Charger circuit with battery protection mechanism

Abstract

A charger circuit for use in controlling charge of a battery pack, which includes a charge control switch, a discharging circuit and a control unit. The charger circuit has at least one power output terminal and one connection terminal for coupling the battery pack. The charge control switch is arranged to selectively provide a power from a power source to the battery pack through the power output terminal. The discharging circuit is selectively coupled to the power output terminal, and arranged to discharge a battery cell of the battery pack when being coupled to the power output terminal. The control unit is coupled to the charge control switch and the discharging circuit, and determines whether to turn off the charge control switch and control the discharging circuit to couple to the power output terminal according to at least an over-voltage detection based on a signal based on the connection terminal.

1 - 15 . (canceled) 
     
     
         16 . A charger circuit for use in controlling charge of a battery pack, the charger circuit comprising:
 at least one power output terminal and at least one connection terminal for coupling to the battery pack;   a charge control switch, arranged to selectively provide power from a power source to the battery pack through the power output terminal;   a discharging circuit comprising a switch and a current source; and   a control unit, coupled to the charge control switch, the at least one connection terminal, and the discharging circuit, wherein:
 the discharging circuit is selectively coupled by the switch to the at least one power output terminal and configured to discharge a battery cell of the battery pack when coupled to the at least one power output terminal, 
 the control unit is configured to determine whether to control the discharging circuit to couple to the at least one power output terminal according to the signal on the at least one connection terminal, and 
 the signal from the battery pack on the at least one connection terminal indicates an over-voltage condition. 
   
     
     
         17 . The charger circuit of  claim 16 , wherein a connection terminal of the at least one connection terminal is coupled to a battery power contact of the battery pack,
 the charger circuit further comprises a voltage sensing circuit arranged to measure a voltage level on the battery power contact to generate an over-voltage detection signal, and   the control unit is configured to open the charge control switch and to control the discharging circuit to couple to the at least one power output terminal if the over-voltage detection signal indicates the over-voltage condition.   
     
     
         18 . The charger circuit of  claim 16 , wherein a connection terminal of the at least one connection terminal is coupled to a battery identification contact of the battery pack,
 the battery pack comprises a detection circuit arranged to generate an over-voltage detection signal at the battery identification contact by detecting whether a voltage level of a positive electrode of a battery cell of the battery pack is higher than a predetermined reference voltage level, and   the control unit is configured to open the charge control switch and to control the discharging circuit to couple to the at least one power output terminal if the over-voltage detection signal indicates the over-voltage condition.   
     
     
         19 . The charger circuit of  claim 16 , wherein the signal on the at least one connection terminal is further arranged to indicate an over-temperature condition. 
     
     
         20 . The charger circuit of  claim 19 , wherein a connection terminal of the at least one connection terminal is coupled to a battery temperature contact of the battery pack, and
 the battery pack comprises a detection circuit that is arranged to generate an over-temperature detection signal at the battery temperature contact by detecting whether a temperature of the battery pack is higher than a predetermined value, and   the control unit is arranged to open the charge control switch and control the discharging circuit to couple to the at least one power output terminal if the over-temperature detection signal indicates the over-temperature condition.   
     
     
         21 . The charger circuit of  claim 16 , wherein the current source of the discharging circuit is connected to a voltage reference level, and
 when the discharging circuit is coupled to the at least one power output terminal through the switch, the discharging circuit provides a current path from the battery cell through the at least one power output terminal to the reference level.   
     
     
         22 . The charger circuit of  claim 16 , wherein the at least one connection terminal is arranged to function as a battery communication line (BCL) of a Mobile Industry Processor Interface (MIPI) battery interface (BIF), and the charger circuit further comprises a BIF module,
 the control unit is configured to obtain information regarding a voltage level of the battery cell from the BCL module,   the control unit is further configured to determine whether to open the charge control switch and to control the discharging circuit to couple to the power output terminal if the information from the BCL module indicates the over-voltage condition, and   the BIF module of the charger circuit is coupled to the BIF module of the battery pack through the BCL.   
     
     
         23 . The charger circuit of  claim 16 , wherein the charge control switch comprises a power MOSFET. 
     
     
         24 . A power system comprising a battery protection mechanism, the power system comprising:
 a battery pack comprising a battery cell; and   a charger circuit, comprising:
 at least one power output terminal and at least one connection terminal for coupling to the battery pack; 
 a charge control switch, arranged to selectively provide power from a power source to the battery pack through the power output terminal; 
 a discharging circuit comprising a switch and a current source; and 
 a control unit, coupled to the charge control switch, the at least one connection terminal, and the discharging circuit, wherein:
 the discharging circuit is selectively coupled by the switch to the at least one power output terminal and configured to discharge a battery cell of the battery pack when coupled to the at least one power output terminal, 
 the control unit is configured to determine whether to control the discharging circuit to couple to the at least one power output terminal according to the signal on the at least one connection terminal, and 
 the signal from the battery pack on the at least one connection terminal indicates an over-voltage condition. 
 
   
     
     
         25 . The power system of  claim 24 , wherein a connection terminal of the at least one connection terminal is coupled to a battery power contact of the battery pack,
 the charger circuit further comprises a voltage sensing circuit arranged to measure a voltage level on the battery power contact to generate an over-voltage detection signal, and   the control unit is configured to open the charge control switch and to control the discharging circuit to couple to the at least one power output terminal if the over-voltage detection signal indicates the over-voltage condition.   
     
     
         26 . The power system of  claim 24 , wherein a connection terminal of the at least one connection terminal is coupled to a battery identification contact of the battery pack,
 the battery pack comprises a detection circuit arranged to generate an over-voltage detection signal at the battery identification contact by detecting whether a voltage level of a positive electrode of a battery cell of the battery pack is higher than a predetermined reference voltage level, and   the control unit is configured to open the charge control switch and to control the discharging circuit to couple to the at least one power output terminal if the over-voltage detection signal indicates the over-voltage condition.   
     
     
         27 . The power system of  claim 24 , wherein the signal on the at least one connection terminal is further arranged to indicate an over-temperature condition. 
     
     
         28 . The charger circuit of  claim 27 , wherein a connection terminal of the at least one connection terminal is coupled to a battery temperature contact of the battery pack, and
 the battery pack comprises a detection circuit that is arranged to generate an over-temperature detection signal at the battery temperature contact by detecting whether a temperature of the battery pack is higher than a predetermined value, and   the control unit is arranged to open the charge control switch and control the discharging circuit to couple to the at least one power output terminal if the over-temperature detection signal indicates the over-temperature condition.   
     
     
         29 . The power system of  claim 24 , wherein the current source of the discharging circuit is connected to a voltage reference level, and
 when the discharging circuit is coupled to the at least one power output terminal through the switch, the discharging circuit provides a current path from the battery cell through the at least one power output terminal to the reference level.   
     
     
         30 . The power system of  claim 24 , wherein the at least one connection terminal is arranged to function as a battery communication line (BCL) of a Mobile Industry Processor Interface (MIPI) battery interface (BIF), and the charger circuit further comprises a BIF module,
 the control unit is configured to obtain information regarding a voltage level of the battery cell from the BCL module,   the control unit is further configured to determine whether to open the charge control switch and to control the discharging circuit to couple to the power output terminal if the information from the BCL module indicates the over-voltage condition, and   the BIF module of the charger circuit is coupled to the BIF module of the battery pack through the BCL.   
     
     
         31 . The power system of  claim 24 , wherein battery pack further comprises:
 a comparing device, having a first input terminal and a second input terminal, the first input terminal being coupled to a positive electrode of the battery cell and the second input terminal being coupled to a reference voltage level, the comparing device configured to compare a voltage level on the positive electrode of the battery cell with the reference voltage level and generate a driving current when the voltage level on the positive electrode of the battery cell is higher than the reference voltage level; and   a resistive circuit, coupled to an output terminal of the comparing device, arranged to generate an over-voltage detection signal when the driving current passes therethrough.   
     
     
         32 . The power system of  claim 31 , wherein the connection terminal of the charger circuit is coupled to a battery identification contact of the battery pack, and the resistive circuit comprises an identification resistor. 
     
     
         33 . The power system of  claim 31 , wherein the connection terminal of the charger circuit is coupled to a battery temperature contact of the battery pack, and the resistive circuit comprises a negative temperature coefficient thermistor. 
     
     
         34 . The power system of  claim 24 , wherein the charge control switch comprises a power MOSFET.