Patent ID: 7414653

Claim:
An active pixel sensor comprising: a photodiode providing a photodiode output current indicative of an intensity of light incident the photodiode; an integrator circuit electrically coupled to the photodiode and configured to provide a pixel voltage representing an integration of the photodiode output current when the photodiode is exposed to light and dark leakage current through the photodiode when the photodiode is not exposed to light and configured to set a reverse bias voltage on the photodiode and respond to at least one control input to set the reverse bias voltage to a first level; and a feedback loop configured to receive the pixel voltage and control the integrator circuit to adjust the reverse bias voltage to substantially reduce the dark leakage current through the photodiode to a desired level, wherein the feedback loop is configured to control the integrator circuit to adjust the reverse bias on the photodiode to maintain a substantially stable pixel voltage when the photodiode is not exposed to light.