ANALOGUE READOUT PRE-PROCESSING CIRCUIT FOR CMOS IMAGE SENSOR AND CONTROL METHOD THEREFOR

摘要

An analogue readout pre-processing circuit for a CMOS image sensor and a control method therefor. The analogue readout pre-processing circuit comprises: an extended counting-type integration cycle-successive approximation mixed-type analogue-digital conversion capacitor network (1) for realizing the readout and analogue-digital conversion of an output signal of a CMOS image sensor; an operational amplifier (2) for achieving an extended counting-type integration cycle-successive approximation mixed-type analogue-digital conversion function by means of "virtual short" of two input ends of the operational amplifier and the principle of charge conservation, wherein an extended counting-type integration can effectively reduce thermal noise and flicker noise in the image sensor; a comparator (3) for comparing magnitudes of voltages at both ends and completing a signal quantization function; and a control signal generator (4) for providing a control signal.