READ AND CLEAR READOUT CIRCUIT AND METHOD OF OPERATION OF AN IR SENSING CHARGE INJECTION DEVICE

摘要

A READ AND CLEAR READOUT CIRCUIT AND METHOD OFOPERATION OF AN IR SENSING CHARGE INJECTION DEVICEABSTRACT OF THE INVENTIONThe invention relates to a read and clear readoutcircuit and a method of operation of an IR sensingarray. The invention eliminates "readout circuit lag"which reduces transient response for an individualsensor, and reduces angular resolution of an array."Readout circuit lag" also emphasizes longer duration IRbackground causing unwanted saturation and restrictionof the dynamic range. Readout circuit lag arises fromthe capacitance of the sensor elements and the capaci-tance of the readout circuit at a node to which thesensor elements are periodically coupled for readout,the IR induced charge being partitioned between thesecapacitances, with that attributable to the sensorcapacitance not being injected, causing readout circuitlag. Elimination of such lag is achieved by followingeach readout step, with a clear or clear and skim stepthat removes charge to the clear level or to the skimlevel, precluding the lag earlier described.