Fast turn-off dual synchronous rectifiers (SR) controller

NEX81915 is a dedicated controller IC for synchronous rectification on the secondary side of resonant converters. It supports operation in discontinuous conduction mode (DCM), continuous conduction mode (CCM) and critical conduction mode (CRM). It has two driver stages for driving the SR MOSFETs. By detecting the Vds of the rectifier, the MOSFETs can be reliably switched on and off, thereby replacing Schottky diodes and improving the efficiency of the resonant converter.

NEX81915 regulates the forward drop voltage of an external synchronous rectifier (SR) MOSFET by decreasing the gate voltage. This allows the SR FET to be turned off quickly when the Vds becomes positive.

NEX81915 is a green and energy-saving product. The turn-on delay time will be increased and the drive current will be decreased to minimize the power consumption at light load. The IC current will drop to a very low level during burst off period. The light load efficiency can be improved.

The device is available in SO8 (SOT96-2) package. Figure 1. Typical application circuit