Method of saving power in communication devices

• US 20030236077A1
• Filed: 04/07/2003
• Published: 12/25/2003
• Est. Priority Date: 04/10/2002
• Status: Abandoned Application

• Current Assignee: Zarlink Semiconductor Inc. (Microchip Technology Incorporated)
• Original Assignee: Zarlink Semiconductor Inc. (Microchip Technology Incorporated)
• Inventors: Sivard, Ake
• Application Number:
  US10/408,274
• Publication Number:
  US 20030236077A1
• Time in Patent Office: Days
• US Class Current: 455/127.1
• CPC Class Codes: H04W 52/0229 where the received signal is a wanted signal
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

An electronic device with a power saving circuit incorporates a radio frequency receiver with low power consumption and including a frequency down converter. A functional device, which may be a high power radio receiver, is normally turned off during a period of inactivity. An analyzer detects a predetermined identification code in a received radio frequency signal and outputs a signal to turn on the functional device.

Claims

1. A power saving circuit for activating an electronic device with a sleep mode and a wake-up mode, comprising:

a radio frequency receiver with low power consumption including;

a down-converter for reducing the frequency of a received signal;

a decoder for decoding a received radio frequency signal; and

an analyzer for detecting a predetermined identification code in said received radio frequency signal and activating said electronic device in response to detection of said predetermined identification code.

2. A power saving circuit as claimed in claim 1, wherein said electronic device is a high power radio frequency receiver for receiving a communication signal.

3. A power saving circuit as claimed in claim 2, wherein said low power radio frequency receiver forms part of said high power radio frequency receiver.

4. A power saving circuit as claimed in claim 2, wherein said low power radio frequency receiver is separate from said high power radio frequency receiver.

5. A power saving circuit as claimed in claim 1, wherein said identification code includes an address of said electronic device.

6. A power saving circuit as claimed in claim 2, wherein said low power receiver operates at a different frequency from said high power radio frequency receiver.

7. A power saving circuit as claimed in claim 1, wherein said identification code is modulated using frequency shift keying.

8. A power saving circuit as claimed in claim 1, wherein said identification code is modulated using amplitude shift keying.

9. A power saving circuit as claimed in claim 1, wherein said receiver with low power consumption further includes a band pass filter and a comparator acting as said decoder.

10. A power saving circuit as claimed in claim 1, further comprising a sensor and a converter for producing DC power from said received radio frequency signal to power said radio frequency receiver with low power consumption.

11. A power saving circuit as claimed in claim 10, wherein said sensor comprises a pick-up coil.

12. A power saving circuit as claimed in claim 11, further comprising a rectifier for rectifying said received signal and feeding it to a low pass filter having a long time constant for generating a DC voltage therefrom and to a low pass filter having a shorter time constant to down-convert said received signal.

13. A power saving circuit as in claim 2, where said electronic device is a receiver of infrared or optical signals.

14. A method of saving power in a remote electronic device having a sleep mode and a wake-up mode, comprising:

transmitting a radio frequency signal with an identification code;

receiving said radio frequency signal at said remote device in the sleep mode;

down-converting said received radio frequency signal;

decoding said down-converted received radio frequency signal; and

in response to detection of a predetermined identification code in said received radio frequency signal, switching said remote electronic device to the wake-up mode.

15. A method as claimed in claim 14, wherein said electronic device includes a high power radio frequency receiver that is activated in response to detection of said predetermined identification code.

16. A method as claimed in claim 14, wherein said identification code includes an address of said device.

17. A method as claimed in claim 15, wherein said signal is transmitted at a frequency different from a frequency of operation of said high power receiver.

18. A method as claimed in claim 14, wherein said identification code is modulated using frequency shift keying.

19. A method as claimed in claim 14, wherein said identification code is modulated using amplitude shift keying.

20. A method as claimed in claim 14, wherein power for receiving said signal in said sleep mode is derived from said received radio frequency signal.

21. A method as claimed in claim 20, wherein said received radio frequency signal is rectified to produce said power.

22. A method as claimed in claim 15, wherein said signal is received in a low power receiver separate from said high power receiver.

23. A method as claimed in claim 15, wherein said signal is received in a low power receiver forming part of said high power receiver.