Patent ID: 8767357

Claim:
An overvoltage protection (OVP) system for a power system which includes multiple switching power supplies having their output voltages connected to a common power bus, comprising: a plurality of OVP circuits adapted for coupling to respective switching power supplies, each of which has one or more switching elements that are driven with respective pulse-width-modulated (PWM) or pulse-frequency-modulated (PFM) drive signals generated by a control circuit which varies said drive signals as needed to regulate an output voltage, the output voltages of said switching power supplies connected to a common power bus, each of said OVP circuits comprising: a bus voltage overvoltage detection circuit having an output which toggles when the voltage on said common power bus exceeds a predetermined reference voltage; a modulation flag detection circuit which receives a value that varies with a parameter associated with the PWM or PFM drive signals generated for the switching power supply to which said OVP circuit is coupled, and has an output which toggles when said parameter value exceeds a predetermined reference parameter value; logic circuitry which receives the outputs of said bus voltage overvoltage detection circuit and said modulation flag detection circuit at respective inputs and is arranged to toggle a first output when the output of said bus voltage overvoltage detection circuit indicates that the voltage on said common power bus exceeds said predetermined reference voltage and the output of said modulation flag detection circuit indicates that said parameter value exceeds said predetermined reference parameter value; and a first overvoltage response circuit arranged to initiate a first course of action for the switching power supply to which said OVP circuit is coupled when said logic circuitry's first output toggles.