Wake-up circuit for an electronic system and method therefor

• US 20020091955A1
• Filed: 01/05/2001
• Published: 07/11/2002
• Est. Priority Date: 01/05/2001
• Status: Active Grant

• Current Assignee: Temic Automotive of North America, Incorporated (Continental AG)
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Christopher, Gary L.
• Granted Patent: US 6,738,914 B2
• Time in Patent Office: Days
• US Class Current: 713/323
• CPC Class Codes: G06F 1/3203 Power management, i.e. event-based initiation of a power-saving mode

Abstract

A telematics communication system (100) for an automotive vehicle includes a telematics control unit (101) electrically coupled to a pushbutton switch (129) via a wire (133). The telematics control unit (101) includes a wake-up circuit (110) having a signal generator (201) and a signal detector (202). The signal generator (201) generates a digital pulse signal (139) having a predetermined amplitude (303) and a predetermined duration (304) for receipt by the pushbutton switch (129) via the wire (133). The signal detector (202), preferably implemented as a comparator (209), has a first bias circuit (207), preferably formed as a first resistor divider circuit, and a second bias circuit (208), preferably formed as a second resistor divider circuit. The signal detector (202) monitors the digital pulse signal (139) to determine whether the pushbutton switch (129) is actuated or is not actuated. The first bias circuit (207) biases the digital pulse signal (139) at a first predetermined direct current (DC) level (301). The second bias circuit (208) biases the digital pulse signal (139) at a second predetermined DC level (302) different from the first predetermined DC level (301). A DC difference (306) between the first predetermined DC level (301) and the second predetermined DC level (302) is less than the predetermined amplitude (303) of the digital pulse signal (139) having the first predetermined DC level or the second predetermined DC level that is not electrically coupled to the pushbutton switch. The signal detector (202) determines that a first difference (307) exists between the predetermined amplitude (303) of a first one of the digital pulse signal (139) biased at the first DC level (301) and the digital pulse signal (139) biased at the second DC level (302) and the predetermined amplitude (303) of a second different one of the digital pulse signal (139) biased at the first DC level (301) and the digital pulse signal (139) biased at the second DC level (302) responsive to the pushbutton switch (129) not being actuated. The signal detector (202) determines that a second difference (308) exists between the predetermined amplitude (303) of the first one of the digital pulse signal (139) biased at the first DC level (301) and the digital pulse signal (139) biased at the second DC level (302) and the predetermined amplitude (303) of a second different one of the digital pulse signal (139) biased at the first DC level (301) and the digital pulse signal (139) biased at the second DC level (302) responsive to the pushbutton switch (129) being actuated. The telematics communication system (100) maintains a low power consumption mode responsive to determining that the first difference (307) exists when the pushbutton switch (129) is not actuated, and enables a normal power consumption mode responsive to determining that the second difference (308) exists when the pushbutton switch (129) is actuated.

Claims

1. A wake-up circuit for an electronic system, comprising:

a signal generator having an output terminal and adapted to generate a digital pulse signal at the output terminal, wherein the digital pulse signal has a predetermined amplitude and a predetermined duration, wherein the output terminal of the signal generator is electrically coupled to a first terminal of a pushbutton switch having a second terminal electrically coupled to a ground potential;

a signal detector having a power supply terminal, a ground terminal, a first input terminal, a second input terminal and an output terminal, wherein the power supply terminal is adapted to receive power from a power supply, wherein the ground terminal is adapted to be electrically coupled to the ground potential, wherein each of the first input terminal and the second input terminal of the signal detector are adapted to receive the digital pulse signal, wherein one of the first input terminal and the second input terminal of the signal detector is electrically coupled to the first terminal of the pushbutton switch, and wherein the signal detector further comprises;

a first bias circuit electrically coupled to the first input terminal of the signal detector and adapted to bias the digital pulse signal at a first predetermined direct current (DC) level; and

a second bias circuit electrically coupled to the second input terminal of the signal detector and adapted to bias the digital pulse signal at a second predetermined DC level different from the first predetermined DC level,

wherein a DC difference between the first predetermined DC level and the second predetermined DC level is less than the predetermined amplitude of the digital pulse signal electrically coupled to the one of the first input terminal and the second input terminal of the signal detector that is not electrically coupled to the first terminal of the pushbutton switch,

wherein a first difference exists between the predetermined amplitude of a first one of the digital pulse signal received at the first terminal of the signal detector and the digital pulse signal received at the second terminal of the signal detector and the predetermined amplitude of a second different one of the digital pulse signal received at the first terminal of the signal detector and the digital pulse signal received at the second terminal of the signal detector responsive to the pushbutton switch not being actuated,

wherein a second difference exists between the predetermined amplitude the first one of the digital pulse signal received at the first terminal of the signal detector and the digital pulse signal received at the second terminal of the signal detector and the predetermined amplitude of the second different one of the digital pulse signal received at the first terminal of the signal detector and the digital pulse signal received at the second terminal of the signal detector responsive to the pushbutton switch being actuated, and

wherein the output terminal of the signal detector generates an output signal having a first level and a second level, different from the first level, wherein the first level is generated responsive to the first difference causing the electronic system to remain in a low power consumption mode, and wherein the second level is generated responsive to the second difference causing the electronic system to transition from the low power consumption mode to a normal power consumption mode.

2. A wake-up circuit according to claim 1 wherein the signal detector further comprises:

a comparator.

3. A wake-up circuit according to claim 1 wherein the first bias circuit further comprises:

a first resistor divider circuit having a first resistor and a second resistor, wherein each of the first resistor and the second resistor of the first bias circuit have a first terminal and a second terminal, wherein the first terminal of the first resistor is electrically coupled to the power supply, wherein the second terminal of the first resistor is electrically coupled to the first terminal of the second resistor and electrically coupled to the first input terminal of the signal detector, and wherein the second terminal of the second resistor is electrically coupled to a ground potential.

4. A wake-up circuit according to claim 1 wherein the second bias circuit further comprises:

a second resistor divider circuit having a third resistor and a fourth resistor, wherein each of the third resistor and the fourth resistor of the second bias circuit have a first terminal and a second terminal, wherein the first terminal of the third resistor is electrically coupled to the output terminal of the signal generator, wherein the second terminal of the third resistor is electrically coupled to the first terminal of the fourth resistor and electrically coupled to the second input terminal of the signal detector, and wherein the second terminal of the fourth resistor is electrically coupled to the ground potential.

5. A wake-up circuit according to claim 1 further comprising:

a capacitor having a first terminal and a second terminal, wherein the first terminal is electrically coupled to the ground potential, wherein the second terminal is electrically coupled to the output terminal of the signal detector, wherein the capacitor is adapted to increase an amount of time that the second level of the output signal is present to provide a lengthened second level of the output signal, and wherein the lengthened second level of the output signal permits the electronic system to transition from the low power consumption mode to the normal power consumption mode.

7. A wake-up circuit according to claim 1 further comprising:

a capacitor having a first terminal and a second terminal, wherein the first terminal is electrically coupled to the ground potential, wherein the second terminal is electrically coupled to the output terminal of the comparator, wherein the capacitor is adapted to increase an amount of time that the second level of the output signal is present to provide a lengthened second level of the output signal, and wherein the lengthened second level of the output signal permits the electronic system to transition from the low power consumption mode to the normal power consumption mode.

6. A wake-up circuit for an electronic system, comprising:

a signal generator having an output terminal and adapted to generate a digital pulse signal at the output terminal, wherein the digital pulse signal has a predetermined amplitude and a predetermined duration, wherein the output terminal of the signal generator is electrically coupled to a first terminal of a pushbutton switch having a second terminal electrically coupled to a ground potential;

a comparator having a power supply terminal, a ground terminal, a first input terminal, a second input terminal and an output terminal, wherein the power supply terminal is adapted to receive power from a power supply, wherein the ground terminal is adapted to be electrically coupled to the ground potential, wherein each of the first input terminal and the second input terminal of the comparator are adapted to receive the digital pulse signal, wherein one of the first input terminal and the second input terminal of the comparator is electrically coupled to the first terminal of the pushbutton switch, and wherein the comparator further comprises;

a first bias circuit electrically coupled to the first input terminal of the comparator and adapted to bias the digital pulse signal at a first predetermined direct current (DC) level, wherein the first bias circuit further includes;

a first resistor divider circuit having a first resistor and a second resistor, wherein each of the first resistor and the second resistor of the first bias circuit have a first terminal and a second terminal, wherein the first terminal of the first resistor is electrically coupled to the power supply, wherein the second terminal of the first resistor is electrically coupled to the first terminal of the second resistor and electrically coupled to the first input terminal of the comparator, and wherein the second terminal of the second resistor is electrically coupled to a ground potential; and

a second bias circuit electrically coupled to the second input terminal of the comparator and adapted to bias the digital pulse signal at a second predetermined DC level different from the first predetermined DC level, wherein the second bias circuit further includes;

a second resistor divider circuit having a third resistor and a fourth resistor, wherein each of the third resistor and the fourth resistor of the second bias circuit have a first terminal and a second terminal, wherein the first terminal of the third resistor is electrically coupled to the output terminal of the signal generator, wherein the second terminal of the third resistor is electrically coupled to the first terminal of the fourth resistor and electrically coupled to the second input terminal of the comparator, and wherein the second terminal of the fourth resistor is electrically coupled to the ground potential.

wherein a DC difference between the first predetermined DC level and the second predetermined DC level is less than the predetermined amplitude of the digital pulse signal electrically coupled to the one of the first input terminal and the second input terminal of the comparator that is not electrically coupled to the first terminal of the pushbutton switch,

wherein a first difference exists between the predetermined amplitude a first one of the digital pulse signal received at the first terminal of the comparator and the digital pulse signal received at the second terminal of the signal detector and the predetermined amplitude of a second different one of the digital pulse signal received at the first terminal of the signal detector and the digital pulse signal received at the second terminal of the comparator responsive to the pushbutton switch not being actuated,

wherein a second difference exists between the predetermined amplitude the first one of the digital pulse signal received at the first terminal of the comparator and the digital pulse signal received at the second terminal of the signal detector and the predetermined amplitude of the second different one of the digital pulse signal received at the first terminal of the signal detector and the digital pulse signal received at the second terminal of the comparator responsive to the pushbutton switch being actuated, and

wherein the output terminal of the comparator generates an output signal having a first level and a second level, different from the first level, wherein the first level is generated responsive to the first difference causing the electronic system to remain in a low power consumption mode, and wherein the second level is generated responsive to the second difference causing the electronic system to transition from the low power consumption mode to a normal power consumption mode.

8. A telematics control unit for a telematics communications system, comprising:

a standby mode power supply electrically coupled to a battery and adapted to operate in a low power consumption mode;

a normal mode power supply electrically coupled to the battery and adapted to operate in a normal power consumption mode; and

a wake-up circuit including;

a signal generator having an output terminal and adapted to generate a digital pulse signal at the output terminal, wherein the digital pulse signal has a predetermined amplitude and a predetermined duration, wherein the output terminal of the signal generator is electrically coupled to a first terminal of a pushbutton switch having a second terminal electrically coupled to a ground potential;

a signal detector having a power supply terminal, a ground terminal, a first input terminal, a second input terminal and an output terminal, wherein the power supply terminal is adapted to receive power from a power supply, wherein the ground terminal is adapted to be electrically coupled to the ground potential, wherein each of the first input terminal and the second input terminal of the signal detector are adapted to receive the digital pulse signal, wherein one of the first input terminal and the second input terminal of the signal detector is electrically coupled to the first terminal of the pushbutton switch, and wherein the signal detector further comprises;

a first bias circuit electrically coupled to the first input terminal of the signal detector and adapted to bias the digital pulse signal at a first predetermined direct current (DC) level; and

a second bias circuit electrically coupled to the second input terminal of the signal detector and adapted to bias the digital pulse signal at a second predetermined DC level different from the first predetermined DC level,

wherein a DC difference between the first predetermined DC level and the second predetermined DC level is less than the predetermined amplitude of the digital pulse signal electrically coupled to the one of the first input terminal and the second input terminal of the signal detector that is not electrically coupled to the first terminal of the pushbutton switch,

wherein a first difference exists between the predetermined amplitude a first one of the digital pulse signal received at the first terminal of the signal detector and the digital pulse signal received at the second terminal of the signal detector and the predetermined amplitude of a second different one of the digital pulse signal received at the first terminal of the signal detector and the digital pulse signal received at the second terminal of the signal detector responsive to the pushbutton switch not being actuated,

wherein a second difference exists between the predetermined amplitude the first one of the digital pulse signal received at the first terminal of the signal detector and the digital pulse signal received at the second terminal of the signal detector and the predetermined amplitude of the second different one of the digital pulse signal received at the first terminal of the signal detector and the digital pulse signal received at the second terminal of the signal detector responsive to the pushbutton switch being actuated, and

wherein the output terminal of the signal detector generates an output signal having a first level and a second level, different from the first level, wherein the first level is generated responsive to the first difference causing the electronic system to remain in a low power consumption mode, and wherein the second level is generated responsive to the second difference causing the telematics communication system to transition from the low power consumption mode to a normal power consumption mode.

9. A telematics control unit according to claim 8 wherein the signal detector further comprises:

a comparator.

10. A telematics control unit according to claim 8 wherein the first bias circuit in the wake-up circuit further comprises:

a first resistor divider circuit having a first resistor and a second resistor, wherein each of the first resistor and the second resistor of the first bias circuit have a first terminal and a second terminal, wherein the first terminal of the first resistor is electrically coupled to the power supply, wherein the second terminal of the first resistor is electrically coupled to the first terminal of the second resistor and electrically coupled to the first input terminal of the signal detector, and wherein the second terminal of the second resistor is electrically coupled to a ground potential.

11. A telematics control unit according to claim 8 wherein the second bias circuit in the wake-up circuit further comprises:

a second resistor divider circuit having a third resistor and a fourth resistor, wherein each of the third resistor and the fourth resistor of the second bias circuit have a first terminal and a second terminal, wherein the first terminal of the third resistor is electrically coupled to the output terminal of the signal generator, wherein the second terminal of the third resistor is electrically coupled to the first terminal of the fourth resistor and electrically coupled to the second input terminal of the signal detector, and wherein the second terminal of the fourth resistor is electrically coupled to the ground potential.

12. A telematics control unit according to claim 8 wherein the wake-up circuit further comprises:

a capacitor having a first terminal and a second terminal, wherein the first terminal is electrically coupled to the ground potential, wherein the second terminal is electrically coupled to the output terminal of the signal detector, wherein the capacitor is adapted to increase an amount of time that the second level of the output signal is present to provide a lengthened second level of the output signal, and wherein the lengthened second level of the output signal permits the telematics communication system to transition from the low power consumption mode to the normal power consumption mode.

14. A telematics communication system according to claim 13 wherein the signal detector in the wake-up circuit further comprises:

a comparator.

15. A telematics communication system according to claim 13 wherein the first bias circuit in the wake-up circuit further comprises:

a first resistor divider circuit having a first resistor and a second resistor, wherein each of the first resistor and the second resistor of the first bias circuit have a first terminal and a second terminal, wherein the first terminal of the first resistor is electrically coupled to the power supply, wherein the second terminal of the first resistor is electrically coupled to the first terminal of the second resistor and electrically coupled to the first input terminal of the signal detector, and wherein the second terminal of the second resistor is electrically coupled to a ground potential.

16. A telematics communication system according to claim 13 wherein the second bias circuit in the wake-up circuit further comprises:

a second resistor divider circuit having a third resistor and a fourth resistor, wherein each of the third resistor and the fourth resistor of the second bias circuit have a first terminal and a second terminal, wherein the first terminal of the third resistor is electrically coupled to the output terminal of the signal generator, wherein the second terminal of the third resistor is electrically coupled to the first terminal of the fourth resistor and electrically coupled to the second input terminal of the signal detector, and wherein the second terminal of the fourth resistor is electrically coupled to the ground potential.

17. A telematics communication system according to claim 13 wherein the wake-up circuit further comprises:

a capacitor having a first terminal and a second terminal, wherein the first terminal is electrically coupled to the ground potential, wherein the second terminal is electrically coupled to the output terminal of the signal detector, wherein the capacitor is adapted to increase an amount of time that the second level of the output signal is present to provide a lengthened second level of the output signal, and wherein the lengthened second level of the output signal permits the telematics communication system to transition from the low power consumption mode to the normal power consumption mode.

13. A telematics communication system comprising:

a telematics control unit including;

a standby mode power supply electrically coupled to a battery and adapted to operate in a low power consumption mode;

a normal mode power supply electrically coupled to the battery and adapted to operate in a normal power consumption mode;

a signal generator having an output terminal and adapted to generate a digital pulse signal at the output terminal, wherein the digital pulse signal has a predetermined amplitude and a predetermined duration;

a wire having a predetermined length and including a first end and a second end, wherein the end of the first wire is electrically coupled to the output terminal of the signal generator and adapted to receive and carry the digital pulse signal; and

a pushbutton switch assembly including;

a pushbutton switch having a first terminal and a second terminal, wherein the terminal of the first pushbutton switch is electrically coupled to a ground potential, and wherein the second terminal of the pushbutton switch is electrically coupled to the second end of the wire to receive the digital pulse signal from the output terminal of the signal generator; and

a resistor having a first terminal and a second terminal, wherein the first terminal of the resistor is electrically coupled to the ground potential, wherein the second terminal of the resistor is electrically coupled to the second terminal of the pushbutton switch;

wherein the telematics control unit further includes;

a wake-up circuit including;

a signal detector having a power supply terminal, a ground terminal, a first input terminal, a second input terminal and an output terminal, wherein the power supply terminal is adapted to receive power from a power supply, wherein the ground terminal is adapted to be electrically coupled to the ground potential, wherein each of the first input terminal and the second input terminal of the signal detector are adapted to receive the digital pulse signal, wherein one of the first input terminal and the second input terminal of the signal detector is electrically coupled to the first terminal of the pushbutton switch, and wherein the signal detector further comprises;

a first bias circuit electrically coupled to the first input terminal of the signal detector and adapted to bias the digital pulse signal at a first predetermined direct current (DC) level; and

a second bias circuit electrically coupled to the second input terminal of the signal detector and adapted to bias the digital pulse signal at a second predetermined DC level different from the first predetermined DC level,

wherein a DC difference between the first predetermined DC level and the second predetermined DC level is less than the predetermined amplitude of the digital pulse signal electrically coupled to the one of the first input terminal and the second input terminal of the signal detector that is not electrically coupled to the first terminal of the pushbutton switch,

wherein a first difference exists between the predetermined amplitude a first one of the digital pulse signal received at the first terminal of the signal detector and the digital pulse signal received at the second terminal of the signal detector and the predetermined amplitude of a second different one of the digital pulse signal received at the first terminal of the signal detector and the digital pulse signal received at the second terminal of the signal detector responsive to the pushbutton switch not being actuated,

wherein a second difference exists between the predetermined amplitude the first one of the digital pulse signal received at the first terminal of the signal detector and the digital pulse signal received at the second terminal of the signal detector and the predetermined amplitude of the second different one of the digital pulse signal received at the first terminal of the signal detector and the digital pulse signal received at the second terminal of the signal detector responsive to the pushbutton switch being actuated, and

wherein the output terminal of the signal detector generates an output signal having a first level and a second level, different from the first level, wherein the first level is generated responsive to the first difference causing the electronic system to remain in a low power consumption mode, and wherein the second level is generated responsive to the second difference causing the telematics communication system to transition from the low power consumption mode to a normal power consumption mode.

18. A method for waking up an electronic system from a low power consumption mode to a normal power consumption mode, the method comprising the steps of:

determining that the electronic system is in the low power consumption mode;

generating a digital pulse signal having a predetermined amplitude and a predetermined duration responsive to the step of determining that the electronic system is in the low power consumption mode;

receiving the digital pulse signal by a pushbutton switch;

monitoring the digital pulse signal to determine whether the pushbutton switch is actuated or is not actuated, further including the steps of;

biasing the digital pulse signal at a first predetermined direct current (DC) level;

biasing the digital pulse signal at a second predetermined DC level different from the first predetermined DC level, wherein a DC difference between the first predetermined DC level and the second predetermined DC level is less than the predetermined amplitude of the digital pulse signal having one of the first predetermined DC level and the second predetermined DC level that is not electrically coupled to the pushbutton switch;

determining that a first difference exists between the predetermined amplitude of a first one of the digital pulse signal biased at the first DC level and the digital pulse signal biased at the second DC level and the predetermined amplitude of a second different one of the digital pulse signal biased at the first DC level and the digital pulse signal biased at the second DC level responsive to the pushbutton switch not being actuated; and

determining that a second difference exists between the predetermined amplitude the first one of the digital pulse signal biased at the first DC level and the digital pulse signal biased at the second DC level and the predetermined amplitude of a second different one of the digital pulse signal biased at the first DC level and the digital pulse signal biased at the second DC level responsive to the pushbutton switch being actuated,

maintaining the low power consumption mode responsive to the step of determining that the first difference exists when the pushbutton switch is not actuated; and

enabling the normal power consumption mode responsive to the step of determining that the second difference exists when the pushbutton switch is actuated.