Hi,

In a half bridge configuration what would prevent using Low side Mosfet
drivers with P-Mos transistors placed on the high side ?

A 12V power supply is used and in that case the Gate-Source voltage will always stay below the usual 20V maximum.

Thanks in advance for any help

 

Can't think of anything that would stop you...

 

Thanks for your response. Looks like the response was obvious but I am not
very comfortable with analog stuff.

Just for confirmation is the following (simplified) schematic correct ?
http://cjoint.com/?ihqeZK5nFH

Which means that with a quad low-side driver I can drive a full bridge with
2 P-Mos at the top and 2 N-Mos at the bottom ?

Just for curiosity what if the bridge power supply was above 20V ?

 

Looks right. Not sure what you are using it for but you want fast-recovery or schotky diodes in reverse-parallel with the MOSFET source-drain to protect them from inductive flyback if you are switching an inductive load.

 

That would work.

If the supply is above 24V, then you need to take the p-channel MOSFETS to 24V to turn them off and not below 4V to turn them on.

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Ah, yeah, the motor voltage has to be equal to or less than the gate-drive voltage so you can turn the PMOS off.

 

By the way I wonder why "Low Side" drivers are called this way as they look pretty generic. This was a little confusing to me.

On the other side "High Side" drivers are very specific as they contain a charge pump and are designed for N-Mos devices placed at the top.

 

Low-side to me means the transistor is stuck "low" to ground. And high-side means the transistor is stuck "high" to +V.

 

Yes but I was refering to high or low side drivers not transistors.
And in that case the symetry does not apply to drivers.