Charging circuit and method for preventing charging power supply from reversely connecting

A charging circuit for preventing charging power supply from reversely connecting applied in an electronic cigarette or electronic cigarette case, comprising:

• a direct current input terminal,
• an unit for preventing charging power supply from reversely connecting electrically with the direct current input terminal,
• a charge management unit electrically connected to the unit for preventing charging power supply from reversely connecting and a rechargeable battery electrically connected with the charge management unit;
• wherein the direct current input terminal is configured to receive an input direct current from a charging power supply;
• wherein the unit for preventing charging power supply from reversely connecting is configured to prevent the direct current input terminal from supplying a reverse direct current for the rechargeable battery,
• wherein when the direct current input terminal supplies the reverse direct current, the unit for preventing charging power supply from reversely connecting is turned off so that the charging power supply to the rechargeable battery is cut off;
• when the direct current input terminal supplies a normal direct current, the unit for preventing charging power supply from reversely connecting is turned on so that the direct current from the direct current input terminal flows into the charge management unit via the unit for preventing charging power supply from reversely connecting;
• wherein the charge management unit is configured to detect charge voltage value and charge current value when the unit for preventing charging power supply from reversely connecting is turned on, to adjust the charged voltage to the rechargeable battery, and further to turn on or off the charge voltage according to detected result;
• wherein the unit for preventing charging power supply from reversely connecting comprises a first MOSFET, and the first MOSFET is a P channel MOSFET;
• a drain of the first MOSFET is connected to an anode of the direct current input terminal directly;
• a source of the first MOSFET is connected to the charge management unit directly;
• and
• a gate of the first MOSFET is connected to a cathode of the rechargeable battery through a sixth resistor and connected to a cathode of the direct current input terminal directly.