Patent ID: 8704491

Claim:
A battery pack, comprising: a first external connection terminal and a second external connection terminal; a battery; a discharge control FET and a charge control FET which are disposed in series between the battery and the second external connection terminal; a battery protection IC for monitoring a voltage of the battery to detect that the voltage of the battery is equal to or lower than an overdischarge voltage, so as to turn OFF the discharge control FET and shut down, and for monitoring the voltage of the battery to detect that the voltage of the battery is equal to or higher than an overcharge voltage, so as to turn OFF the charge control FET, wherein the battery protection IC comprises a first voltage monitoring terminal coupled to the second external connection terminal; and a control IC for controlling the battery pack on a given occasion, the control IC comprising a second voltage monitoring terminal coupled to the second external connection terminal, the control IC operable to monitor a voltage of the second voltage monitoring terminal to detect that the battery enters an overdischarge state and then shut down, whereby the battery protection IC comprises no terminal for communicating with the control IC regarding the voltage of the battery; the control IC comprising: a comparator coupled to the second voltage monitoring terminal; a logic circuit coupled to the comparator and operable to output an enable signal; a temperature voltage generating circuit operable to receive the enable signal; a reference voltage generating circuit operable to receive the enable signal; and a temperature detection comparator operable to output a detection signal based on a temperature voltage from the temperature voltage generating circuit and a reference voltage from the reference voltage generating circuit.