Battery protection circuit and over-current blocking method using same

A battery protection circuit connected to a battery and to an external system, the external system including a power management unit having a sensing resistor for sensing an incoming battery current, the battery protection circuit comprising:

• a battery charge/discharge input and output unit connected to the external system;
• a control unit configured to sense overcurrent by overcharge and overdischarge with the sensing resistor of the external system and control a charge/discharge control FET;
• a charge control FET configured to control a flow of charge current of the battery under control of the control unit;
• and
• a discharge control FET configured to control a flow of discharge current of the battery under control of the control unit,
• wherein the control unit is connected to both ends of the sensing resistor of the power management unit of the external system to sense overcurrent by overcharge and overdischarge of the battery from a voltage at both ends of the sensing resistor,
• wherein the power management unit of the external system includes a power management IC and the sensing resistor mounted in a peripheral circuit of the power management IC, and
• wherein the battery does not include a separate shunt resistor to reduce a size of the battery.