Interface Circuit for Driving a Switched Power Transformer in a Regulated Power Supply
Original Publication Date: 1985-Apr-01
Included in the Prior Art Database: 2005-Feb-18
In a switching regulated power supply the regulation is performed by switching the rectified voltage provided by the power line and applied to a power transformer 10. The switching is performed either using a full bridge comprising four switches S1, S2, S3, and S4, as shown in Fig. 1, or simply two switches. In either case, the switches are controlled through a control circuit 12 conventionally comparing the output voltage Vout to a reference voltage Vref and controlling a driver circuit 14. The control circuit controls the driver to provide two signals, one for controlling S1 and S2, the other for controlling S3 and S4. To avoid having any DC component in the transformer coupling, the primary winding of transformer 16 is driven from both sides differentially, with delayed pulses, as shown in Fig.