Patent ID: 8896158
Filing Date: 2014-11-25
Classification: H03H

Abstract:
1. A variable capacitance circuit comprising: a first node, to which an alternate current signal with a reference potential as a center voltage is applied; a first capacitor having a first electrode connected to the first node and a second electrode connected to a second node which is different from the first node; a second capacitor having a first electrode connected to the second node, and a second electrode connected to a reference potential terminal to which the reference potential is applied; a third capacitor having a first electrode connected to the second node, and a second electrode connected to a third node which is different from the first node and the second node; a transistor for controlling a capacitance, having a drain connected to the third node, a source connected to the reference potential terminal, and a gate to which a capacitance control signal is applied; and a bias circuit which applies a first bias voltage to the third node.