Small-outline synchronous rectification MOSFET driver

Diodes has announced the APR346 Secondary Side Synchronous Rectification MOSFET Driver, providing increased efficiency for off-line power adapters delivering 5V to 20V DC from an AC supply.

Designed to operate in Continuous Conduction Mode (CCM), Discontinuous Conduction Mode (DCM) and Quasi-Resonant mode (QR), the APR346 is used to drive an external MOSFET to deliver the benefits of Synchronous Rectification (SR), which provides significantly higher performance and efficiency than diode-based secondary side rectification.

SR is now preferred by power adapter manufacturers and is expected to form the basis of power adapters for notebooks, mobile phones and a range of other portable devices, many of which will be adopting the USB Type-C connector with PD (Power Delivery) capabilities.

The APR346 requires very few additional components and, because it is designed to operate with an external MOSFET, it offers maximum design flexibility.

With fast turn-on and turn-off times of 70ns and 100ns (typical) respectively, it achieves high performance through directly sensing the Drain-Source voltage of the external MOSFET and rapidly turning the MOSFET on or off according to demand from the load.

A built-in minimum on-time of 1.6μs (typical) effectively blanks out any potential Drain voltage ringing to maintain efficient operation as the load current begins to flow through the channel.

Author
Neil Tyler