Lithium battery control circuit and lithium battery charger with surge current protection

A lithium battery control circuit, adapted to control a lithium battery charger and receive a sense current signal from a current sense circuit, a feedback signal from a feedback circuit and a duty ratio signal from a logic control circuit, and comprising:

• a smooth transition circuit, generating a first voltage according to the sense current signal and the feedback signal, generating a second voltage according to a mode signal, and comparing the first voltage with the second voltage to generate a reset signal, wherein the sense current signal is related to an output current, the feedback signal is related to an output voltage, the mode signal is configured to indicate whether or not in a first charging mode, and the second voltage in the first charging mode is less than the second voltage in a non-first charging mode;
• and
• an off-time control circuit, converting the feedback signal to generate a first current by a voltage-to-current mechanism, and generating a set signal by using the first current and the duty ratio signal, and controlling a driving circuit and an output stage according to the duty ratio signal to prevent the battery control circuit from subharmonic oscillation.