 18:13