Wake up device for a communications system

• US 5,790,946 A
• Filed: 04/19/1995
• Issued: 08/04/1998
• Est. Priority Date: 07/15/1993
• Status: Expired due to Term

• Current Assignee: Round Rock Research LLC
• Original Assignee: Micron Technology, Inc.
• Inventors: Rotzoll, Robert R.
• Primary Examiner(s): VO, NGUYEN THANH
• Application Number:
  US08/424,827
• Time in Patent Office: 1,203 Days
• Field of Search: 342/51, 342/44, 342/42, 342/50, 342/43, 340/825.54, 340/825.34, 340/825.59, 340/825.72, 340/825.71, 340/825.58, 340/825.36, 340/825.49, 340/573, 340/870.02, 455/38.1, 455/38.2, 455/38.3, 455/343, 455/54.1, 455/68, 455/70, 455/88, 455/67.1, 455/151.1, 455/151.2, 455/353, 455/352, 375/377, 370/84
• US Class Current: 455/343.1
• CPC Class Codes: H04W 52/0229 where the received signal is a wanted signal
• CPC Class Codes: H04W 52/028 switching on or off only a part of the equipment circuit blocks
• CPC Class Codes: H04W 52/0293 having a sub-controller with a low clock frequency switching on and off a main controller with a high clock frequency
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

A communication system includes a first communication device for receiving data and a wake up signal. Operation of the first communication device includes an active mode of operation and a sleep mode of operation for reducing power consumption. Further, the system includes a switch for switching the first communication device to and from sleep mode in response to receiving the wake up signal. The system also includes a second communication device for transmitting data to the first device during its active mode, and for transmitting the wake up signal to the first device during its sleep mode.

Claims

1. An electrical communications receiver which transitions from a sleep mode to an active mode upon receiving one or more specific electrical signals, the receiver consuming less electrical power in the sleep mode than in the active mode, comprising:

a) an antenna for receiving an RF signal;

b) a wake-up receiver circuit, coupled to the antenna, which operates when the communications receiver is in the sleep mode, including

i) an RP bandpass filter, connected to receive the RF signal from the antenna, for detecting when the RF signal has a predetermined carrier frequency,

ii) an envelope filter, connected to receive an RF signal from the RF bandpass filter, for demodulating the RF signal so as to output a baseband signal, and

iii) a data rate detector which detects when the baseband signal has a predetermined data rate; and

c) a switch for changing the communications receiver from the sleep mode to the active mode when both the RF bandpass filter detects said predetermined carrier frequency and the data rate detector detects said predetermined data rate.

2. An electrical communications system comprising:

(1) an electrical communications receiver having a sleep mode and an active mode, the receiver consuming less electrical power in the sleep mode than in the active mode, wherein the receiver includes

a) a receiver input for receiving an RF signal;

b) a wake-up receiver circuit, coupled to the receiver input, which operates when the communications receiver is in the sleep mode, including

i) an RF bandpass filter, connected to receive the RF signal from the receiver input, for detecting when the RF signal has a predetermined carrier frequency, and for outputting a bandpass filtered RF signal;

ii) an envelope filter, connected to receive the bandpass filtered RF signal from the RF bandpass filter, for demodulating the bandpass filtered RF signal so as to output a baseband signal, and

iii) a data rate detector which detects when the baseband signal has a predetermined data rate; and

c) a switch for changing the communications receiver from the sleep mode to the active mode when both the RF bandpass filter detects said predetermined carrier frequency and the data rate detector detects said predetermined data rate; and

(2) an electrical communications transmitter which transmits to the receiver, while the receiver is in its sleep mode, a signal having said predetermined carrier frequency and said predetermined wake-up data rate so as to put the receiver into its active mode, and which transmits data to the receiver while the receiver is in its active mode.

3. An electrical communications receiver, comprising:

a master receiver circuit having a sleep mode and an active mode such that the master receiver circuit continuously and uninterruptibly consumes substantially less power in the sleep mode than in the active mode;

a receiver input for receiving an RF signal;

a wake-up receiver circuit which operates when the communications receiver is in the sleep mode, including

an RF bandpass filter, connected to receive the RF signal from the receiver input, for detecting when the RF signal has a predetermined carrier frequency, and for outputting a bandpass filtered RF signal;

an envelope filter for demodulating the bandpass filtered RF signal from the RF bandpass filter so as to output a baseband signal, and

a data rate detector which detects when the baseband signal has a predetermined data rate; and

a switch for changing the master receiver circuit from the sleep mode to the active mode when both the RF bandpass filter detects said predetermined carrier frequency and the data rate detector detects said predetermined data rate.