Battery protecting circuit
First Claim
1. Battery protecting circuit comprising:
- battery protecting circuit controling ON/OFF of a first switching circuit inserted in a first power feeding path between an external power source and a battery, and it has the following circuits;
a first switch driver generating a first driving voltage by boosting the voltage generated in said first power feeding path corresponding to an input control signal, and turns ON said first switching circuit with said first driving voltage;
a second switch driver generating a second driving voltage lower than the voltage generated in a second power feeding path between said external power source and said battery corresponding to the input control signal, and turns ON a second switching circuit inserted in said second power feeding path with the second driving voltage; and
a controller outputing said control signal such that when the voltage of said battery reaches the voltage needed for the boosting operation of said first switch driver, said first switch driver stops the boosting operation, and said second switch driver generates said second driving voltage.
1 Assignment
0 Petitions
Accused Products
Abstract
This invention provides a battery protecting circuit where even if the battery voltage falls nearly to zero volts due to overdischarge or the like while an NMOS transistor set in the power feeding path on the side of the positive electrode of the battery is turned ON/OFF, it is still possible to charge the battery by a constant charging current in a stable way. When the voltage of battery B1 has not reached the voltage needed for generating the driving voltage of NMOS transistors Q1, Q2 in drives 111, 112, the boosting operation of drives 111, 112 is stopped, and PMOS transistor Q3 inserted in a power feeding path different from that of said transistors is turned ON by driver 113. In driver 113, by clamping voltage VDD generated in the power feeding path of PMOS transistor Q3 to a voltage lower than it, driving voltage ZVO of PMOS transistor Q3 is generated without performing a boosting operation.
-
Citations
20 Claims
-
1. Battery protecting circuit comprising:
-
battery protecting circuit controling ON/OFF of a first switching circuit inserted in a first power feeding path between an external power source and a battery, and it has the following circuits; a first switch driver generating a first driving voltage by boosting the voltage generated in said first power feeding path corresponding to an input control signal, and turns ON said first switching circuit with said first driving voltage; a second switch driver generating a second driving voltage lower than the voltage generated in a second power feeding path between said external power source and said battery corresponding to the input control signal, and turns ON a second switching circuit inserted in said second power feeding path with the second driving voltage; and a controller outputing said control signal such that when the voltage of said battery reaches the voltage needed for the boosting operation of said first switch driver, said first switch driver stops the boosting operation, and said second switch driver generates said second driving voltage. - View Dependent Claims (2, 3, 4, 5, 6, 7, 19, 20)
-
-
8. Battery protecting circuit that controls ON/OFF of a switching circuit inserted in a power feeding path between an external power source and a battery, comprising:
-
a switch driver that generates a voltage by boosting the voltage generated in said power feeding path corresponding to an input control signal, and turns ON said switching circuit with said boosted voltage; a driving voltage feeding circuit that feeds the voltage for turning ON said switching circuit from said external power source through said power feeding path to said switching circuit corresponding to the input control signal; and a controller that outputs said control signal such that when the voltage of said battery does not reach the voltage needed for the boosting operation of said switch driver, said switch driver stops the boosting operation and said driving voltage feeding circuit feeds a driving voltage to said switching circuit. - View Dependent Claims (9, 10, 11)
-
-
12. Battery protecting circuit for driving first and second transistors of a battery device that has a secondary battery and first and second transistors connected in series between a power source terminal of the secondary battery and an external power source terminal comprising
the battery protecting circuit has a first driver that feeds a first driving signal to the control terminal of said first transistor, a second driver that feeds a second driving signal to the control terminal of said second transistor; -
a mode selector that contains a mode selection terminal that applies a voltage corresponding to the voltage fed to the external power source terminal or a reference voltage, a fourth transistor that can be connected between a connection middle point between said first transistor and said second transistor and the control terminal of said second transistor, and a driver for feeding a fourth driving signal to the control terminal of said fourth transistor corresponding to the voltage applied on said mode selection terminal; and
whereinwhen current is fed from the external power source terminal to the secondary battery, if the voltage appearing at said mode selection terminal is a voltage corresponding to the voltage fed to said external power source terminal, said fourth transistor is turned ON. - View Dependent Claims (13, 14)
-
-
15. Battery protecting circuit for driving the first, second and third transistors of a battery device that has a secondary battery, a first and a second transistor connected in series between a power source terminal of the secondary battery and an external power source terminal and a third transistor connected between a connection middle point between said first transistor and said second transistor and the power source terminal of the secondary battery comprising
the battery protecting circuit has a first driver that feeds a first driving signal to the control terminal of said first transistor; -
a second driver that feeds a second driving signal to the control terminal of said second transistor; a third driver that feeds a third driving signal to the control terminal of said third transistor; a mode selector that contains a mode selection terminal that applies a voltage corresponding to the voltage fed to the external power source terminal or a reference voltage, a fourth transistor that can be connected between the connection middle point between said first transistor and said second transistor and the control terminal of said second transistor, and a driver for feeding a fourth driving signal to the control terminal of said fourth transistor corresponding to the voltage applied on said mode selection terminal, a voltage monitoring circuit for monitoring the voltage fed to the external power source terminal; a power source circuit, with power fed from the connection middle point between said first transistor and said second transistor, which starts feeding of an internal power source voltage after said voltage monitoring circuit detects a prescribed voltage; when current is fed from the external power source terminal to the secondary battery; if the voltage appearing at said mode selection terminal is a voltage corresponding to the reference voltage, said fourth transistor is turned OFF; and
whereinwhen an internal power source voltage is not fed from said power source circuit, said third driver responds to the voltage appearing at the connection middle point between said first transistor and said second transistor and feeds the third driving signal to turn ON said third transistor. - View Dependent Claims (16, 17, 18)
-
Specification