Battery protection IC and battery device
View Patent ↗Provided are a battery protection IC and a battery device, which are capable of ensuring safety even when a charger is connected in a reverse direction. The battery protection IC includes a first switch element provided between an overcurrent detection terminal and a VDD terminal so that, when the charger is connected with reverse polarity, the first switch element interrupts a current path between the overcurrent detection terminal and the VDD terminal. The battery protection IC further includes a second switch element provided between a charge control terminal and the VDD terminal so that, when the charger is connected with reverse polarity, the second switch element interrupts a current path between the charge control terminal and the VDD terminal.
1. A battery protection IC for monitoring a voltage and a current of a secondary battery to control charge/discharge of the secondary battery, the battery protection IC comprising:
a VDD terminal and a VSS terminal to be connected to the secondary battery;
an overcurrent detection terminal to be connected to an external terminal;
a charge control terminal to be connected to a charge control FET for controlling a charge current of a charger for charging the secondary battery; and
a first switch element provided in a current path that exists between the overcurrent detection terminal and the VDD terminal, the first switch comprising a first node and a second node, wherein when the first switch is in an on state, current flows between the first node and the second node,
wherein, when the charger is connected with reverse polarity, the first switch element switches to an off state and blocks current flow between the first node and the second node, which thereby blocks current flow into the overcurrent detection terminal and out through the VDD terminal.
2. A battery protection IC according to claim 1 , wherein the first switch element comprises an NMOS transistor including a drain connected to the overcurrent detection terminal and a gate connected to the VDD terminal.
3. A battery protection IC according to claim 2 , further comprising a second NMOS transistor including a source connected to a source of the first switch element, a drain connected to the VDD terminal, and a gate connected to the overcurrent detection terminal.
4. A battery protection IC according to claim 1 , further comprising a second switch element provided between the charge control terminal and the VDD terminal,
wherein, when the charger is connected with reverse polarity, the second switch element interrupts a current path between the charge control terminal and the VDD terminal.
5. A battery protection IC according to claim 4 , wherein the second switch element comprises an NMOS transistor including a drain connected to the charge control terminal and a gate connected to the VDD terminal.
6. A battery device, comprising:
a first external terminal and a second external terminal to be connected to a charger;
a secondary battery, a discharge control FET, and the charge control FET which are connected in series between the first external terminal and the second external terminal; and
the battery protection IC according to claim 1 , to which a voltage of the secondary battery and a voltage of the second external terminal are input, for controlling charge/discharge of the secondary battery.