Mosfet driver for synchronous rectification from Diodes

The driver is designed for AC-DC rectification circuits in general consumer applications, notebooks, and USB adapters.

It’s capable of driving an external mosfet in both high-side and low-side secondary-side synchronous-rectifier configurations.

This device supports secondary-side output voltages up to 20V in continuous conduction mode, discontinuous conduction mode, and quasi-resonant flyback modes.

These options give designers freedom over how they implement synchronous rectification.

Manufacturers often choose an external mosfet when implementing synchronous rectification as it provides greater efficiency converters, Diodes claims.

The device boasts turn-on and turn-off times of 2.2nF, which are said to reduce power loss and ensure safe operation when in CCM mode.

It also features a blanking period to set the minimum turn-on period for the mosfet; this limits the impact of voltage ringing.

The APR348 also features a light load mode, which uses an internal timer to skip cycles when there is no load or only a light load detected at the output.

This aims to lower standby power at no load.

In addition, high-side switching does not require an additional transformer winding.