Patent ID: 7990210
Filing Date: 2011-08-02
Classification: H03F,H03H

Abstract:
1. An amplifier comprising: a first variable capacitance device; a second variable capacitance device, electrically connected to said first variable capacitance device, and of an inverse conductivity type from said first variable capacitance device; a third variable capacitance device of the same conductivity type as said first variable capacitance device; a fourth variable capacitance device electrically connected to said third variable capacitance device, said fourth variable capacitance device being of the same conductivity type as said second variable capacitance device and of an inverse conductivity type from said first and third variable capacitance devices; and a first input unit for selectively inputting a bias voltage and a voltage signal to said first variable capacitance device, said second variable capacitance device, said third variable capacitance device, and said fourth variable capacitance device, wherein, when said bias voltage and said voltage signal are input to said first variable capacitance device, said second variable capacitance device, said third variable capacitance device, and said fourth variable capacitance device, a capacitance of said first variable capacitance-device, said second variable capacitance device, said third variable capacitance device, and said fourth variable capacitance device is taken as a first value, wherein said voltage signal is amplified with the capacitance of said first variable capacitance device, said second variable capacitance device, said third variable capacitance device, and said fourth variable capacitance device as a second value smaller than said first value, and wherein a ratio of a first capacitance of said first variable capacitance device and said fourth variable capacitance device, and a second capacitance of said second variable capacitance device and said third variable capacitance device does not change.