Patent ID: 7509113
Filing Date: 2009-03-24
Classification: G01J,H04M,Y02D

Abstract:
1. A circuit, capable of detecting and sensing photons under consideration of side effects such as temperature changes, drift, aging and ambient light influences thus generating an appropriately corrected output signal of the circuit, and having an optical input facility and an output terminal as well as terminals for supply voltages and ground connections, comprising: two sets of a basic photo sensitive circuit being operated in parallel to each other, one set in light mode and the other in dark mode; each set comprising: a photo diode connected to both the gate input of a field effect transistor and to one contact of a switching device; said switching device also connected to said supply voltage; said field effect transistor connected with its drain input to said supply voltage and connected with its source input to both a current source and an amplifier input; said current source also connected to ground; and a common differential amplifier used commonly for both sets thus having two of said amplifier inputs and outputs; with a common control circuit for the processing of the signals delivered from said outputs of said operational amplifier, thus generating said appropriately corrected output signal of the circuit.