US Patent 9660516 Switching controller with reduced inductor peak-to-peak ripple current variation

A switching controller having an over voltage protection circuit is disclosed. The over voltage protection circuit detects whether the output voltage is higher than an over voltage threshold and turns on the rectifier when the output voltage is higher than an over voltage threshold. The over voltage protection circuit detects whether a current flowing through a rectifier is lower than a negative current limit and further turns off the rectifier for a time period when the current flowing through the rectifier is lower than the negative current limit. The off time period varies inversely with the input voltage.