MOSFET driver for synchronous rectification supports CCM, DCM and QR operation

Diodes Incorporated has introduced the APR348 secondary-side, multi-mode synchronous rectification MOSFET driver, created for AC/DC rectification circuits in general consumer applications, notebooks, and USB adapters.

The device can drive the external MOSFET in high-side and low-side secondary-side synchronous-rectifier configurations. The efficient and flexible device supports secondary-side output voltages up to 20V in CCM, DCM, and QR flyback modes. These options provide development teams complete freedom over how they implement synchronous rectification.

An important design feature of the device is fast turn-on and turn-off times, which lessens power loss and provides safe operation when in CCM mode. The device also highlights a blanking period to set the minimum turn-on period for the MOSFET; this dramatically improves performance by restricting the impact of voltage ringing.

The device also offers a light load mode, which employs an internal timer to skip cycles when there is no load or only a light load identified at the output. This design provides lower standby power at no load. Also, high-side switching does not need a further transformer winding, further reducing the BOM cost.