Charging current control method and charging system

• US 8,710,803 B2
• Filed: 11/04/2011
• Issued: 04/29/2014
• Est. Priority Date: 09/23/2011
• Status: Active Grant

• Current Assignee: Askey Computer Corporation (ASUSTek Computer, Inc.), Askey Technology Jiangsu Ltd (ASUSTek Computer, Inc.)
• Original Assignee: Askey Computer Corporation (ASUSTek Computer, Inc.), Askey Technology Jiangsu Ltd (ASUSTek Computer, Inc.)
• Inventors: Hsieh, Ching-Feng, Huang, Jui-Chuan
• Primary Examiner(s): WILLIAMS, ARUN C
• Application Number:
  US13/289,124
• Publication Number:
  US 20130076312A1
• Time in Patent Office: 907 Days
• Field of Search: 320/145
• US Class Current: 320/145
• CPC Class Codes: H02J 2207/20 Charging or discharging characterised by the power electronics converter
• CPC Class Codes: H02J 7/007194 of the battery
• CPC Class Codes: H02J 7/04 Regulation of charging current or voltage

Abstract

A charging method and a charging system are introduced for controlling a charging current by a PWM method. A charging IC is controlled to supply the charging current to a battery, and a control unit is used to generate a PWM signal with a duty cycle, and a filter unit is used to convert the PWM signal into a voltage signal to be supplied to the charging IC, and the control unit determines whether a current of a battery detected by the battery status detection unit reaches a regular current, so that a PWM signal with a duty cycle greater than the previous duty cycle by a default increased cycle is provided if the detected current has not reached the regular current. Thus, the feature of the PWM signal is used to set the charging current according to the capacity of the battery automatically.

Claims

1. A charging current control method, for controlling a charging IC to supply a corresponding charging current to a battery, comprising the steps of:

(A) providing a PWM signal with a duty cycle;

(B) converting the PWM signal with the duty cycle into a corresponding voltage and supplying the voltage to the charging IC, so that the charging IC supplies the corresponding charging current to the battery according to the voltage;

(C) obtaining a detected current and a regular current of the battery;

(D) determining whether the detected current of the battery has reached the regular current;

if yes, ending the adjustment of the charging current, or else entering into Step (E); and

(E) returning to the Step (A), and providing a PWM signal with a duty cycle higher a default increased cycle in the Step (A).

2. The control method of claim 1, further comprising the steps of:

(a) obtaining a detected temperature of the battery;

(b) determining whether the detected temperature has reached the first threshold;

if no, then returning to the Step (a), or else entering into Step (c);

(c) reducing the current duty cycle of the PWM signal by a default decreased cycle;

(d) obtaining the current detected temperature of the battery, and determining whether the detected temperature has reached the first threshold and is greater than a predetermined temperature of the first threshold;

if no, then returning to the Step (a), or else entering into the Step (e); and

(e) reducing the current duty cycle of the PWM signal by the default decreased cycle for every increase of the predetermined temperature compared with the first threshold, until the current duty cycle of the PWM signal drops to 0%.

3. The control method of claim 1, wherein the PWM signal with the duty cycle is processed by an integration to produce the corresponding voltage by using a RC filter circuit in the Step (B).

4. The control method of claim 1, further providing a PWM signal with a duty cycle of 10% in the Step (A).

5. The control method of claim 2, wherein the default decreased cycle is set to 20% of the current duty cycle, and the predetermined temperature is set to 1°

C.

6. The control method of claim 2, wherein the current duty cycle of the PWM signal drops to 0% when the detected temperature rises to the second threshold in Step (e).

7. The control method of claim 6, wherein the first threshold is set to 40°

C., and the second threshold is set to 45°

C.

8. A charging system, for using a charging IC to supply a corresponding charging current to a battery, comprising:

a battery status detection unit, coupled to the battery, for producing a detected current and a regular current of the battery;

a control unit, coupled to the battery status detection unit, for receiving the detected current and the regular current, generating a PWN signal with a duty cycle, and providing a PWM signal with a duty cycle greater than the previous duty cycle by a default increased cycle, when the control unit determines that the detected current of the battery has not reached the regular current; and

a filter unit, coupled to the charging IC and the control unit, for receiving the PWM signal generated by the control unit, converting the PWM signal into a corresponding a voltage, and supplying the voltage to the charging IC.

9. The charging system of claim 8, wherein the filter unit comprises:

a resistor, having a first terminal coupled to the control unit, and a second terminal coupled to the charging IC; and

a capacitor, coupled between the second terminal and a ground.

10. The charging system of claim 8, wherein the battery status detection unit is provided for obtaining a detected temperature of the battery;

the control unit determines whether the detected temperature has reached a first threshold, and reduces the current duty cycle of the PWM signal by a default decreased cycle when the detected temperature has reached the first threshold.

11. The charging system of claim 10, wherein the control unit is provided for reducing the current duty cycle of the PWM signal by the default decreased cycle for every increase of a predetermined temperature, when the detected temperature is determined to be greater than the first threshold.

12. The charging system of claim 11, wherein the control unit is provided for reducing the current duty cycle of the PWM signal to 0%, when the detected temperature rises to the second threshold.