Ambient light detection with digitized output

• US 20040195494A1
• Filed: 04/04/2003
• Published: 10/07/2004
• Est. Priority Date: 04/04/2003
• Status: Active Grant

• Current Assignee: Avago Technologies International Sales Pte Limited (Broadcom, Inc.)
• Original Assignee: Avago Technologies ECBU IP Singapore Pte Limited (Broadcom, Inc.)
• Inventors: Tan, Wee Sin, Kok, Boon How, Tan, Soon Lee
• Granted Patent: US 7,109,465 B2
• Time in Patent Office: Days
• US Class Current: 250/214.0AL
• CPC Class Codes: G09G 2320/0626 for control of overall brightness
• CPC Class Codes: G09G 2330/021 Power management, e.g. power saving
• CPC Class Codes: G09G 2360/144 the light being ambient light
• CPC Class Codes: G09G 3/3413 Details of control of colour illumination sources
• CPC Class Codes: H04M 1/22 Illumination; Arrangements for improving the visibility of characters on dials
• CPC Class Codes: H04M 2250/12 including a sensor for measuring a physical value, e.g. temperature or motion
• CPC Class Codes: H04W 52/027 by controlling a display operation or backlight unit
• CPC Class Codes: H05B 47/11 by determining the brightness or colour temperature of ambient light
• CPC Class Codes: Y02B 20/40 Control techniques providing energy savings, e.g. smart controller or presence detection
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

A system and method of ambient light detection with digitized output. A light sensitive device is coupled to electronic circuitry for receiving an output of the light sensitive device corresponding to a level of ambient light. The electronic circuitry compares the output to a threshold level. The threshold level corresponds to a desired level of light. The electronic circuitry for provides an output signal indicative of said desired level of light.

Claims

1. An ambient light detection device comprising:

a light sensitive device;

electronic circuitry coupled to said light sensitive device for receiving an output of said light sensitive device corresponding to a level of ambient light;

said electronic circuitry also for comparing said output to a threshold level, said threshold level corresponding to a desired level of light; and

said electronic circuitry for providing an output signal indicative of said desired level of light.

2. The ambient light detection device of claim 1 wherein said output signal comprises substantially two states.

3. The ambient light detection device of claim 1 wherein said light sensitive device comprises gallium arsenide phosphate.

4. The ambient light detection device of claim 1 wherein said ambient light detector is contained in a semiconductor package.

5. The ambient light detection device of claim 1 wherein said electronic circuitry further comprises a selectable gain control for determining amplification of said electrical signal.

6. The ambient light detection device of claim 5 wherein said selectable gain control is selected via digital input.

7. The ambient light detection device of claim 1 wherein said electronic circuitry further comprises a selectable low power quiescent mode.

20. The computer system of claim 1 wherein said electronic circuitry further comprises:

a selectable low power quiescent mode.

8. A method of determining presence of desirable ambient light comprising:

converting ambient light energy into an electrical signal;

comparing said electrical signal to a threshold level, said threshold level corresponding to a desired level of light; and

generating an output signal indicative of a result of said comparing.

9. The method of claim 8 wherein said output signal comprises substantially two states.

10. The method of claim 8 wherein said converting comprises:

utilizing gallium arsenide phosphate to convert said ambient light energy into said electrical signal.

11. The method of claim 8 further comprising:

selecting a gain level from a plurality of gain levels to amplify said electrical signal.

12. The method of claim 11 wherein said selecting comprises:

utilizing a digital input to select said gain level.

13. The method of claim 8 further comprising:

selecting a low power quiescent mode subsequent to said generating.

14. A battery powered computer system comprising:

a processor;

a light sensitive device disposed to receive ambient light falling upon said computer system;

electronic circuitry coupled to said light sensitive device for receiving an output of said light sensitive device corresponding to a level of said ambient light;

said electronic circuitry also for comparing said output to a threshold level, said threshold level corresponding to a desired level of light; and

said electronic circuitry coupled to said processor for providing an output signal indicative of said desired level of light.

15. The computer system of claim 14 wherein said output signal comprises substantially two states.

16. The computer system of claim 14 wherein said light sensitive device comprises:

utilizing gallium arsenide phosphate to convert said ambient light energy into said electrical signal.

17. The computer system of claim 14 wherein said ambient light detector is contained in a semiconductor package.

18. The computer system of claim 14 wherein said electronic circuitry further comprises:

a selectable gain control for determining amplification of said electrical signal.

19. The computer system of claim 18 wherein said selectable gain control is selected via digital input from said processor.