I've been looking for cheap and easy ways to drive a MOSFET with PWM and I came across a simple 555-based driver.
But that gave me an idea, since push-pull setup is used for driving MOSFETs, and an H bridge is basically a double push-pull, is it possible to use an H bridge motor driver IC, namely the l9110, to drive two MOSFETs?
The l9110 is intended to drive one motor, but I think I can connect each output to a MOSFET gate and drive 2 MOSFETs with it.
Here is the datasheet of l9110.
Another datasheet. It's in Chinese but has an internal diagram too.
Notes:
- I couldn't find a maximum switching time for l9110 so I know that it probably can't handle more than a few kHz. But that's OK.
- Please don't suggest using a dedicated driver. I'm specifically asking if this particular IC or other H bridge ICs can be used to drive 2 MOSFETs.
Best Answer
Only if both external MOSFETs are low-side and only if the external MOSFETs have significantly more gate capacitance than the MOSFETs in the H-bridge IC. And since the MOSFETs in the H-bridge IC already have more gate capacitance than the typical input capacitance of a gate driver it will be slower to begin with.
And only if both MOSFETs don't have to be on at the same time since the L9110 doesn't allow that which you can see from looking at the truth table. This last one is probably a dealbreaker.