High Side Mosfet Driver Pulse Transformer

Noise immunity negative voltage robustness of the high side driver.

High side mosfet driver pulse transformer.

It has been optimized for both capacitive load drive and pulse transformer demagnetization. Here s a scope grab showing the pulse from the driver and the voltage on the mosfet side of the transformer. The yellow trace shows the voltage drop when the mosfet turns on and then when it closes the voltage climbs again and oscillates. Circuit block diagram it can therefore directly drive a low side switch and through a pulse transformer an high side switch.

High side driver supply bootstrap supply is requested. Matched propagation delay between high and low side drive prevents any unbalanced transformer usage. A special section deals with the gate drive requirements of the mosfets in synchronous rectifier applications. With gate drive transformer both hi lo side mosfets will get equal amplitude gate drive signals where as with bootstrapping technique used in chips the hi side gate pulse amplitude will be lesser than lo side gate pulse due to associated drop of bootstrap diode coming into picture in hi side.

A pulse transformer is an isolation transformer which can operate at speeds often needed for half bridge gate driver applications up to 1 mhz. Gate charge of the mosfet to be driven bias voltage allowed ripple and discharge during switching switching frequency maximum high side pulse width minimum low side pulse width. Procedure for ground referenced and high side gate drive circuits ac coupled and transformer isolated solutions are described in great details. A gate driver ic can be used to deliver the high currents needed for charging the capacitive mosfet gates.

The blue trace is the gate and shows the 1 duty cycle i was using at this point. For more information see the overview for mosfet and igbt gate drivers product page.