US Patent 7148727 Read-out circuit for infrared detectors

The present invention is related to a device comprising a capacitive feedback transimpedance operational amplifier, that comprises a main operational amplifier (with a first input, a second input and an output) and an integrating capacitor, connected between the second input and the output, and a first switch connected in parallel to the integrating capacitor. The device further comprises an auto-zero operational amplifier having a third input and a fourth input, whereby to the third input and the first input signals at virtual ground potential are applied. The fourth input is connected to the output by a circuit comprising two offset error capacitors, a second switch and a third switch.