Methods and apparatus for a battery

1. A circuit adapted to control a battery, comprising:

a plurality of connection terminals, comprising:

a positive terminal;

a negative terminal; and

a control terminal;

a protection circuit connected between the battery and the negative terminal and configured to control electric discharge of the battery;

a control circuit connected to the protection circuit and comprising:

a first switch connected to the negative terminal; and

a second switch connected to the control terminal; and

a third switch connected between the control terminal and the negative terminal.

2. The circuit according to claim 1 , wherein the control circuit further comprises a resistor connected between the first switch and the negative terminal.

3. The circuit according to claim 1 , wherein the first switch selectively connects the negative terminal to a supply voltage.

4. The circuit according to claim 1 , wherein the second switch selectively connects the control terminal to a first supply voltage and a second supply voltage.

5. The circuit according to claim 1 , wherein the control circuit further comprises a resistor connected between the second switch and the control terminal.

6. The circuit according to claim 1 , wherein the third switch comprises a mechanical switch adapted for manual operation.

7. The circuit according to claim 1 , wherein the protection circuit comprises a first field-effect transistor and a second field effect transistor.

8. The circuit according to claim 1 , wherein the control circuit further comprises a control sub-circuit adapted to:

detect operation of the protection circuit; and

operate the first and second switches.

9. A method for controlling discharging of a battery in a battery pack and integrated within an electronic device, wherein the electronic device is free of a connection to an external power supply, comprising:

during a first stage, comprising starting conditions of:

an external switch in an OFF position;

a first switch disconnected from a first supply voltage; and

a second switch connected to the first supply voltage;

during a second stage:

turning ON the external switch to connect a negative terminal of the battery pack to a control terminal of battery pack for a first time period;

turning OFF a first transistor and a second transistor;

increasing a voltage potential of a negative terminal of the battery pack to be equal to a voltage potential of a positive terminal of the battery pack, wherein the negative terminal is connected to the first switch; and

inverting a polarity of a control terminal, wherein the control terminal is connected to the external switch and the second switch; and

entering a third stage, wherein the first and second transistors are OFF.

10. The method according to claim 9 , further comprising turning OFF the external switch at a time after the first time period has ended.

11. The method according to claim 9 , wherein increasing the voltage potential of the negative terminal to be equal to the voltage potential of the positive terminal comprises:

connecting the first internal switch to the first supply voltage; and

connecting the control terminal to a second supply voltage using a second internal switch.

12. The method according to claim 9 , further comprising, during a fourth stage:

turning ON the external switch for a second time period; and

increasing a voltage potential of the control terminal.

13. The method according to claim 12 , wherein the first time period is approximately two seconds and the second time period is approximately one second.

14. The method according to claim 12 , wherein the fourth stage further comprises:

disconnecting the first internal switch from the first supply voltage;

connecting the second internal switch to the second supply voltage;

turning ON the first and second transistors; and

turning OFF the external switch.

15. A system capable of connecting to a load, comprising:

a battery pack comprising:

a battery;

a first pack terminal;

a second pack terminal;

a third pack terminal; and

an integrated circuit connected to:

the battery;

the first pack terminal; and

the second pack terminal;

wherein the integrated circuit comprises:

a protection circuit comprising a transistor; and

a control circuit connected to the protection circuit and comprising:

 a first switch connected to the second pack terminal; and

 a second switch connected to the third pack terminal; and

a third switch connected between the second and third terminals and adapted to connect the load to the third terminal.

16. The system according to claim 15 , wherein the third switch comprises a mechanical switch adapted for manual operation.

17. The system according to claim 15 , wherein the control circuit further comprises a resistor connected between the first switch and the second pack terminal.

18. The system according to claim 15 , wherein the first switch selectively connects the third pack terminal to a positive-voltage supply.

19. The system according to claim 15 , wherein the second switch selectively connects the third pack terminal to a first supply voltage and a second supply voltage.

20. The system according to claim 15 , wherein the control circuit further comprises a resistor connected between the second switch and the third pack terminal.