Wake-up controller and a method therefor for power control over peripheral circuitry based upon slots of a data field

• US 20080055099A1
• Filed: 08/28/2007
• Published: 03/06/2008
• Est. Priority Date: 08/31/2006
• Status: Active Grant

• Current Assignee: LAPIS Semiconductor Co., Ltd. (ROHM Co., Ltd.)
• Original Assignee: OKI Electric Industry Company Limited
• Inventors: Wada, Hideaki, Tabata, Hirosuke
• Granted Patent: US 7,876,207 B2
• Time in Patent Office: Days
• US Class Current: 340/658
• 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

In a wake-up control device for waking up a peripheral circuit such as a transmitter/receiver in a radio communication device, during a standby time in which an RF unit and a processing unit are powered off by a switch, an RF signal is received to produce a detection signal by a detector. The detection signal is transferred to the wake-up controller to be sampled. The header and other fields are detected and counted. A control signal is in turn produced by the respective counts to turn on the switch.

Claims

1. A wake-up control device comprising:

a detector for receiving a predetermined frequency signal to produce a detection signal;

a controller operative in response to the detection signal for producing a control signal performing a wake-up control; and

a switch circuit operative in response to said controller for using at least the predetermined frequency signal to power on or off a transmitter/receiver transmitting or receiving information;

said controller sampling the detection signal to turn on or off said switch circuit based on a number of slots in a header field and a data field forming a frame of the predetermined frequency signal.

2. The device in accordance with claim 1, further comprising:

a sampling circuit operative in response to the header field detected for producing a first count-up signal, and operative in response to a filed detected other than the header field for producing a second count-up signal;

a first detection counter for counting the first count-up signal;

a second detection counter for counting the second count-up signal; and

a decision circuit operative in response to a count in said first and second detection counters for determining whether said switch circuit is to be turned on or off.

3. The device in accordance with claim 2, wherein said controller comprises a shift register for shifting the detection signal by one stage and two stages to produce a first and a second detection signal, and for producing a logical AND of the first and second detection signals,

said sampling circuit using the logical AND to produce the first and second count-up signals.

4. The device in accordance with claim 2, wherein said decision circuit comprises a timer for measuring time to perform a pattern check more than once for the detection signal, said decision circuit producing a control signal controlling to turn on said switch circuit after performing the pattern check more than once.

5. The device in accordance with claim 2, wherein said decision circuit comprises a pattern check counter for checking a periodical transition of the detection signal between a low level and a high level, said decision circuit producing a control signal controlling to turn on said switch circuit based on a frame pattern other than a pattern changing in a short period.

6. The device in accordance with claim 1, wherein said switch circuit is connected to a processor for processing a radio communication service, said switch circuit being responsive to the control signal to supply said processor with an electric power.

7. The device in accordance with claim 1, wherein the predetermined frequency signal is of a radio frequency.

8. The device in accordance with claim 1, wherein said detector detects a radio frequency signal of Dedicated Short Range Communications (DSRC), said transmitter/receiver transmitting or receiving the radio frequency signal of DSRC.

9. The device in accordance with claim 1, wherein said wake-up controller is powered by a battery.

10. A method for wake-up control comprising the steps of:

receiving a predetermined frequency signal to produce a detection signal;

producing a control signal to perform a wake-up control in response to the detection signal;

using at least the predetermined frequency signal in response to the control signal to power on or off a transmitter/receiver transmitting or receiving information; and

sampling the detection signal to power on or off the transmitter/receiver based on a number of slots of a header field and a data field forming a frame of the predetermined frequency signal.

11. The method in accordance with claim 10, further comprising the steps of:

detecting the header field to produce a first count-up signal, and detecting a field other than the header field to produce a second count-up signal;

counting the first and second count-up signals; and

powering on or off the transmitter/receiver based on a count obtained in said step of counting.

12. The method in accordance with claim 10, further comprising the steps of:

shifting the detection signal by one stage and two stages to produce a first and a second detection signal;

producing a logical AND of the first and second detection signals; and

using the logical AND to produce the first and second count-up signals.

13. The method in accordance with claim 12, further comprising the steps of:

measuring time to perform a pattern check more than once for the detection signal; and

performing the pattern check more than once and thereafter powering on or off the transmitter/receiver.

14. The method in accordance with claim 12, further comprising the steps of:

performing pattern check of checking a periodical transition of the detection signal between a low level and a high level to thereby exclude a pattern changing in a short period from a frame pattern; and

powering on or off the transmitter/receiver based on a frame pattern excluding the pattern changing in the short period.