MOSFET driver for synchronous rectification supports CCM

The APR348 is capable of driving the external MOSFET driver in both high-side and low-side secondary-side synchronous-rectifier configurations. This flexible and efficient device supports secondary-side output voltages up to 20V in continuous conduction mode (CCM), discontinuous conduction mode (DCM), and quasi-resonant (QR) flyback modes. These options give development teams total freedom over how they implement synchronous rectification.

Manufacturers often choose an external MOSFET when implementing synchronous rectification as it provides greater efficiency converters. As the APR348 requires very few additional external components, engineers can still realise extremely small and efficient power supply designs that meet the demands of the consumer sector.

A key design feature of the APR348 is fast turn-on and turn-off times, which reduces power loss and ensures safe operation when in CCM mode. The device also features a blanking period to set the minimum turn-on period for the MOSFET; this significantly improves performance by limiting the impact of voltage ringing.

The APR348 also features a light load (LL) mode, which uses an internal timer to skip cycles when there is no load or only a light load detected at the output. This design delivers lower standby power at no load. In addition, high-side switching does not require an additional transformer winding, further minimising the bill of materials cost.

The APR348 is available in the SOT26 Type CJ package and priced at $0.116 each in 1,000 piece quantities.