Patent ID: 8586940
Filing Date: 2013-11-19
Classification: G01T,H04N

Abstract:
1. An X-ray active pixel sensor (APS) readout circuit, comprising: an X-ray active pixel sensing unit, comprising a sensor, wherein the X-ray active pixel sensing unit at least is operated in a resetting period and a sampling period; in the sampling period, an X-ray irradiation amount is sensed by the sensor to obtain a sensing voltage in varying, and a current signal for output is obtained by subtracting a sensing current from a base current is output; and the sensing current is generated according to the sensing voltage; an integrating unit, coupled with the X-ray active pixel sensing unit, to receive the current signal and convert the current signal into a voltage signal, wherein the integrating unit comprises a short circuit switch; functions of the short circuit switch comprise: being used for resetting the integrating unit when being switched on in the resetting period, and directly outputting the voltage signal in the sampling period; a voltage offset unit, connected to an output terminal of the integrating unit, wherein the voltage offset unit generates an offset voltage, which is used for accordingly removing the base voltage of the voltage signal in the sampling period to obtain an amplified sensing voltage; and an analog-to-digital converter (ADC), for converting the sensing voltage.