Patent ID: 9667209
Date: 2017-05-30
CPC Classifications: H03F

Claim:
1. An amplifying device comprising: a first amplifying unit having a differential pair of transistors each with a control electrode, the first amplifying unit amplifying a difference between voltages at the control electrodes of the respective transistors, and outputting a first output voltage of the first amplifying unit; a second amplifying unit that amplifies the first output voltage of the first amplifying unit and outputs a second output voltage of the second amplifying unit; a state detecting unit that detects a state wherein the second output voltage of the second amplifying unit is lower than an input voltage of the amplifying device by a voltage difference defined as a negative offset voltage, the input voltage having a lower potential than an absolute value of the negative offset voltage; and an offset voltage correcting unit that, when the state is detected, corrects the negative offset voltage to a positive offset voltage, defined as a positive voltage difference of the second output voltage relative to the input voltage, wherein the second output voltage of the second amplifying unit has a higher potential than the input voltage of the amplifying device.