A 0.45–0.7V sub-microwatt CMOS image sensor for ultra-low power applications

This work describes a low voltage CMOS image sensor with a pulsewidth modulation read-out that is optimized for ultra-low power wireless applications. A new pixel structure targeted at low voltage operation is implemented in a 128×128 pixel test-chip in a 0.13µm technology. Measurements show that the image sensor is functional over the range Vdd=0.45V−0.7V. At Vdd=0.5V, the image sensor consumes 140nJ/frame at 8.5fps with a signal-to-noise ratio of 23.4dB at saturation.