US Patent:
20090121889, May 14, 2009
Inventors:
Xijian Lin - Fremont CA, US
Zhong Li - Campbell CA, US
Wendy Ng - San Jose CA, US
Phillip J. Benzel - Pleasanton CA, US
Oleg Steciw - Los Altos CA, US
Assignee:
INTERSIL AMERICAS INC. - Milpitas CA
International Classification:
G08B 21/00
Abstract:
In an embodiment, a proximity sensor includes a driver, a photo-diode (PD) and an analog-to-digital converter (ADC). The proximity sensor can also include a controller to control the driver. The driver selectively drives a light source, e.g., an infrared (IR) light emitting diode (LED). The PD, which produces a current signal indicative of the intensity of light detected by the PD, is capable of detecting both ambient light and light produced by the light source that is reflected off an object. The ADC receives one or more portion of the current signal produced by the PD. The ADC produces one or more digital output that can be used to estimate the proximity of an object to the PD in a manner that compensates for ambient light detected by the PD and transient changes to the detected ambient light.