Differential amplifier, semiconductor device and offset cancellation method

An offset cancellation method for cancelling an offset voltage of an input terminal pair of a differential amplifier,

• wherein the differential amplifier includes:
• a current source that is connected to a first power supply in which a suppliable current is a first current;
• an active element pair that is connected to the current source, and amplifies a signal input to an input terminal pair to output an output signal pair;
• a load element pair that is connected to a second power supply different in power supply voltage from the first power supply, the load element pair serving for outputting the output signal pair to an output terminal pair;
• and
• a capacitance element pair that is inserted between an external input terminal pair and the input terminal pair,
• the offset cancellation method comprising:
• performing an offset cancellation operation to charge the capacitance element pair such as to cause the capacitance element pair to generate a voltage by short-circuiting corresponding terminals between the output terminal pair and the input terminal pair, the voltage being obtained by converting an offset voltage of the input terminal pair into an input voltage;
• and
• controlling a current suppliable by the current source to be a second current larger than a first current at a time of performing the offset cancellation operation.