Boosted readout for CMOS APS pixels

In order to reduce power consumption and improve low-voltage operation capability of standard three transistor (3T) CMOS active pixel sensor (APS), new pixel readout is proposed utilizing supply boosting technique (SBT). Pixel supply voltage as well as reset and select signals for APS pixel are boosted to achieve wider and extended linear operating range in a standard CMOS process with high-Vt transistors. Reset and supply boosting was used for extending dynamic range of the pixel source follower (PSF) amplifier, while the select signal boosting was utilized for linearizing transfer characteristics of the PSF. Extension of PSF dynamic range using reset, select, and supply boosting (RSSB) resulted in operation of 3T APS pixel at 1.2V supply with 150mV dynamic range even though the threshold of the NMOS device was 0.8V. Proposed method does not degrade the device reliability margins and use single supply input.