Apparatus for controlling LED indicator of charging status at the primary control side of an AC-DC power charger

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.