Apparatus and method of recharging a battery using a USB device in a portable device

1. An apparatus for recharging a battery of a portable device comprising:

a voltage detector for detecting a voltage of the battery and for generating a signal for turning on a switch when the detected voltage is a voltage within a specific range;

a manipulator for receiving the signal from the voltage detector and for manipulating the switch;

a switch unit for turning the switch one of on and off based on the manipulator; and

a resistor for adjusting a quantity of an electric current to be supplied to the battery.

2. The apparatus of claim 1 , wherein, when the detected voltage of the battery is a preset maximum recharge voltage, the battery is recharged with a maximum recharge current of a universal serial bus (USB).

3. The apparatus of claim 2 , wherein the preset maximum recharge voltage is a voltage between an over-discharge protection voltage of the battery and a voltage when the portable device is automatically turned off.

4. The apparatus of claim 1 , wherein the manipulator comprises an AND gate for a logical value of “HIGH” when the detected voltage of the battery is the voltage within the specific range.

5. The apparatus of claim 1 , wherein the switch unit comprises an N-channel metal oxide semiconductor (NMOS) turned on to deliver a recharge current to the battery when a logical value of “HIGH” is input from the manipulator.

6. The apparatus of claim 1 , wherein the resistor is variably set according to a preset maximum recharge voltage.

7. The apparatus of claim 1 , wherein the voltage within the specific range is a voltage greater than an over-discharge protection voltage of the battery and less than a full recharge voltage of the battery.

8. The apparatus of claim 1 , further comprising:

a diode for preventing a recharge current from flowing back;

a USB cable for delivering a USB voltage and a current supplied from a USB power supply to the portable device; and

a data communication port for applying the USB voltage and the USB current delivered through the USB cable to the diode.

9. A method of recharging a battery of a portable device, comprising:

detecting a voltage of the battery by a recharge unit of the portable device; and

recharging the battery with a maximum recharge current when the detected voltage of the battery is a preset maximum recharge voltage.

10. The method of claim 9 , wherein the recharging of the battery comprises:

supplying a voltage and a current from a USB power supply to the data communication port; and

recharging the battery, by a recharge circuit, with a recharge current when a voltage of the battery is a voltage within a specific range.

11. The method of claim 10 , wherein the recharging of the battery with the recharge current comprises:

detecting the voltage of the battery within the specific range by a voltage detector;

receiving the voltage through the data communication port; and

turning a switch on to deliver the recharge current to the battery when the voltage of the battery is the voltage within the specific range.

12. The method of claim 11 , wherein the voltage within the specific range is a voltage greater than a preset maximum recharge voltage of the battery and lower than a full recharge voltage.

13. The method of claim 12 , wherein the preset maximum recharge voltage is a voltage between an over-discharge protection voltage of the battery and a voltage when the portable device is automatically turned off.

14. The method of claim 9 , further comprising:

detecting, by a recharge unit of the portable device, a voltage exceeding the preset maximum recharge voltage of the battery and lower than a full recharge voltage; and

recharging, by the recharge unit, the battery with a recharge current based on the detected voltage of the battery when the detected voltage is a voltage exceeding the preset maximum recharge voltage of the battery and lower than a full recharge voltage.

15. The method of claim 14 , wherein the recharge current is substantially the same as the maximum recharge current of a USB at the preset maximum recharge voltage, and decreases at a preset ratio as the voltage of the battery increases.

16. The method of claim 15 , wherein the preset maximum recharge voltage is a voltage when the battery is discharged and the portable device is automatically turned off.

17. The method of claim 15 , wherein the preset maximum recharge voltage is determined between an over-discharge protection voltage of the battery and a voltage when the portable device is automatically turned off.

18. A method of recharging a battery of a portable device, comprising:

determining, by a recharge unit of the portable device, a voltage of the battery;

recharging, by the recharge unit, the battery with a maximum recharge current when the voltage of the battery is a preset maximum recharge voltage as a result of the determination; and

recharging, by the recharge unit, the battery with a recharge current based on the voltage of the battery when the voltage of the battery exceeds the preset maximum recharge voltage and is lower than a full recharge voltage as a result of the determination.

19. The method of claim 18 , wherein the preset maximum recharge voltage is a voltage between an over-discharge protection voltage of the battery and a voltage when the portable device is automatically turned off.

20. The method of claim 18 , wherein the recharge current is substantially the same as the maximum recharge current at the preset maximum recharge voltage, and decreases at a preset ratio as the voltage of the battery increases.