# H-bridge design for Peltier

I am using a pelter module to cool a chamber, I also use the same module to heat the chamber just by reversing the voltage to to.(separately tested and working). This lead me to look for a H-bridge IC to do the same. But I really couldn't find something which supports up to 5 Amps(peltier peaks to 4A) easily. Hence I decided to make a circuit for the same.

I would be using a micro controller at 3.3v to control this, so I want to ask you guys if its okay to use a circuit like this to drive it? or am i missing something?

• You can get off-the-shelf H-bridge modules pretty easily, but you might be looking in the wrong place. On digikey, for example, they're sorted under "discrete semiconductor products"->"Transistors - FETs, MOSFETs - arrays". You might have trouble finding one with both N and P channel FETs, though, as for high powers it's much more common to use all N-channel FETs along with high-side driver circuitry. – Hearth Mar 4 '19 at 14:43
• On the other hand, making a H-bridge yourself is not a bad idea either. If you want to do this, though, you should pick some FETs first and see how you'll be able to drive them. It's likely you'll need some form of driver IC for the PWM. – Hearth Mar 4 '19 at 14:44

Peltier modules don't like being driven by PWM; see this question. Peltier coolers suffer from $$\I^2R\$$ losses; if you drive them with a continuous voltage then those losses are minimized; drive them with PWM and those losses are maximized.