发明名称 |
AMBIENT LIGHT DETECTION |
摘要 |
Ambient light is detected by a photodiode circuit by measuring the time taken for a digital output of the photodiode circuit to change state in response to exposure of a photodiode of the photodiode circuit to that ambient light. A nominal time for state change is calculated based on photodiode circuit characteristics. Furthermore, an effective time for the photodiode circuit digital output to change state is determined in a calibration mode where the photodiode has been disconnected and a reference current is applied to the circuit. An illumination value of the detected ambient light is then calculated as a function of: the measured time, the effective time and the nominal time.
|
申请公布号 |
US2011141078(A1) |
申请公布日期 |
2011.06.16 |
申请号 |
US20100884986 |
申请日期 |
2010.09.17 |
申请人 |
STMICROELECTRONICS (RESEARCH & DEVELOPMENT) LIMITE;STMICROELECTRONICS SAS (MOROC);STMICROELECTRONICS (GRENOBLE 2) SAS |
发明人 |
RAYNOR JEFFREY;ZAKRITI ABDELOUAHID;VIVIEN STEPHANE;MELLOT PASCAL |
分类号 |
G06F3/038;G01D18/00;G01J1/44 |
主分类号 |
G06F3/038 |
代理机构 |
|
代理人 |
|
主权项 |
|
地址 |
|