Patent ID: 6727749
Filing Date: 2004-04-27
Classification: G06G,G06J

Abstract:
A circuit for adding a plurality of input signals, comprising:an amplifier having inverting and non-inverting input terminals and an output terminal; a first sampling circuit coupled between a first input signal and a first reference signal to store a first voltage across a first capacitor in response to a first clock phase; a second sampling circuit coupled between a second input signal and a second reference signal to store a second voltage across a second capacitor in response to the first clock phase; and a switching circuit coupled to the amplifier and the first and second sampling circuits, wherein, in response to a second clock phase, the switching circuit switches the first capacitor storing the first voltage between the inverting input terminal and the output terminal of the amplifier, and further switches the second capacitor storing the second voltage between the non-inverting input terminal and a third input signal.