Title:
ILLUMINANCE SENSOR AND ELECTRONIC DEVICE
Document Type and Number:
WIPO Patent Application WO/2007/135947
Kind Code:
A1
Abstract:
An illuminance sensor (1) mounted on an electronic device includes a plurality of amplifiers (11, 12). The amplifiers (11, 12) change their amplification ratios by receiving signals (S1, S2) corresponding to the respective amplifiers (11, 12). By combining the amplification ratios (such as Œ10 or Œ1) of the amplifiers (11,12), current outputted from a photodiode (10) is amplified with amplification ratio of, for example, Œ1, Œ10, or Œ100. Thus, an appropriate amplification ratio can be selected in accordance with the current outputted from the photodiode (10). Moreover, it is possible to control voltage (VOUT) outputted from the illuminance sensor (1) to be within the maximum range of input voltage of an AD converter (21).
Inventors:
UEDAIRA YOSHITSUGU (JP)
FUJINO JUNJI (JP)
FUJINO JUNJI (JP)
Application Number:
PCT/JP2007/060128
Publication Date:
November 29, 2007
Filing Date:
May 17, 2007
Export Citation:
Assignee:
ROHM CO LTD (JP)
UEDAIRA YOSHITSUGU (JP)
FUJINO JUNJI (JP)
UEDAIRA YOSHITSUGU (JP)
FUJINO JUNJI (JP)
International Classes:
G01J1/42; G01J1/02; G01J1/44; H04M1/00; H05B37/02
Foreign References:
| JP2002250659A | 2002-09-06 | |||
| JPH06224647A | 1994-08-12 | |||
| JPH06169294A | 1994-06-14 | |||
| JP2005083755A | 2005-03-31 | |||
| JP2006058058A | 2006-03-02 | |||
| JP2006277967A | 2006-10-12 |
Attorney, Agent or Firm:
FUKAMI, Hisao et al. (Nakanoshima Central Tower 22nd Floor,2-7, Nakanoshima 2-chom, Osaka-shi Osaka 05, JP)
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