High charge capacity focal plane array readout cell

Abstract

A high charge capacity readout cell in a hybrid focal plane detector array on a complementary metal oxide semiconductor integrated circuit chip. An input transistor that provides a buffer for the detectors of the array, couples to a source of bias voltage, which controls the operation of the transistor. An integrating capacitor uses a variable source of terminating voltage to increase the amount of charge it integrates. A read signal causes an output transistor to read the charge from the capacitor to a readout line and to initialize the capacitor. The termination voltage of the integrating capacitor is changed during the time that the detector current is integrated, thus increasing the change in total voltage across the capacitor. This allows a greater amount of charge to be integrated with the capacitor which improves the signal-to-noise ratio of the focal plane array.