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This paper describes the CMOS circuit design of two different kinds of fast infrared tracking systems with 4 x 1 CMOS thermopile array for fast detecting changes of infrared radiation due, for instance, to the moving of thermal object. The circuit is based on a charge-based measurement (CBM) design originating at the University of California, Berkeley, for measuring crosstalk on integrated circuits. The basic front-end sensor circuit comprises seven MOSFETs and integrates the voltage signal of thermopile sensor into a current source. We propose a winner-take-all (WTA) circuit and a new preliminary level of thermopile array image processing on chip which the sensor array fully is integrated by using a 2P4M 0.35 mum standard CMOS technology. A differential amplifier receives the outputs from two sensor circuits. The second architecture uses two low offset operational amplifiers (OPA) which compares two pairs output signals of thermopiles and indentify the largest one to give digital signal with high or low. Both of two systems can identify the position of targets very quickly and efficiently without complicated processing circuits and complex analog signals to digital signals circuits. For the two systems, To simulate and implement the infrared thermal sensor array in this paper, both systems show accurate and successful results, although they have different responses and resolution. So far the results have shown that integrated thermopile array with winner-take-all (WTA) and low offset operational amplifiers can approach a high level of development, reliability and easy for high accuracy infrared tracking applications.