Hi all,
First-time poster here, please be gentle
I'm looking for a device which I suspect has gone out of fashion.
I want to build a synchronous-rectifier DC-DC switcher which can go to 100% duty cycle (DC). I will need a gate driver chip for the mosfets, as I want to use quite a high PWM frequency. I can find all sorts of bootstrap-style gate drivers designed for using two N-channel fets, which use a capacitor to boost the gate voltage for the high-side N-channel fet. They also have an integrated dead-time generator to prevent shoot-through currents. But, I understand these won't work for me as they can't go to 100% duty cycle because they require some switching to recharge their bootstrap capacitor.
I therefore intend to use a P-channel high-side fet and an N-channel low-side fet. So, I want to find a gate driver chip that has the following characteristics:
- Dual gate driver for PMOS high-side and NMOS low-side half-bridge
- (This means both outputs are in-phase, barring dead-time generation)
- Single TTL PWM input
- Automatic dead-time generation
- Will allow me to go to 100% duty cycle with the high-side fet permanently on and the low-side fet permanently off
I've searched high and low on my favourite component suppliers' sites and semiconductor manufacturers' sites, without success. They have dozens of varieties of bootstrap-style devices for driving dual NMOS half-bridges, but none for PMOS/NMOS. Does anyone know if such a beast exists?
First-time poster here, please be gentle
I'm looking for a device which I suspect has gone out of fashion. I want to build a synchronous-rectifier DC-DC switcher which can go to 100% duty cycle (DC). I will need a gate driver chip for the mosfets, as I want to use quite a high PWM frequency. I can find all sorts of bootstrap-style gate drivers designed for using two N-channel fets, which use a capacitor to boost the gate voltage for the high-side N-channel fet. They also have an integrated dead-time generator to prevent shoot-through currents. But, I understand these won't work for me as they can't go to 100% duty cycle because they require some switching to recharge their bootstrap capacitor.
I therefore intend to use a P-channel high-side fet and an N-channel low-side fet. So, I want to find a gate driver chip that has the following characteristics:
- Dual gate driver for PMOS high-side and NMOS low-side half-bridge
- (This means both outputs are in-phase, barring dead-time generation)
- Single TTL PWM input
- Automatic dead-time generation
- Will allow me to go to 100% duty cycle with the high-side fet permanently on and the low-side fet permanently off
I've searched high and low on my favourite component suppliers' sites and semiconductor manufacturers' sites, without success. They have dozens of varieties of bootstrap-style devices for driving dual NMOS half-bridges, but none for PMOS/NMOS. Does anyone know if such a beast exists?
