APPARATUS FOR PREVENTING CAPACITOR CHARGER FROM OVERCHARGING AND METHOD THEREOF

• US 20070164705A1
• Filed: 01/13/2006
• Published: 07/19/2007
• Est. Priority Date: 01/13/2006
• Status: Active Grant

• Current Assignee: Leadtrend Technology Corporation
• Original Assignee: Leadtrend Technology Corporation
• Inventors: Chu, Yi-Shan, Chuang, Ming-Nan
• Granted Patent: US 7,446,506 B2
• Time in Patent Office: Days
• US Class Current: 320/128
• CPC Class Codes: H01G 11/14 Arrangements or processes for adjusting or protecting hybrid or EDL capacitors emergency protective circuit arrangements specially adapted for capacitors, and effecting automatic switching in the event of an undesired change from normal working conditions H02H7/16; emergency protective circuit arrangements for limiting excess current or voltages without disconnection H02H9/00
• CPC Class Codes: H02H 7/16 for capacitors for synchronous capacitors H02H7/06
• CPC Class Codes: H02J 50/05 using capacitive coupling
• CPC Class Codes: H02J 50/80 involving the exchange of data, concerning supply or distribution of electric power, between transmitting devices and receiving devices
• CPC Class Codes: H02J 7/0031 using battery or load disconnect circuits H02J9/002 takes precedence
• CPC Class Codes: Y02E 60/13 Energy storage using capacitors

Abstract

The present invention provides an apparatus for controlling a capacitor charging circuit and a method thereof. The apparatus includes a first comparator, a second comparator, and a controller. The first comparator, which is coupled to the charging circuit, receives a voltage level and compares the voltage level with a reference voltage level to generate a first indication signal. The voltage level corresponds to an output voltage of the charging circuit. The second comparator receives a control value and compares the control value with a threshold value to generate a second indication signal. The controller, which is coupled to the charging circuit, the first comparator and the second comparator, generates a control signal according to the first indication signal and the second indication signal to turn the charging circuit on and off, and further generates the control value according to the control signal.

Claims

1. An apparatus for controlling a charging circuit, the apparatus comprising:

a first comparator, coupled to the charging circuit, for receiving a voltage level and comparing the voltage level with a reference voltage level to generate a first indication signal, wherein the voltage level corresponds to an output voltage of the charging circuit;

a second comparator, for receiving a control value and comparing the control value with a threshold value to generate a second indication signal; and

a controller, coupled to the charging circuit, the first comparator, and the second comparator, the controller for generating a control signal according to the first indication signal and the second indication signal for turning the charging circuit on and off, and further for generating the control value according to the control signal.

2. The apparatus of claim 1, wherein the controller monitors a duty cycle of the control signal to generate the control value.

3. The apparatus of claim 2, wherein the reference voltage level is set according to the output voltage of the charging circuit, the charging circuit controlled by the control signal having the duty cycle equal to the threshold value.

4. The apparatus of claim 1, wherein the first and second comparators are implemented by operational amplifiers.

5. The apparatus of claim 1, wherein the controller generates the control signal to disable the charging circuit when the first indication signal indicates that the voltage level has not reached the reference voltage level and the second indication signal indicates that the control value has reached the threshold value.

6. The apparatus of claim 1, wherein the charging circuit has a Flyback configuration.

7. A method for controlling a charging circuit, the method comprising:

comparing a voltage level with a reference voltage level to generate a first indication signal, wherein the voltage level corresponds to an output voltage of the charging circuit;

comparing a control value with a threshold value to generate a second indication signal;

generating a control signal according to the first indication signal and the second indication signal, the control signal for turning the charging circuit on and off; and

generating the control value according to the control signal.

8. The method of claim 7, wherein the control value is generated by monitoring a duty cycle of the control signal.

9. The method of claim 8, wherein the reference voltage level is set according to the output voltage of the charging circuit, the charging circuit controlled by the control signal having the duty cycle equal to the threshold value.

10. The method of claim 7, wherein when the first indication signal indicates that the voltage level has not reached the reference voltage level and the second indication signal indicates that the control value has reached the threshold value, the control signal disables the charging circuit.

11. The method of claim 7, wherein the charging circuit has a Flyback configuration.

12. An apparatus for controlling a charging circuit, the apparatus comprising:

a first detector coupled to the charging circuit, the first detector for detecting a voltage level at a first time and generating a first indication value corresponding to the voltage level at the first time, wherein the voltage level corresponds to an output voltage of the charging circuit;

a second detector coupled to the charging circuit, the second detector for detecting the voltage level at a second time after the first time and generating a second indication value corresponding to the voltage level at the second time; and

a controller coupled to the charging circuit, the first detector, and the second detector, the controller for receiving the first and second indication values, and further for generating a control signal according to the first and second indication values for turning the charging circuit on and off.

13. The apparatus of claim 12, wherein each voltage level is a fraction of the output voltage of the charging circuit.

14. The apparatus of claim 12, wherein the controller generates the control signal to disable the charging circuit when the first indication value is greater than the second indication value.

15. The apparatus of claim 12, wherein the charging circuit has a Flyback configuration.

16. A method for controlling a charging circuit, the method comprising:

detecting a voltage level at a first time and generating a first indication value corresponding to the voltage level at the first time, the voltage level corresponding to an output voltage of the charging circuit;

detecting the voltage level at a second time after the first time and generating a second indication value corresponding to the voltage level at the second time; and

generating a control signal according to the first indication value and the second indication value for turning the charging circuit on and off.

17. The method of claim 16, wherein each voltage level is a fraction of the output voltage of the charging circuit.

18. The method of claim 16, wherein when the first indication value is greater than the second indication value, the control signal disables the charging circuit.

19. The method of claim 16, wherein the charging circuit has a Flyback configuration.