The invention relates to an intelligent charger with a universal serial
bus (
USB) interface. AC 220V current sequentially passes through a sorting circuit, a filtering
voltage-stabilization circuit and a
voltage transformation circuit and then is output to a
USB device to be charged, the output end of the
voltage transformation circuit is connected with a charging state detection circuit, a
USB interface of the USB device to be charged is connected with a pull and plug detection circuit, the output ends of the charging state detection circuit and the pull and plug detection circuit are connected with a device comprehensive
state logic operation circuit, the output end of the device comprehensive
state logic operation circuit is connected with an on / off
control circuit, the output end of the on / off
control circuit is connected with the output end of a rectification circuit and can be used for switching on / off the input of a power supply, and the output end of the voltage transformation circuit is used for controlling
duty cycle of a switching tube in the voltage transformation circuit according to a
control signal output from a voltage-
stabilization control circuit. By the intelligent charger, the access and the pull-out of a charging device are intelligently detected, power is automatically
cut off from a source head after the device is pulled out, charging is automatically carried out after the device is inserted, and power is automatically
cut off after the charging is full; and meanwhile, the intelligent charger has an
overcurrent protection function, and the power supply is automatically
cut off when
overcurrent occurs so as to prevent an accident.