Self-adaptive input power charger and method for controlling input current of charger

A self-adaptive input power charger, comprising:

• a) a power stage circuit configured to receive an input voltage and an input current from an external input power supply for charging a battery;
• b) a comparison circuit comprising a first error amplifier configured to receive said input voltage and a first reference voltage, and to generate a comparison result indicating that said input power supply has entered a current-limiting state when said input voltage is less than said first reference voltage;
• c) a current regulation circuit configured to generate a first control signal in response to said comparison result, wherein said current regulation circuit comprises a first diode having a cathode coupled to said comparison result, and an anode coupled to said first control signal;
• and
• d) a driving control circuit coupled to said anode of said first diode, and being configured to control a duty cycle of a power switch in said power stage circuit based on said first control signal to limit said input current of said charger.