Reducing current leakage and improving shelf life time of battery-based-devices

• US 9,184,608 B2
• Filed: 09/14/2012
• Issued: 11/10/2015
• Est. Priority Date: 11/04/2008
• Status: Active Grant

• Current Assignee: Avago Technologies International Sales Pte Limited (Broadcom, Inc.)
• Original Assignee: Broadcom Corporation (Broadcom, Inc.)
• Inventors: Esnard, Domitille, Walley, John, Pandula, Louis
• Primary Examiner(s): Muralidar, Richard V
• Application Number:
  US13/618,501
• Publication Number:
  US 20130009698A1
• Time in Patent Office: 1,152 Days
• Field of Search: 320157-159, 320162-164, 361/92, 361/78, 361/79, 361/86, 361/88, 361/90
• US Class Current: 1/1
• CPC Class Codes: H02J 7/0031 using battery or load disconnect circuits H02J9/002 takes precedence
• CPC Class Codes: H02J 9/005 using a power saving mode for copiers G03G15/5004
• CPC Class Codes: Y02B 70/30 Systems integrating technologies related to power network operation and communication or information technologies for improving the carbon footprint of the management of residential or tertiary loads, i.e. smart grids as climate change mitigation technology in the buildings sector, including also the last stages of power distribution and the control, monitoring or operating management systems at local level
• CPC Class Codes: Y04S 20/20 End-user application control systems

Abstract

An electronic device includes a rechargeable battery, an electrical circuit, a battery safety circuit, and a power down mode circuit. The electrical circuit is configured to generate a power mode control signal. The power down mode circuit receives the power mode control signal. If the power mode control signal has a first value, the power down mode circuit is configured to force a voltage at a first port of the battery safety circuit to a voltage value that is less than an under voltage lock out (UVLO) threshold value of the battery safety circuit to transition the electronic device from a normal operating mode to a low current power down mode. The electronic device may further include a wake up mode circuit.

Claims

1. A method, comprising:

receiving an electronic device that includes a rechargeable battery and a battery safety circuit, wherein a first terminal of the rechargeable battery and a port of the battery safety circuit are coupled at a battery voltage signal from the rechargeable battery, and a second terminal of the rechargeable battery is coupled to a reference voltage signal; and

forcing a voltage at the port of the battery safety circuit to a voltage value relative to a threshold value of the battery safety circuit to transition the electronic device from a normal mode to a low current power-down mode.

2. The method of claim 1, further comprising:

coupling a charge voltage across the first and second terminals of the rechargeable battery to cause the electronic device to transition to the normal mode.

3. The method of claim 1, further comprising:

receiving a wireless communication signal at the electronic device that includes a shut down command; and

wherein said forcing comprises;

generating a power mode control signal in the electronic device to have a first value configured to force the voltage at the port of the battery safety circuit to the voltage value that is less than a UVLO threshold value upon receiving the shut down command.

4. The method of claim 1, wherein the battery safety circuit includes a first transistor, a second transistor, and a safety component that has a first port coupled to the battery voltage signal, a second port coupled to the reference voltage signal, a third port coupled to a first terminal of the first transistor, a fourth port coupled to a first terminal of the second transistor, and a fifth port coupled to the reference voltage signal between the second transistor and the electrical circuit, wherein the first transistor and second transistor are coupled in series in the reference voltage signal between the second terminal of the rechargeable battery and the electrical circuit.

5. The method of claim 4, wherein the electronic device includes a third transistor that has a first terminal that receives the power mode control signal, a second terminal coupled to the reference voltage signal between the second transistor and the electrical circuit, and a third terminal coupled to the battery voltage signal, wherein said forcing comprises:

generating a power mode control signal in the electronic device to have a first value configured to cause the third transistor to couple the port to the reference voltage signal to transition the electronic device from the normal mode to the low current power-down mode.

6. The method of claim 1, further comprising:

forcing the voltage at the port of the battery safety circuit to a second voltage value that is greater than a UVLO threshold value of the battery safety circuit to transition the electronic device from the low current power down mode to the normal operating mode.

7. The method of claim 4, further comprising:

bypassing at least the first transistor in the reference voltage signal to transition the electronic device from the low current power down mode to the normal operating mode.

8. The method of claim 7, wherein the electronic device includes a switch configured to bypass the first transistor in the reference voltage signal, wherein said bypassing comprises:

temporarily closing the switch to bypass the first transistor in the reference voltage signal to transition the electronic device from the low current power down mode to the normal operating mode.

9. An electronic device, comprising:

a battery safety circuit that has a first port coupled to a battery voltage signal at a first terminal of a rechargeable battery of the electronic device and a second port coupled to a reference voltage signal at a second terminal of the rechargeable battery; and

a power down mode circuit configured to receive a power mode control signal;

wherein if the power mode control signal has a first value, the power down mode circuit is configured to force a voltage at the first port to a voltage value relative to a threshold value of the battery safety circuit to transition the electronic device from a normal operating mode to a low current power down mode.

10. The electronic device of claim 9, wherein the battery safety circuit is configured to cause the electronic device to transition from the low current power down mode to the normal operating mode if a charge voltage is coupled across the first and second terminals of the rechargeable battery.

11. The electronic device of claim 9, further comprising:

an electrical circuit configured to generate the power mode control signal,

wherein the electrical circuit includes a receiver, wherein the electrical circuit is configured to generate the power mode control signal to have the first value if a shut down command is received by the receiver in a wireless communication signal.

12. The electronic device of claim 9, wherein the electrical circuit comprises:

an integrated circuit having a first port coupled to the battery voltage signal, a second port coupled to the reference voltage signal, and a third port that outputs the power mode control signal.

13. The electronic device of claim 9, wherein the battery safety circuit comprises:

a first resistor;

a second resistor;

a first transistor;

a second transistor; and

a safety component that includes the first port, the second port, a third port, a fourth port, and a fifth port, wherein the first port is coupled to the battery voltage signal through the first resistor, the second port is coupled to the reference voltage signal, the third port is coupled to a first terminal of the first transistor, the fourth port is coupled to a first terminal of the second transistor, and the fifth port is coupled to a first terminal of the second resistor;

wherein the first transistor and second transistor are coupled in series in the reference voltage signal between the second terminal of the rechargeable battery and the electrical circuit; and

wherein a second terminal of the second resistor is coupled to the reference voltage signal between the second transistor and the electrical circuit.

14. The electronic device of claim 13, wherein the power down mode circuit comprises:

a third transistor that has a first terminal that receives the power mode control signal, a second terminal coupled to the reference voltage signal between the second transistor and the electrical circuit, and a third terminal coupled to the first port of the safety component.

15. The electronic device of claim 14, wherein the power down mode circuit further comprises:

a third resistor;

a fourth resistor; and

a capacitor;

wherein the third terminal of the third transistor is coupled to the first port of the safety component through the third resistor;

wherein the first terminal of the third transistor is configured to receive the power mode control signal through the fourth resistor;

wherein the second terminal of the third transistor is coupled to the reference voltage signal between the second transistor and the electrical circuit; and

wherein the capacitor has a first terminal coupled to the first terminal of the third transistor and a second terminal coupled to the reference voltage signal between the second transistor and the electrical circuit.

16. The electronic device of claim 15, wherein the threshold value of the battery safety circuit is an under voltage lock out (UVLO) threshold value;

and

further comprising;

a wake up mode circuit configured to force the first port to a voltage value that is greater than the UVLO threshold value of the battery safety circuit to transition the electronic device from the low current power down mode to the normal operating mode.

17. The electronic device of claim 16, wherein the wake up mode circuit includes a switch having a first terminal coupled to the reference voltage signal between the second transistor and the electrical circuit, and a second terminal coupled to the second terminal of the rechargeable battery.

18. The electronic device of claim 16, wherein the wake up mode circuit includes a switch having a first terminal coupled to the reference voltage signal between the first transistor and the second transistor, and a second terminal coupled to the second terminal of the rechargeable battery.

19. The electronic device of claim 16, wherein the wake up mode circuit comprises:

a fourth transistor;

a fifth transistor;

a switch;

a second capacitor;

a fifth resistor;

a sixth resistor; and

a seventh resistor;

wherein the fourth transistor has a first terminal coupled to a first terminal of the fifth resistor, a second terminal coupled to a wake up signal generated by the electrical circuit, and a third terminal coupled to the reference voltage signal between the second transistor and the electrical circuit;

wherein the fifth resistor has a second terminal coupled to a first terminal of the switch;

wherein the switch has a second terminal coupled to the battery voltage signal, and a third terminal coupled to a first terminal of the sixth resistor;

wherein the second capacitor has a first terminal coupled to the first terminal of the switch, and a second terminal coupled to a second terminal of the sixth resistor and a first terminal of the seventh resistor;

wherein the fifth transistor has a first terminal coupled to a second terminal of the seventh resistor, a second terminal coupled to the reference voltage signal between the first transistor and the second transistor, and a third terminal coupled to the second terminal of the rechargeable battery; and

wherein the switch is operable to temporarily couple together the first and second terminals of the switch to enable the wake up mode circuit to force the battery voltage signal to a voltage value that is greater than the UVLO threshold value of the battery safety circuit, and to return to coupling together the first and third terminals of the switch.

20. An electronic device, comprising:

a battery safety circuit that has a first port coupled to a battery voltage signal of a rechargeable battery and a second port coupled to a reference voltage signal of the rechargeable battery; and

a receiver configured to wirelessly receive a shut down command;

wherein, in response to the received shut down command, a voltage at the first port is configured to be forced to a voltage value that is less than an under voltage lock out (UVLO) threshold value of the battery safety circuit to transition the electronic device from a normal operating mode to a low current power down mode.

21. The electronic device of claim 20, wherein the battery safety circuit is configured to cause the electronic device to transition from the low current power down mode to the normal operating mode if a charge voltage is coupled across the battery voltage signal and the reference voltage signal.

22. The electronic device of claim 21, further comprising:

a wake up mode circuit configured to force the first port to a voltage value that is greater than the UVLO threshold value of the battery safety circuit to transition the electronic device from the low current power down mode to the normal operating mode.

23. The electronic device of claim 20, further comprising:

an electrical circuit configured to generate a power mode control signal to have a first value when the shut down command is received by the receiver in a wireless communication signal; and

a power down mode circuit configured to receive the power mode control signal;

wherein if the power mode control signal has a first value, the power down mode circuit is configured to force the voltage at the first port to the voltage value that is less than the UVLO threshold value of the battery safety circuit to transition the electronic device from the normal operating mode to the low current power down mode.

24. The electronic device of claim 20, further comprising:

a transistor configured to be turned off to transition the electronic device from the normal operating mode to the low current power down mode.

25. The electronic device of claim 24, wherein the transistor is a metal oxide semiconductor field effect transistor (MOSFET).

26. A method in an electronic device, comprising:

wirelessly receiving a shut down command; and

in response to the received shut down command, forcing a voltage at a first port of a battery safety circuit of the electronic device that is coupled to a battery voltage signal of a rechargeable battery of the electronic device to a voltage value that is less than an under voltage lock out (UVLO) threshold value of the battery safety circuit to transition the electronic device from a normal operating mode to a low current power down mode, the battery safety circuit having a second port coupled to a reference voltage signal of the rechargeable battery.

27. The method of claim 26, further comprising:

receiving a charge voltage across the battery voltage signal and the reference voltage signal; and

transitioning the electronic device from the low current power down mode to the normal operating mode in response to receiving the charge voltage.

28. The method of claim 27, wherein said transitioning comprises:

forcing the first port to a voltage value that is greater than the UVLO threshold value of the battery safety circuit to transition the electronic device from the low current power down mode to the normal operating mode.

29. The method of claim 26, wherein said forcing comprises:

generating a power mode control signal to have a first value when the shut down command is received; and

forcing the voltage at the first port to the voltage value that is less than the UVLO threshold value of the battery safety circuit to transition the electronic device from the normal operating mode to the low current power down mode in response to the power mode control signal having the first value.

30. The method of claim 26, further comprising:

turning off a transistor to transition the electronic device from the normal operating mode to the low current power down mode.