GAIN CIRCUIT

A gain circuit comprises a main amplification unit and a first refresh unit. The main amplification unit comprises an amplifier, a first capacitor connected between a first input terminal of the gain circuit and a first input terminal of the amplifier, and a second capacitor connected between the first input terminal of the amplifier and a first output terminal of the amplifier. The first refresh unit comprises a first capacitor connected with a first terminal of the first capacitor to a common node of the first refresh unit , and a second capacitor connected with a first terminal of the second capacitor to the common node of the first refresh unit. The common node of the first refresh circuit is arranged to be supplied with a reference voltage (Vref, Vcm, ref) during a first phase of a refresh interval and connected to the first input terminal of the amplifier during a second phase of the refresh interval. Furthermore, a second terminal of the first capacitor of the first refresh unit is arranged to be supplied with an input voltage (Vcm, in) of the gain circuit during the first phase of the refresh interval and connected to the first input terminal of the gain circuit during the second phase of the refresh interval. Moreover, a second terminal of the second capacitor of the first refresh unit is arranged to be supplied with a first voltage, which is an output voltage (Vcm, out) or output reference voltage of the amplifier, during the first phase of the refresh interval and connected to the first output terminal of the amplifier during the second phase of the refresh interval.