Method of operating a photoconductor in an imaging system, and read-out circuit employing an ac-biased photoconductor

Abstract

A photoconductor read out circuit includes a biasing signal generator connected to apply an alternating current biasing signal to a first terminal of the photoconductor. An input capacitance connected to a second terminal of the photoconductor stores charge applied to that terminal. A charge transfer amplifier included in the read out circuit receives a demodulating signal and functions to transfer charge to a summing node in response to the charge stored by the input capacitance and in coordination with the demodulating signal. A charge collection arrangement included in the read out circuit selectively resets the summing node to a base charge level, and stores charge applied to the summing node between resets to the base charge level. A sampling arrangement included in the read out circuit selectively applies a charge from the summing node to an output node, selectively presets the output node to a base output charge level, and stores charge applied to the output node between presets to the base output charge level. The charge stored at the output node between presets represents an output data signal from the read out circuit.