Patent ID: 8542073

Claim:
A variable-capacitance device comprising: a first capacitance element coupled between a first power supply terminal and an output terminal; a capacitance selection switch configured to turn on or off in accordance with a capacitance switching signal; a second capacitance element coupled in parallel to the first capacitance element and in series to the capacitance selection switch; and an error correction circuit configured to operate such that in a state in which the capacitance selection switch is in an OFF state, in response to a charge reset signal that causes a voltage at the output terminal to be reset to a reset voltage, the error correction circuit substantially eliminates a difference between the voltage at the output terminal and a voltage at a capacitance switching node at which the second capacitance element is coupled to the capacitance selection switch, wherein the error correction circuit includes: a first switch circuit configured to apply a reset voltage to the capacitance switching node in response to the charge reset signal, wherein the reset voltage is supplied from a second power supply terminal; and a second switch circuit coupled in series to the first switch circuit and configured to switch the first switch circuit between an enable state and a disable state wherein the second switch circuit is controlled exclusively with respect to the capacitance selection switch in terms of their ON state.