| 摘要 |
The present invention relates to the field of CMOS image sensors, and provides a digital pixel sensor that can unify change rates of two sections of reference voltages in the two-section comparison technique. Thus, according to the technical scheme of the present invention, a digital pixel exposure method using a multi-ramp voltage as a reference voltage is adopted and comprises the following steps: the method is implemented by means of a PWM pixel array, PWM pixels are composed of a photodiode (PD), a reset transistor (MRST), a pixel-level comparator, a column-level comparator and a pixel-level or column-level or array-level storage, the input end of the pixel-level comparator is provided with a PD node voltage and a set reference voltage, a PWM type digital pixel enters an exposure stage after resetting, and exposure time is divided into a reset sampling stage Trs and an integral sampling stage Tis; the reference voltage of the reset sampling stage linearly rises to Vref_rsh from Vref_rsl. The present invention is mainly applied to designing and manufacturing of CMOS image sensors. |
