Salient integration mode active pixel sensor

摘要

A salient integration mode active pixel sensor. The active pixel sensor includes an amplify/compare transistor which has a threshold voltage. The amplify/compare transistor couples an input of the amplify/compare transistor to an output of the amplify/compare transistor when the input of the amplify/compare transistor exceeds the threshold voltage. A photo-diode generates a signal voltage which has a voltage level dependent upon the intensity of light received by the photo-diode. The signal voltage is coupled to the input of the amplify/compare transistor. A reset element couples a reset line to the photo-diode and discharges the photo-diode when the reset line is active. A coupling capacitor for couples a select line to the input of the amplify/compare transistor. The select line causes the input to the amplify/compare transistor to exceed the threshold voltage and thereby couple the signal voltage to the output of the amplify/compare transistor. The amplify/compare transistor can be an N-type MOSFET and the reset transistor can be an N-type MOSFET. Further, a back gate of the amplify/compare transistor is generally connected to a circuit ground.