SECONDARY-BATTERY MONITORING DEVICE AND BATTERY PACK
First Claim
1. A secondary-battery monitoring device comprising:
- first and second battery connection terminals to which a secondary battery is to be connected;
first and second external terminals to which a load or a charger is to be connected;
a first current path arranged between the first battery connection terminal and the first external terminal;
a second current path arranged between the second battery connection terminal and the second external terminal;
a switch circuit including a pair of FETs that control a flow of a discharge current and a flow of a charge current, respectively, the switch circuit being inserted in the second current path so as to control the charge current and the discharge current flowing in the secondary battery; and
a switch control unit,wherein the switch control unit is provided with;
a second power-supply terminal connected to the second current path at a line connecting the second battery connection terminal and one node on the second current path of the switch circuit;
a first power-supply terminal to which a first power supply voltage from the secondary battery is supplied via the first current path with using a voltage at the second power-supply terminal as a reference;
a pair of control terminals;
driver circuits configured to supply control voltages to gates of corresponding FETs via the control terminals;
a detection terminal connected to the second current path at a line connecting the other node on the second current path of the switch circuit and the second external terminal;
a first detection circuit configured to monitor the charge current flowing in the second current path based on a detection voltage detected at the detection terminal, and output a detection signal when the detection voltage reaches a predetermined value;
a second detection circuit configured to monitor the discharge current and output a detection signal when the detection voltage reaches a predetermined value; and
a control circuit configured to supply the control voltage via the corresponding driver circuit in response to the detection signal to carry out control of shutting off the corresponding FET, andwherein at least one of the first and second detection circuits is provided with;
a comparator circuit configured to determine, based on a voltage of one input node of the comparator circuit serving as a reference voltage, magnitude of a voltage of the other input node of the comparator circuit to output the detection signal based on a result of the determination; and
a voltage correction circuit configured to generate a correction voltage having a characteristic that varies by a slope approximating a slope of variation in the detection voltage that decreases along with an increase in the first power supply voltage, add the correction voltage to the detection voltage or a reference power supply voltage with such a polarity as canceling the slope of variation caused in the detection voltage by the slope of variation in the correction voltage, and input the voltage thus corrected to the comparator circuit.
2 Assignments
0 Petitions
Accused Products
Abstract
A secondary-battery monitoring device capable of realizing highly reliable overcurrent detection and a battery pack having it are provided. When an overcurrent flowing to a secondary battery is to be detected by utilizing a current detection voltage generated via on-resistance of a discharge-control switch and a charge-control switch, a voltage correction circuit that generates a correction voltage having a characteristic varied by positive slope or negative slope along with increase in a power supply voltage is provided, and the correction voltage is added to the detection voltage or a reference power supply voltage with the polarity that cancels out the slope of voltage variation caused in the detection voltage, and then the voltage is input to a comparator circuit. In this manner, variation in the overcurrent determination current is reduced.
-
Citations
22 Claims
-
1. A secondary-battery monitoring device comprising:
-
first and second battery connection terminals to which a secondary battery is to be connected; first and second external terminals to which a load or a charger is to be connected; a first current path arranged between the first battery connection terminal and the first external terminal; a second current path arranged between the second battery connection terminal and the second external terminal; a switch circuit including a pair of FETs that control a flow of a discharge current and a flow of a charge current, respectively, the switch circuit being inserted in the second current path so as to control the charge current and the discharge current flowing in the secondary battery; and a switch control unit, wherein the switch control unit is provided with; a second power-supply terminal connected to the second current path at a line connecting the second battery connection terminal and one node on the second current path of the switch circuit; a first power-supply terminal to which a first power supply voltage from the secondary battery is supplied via the first current path with using a voltage at the second power-supply terminal as a reference; a pair of control terminals; driver circuits configured to supply control voltages to gates of corresponding FETs via the control terminals; a detection terminal connected to the second current path at a line connecting the other node on the second current path of the switch circuit and the second external terminal; a first detection circuit configured to monitor the charge current flowing in the second current path based on a detection voltage detected at the detection terminal, and output a detection signal when the detection voltage reaches a predetermined value; a second detection circuit configured to monitor the discharge current and output a detection signal when the detection voltage reaches a predetermined value; and a control circuit configured to supply the control voltage via the corresponding driver circuit in response to the detection signal to carry out control of shutting off the corresponding FET, and wherein at least one of the first and second detection circuits is provided with; a comparator circuit configured to determine, based on a voltage of one input node of the comparator circuit serving as a reference voltage, magnitude of a voltage of the other input node of the comparator circuit to output the detection signal based on a result of the determination; and a voltage correction circuit configured to generate a correction voltage having a characteristic that varies by a slope approximating a slope of variation in the detection voltage that decreases along with an increase in the first power supply voltage, add the correction voltage to the detection voltage or a reference power supply voltage with such a polarity as canceling the slope of variation caused in the detection voltage by the slope of variation in the correction voltage, and input the voltage thus corrected to the comparator circuit. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
-
-
10. A secondary-battery monitoring device comprising:
-
first and second battery connection terminals to which a secondary battery is to be connected; first and second external terminals to which a load or a charger is to be connected; a first current path arranged between the first battery connection terminal and the first external terminal; a second current path arranged between the second battery connection terminal and the second external terminal; a switch circuit including a pair of FETs that control a flow of a discharge current and a flow of a charge current, respectively, the switch circuit being inserted in the second current path so as to control the charge current and the discharge current flowing in the secondary battery; and a switch control unit, wherein the switch control unit is provided with; a second power-supply terminal connected to the second current path at a line connecting the second battery connection terminal and one node on the second current path of the switch circuit; a first power-supply terminal to which a first power supply voltage from the secondary battery is supplied via the first current path with using a voltage at the second power-supply terminal as a reference; a pair of control terminals; driver circuits configured to supply control voltages to gates of corresponding FETs via the control terminals; a detection terminal connected to the second current path at a line connecting the other node on the second current path of the switch circuit and the second external terminal; a first detection circuit configured to monitor the charge current flowing in the second current path based on a detection voltage detected at the detection terminal, and output a detection signal when the detection voltage reaches a predetermined value; a second detection circuit configured to monitor the discharge current and output a detection signal when the detection voltage reaches a predetermined value; and a control circuit configured to supply the control voltage via the corresponding driver circuit in response to the detection signal to carry out control of shutting off the corresponding FET, and wherein at least one of the first and second detection circuits is provided with; a comparator circuit configured to determine, based on a voltage of one input node of the comparator circuit serving as a reference voltage, magnitude of a voltage of the other input node of the comparator circuit to output the detection signal based on a result of the determination; and a voltage correction circuit configured to generate a correction voltage having a characteristic that is approximated by a linear function with respect to a characteristic of the detection voltage varied depending on the first power supply voltage, add the correction voltage to the detection voltage or a reference power supply voltage with such a polarity as canceling the slope of voltage variation caused in the detection voltage by the slope of variation in the correction voltage, and input the voltage thus corrected to the comparator circuit. - View Dependent Claims (11, 12, 13, 14)
-
-
15. A secondary-battery monitoring device comprising:
-
first and second battery connection terminals to which a secondary battery is to be connected; first and second external terminals to which a load or a charger is to be connected; a first current path arranged between the first battery connection terminal and the first external terminal; a second current path arranged between the second battery connection terminal and the second external terminal; a switch circuit including a pair of FETs configured to control a flow of a discharge current and a flow of a charge current, respectively, the switch circuit being inserted in the second current path so as to control the charge current and the discharge current flowing in the secondary battery; and a switch control unit, wherein the switch control unit is provided with; a second power-supply terminal connected to the second current path at a line connecting the second battery connection terminal and one node on the second current path of the switch circuit; a first power-supply terminal to which a first power supply voltage from the secondary battery is supplied via the first current path with using a voltage at the second power-supply terminal as a reference; a pair of control terminals; driver circuits configured to supply control voltages to gates of corresponding FETs via the control terminals; a detection terminal connected to the second current path at a line connecting the other node on the second current path of the switch circuit and the second external terminal; a first detection circuit configured to monitor the charge current flowing in the second current path based on a detection voltage detected at the detection terminal, and output a detection signal when the detection voltage reaches a predetermined value; a second detection circuit configured to monitor the discharge current and output a detection signal when the detection voltage reaches a predetermined value; and a control circuit configured to supply the control voltage via the corresponding driver circuit in response to the detection signal to carryout control of shutting off the corresponding FET, and wherein at least one of the first and second detection circuits is provided with; a comparator circuit configured to determine, based on a reference power supply voltage applied to one input node serving as a reference voltage, magnitude of a voltage of the other input node to output the detection signal based on a result of the determination; and a voltage correction circuit including;
a first resistor voltage dividing circuit configured to subject the first power supply voltage to a resistor voltage division at a first resistance ratio; and
a second resistor voltage dividing circuit configured to subject the voltage that has undergone the voltage division in the first resistor voltage dividing circuit to a voltage division at a second resistance ratio based on the detection voltage serving as a reference, the voltage correction circuit being configured to input the voltage generated by the voltage division in the second resistor voltage dividing circuit to the other input node of the comparator circuit.
-
-
16. A secondary-battery monitoring device comprising:
-
first and second battery connection terminals to which a secondary battery is to be connected; first and second external terminals to which a load or a charger is to be connected; a first current path arranged between the first battery connection terminal and the first external terminal; a second current path arranged between the second battery connection terminal and the second external terminal; a switch circuit including a pair of FETs configured to control a flow of a discharge current and a flow of a charge current, respectively, the switch circuit being inserted in the second current path so as to control the charge current and the discharge current flowing in the secondary battery; and a switch control unit, wherein the switch control unit is provided with; a second power-supply terminal connected to the second current path at a line connecting the second battery connection terminal and one node on the second current path of the switch circuit; a first power-supply terminal to which a first power supply voltage from the secondary battery is supplied via the first current path with using a voltage at the second power-supply terminal as a reference; a pair of control terminals; driver circuits configured to supply control voltages to gates of corresponding FETs via the control terminals; a detection terminal connected to the second current path at a line connecting the other node on the second current path of the switch circuit and the second external terminal; a first detection circuit configured to monitor the charge current flowing in the second current path based on a detection voltage detected at the detection terminal, and output a detection signal when the detection voltage reaches a predetermined value; a second detection circuit configured to monitor the discharge current and output a detection signal when the detection voltage reaches a predetermined value; and a control circuit configured to supply the control voltage via the corresponding driver circuit in response to the detection signal to carryout control of shutting off the corresponding FET, and wherein at least one of the first and second detection circuits is provided with; a comparator circuit configured to determine, based on a voltage of one input node of the comparator circuit serving as a reference voltage, magnitude of a voltage of the other input node of the comparator circuit to output the detection signal based on a result of the determination; and a voltage correction circuit configured to generate a correction voltage having a characteristic that is approximated by a quadratic function with respect to a characteristic of the detection voltage varied depending on the first power supply voltage, add the correction voltage to the detection voltage or a reference power supply voltage with such a polarity as canceling the slope of voltage variation caused in the detection voltage by the slope of variation in the correction voltage, and input the voltage thus corrected to the comparator circuit. - View Dependent Claims (17, 18)
-
-
19. A secondary-battery monitoring device comprising:
-
first and second battery connection terminals to which a secondary battery is to be connected; first and second external terminals to which a load or a charger is to be connected; a first current path arranged between the first battery connection terminal and the first external terminal; a second current path arranged between the second battery connection terminal and the second external terminal; a switch circuit including a pair of FETs configured to control a flow of a discharge current and a flow of a charge current, respectively, the switch circuit being inserted in the second current path so as to control the charge current and the discharge current flowing in the secondary battery; and a switch control unit, wherein the switch control unit is provided with; a second power-supply terminal connected to the second current path at a line connecting the second battery connection terminal and one node on the second current path of the switch circuit; a first power-supply terminal to which a first power supply voltage from the secondary battery is supplied via the first current path with using a voltage at the second power-supply terminal as a reference; a pair of control terminals; driver circuits configured to supply control voltages to gates of corresponding FETs via the control terminals; a detection terminal connected to the second current path at a line connecting the other node on the second current path of the switch circuit and the second external terminal; a first detection circuit configured to monitor the charge current flowing in the second current path based on a detection voltage detected at the detection terminal, and output a detection signal when the detection voltage reaches a predetermined value; a second detection circuit configured to monitor the discharge current and output a detection signal when the detection voltage reaches a predetermined value; and a control circuit configured to supply the control voltage via the corresponding driver circuit in response to the detection signal to carry out control of shutting off the corresponding FET, and wherein at least one of the first and second detection circuits is provided with; a comparator circuit configured to determine, based on a voltage of one input node of the comparator circuit serving as a reference voltage, magnitude of a voltage of the other input node of the comparator circuit to output the detection signal based on a result of the determination; and a voltage correction circuit configured to correct the input to the comparator circuit by either way of; (a) a configuration of the voltage correction circuit including a circuit configured to generate a correction voltage having such a characteristic as increasing by a positive slope along with an increase in the first power supply voltage, a circuit configured to generate a corrected detection voltage by adding the correction voltage to the detection voltage, and a circuit configured to input the corrected detection voltage to the other input node and a reference power supply voltage to the one input node;
or(b) a configuration of the voltage correction circuit including a circuit configured to generate a correction voltage having such a characteristic as reducing by a negative slope along with an increase in the first power supply voltage, a circuit configured to generate a corrected reference voltage by adding the correction voltage to a reference power supply voltage, and a circuit configured to input the corrected reference voltage to the one input node and the detection voltage to the other input node. - View Dependent Claims (20)
-
-
21. A battery pack comprising:
-
a secondary battery; first and second battery connection nodes to which the secondary battery is coupled; first and second external terminals to which a load or a charger is to be coupled; a first current path arranged between the first battery connection node and the first external terminal; a second current path arranged between the second battery connection node and the second external terminal; a switch circuit inserted in the second current path so as to control a charge current and a discharge current flowing in the secondary battery and made up of a first FET configured to control a flow of the discharge current and a second FET configured to control a flow of the charge current; and a switch control circuit configured to control on/off of the switch circuit, wherein the switch control circuit is provided with; a first power-supply node connected to the second current path at a line coupling the second battery connection node and one node on the second current path of the switch circuit; a second power-supply node coupled to the first current path and supplied with a first power supply voltage from the secondary battery via the first battery connection node with a voltage on the first power-supply node serving as a reference; first and second control nodes; a first driver circuit configured to supply a control voltage to a gate of the first FET via the first control node; a second driver circuit configured to supply a control voltage to a gate of the second FET via the second control node; a detection node connected to the second current path at a line coupling the second external terminal and the other node on the second current path of the switch circuit; a first detection circuit configured to monitor the charge current flowing to the secondary battery based on a detection voltage generated at the detection node, and output a detection signal when the detection voltage reaches a predetermined value; a second detection circuit configured to monitor the discharge current, and output a detection signal when the current exceeds a predetermined current; and a control circuit configured to shut off the charge current or the discharge current flowing in the secondary battery by supplying a control voltage via the corresponding driver circuit to shut off the corresponding FET when the detection signal is output, and wherein at least either one of the first and second detection circuits is provided with; a comparator circuit configured to determine, based on a voltage of one input node of the comparator circuit serving as a reference, magnitude of a voltage of the other input node of the comparator circuit, and output the detection signal based on a result of the determination; and a voltage correction circuit configured to generate a correction voltage having such a characteristic that varies by a slope approximating a slope of the detection voltage which decreases along with an increase in the first power supply voltage, add the correction voltage to the detection voltage or a reference power supply voltage with such a polarity as canceling the slope of the voltage variation caused in the detection voltage by the slope of variation in the correction voltage, and input the thus corrected voltage to the comparator circuit.
-
-
22. A battery pack comprising:
-
a secondary battery; first and second battery connection nodes to which the secondary battery is coupled; first and second external terminals to which a load or a charger is to be coupled; a first current path arranged between the first battery connection node and the first external terminal; a second current path arranged between the second battery connection node and the second external terminal; a switch circuit inserted in the second current path so as to control a charge current and a discharge current flowing in the secondary battery and made up of a first FET configured to control a flow of the discharge current and a second FET configured to control a flow of the charge current; and a switch control circuit configured to control on/off of the switch circuit, wherein the switch control circuit is provided with; a first power-supply node connected to the second current path at a line coupling the second battery connection node and one node on the second battery connection of the switch circuit; a second power-supply node coupled to the first current path and supplied with a first power supply voltage from the secondary battery via the first battery connection node with the voltage on the first power-supply node serving as a reference; first and second control nodes; a first driver circuit configured to supply a control voltage to a gate of the first FET via the first control node; a second driver circuit configured to supply a control voltage to a gate of the second FET via the second control node; a detection node connected to the second current path at a line coupling the second external terminal and the other node on the second current path of the switch circuit; a first detection circuit configured to monitor the charge current flowing to the secondary battery based on a detection voltage generated at the detection node, and output a detection signal when the detection voltage reaches a predetermined value; a second detection circuit configured to monitor the discharge current, and output a detection signal when the current exceeds a predetermined current; and a control circuit configured to shut off the charge current or the discharge current flowing in the secondary battery by supplying a control voltage via the corresponding driver circuit to shut off the corresponding FET when the detection signal is output, and wherein at least either one of the first and second detection circuits is provided with; a comparator circuit configured to determine, based on a voltage of one input node of the comparison circuit serving as a reference, magnitude of a voltage of the other input node of the comparison circuit, and output the detection signal based on a result of the determination; and a voltage correction circuit configured to generate a correction voltage having a characteristic that is approximated by a linear function or a quadratic function with respect to a characteristic of the detection voltage varied depending on the first power supply voltage, add the correction voltage to the detection voltage or a reference power supply voltage with such a polarity as canceling a slope of a voltage variation caused in the detection voltage by a slope of variation in the correction voltage, and input the correction voltage thus obtained to the comparator circuit.
-
Specification