Apparatus for controlling LED indicator of charging status at the primary control side of an AC-DC power charger
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.
1. A charger, comprising: 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 the charge status comprises:
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; and
a display driver for driving the display module to display the charge status based on the current charge status; and
wherein said detecting module comprises:
a frequency obtaining unit for obtaining the working frequency of said detecting chip for monitoring the charge status, wherein the working frequency is proportional to the charging current; and
a frequency-electrical signal converter for converting the working frequency to an electrical signal which is proportional to the charging current.
2. The charger according to claim 1 , wherein said detecting module further comprises:
a sample and hold circuit for sampling electrical signal from the primary auxiliary winding of the transformer; and
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.
3. The charger according to claim 1 , 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.
4. The charger according to claim 3 , 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.
5. The charger according to claim 4 , 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; and wherein the first and second LEDs are common-anode LED.
6. The charger according to claim 4 , 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; and wherein the first and second LEDs are common-cathode LED.
7. The charger according to claim 3 , 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.
8. A charge status indicator, comprising: 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 the charge status comprises:
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; and
a display driver for driving the display module to display the charge status based on the current charge status; and
wherein said detecting module comprises:
a frequency obtaining unit for obtaining the working frequency of said detecting chip for monitoring the charge status, wherein the working frequency is proportional to the charging current; and
a frequency-electrical signal converter for converting the working frequency to an electrical signal which is proportional to the charging current.
9. The charge status indicator according to claim 8 , wherein said detecting module further comprises:
a sample and hold circuit for sampling electrical signal from the primary auxiliary winding of the transformer; and
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.
10. The charge status indicator according to claim 8 , 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.
11. The charge status indicator according to claim 10 , 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.
12. The charge status indicator according to claim 11 , 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; and wherein the first and second LEDs are common-anode LED.
13. The charge status indicator according to claim 11 , 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; and wherein the first and second LEDs are common-cathode LED.
14. The charge status indicator according to claim 10 , 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.