A CMOS readout circuit scheme for uncooled micro-bolometer arrays has been proposed. The proposed circuit introduces dummy pixel structures for compensating self-heating effect and utilizes analog EEPROMs for correcting inter-pixel process variations. In the dummy pixel structures, two IR-shielded pixel columns with dummy bolometer resistors are located at each sice (left and right) of sensor array. The currents in the dummy resistors are distributed by current mirrors and interpolated by a resistive divider, providing a current ramp caused by self-heating effect. This structure reduces self-heating effect of the micro-bolometer array by a factor of ten. The remaining offsets are compensated pixel-by-pixel by analog EEPROMs. If no compensation is made, a large portion of the dynamic range (approximately 100 times of the maximum image signal range) must be reserved in the succeeding readout circuitry. The proposed structure can reduce the required dynamic range of 18-bit down to 10-bit and row-by-row integration circuitry can be effectively implemented as the result of reduced signal range.
