Patent ID: 8854780
Filing Date: 2014-10-07
Classification: H02H

Abstract:
1. A protection circuit for a battery pack, the protection circuit comprising: an external terminal configured to be connected to a charger or an external device; a cell terminal configured to be connected to a battery; a storage unit for storing a plurality of protection level specifications of multiple batteries, wherein the specifications each include data of over-charge and over-discharge reference currents and over-charge and over-discharge reference voltages for protecting the battery; a digital-to-analog (D/A) converter electrically connected to the storage unit and configured to read the protection level specifications stored in the storage unit and to convert the protection level specifications into analog protection level specifications as analog data; a measurement unit connected to the cell terminal and configured to measure charge and discharge voltages and charge and discharge currents of the battery; a comparison unit electrically connected to the measurement unit and the D/A converter and configured to compare the charge and discharge voltages and the charge and discharge currents measured by the measurement unit with the analog protection level specifications from the D/A converter; a charge/discharge field effect transistor (FET) connected between the cell terminal and the external terminal in series and configured to be turned off during over-charge and over-discharge; a controller unit electrically connected to the comparison unit and the charge/discharge FET, and configured to determine over-charge and over-discharge according to a signal output from the comparison unit, and configured to control driving of the charge/discharge FET; and wherein the storage unit receives and stores the protection level specifications based on characteristics of multiple batteries and the storage unit stores multiple protection level specifications and is configured to read one of the protection level specifications according to characteristics of the battery.