APPARATUS FOR CONTROLLING LED INDICATOR OF CHARGING STATUS AT THE PRIMARY CONTROL SIDE OF AN AC-DC POWER CHARGER

• US 20100321193A1
• Filed: 06/23/2009
• Published: 12/23/2010
• Est. Priority Date: 06/23/2009
• Status: Active Grant

• Current Assignee: Fremont Micro Devices Corporation
• Original Assignee: Evergreen Micro Devices Co., Ltd.
• Inventors: Liao, Weiming, Zheng, Yue, Ku, Matthew Man Ho
• Granted Patent: US 8,427,114 B2
• Time in Patent Office: Days
• US Class Current: 340/657
• CPC Class Codes: H02J 7/0048 Detection of remaining charge capacity or state of charge [SOC]

Abstract

The present invention relates to a charge status indicator and a charger. The charger comprises a charging power supply and a charge status indicator, wherein, the charge status indicator comprises a detecting chip for monitoring charge status connected between the primary winding of transformer and ground, and a display module used for displaying the charge status, wherein, said detecting chip for monitoring charge status comprising: a detecting module for detecting the charging state of the charge power supply; a comparing module for determining the current charge status based on the detected charging state. By employing the charger or the charge status indicator for a charger, a primary-side feedback control Flyback SMPS may be employed, just a simple and reliable circuit is needed, and higher efficient can be achieved.

Claims

1. A charger which comprises a charging power supply and a charge status indicator, wherein, the charge status indicator comprises a detecting chip for monitoring charge status connected between the primary winding of transformer and ground, and a display module used for displaying the charge status, wherein, said detecting chip for monitoring charge status comprising:

a detecting module for detecting the charging state of the charge power supply;

a comparing module for determining the current charge status based on the detected charging state.

2. The charger according to claim 1, wherein, said detecting chip for monitoring charge status further comprises a display driver for driving the display module to display the charge status based on the current charge status.

3. The charger according to claim 2, wherein, said detecting module further comprises:

a frequency obtaining unit for obtaining the working frequency of the detecting chip for monitoring charge status, wherein, the working frequency is proportional to the charging current;

a frequency-electrical signal converter for converting the working frequency to an electrical signal which is proportional to the charging current.

4. The charger according to claim 2, wherein, said detecting module further comprises:

a sample and hold circuit for sampling electrical signal from the primary auxiliary winding of the transformer;

an error amplifier for comparing the sample electrical signal with a reference value and outputting an electrical signal which is proportional to the charging current.

5. The charger according to claim 2, wherein, said comparing module comprises a comparator and a filter, wherein, the forward input end of the comparator is connected to the detecting module to obtain an electrical signal which is proportional to the charging current;

the reverse input end of the comparator is connected to a reference electrical signal, the output end of the comparator is connected to the input end of the filter, and the output end of the filter is connected to the display driver to output the charging state.

6. The charger according to claim 5, wherein, said display driver comprises a first driver connected to the output end of the filter for driving the display module to display the first charge status, and a second driver connected to the output end of the filter for driving the display module to display the second charge status.

7. The charger according to claim 6, wherein, the display module comprises a first LED driven by the first driver, a second LED driven by the second driver, and a current-limiting resistor connected between the anodes of the first and second LEDs and the power supply;

wherein, the first and second LEDs are common-anode LED.

8. The charger according to claim 6, wherein, the display module comprises a first LED driven by the first driver, a second LED driven by the second driver, and a current-limiting resistor connected between the cathodes of the first and second LED and the ground;

wherein, the first and second LEDs are common-cathode LED.

9. The charger according to claim 5, wherein, the display driver comprises a third driver connected to the output end of the filter for driving the display module to display the first and second charge status, and the display module comprises a third LED driven by the third driver, and a current-limiting resistor connected between the anode of the third LED and the power supply.

10. A charge status indicator, wherein, it comprises a detecting chip for monitoring charge status connected between the primary winding of transformer and ground, and a display module used for displaying the charge status, wherein, said detecting chip for monitoring charge status comprising:

a detecting module for detecting the charging state of the charge power supply;

a comparing module for determining the current charge status based on the detected charging state.

11. The charge status indicator according to claim 10, wherein, said detecting chip for monitoring charge status further comprises a display driver for driving the display module to display the charge status based on the current charge status.

12. The charge status indicator according to claim 11, wherein, said detecting module further comprises:

a frequency obtaining unit for obtaining the working frequency of the detecting chip for monitoring charge status, wherein, the working frequency is proportional to the charging current;

a frequency-electrical signal converter for converting the working frequency to an electrical signal which is proportional to the charging current.

13. The charge status indicator according to claim 11, wherein, said detecting module further comprises:

a sample and hold circuit for sampling electrical signal from the primary auxiliary winding of the transformer;

an error amplifier for comparing the sample electrical signal with a reference value and outputting an electrical signal which is proportional to the charging current.

14. The charge status indicator according to claim 11, wherein, said comparing module comprises a comparator and a filter, wherein, the forward input end of the comparator is connected to the detecting module to obtain an electrical signal which is proportional to the charging current;

the reverse input end of the comparator is connected to a reference electrical signal, the output end of the comparator is connected to the input end of the filter, and the output end of the filter is connected to the display driver to output the charging state.

15. The charge status indicator according to claim 14, wherein, said display driver comprises a first driver connected to the output end of the filter for driving the display module to display the first charge status, and a second driver connected to the output end of the filter for driving the display module to display the second charge status.

16. The charge status indicator according to claim 15, wherein, the display module comprises a first LED driven by the first driver, a second LED driven by the second driver, and a current-limiting resistor connected between the anodes of the first and second LEDs and the power supply;

wherein, the first and second LEDs are common-anode LED.

17. The charge status indicator according to claim 15, wherein, the display module comprises a first LED driven by the first driver, a second LED driven by the second driver, and a current-limiting resistor connected between the cathodes of the first and second LED and the ground;

wherein, the first and second LEDs are common-cathode LED.

18. The charge status indicator according to claim 14, wherein, the display driver comprises a third driver connected to the output end of the filter for driving the display module to display the first and second charge status, and the display module comprises a third LED driven by the third driver, and a current-limiting resistor connected between the anode of the third LED and the power supply.