Patent ID: 6777984
Filing Date: 2004-08-17
Classification: H03F

Abstract:
A differential amplifying apparatus which has first and second input terminals for receiving input voltages and first and second output terminals for outputting output voltages, comprising:a first differential pair circuit including a pair of transistors having corresponding control electrodes connected to the first and second input terminals; a second differential pair circuit including a pair of transistors having corresponding control electrodes connected to the first and second input terminals, and possessing conductivity with a polarity opposite from the first differential pair circuit; a first current source connected between the first differential pair circuit and a first power source terminal and configured to bias the first differential pair circuit; a second current source connected between the second differential pair circuit and a second power source terminal and configured to bias the second differential pair circuit; a load circuit connected between the first differential pair circuit and the second power source terminal and configured to load the first differential pair circuit; a first current mirror circuit connected between a corresponding output terminal of the second differential pair circuit and the first power source terminal and having an output terminal connected to the second output terminal; a second current mirror circuit connected between a corresponding output terminal of the second differential pair circuit and the first power source terminal and having an output terminal connected to the first output terminal; and a first voltage amplifying circuit configured to amplify voltages output from output terminals of the first differential pair circuit and to output amplified voltages to the first and second output terminals, wherein said amplified voltages output to the first and second output terminals have a desired gain relative to said input voltages.