Patent ID: 6434023
Filing Date: 2002-08-13
Classification: H02M

Abstract:
A switched-mode power supply, comprising:a bridge rectifier having AC voltage inputs for receiving an AC voltage and DC outputs; an electrolytic capacitor; a transformer having a primary winding and a secondary winding; a first series circuit containing said primary winding of said transformer and a controllable switch having a control input, said first series circuit connected in parallel with said electrolytic capacitor and together defining a parallel circuit connected to said DC outputs of said bridge rectifier; a control unit having a control input and an output connected to said control input of said controllable switch; a second series circuit containing a diode and a first capacitance and connected in parallel with said secondary winding of said transformer; a capacitive voltage divider formed of a second capacitance, a center tap, and a third capacitance, said capacitive voltage divider connected in parallel with said electrolytic capacitor; and a comparator having a first input connected to said center tap of said capacitive voltage divider, a second input to be connected to a reference voltage, and an output connected said control input of said control unit.