I need to control two 12v motors that draw ~8 amps each. They are going to be throttled way down using PWM and PID control, I only really need 20% or so of their output, but I can not change them for better motors. Now I already have some nice half-bridge chips in my parts drawer, BTN7970P. Since I don't need to reverse the motors I will use one chip per motor. My question is is it better to do the PWM and such on the high side or low side? I assume it makes a magical difference I am unaware of. The whole motor assembly will likely be a few feet from my control electronics, so I am thinking I may put the chips in a seperate enclousure mounted directly to the motors w/ ultrfast recovery diodes on nice short leads and run the PWM control logic over the long distance, rather than power, to keep noise in check.
thanks folks, the real question is, high side or low side?