Patent ID: 8441230

Claim:
A battery charger comprising: a housing including a charging port configured to receive a battery pack; a power supply module electrically connected to a power source and configured to supply power to the battery charger, wherein the battery charger is configured to operate in a normal operational power mode and a low operational power mode; a controller configured to determine whether the charging port is to receive a first charging current, determine whether the charging port is to receive a second charging current, wherein the first charging current is greater than the second charging current, operate the battery charger in the normal operational power mode when the charging port is to receive the first charging current or the second charging current, and detect the presence of the battery pack in the charging port; and a protection circuit including a first semiconductor switch configured to allow the first charging current or the second charging current to be supplied to the charging port when the protection circuit is receiving a charging signal from the controller, and a second semiconductor switch configured to prevent the charging current from being supplied to the charging port when the protection circuit is not receiving the charging signal from the controller.