A CMOS Image Sensor(CIS) mounted on mobile security appliances always needs a low power consumption because of the battery life cycle. In this paper, we propose novel power reduction techniques such as a low power single slope A/D converter, a configurable pixel resolution, and so on. Based on 0.11um CMOS process, the chip satisfies QVGA resolution(320×240) whose pitch is 5.0um and whose structure is 4-Tr active pixel sensor. The ADC in the middle of CIS has a 8-bit resolution, the operating speed of CIS is 50 frame/s, and the power consumption is 10mW at 3.3V(Analog)/1.5V(Digital) power supply. When a configurable pixel resolution is applied, the power consumption is 3.3mW at a 1/4 low resolution mode.