Patent ID: 8222591

Claim:
A proximity sensor, comprising: a driver adapted to selectively drive a light source; a photodiode (PD) adapted to produce a photodiode current signal (Idiode) indicative of an intensity of light detected by the PD, where the light detected by the PD can include ambient light and/or light transmitted by the light source that was reflected off an object proximate the PD; an analog-to-digital converter (ADC) with analog-to-digital-to-analog (ADA) feedback; and a controller adapted to control the driver and the ADC with ADA feedback; wherein a digital output of the ADC with ADA feedback is indicative of a proximity of an object to the PD with at least a majority of the ambient light detected by the PD rejected; wherein the controller and the ADC with the ADA feedback are configured to (a) during a first period of time when the light source is not driven to transmit light, produce M-bits of data indicative of an intensity of ambient light detected by the PD; (b) during a further period of time, at least a portion of which the light source is driven to transmit light, (b.1) convert the M-bits of data to a first analog signal indicative of the intensity of the ambient light detected by the PD during the first period of time (b.2) receive a second analog signal indicative of an intensity of light detected by the PD during the further period of time; (b.3) subtract the first analog signal from the second analog signal to produce a third analog signal indicative of a proximity of an object to the PD with at least a majority of the ambient light detected by the PD rejected; and (b.4) convert the third analog signal to N-bits of data, which is the digital output of the ADC with ADA feedback.