BJT PIXEL CIRCUIT CAPABLE OF CANCELLING AMBIENT LIGHT INFLUENCE, IMAGE SYSTEM INCLUDING THE SAME AND OPERATING METHOD THEREOF

摘要

There is provided a BJT pixel circuit including a BJT transistor, a photodiode, a first storage capacitor and a second storage capacitor. The first storage capacitor is configured to discharge, via the BJT transistor, to a first output voltage in a first exposure time of the photodiode. The second storage capacitor is configured to discharge, via the BJT transistor, to a second output voltage in a second exposure time of the photodiode.

主权项

1. A BJT pixel circuit, configured to generate voltage signals corresponding to a light source signal, the light source signal including a light-on level and a light-off level, the pixel circuit comprising:
a photodiode; a first shutter switch configured to control a first exposure time of the photodiode to correspond to the light-on level according to a first shutter signal; a second shutter switch configured to control a second exposure time of the photodiode to correspond to the light-off level according to a second shutter signal; a first storage capacitor having a first terminal coupled to the photodiode via the first shutter switch and a second terminal coupled to a ground, the first storage capacitor configured to hold a first predetermined voltage before the first exposure time and discharge, via the photodiode, to a first output voltage in the first exposure time; and a second storage capacitor having a first terminal coupled to the photodiode via the second shutter switch and a second terminal coupled to the ground, the second storage capacitor configured to hold a second predetermined voltage before the second exposure time and discharge, via the photodiode, to a second output voltage in the second exposure time.