Patent ID: 7411367

Claim:
A full bridge circuit capable of fixing output voltage comprising: a first switch; a second switch, having an output end coupled to an output end of the first switch for generating a first output voltage; a third switch having an input end coupled to an input end of the first switch; a fourth switch having an input end coupled to an input end of the second switch and an output end coupled to an output end of the third switch for generating a second output voltage; a first controller having a first output end coupled to a control end of the first switch and a second output end; a second controller having a first output end coupled to a control end of the third switch and a second output end; a first operational amplifier having a first input end coupled to the first switch and to the second switch for receiving the first output voltage, and a second input end for receiving a first reference voltage; a first multiplexer having a first input end coupled to an output end of the first operational amplifier, a second input end coupled to the second output end of the first controller, a control end coupled to the first controller, and an output end coupled to a control end of the second switch, the first multiplexer used for connecting to the first input end or the second input end according to a first control signal received by the control end; a second operational amplifier having a first input end coupled to the third switch and to the fourth switch for receiving the second output voltage, and a second input end for receiving a second reference voltage; and a second multiplexer having a first input end coupled to an output end of the second operational amplifier, a second input end coupled to the second output end of the second controller, a control end coupled to the second controller, and an output end coupled to a control end of the fourth switch, the second multiplexer used for connecting to the first input end or the second input end according to a second control signal received by the control end.