SRK1001

The SRK1001 controller is designed for secondary side synchronous rectification (SR) in flyback converters, suitable for operation in QR and mixed CCM/DCM fixed frequency circuits.

It provides a high-current gate-drive output capable of driving N-channel Power MOSFETs.

The control scheme of this IC is such that the SR MOSFET is switched on as soon as current starts flowing through its body diode, and then switched off as current approaches zero.

The fast turn-on with minimum delay and innovative adaptive turn-off logic allow maximizing the conduction time of the SR MOSFET and eliminating the effect of parasitic inductance in the circuit.

The device enters low consumption mode when it detects primary controller burst-mode operation, or when the DIS pin is pulled up by the user, or when the SR MOSFET conduction falls below the programmed minimum T_ON. This improves the converter efficiency at light load, where synchronous rectification is no longer beneficial.

After the converter restarts switching or the DIS pin goes low again and the IC detects that the current conduction in the rectifiers has increased 20% above the min T_ON programmed value, the IC exits low consumption mode and resumes switching operation.