US Patent 7170760 Switching power supply with clamping circuit

A switching power supply with clamping circuit includes a clamping circuit between a slave output terminal and a master output terminal thereof, to prevent voltage drift at the slave output terminal. The clamping circuit includes a switching circuit connected between the slave output terminal and the master output terminal, and a voltage stabilizing circuit connected between the slave output terminal and the switching circuit. When the output voltage at the slave output terminal steps up to a certain level, the voltage stabilizing circuit functions and enables the switching circuit, and therefore prevents the output voltage from climbing higher than the load requires.