[Jshwaa]

Sorry, *reaches out to shake hand*, my woman's got PMS, lol. Actually she's 4.5 months pregnant, even worse. We just found out we're havin' a girl, at her 20 week ultra-sound. Autumn Ann Richardson is going to be her name.

Anyway. What are some of the combined R(DS) values of some of your guys' h-bridge design? To figure that out, just look up the R(DS) value for both of the N-channel and P-channel FET's you'll be using, and add them. *NOTE* Make sure that you refer to the R(DS) value that corresponds to the V(GS) that you will be applying to the FET. For example, with the 4562's, there is a R(DS) rating of 0.035 Ohms for the N-channel IF you apply 2.5V PWM to its gate, however, if you apply 4.5V PWM to its gate, that resistance goes down to 0.025 Ohms. So gate voltage is very important in determining the overall resistance that the h-bridge is going to present to the drive current that goes through the motor. More resistance means when more current is driven through the channel, more power is going to be needing to be dissipated. If the power doesn't dissipate rapidly enough, then the FET burns up.

I got a combined R(DS) of 0.028 Ohms using IRF3205 and IRF4905 power FET's. I can acquire this because I'm going to be driving the gates using >10V PWM. And if I stack them, that R(DS) goes down to 0.014 Ohms. If I go 3 high, then that goes down to 0.009 Ohms. Just curious what some other people's designs were reaping and with what FET's.