Patent ID: 7061074

Claim:
A photodetector comprising: a phototransistor having an emitter and a base; a bipolar transistor having a second emitter and a second base; a first Metal Oxide Semiconductor Field Effect Transistor (MOSFET) which acts as a closed switch when the first MOSFET is tied low; a first integration capacitor wherein after a certain integration period, where the Darlington phototransistor is allowed to charge up, the first integration capacitor and a second integration capacitor sample the charge which is then held onto a hold capacitor; and a second MOSFET which acts as a closed switch when the second MOSFET is tied low; wherein the emitter of the phototransistor is connected to the second base of the bipolar transistor, wherein an emitter current of the phototransistor becomes a base current of the bipolar transistor, wherein the second emitter is connected to the first integration capacitor; and wherein once the charge has been transferred to the hold capacitor, a reset MOSFET is strobed low thus resetting the first and second integration capacitors to a voltage Vdd.