Controller for a quasi-resonant switch mode power supply

摘要

A switched mode power supply (SMPS) controller is disclosed. The controller comprises a monitoring circuit adapted to monitor the rate of change of a voltage at an input (1) and to monitor the drop in voltage at the input (1) from a peak value. The controller is adapted to generate a signal for closing the switch when the monitored rate of change falls below a first predetermined threshold and the monitored drop in voltage exceeds a second predetermined threshold.