AMPLIFYING DEVICE AND OFFSET VOLTAGE CORRECTION METHOD

摘要

An output voltage delay time caused by the relationship between offset voltage and input voltage is shortened. A single power supply amplifying device includes first and second amplifying units, a state detecting unit, and an offset voltage correcting unit. The first amplifying unit has differential pair transistors and amplifies the difference between input voltages. The second amplifying unit amplifies a first output voltage of the first amplifying unit. The state detecting unit detects a state where a negative offset voltage that causes a second output voltage of the second amplifying unit to be lower than the input voltage occurs, and a potential of the input voltage is lower than the absolute value of the negative offset voltage. The offset voltage correcting unit then corrects the negative offset voltage to a positive offset voltage that causes the second output voltage to be higher than the input voltage.

主权项

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.