STMicroelectronics SRK1001 Adaptive Synch Rectification Controller

The SR MOSFET is switched on as soon as the current starts flowing through its body diode and then switched off as the current approaches zero, implementing the control scheme. The device features a fast turn-on with minimum delay and innovative adaptive turn-off logic, allowing the conduction time of the SR MOSFET to reach maximum. This sequence also eliminates the effect of parasitic inductance in the circuit. Low consumption mode can be achieved in three ways, when the STMicroelectronics SRK1001 detects primary controller burst-mode operation, when the DIS pin is pulled up by the user, or when the SR MOSFET conduction falls below the programmed minimum TON. Additionally, 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 TON programmed value, the IC exits low consumption mode and resumes switching operation.