Standard linear CMOS image sensor insensitive to temperature variations

Abstract

CMOS vision sensors, as all electronic systems, are very sensitive to temperature variation. Mainly, this sensitivity limits their DC electrical behaviour. So far, no elegant integrated solution of this shortcoming has been proposed. In this paper, we introduce a compensation technique within the circuit in order to decrease power consumption and response time. To overcome this defect caused by temperature, we propose a temperature compensation method based on drain current I DS characteristics with temperature. Among these characteristics we have a Zero Temperature Coefficient (ZTC) which will be used to compensate temperature variation. With this method, we reduce 98% of the influence of temperature on the output value of a standard CMOS image sensor, and obtain good temperature stability (1mV) in the temperature ranges from −30°C to 125°C. The proposed temperature compensation method is described in details in this paper. Finally, we present simulations results, along with advantages and disadvantages of our compensation method.