Method and system to enhance differential dynamic range and signal/noise in CMOS range finding systems using differential sensors

For use with a differential pixel responsive to optical energy, a detection response of said differential pixel having a common mode component and a differential component, differential dynamic range enhancing circuitry to enhance effective dynamic range of said differential pixel, said differential dynamic range enhancing circuitry comprising:

• compensation circuitry adding a compensating offset to avoid a saturation magnitude differential signal level;
• and
• means for recording effective sum of said compensating offsets added to avoid said saturation magnitude;
• wherein effective value of said differential signal V(t) is proportional to V(OUT) ±K·(effective sum of said compensating offsets), where K is a constant.

A method to reduce effective noise in the pixel signal readout path of an array of differential pixels, the method including:

• (a) providing active gain for said differential pixels;
• (b) individually varying said active gain for at least one of said differential pixels to determine a maximum allowable gain for said differential pixel;
• (c) recording maximum allowable active gain determined for said differential pixel at step (b) and also recording a signal value for said differential pixel at said maximum allowable active gain;
• and
• (d) operating said differential pixel at said maximum allowable active gain recorded at step (c);
• wherein effect of noise in components downstream of said pixel is reduced and signal/noise ratio is enhanced.

For use with a differential pixel responsive to optical energy, said differential pixel having a detection response with a common mode component and a differential component, signal/noise enhancement circuitry to reduce effective noise in the pixel signal readout path of an array of said differential pixels, the signal/noise enhancement circuitry including:

• a gain programmable amplifier providing active gain for said differential pixel;
• means coupled to each said gain programmable amplifier for individually varying active gain for said differential pixel to determine a maximum allowable active gain for said differential pixel;
• for each said differential pixel, means for recording maximum allowable active gain for each of said differential pixels and for recording a signal value for each said differential pixel at said maximum allowable gain;
• and
• operating said differential pixel at said maximum allowable active gain;
• wherein effect of noise in components downstream of said differential pixels is reduced and signal/noise ratio is enhanced.