need help with mosfet theory.

[fzn10]

I have an H-bridge configuration circuit, and i want to drive the gates through a PIC microcontroller. The problem is that the logic signals are only (0 to 5V), so im gona need a mosfet driver to succesfully turn on and turn off the mosfets. I read somewhere in which i referenssed is that you can bypass this driver by placing P-Channel MosFets on the top and N-channel MOSFETs on the bottom of the H bridge, could some one please tell me how and why this actually works, the advantages are obvious in that you dont need a driver, but are there any draw backs to such a configuration.

Thanks

Reference
**broken link removed**

 

[Papabravo]

It works because you connect the P-channel source to the supply and drive the gate to ground providing a negative Vgs.

The drawback is that P-channel MOSFETS are generally slower than N-channel MOSFETS. This can lead to a period of time where both MOSFETS are on, providing a short across the power supply. You could try to match the current handling characteristics and the turn on and turn off times but you will find this a daunting enterprise.

 

[fzn10]

Thanks man your a star