THE SWITCHED CAPACITOR VARIABLE GAIN AMPLIFIER HAVING A HIGH GAIN LINEARITY

摘要

A switched capacitor variable gain amplifier is provided to reduce a voltage gain error due to capacitor mismatching by sharing a sampling capacitor in a sampling phase and an amplifying phase. A first sampling capacitor module(320A) and a second sampling capacitor module(320B) include a first sampling capacitor and a first variable capacitor and stores an input voltage in the sampling phase respectively. An operational amplifier amplifies the difference between input voltages in the amplifying phase. A first amplifying capacitor module(330A) and a second amplifying capacitor module(330B) share the first and second sampling capacitor modules and the first sampling capacitor and determine a voltage gain value of the input voltage according to the capacitance of a compensation capacitor, a second variable capacitor, and the shared first sampling capacitor. A plurality of sampling switches(340) and amplifying switches(350) are opened or closed in the sampling phase and the amplifying phase.