Would this work for a H bridge?

[SuburbanGuy]

Hi,

I am pretty new to Electronics design. I am just wondering if I could use 4 of these (https://www.sparkfun.com/products/10213 they currently ship the FQP30N06L variant) N channel MOSFETs in a H bridge or would I have to use 2 of these (https://www.sparkfun.com/products/10349) P channel MOSFETs on the high side?

[Psi]

If you use 4x N-channel fets you need another (higher) voltage source to turn the high side fet gates on. This is because you need to get the gate at least 3V higher than the source and when the fet is on VDrain more or less equals VSource. Remember, drain is your bridge V+, so you need more than that.

If you use 2x N-channel and 2x P-channel you dont need the extra supply but you do need an extra transistor (per side) to drive the P-channel gates (since the gate logic is inverted)

[BeerCannon]

Why not just use an L293D integrated circuit?  (If your project is using reasonably small motors..)  It's a "quad half H-bridge", which is effectively two full H bridges on a chip.  Great little chip to control two DC motors for small projects.  Check the datasheet for it and see if it can handle your current demands, etc.

Oddwires sells the chip for $1.95 US.  It's the "D" version of the chip which has clamping diodes built-in.

(The web site text says "stepper motor" driver, not sure why.. it's just as good for DC motors.)

http://www.oddwires.com/l293d-stepper-motor-controller-driver-ic/