Patent ID: 7538605
Filing Date: 2009-05-26
Classification: H03F

Abstract:
1. An amplifier device capable of reducing offset voltage comprising: an offset voltage cancellation device comprising an input voltage reception end, a first output end, and a second output end, for receiving an input voltage through the input voltage reception end, and compensating the offset voltage according to an operating mode, so as to output a compensating result from the first output end and the second output end; an input stage circuit for outputting an amplified signal according to the compensating result outputted from the first output end and the second output end of the offset voltage cancellation device; an output stage circuit for outputting an amplified voltage and a first feedback voltage according to a front stage amplified signal outputted from the input stage circuit; a pseudo output stage circuit for outputting a second feedback voltage according to the front stage amplified signal outputted from the input stage circuit; a switch circuit coupled to the input stage circuit, the output stage circuit, and the pseudo output stage circuit, for transmitting the front stage amplified signal outputted from the input stage circuit to the output stage circuit and transmitting the first feedback voltage outputted from the output stage circuit to the input stage circuit, or transmitting the front stage amplified signal outputted from the input stage circuit to the pseudo output stage circuit and transmitting the second feedback voltage outputted from the pseudo output stage circuit to the input stage circuit, according to the operating mode; and a voltage output end for outputting the amplified voltage from the output stage circuit.