Secondary battery protection integrated circuit and battery device

Abstract

To easily change a circuit characteristic such as determination voltage.SOLUTION: A secondary battery protection integrated circuit comprises: a plurality of terminals including a power supply terminal, a ground terminal, a selection terminal, and a control terminal; a selection circuit that changes a first determination voltage in accordance with a resistance value of a first resistance element externally connected to the selection terminal; and a control circuit that outputs a signal for controlling charging or discharging of a secondary battery from the control terminal in accordance with a result of comparison of a power supply voltage between the power supply terminal and the ground terminal with the first determination voltage.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to a secondary battery protection integrated circuit and a battery device.

Background Art

[0002] Conventionally, a battery protection integrated circuit including a memory unit that stores characteristic setting data for setting circuit characteristics of the battery protection integrated circuit, and a setting circuit that sets the circuit characteristics of the battery protection integrated circuit to circuit characteristics corresponding to the content of the characteristic setting data read from the memory unit is known. When the characteristic setting data written to the memory unit changes, the circuit characteristics of the battery protection integrated circuit change, so it is possible to cope with a plurality of different circuit characteristics with a common circuit configuration.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the case of a method of writing characteristic setting data for setting circuit characteristics such as a determination voltage to a memory, facilities and techniques for reliably writing the data to the memory are required. Therefore, it may be difficult to cope with data writing to the memory.

[0005] The present disclosure provides a secondary battery protection integrated circuit and a battery device in which circuit characteristics such as a determination voltage can be easily changed.

Means for Solving the Problems

[0006] The secondary battery protection integrated circuit according to the first aspect is a plurality of terminals including a power supply terminal, a ground terminal, a selection terminal, and a control terminal, A selection circuit that changes a first determination voltage according to the resistance value of a first resistance element externally connected to the selection terminal; A control circuit that outputs, from the control terminal, a signal for controlling charging or discharging of the secondary battery according to a result of comparing a power supply voltage between the power supply terminal and the ground terminal with the first determination voltage.

[0007] The secondary battery protection integrated circuit according to the second aspect A plurality of terminals including a power supply terminal, a ground terminal, a selection terminal, a monitoring terminal, and a control terminal; A selection circuit that changes a second determination voltage according to the resistance value of a second resistance element externally connected to the selection terminal; A control circuit that outputs, from the control terminal, a signal for controlling charging or discharging of the secondary battery according to a result of comparing a first potential difference between the monitoring terminal and the power supply terminal or a second potential difference between the monitoring terminal and the ground terminal with the second determination voltage.

[0008] The secondary battery protection integrated circuit according to the third aspect A plurality of terminals including a power supply terminal, a ground terminal, a first selection terminal, a second selection terminal, a monitoring terminal, and a control terminal; A selection circuit that changes a first determination voltage according to the resistance value of a first resistance element externally connected to the first selection terminal and changes a second determination voltage according to the resistance value of a second resistance element externally connected to the second selection terminal; A control circuit that outputs, from the control terminal, a signal for controlling charging or discharging of the secondary battery according to a result of comparing a power supply voltage between the power supply terminal and the ground terminal with the first determination voltage, and outputs, from the control terminal, a signal for controlling charging or discharging of the secondary battery according to a result of comparing a first potential difference between the monitoring terminal and the power supply terminal or a second potential difference between the monitoring terminal and the ground terminal with the second determination voltage.

[0009] The secondary battery protection integrated circuit according to the fourth aspect A plurality of terminals including a power supply terminal, a ground terminal, a selection terminal, a monitoring terminal, and a control terminal; A selection circuit that changes a first determination voltage and a second determination voltage according to a resistance value of a first resistance element externally connected to the selection terminal; According to a result of comparing a power supply voltage between the power supply terminal and the ground terminal with the first determination voltage, a signal for controlling charging or discharging of the secondary battery is output from the control terminal, and a first potential difference between the monitoring terminal and the power supply terminal or a second potential difference between the monitoring terminal and the ground terminal is compared with the second determination voltage, and a control circuit that outputs a signal for controlling charging or discharging of the secondary battery from the control terminal.

Effect of the Invention

[0010] According to the present disclosure, circuit characteristics such as determination voltage can be easily changed.

Brief Description of the Drawings

[0011]

Figure 1

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Embodiments for Carrying Out the Invention

[0012] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings.

[0013] FIG. 1 is a circuit block diagram showing an example of a system including a secondary battery protection integrated circuit according to the first embodiment. The system 501 shown in FIG. 1 includes a battery device 401 and an electronic device 300.

[0014] The electronic device 300 is a device connected to the battery device 401. The electronic device 300 may be a charger that charges the battery device 401, or a load that operates with the power supplied from the battery device 401. Specific examples of such a load include a mobile phone, a smartphone, a tablet device, earphones, etc. The electronic device 300 is not limited to these devices.

[0015] The battery device 401 may be externally attached to the electronic device 300 or may be built into the electronic device 300. The battery device 401 is, for example, a battery pack that is detachably housed within the electronic device 300 and can supply power to the electronic device 300 while connected thereto. The battery device 401 and the electronic device 300 are mutually connected via a plurality of terminals (a positive power terminal (terminal P+) and a negative power terminal (terminal P−)) shown in FIG. 1. For example, the terminal P+ and the terminal P− are electrically connected to a charger (electronic device 300) when charging the secondary battery 210.

[0016] The battery device 401 includes a secondary battery 210 and a battery protection device 601.

[0017] The secondary battery 210 is an example of a rechargeable battery. The secondary battery 210 supplies power to the electronic device 300 connected to the terminal P+ and the terminal P−. The secondary battery 210 can be charged by a charger connected to the terminal P+ and the terminal P−. Specific examples of the secondary battery 210 include a lithium-ion battery and a lithium polymer battery. The secondary battery 210 has a positive electrode 211 and a negative electrode 212.

[0018] The battery protection device 601 is an example of a secondary battery protection device that operates using the secondary battery 210 as a power source. The battery protection device 601 protects the secondary battery 210 from overcharging etc. by controlling the charging of the secondary battery 210, and protects the secondary battery 210 from over-discharging etc. by controlling the discharging of the secondary battery 210. The battery protection device 601 includes, for example, the terminal P+, the terminal P−, the terminal B+, the terminal B−, the resistance elements R1, R2, R21, R22, R23, the capacitor C21, the power line 201, the ground line 202, the switch circuit 203, and the protection IC (Integrated Circuit) 101.

[0019] The battery protection device 601 is a component including, for example, a substrate on which at least the protection IC 101 and the resistance elements R1 and R2 are mounted.

[0020] Terminal P+ is an example of a load positive terminal, to which the power line of the electronic device 300 is connected. Terminal P- is an example of a load negative terminal, to which the ground line of the electronic device 300 is connected. Terminal B+ is an example of a battery positive terminal, which is connected to the positive electrode 211 of the secondary battery 210. Terminal B- is an example of a battery negative terminal, which is connected to the negative electrode 212 of the secondary battery 210.

[0021] Terminal B+ and terminal P+ are connected by a power line 201, which is a current path on the positive side. The power line 201 is a power path connecting between terminal B+ and terminal P+. The power line 201 functions as a charging path through which the charging current of the secondary battery 210 flows and a discharging path through which the discharging current of the secondary battery 210 flows.

[0022] Terminal B- and terminal P- are connected by a ground line 202, which is a current path on the negative side. The ground line 202 is a power path connecting between terminal B- and terminal P-. The ground line 202 functions as a charging path through which the charging current of the secondary battery 210 flows and a discharging path through which the discharging current of the secondary battery 210 flows.

[0023] The switch circuit 203 is provided on the ground line 202 between terminal B- and terminal P-. The switch circuit 203 includes, for example, a charging control transistor TR1 and a discharging control transistor TR2, and is a series circuit in which the charging control transistor TR1 and the discharging control transistor TR2 are connected in series. The charging control transistor TR1 is a semiconductor switching element that shuts off the charging path of the secondary battery 210. The discharging control transistor TR2 is a semiconductor switching element that shuts off the discharging path of the secondary battery 210.

[0024] In the case of FIG. 1, the charge control transistor TR1 cuts off the ground line 202 through which the charging current of the secondary battery 210 flows, and the discharge control transistor TR2 cuts off the ground line 202 through which the discharge current of the secondary battery 210 flows. The charge control transistor TR1 and the discharge control transistor TR2 are switching elements that switch between conducting and blocking the ground line 202, and are inserted in series with the ground line 202. The charge control transistor TR1 and the discharge control transistor TR2 are, for example, N-channel type MOSFETs (Metal Oxide Semiconductor Field Effect Transistors).

[0025] The charge control transistor TR1 has a parasitic diode D1 between the drain and the source, with the forward direction being opposite to the direction of the charging current of the secondary battery 210. The charge control transistor TR1 is a switching element inserted in series with the ground line 202 such that the forward direction of the parasitic diode D1 coincides with the direction in which the discharge current of the secondary battery 210 flows.

[0026] The discharge control transistor TR2 has a parasitic diode D2 between the drain and the source, with the forward direction being opposite to the direction of the discharge current of the secondary battery 210. The discharge control transistor TR2 is a switching element inserted in series with the ground line 202 such that the forward direction of the parasitic diode D2 coincides with the direction in which the charging current of the secondary battery 210 flows.

[0027] The protection IC101 is an example of a secondary battery protection integrated circuit. The protection IC101 operates using the secondary battery 210 as a power source.

[0028] The protection IC 101 has a function of protecting the secondary battery 210 from over-discharge and the like by controlling the switch circuit 203. For example, when the protection IC 101 detects abnormal charging (such as overcharging, overcurrent in the charging direction (charging overcurrent), etc.) by the detection circuit 222, it protects the secondary battery 210 from abnormal charging by turning off the charging control transistor TR1. On the other hand, when the protection IC 101 detects abnormal discharging (such as over-discharging, overcurrent in the discharging direction (discharging overcurrent), etc.) by the detection circuit 222, it protects the secondary battery 210 from abnormal discharging by turning off the discharging control transistor TR2.

[0029] The protection IC 101 includes, for example, a charging control terminal (terminal COUT), a discharging control terminal (terminal DOUT), a detection terminal (terminal VM), a power supply terminal (terminal VDD), a ground terminal (terminal VSS), a current detection terminal (terminal CS), a first selection terminal (terminal SEL1), and a second selection terminal (terminal SEL2). These terminals are, for example, external connection terminals for connecting the internal circuit of the protection IC 101 to the outside of the protection IC 101.

[0030] The terminal COUT is connected to the gate (control electrode) of the charging control transistor TR1 and outputs a signal for turning on or off the charging control transistor TR1. The terminal DOUT is connected to the gate (control electrode) of the discharging control transistor TR2 and outputs a signal for turning on or off the discharging control transistor TR2.

[0031] The terminal VM is an example of a monitoring terminal used for monitoring the potential of the terminal P-, and is connected to the terminal P-. The terminal VM is used, for example, by the control circuit 221 in the protection IC 101 to monitor the connection of the electronic device 300 or the charger. The terminal VM is connected to the ground line 202 via the resistance element R23 between the switch circuit 203 and the terminal P-. The terminal VM is electrically connected to the ground line 202 on the side opposite to the secondary battery 210 with respect to the switch circuit 203.

[0032] The terminal VM may be used to detect the charging overcurrent or discharging overcurrent flowing through the secondary battery 210, similar to the terminal CS described later.

[0033] The terminal VDD is the power supply terminal of the protection IC 101 and is connected to the positive electrode 211 of the secondary battery 210 and the power supply line 201 via the resistor element R21. The terminal VSS is the ground terminal of the protection IC 101 and is connected to the negative electrode 212 of the secondary battery 210. The capacitor C21 is connected between the terminal VDD and the terminal VSS. The terminal VSS is connected to the ground line 202 between the switch circuit 203 and the negative electrode 212. In this example, the terminal VSS is connected to the ground line 202 between the resistor element R22 and the negative electrode 212.

[0034] The terminal CS is an example of a monitoring terminal used to monitor the charging current or discharging current flowing through the secondary battery 210, and is connected to the ground line 202 between the resistor element R22 and the switch circuit 203 (the source of the discharge control transistor TR2). The resistor element R22 is inserted in series with the ground line 202. One end of the resistor element R22 is connected to the terminal VSS, and the other end is connected to the terminal CS. The detection circuit 222 in the protection IC 101 can detect the charging overcurrent or discharging overcurrent flowing through the secondary battery 210 by detecting the potential difference between the terminal VSS and the terminal CS. The resistor element R22 functions as a sense resistor for detecting the current flowing through the secondary battery 210.

[0035] The terminal SEL1 is a terminal for selecting the specifications of the first determination voltages (in this example, the overcharge detection voltage Vdet1 and the overdischarge detection voltage Vdet2), and the resistor element R1 is externally connected. The resistor element R1 is an example of a first resistor element provided outside the protection IC 101. The terminal SEL1 is connected to the ground line 202 between the switch circuit 203 and the negative electrode 212 via the resistor element R1. In this example, the terminal SEL1 is connected to the ground line 202 between the resistor element R22 and the negative electrode 212.

[0036] Terminal SEL2 is a terminal for selecting the specifications of the second determination voltage (in this example, the discharge overcurrent detection voltage Vdet3 and the charge overcurrent detection voltage Vdet4), and the resistance element R2 is externally connected. The resistance element R2 is an example of a second resistance element provided outside the protection IC101. Terminal SEL2 is connected to the ground line 202 between the switch circuit 203 and the negative electrode 212 via the resistance element R2. In this example, terminal SEL2 is connected to the ground line 202 between the resistance element R22 and the negative electrode 212.

[0037] The protection IC101 includes a detection circuit 222, a control circuit 221, a first selection circuit 231, and a second selection circuit 232.

[0038] The detection circuit 222 detects overcharging of the secondary battery 210 by monitoring the power supply voltage Vdd between the terminal VDD and the terminal VSS. The detection circuit 222 compares the power supply voltage Vdd with the overcharge detection voltage Vdet1, and generates an overcharge detection signal indicating that overcharging of the secondary battery 210 has been detected when the power supply voltage Vdd is higher than the overcharge detection voltage Vdet1.

[0039] The detection circuit 222 detects the charge overcurrent of the secondary battery 210 by monitoring the potential difference ΔV2 between the terminal VSS and the terminal CS (or the terminal VM). The detection circuit 222 compares the potential difference ΔV2 with the charge overcurrent detection voltage Vdet4, and generates a charge overcurrent detection signal indicating that the charge overcurrent of the secondary battery 210 has been detected when the potential difference ΔV2 is lower than the charge overcurrent detection voltage Vdet4 with respect to the terminal VSS. In other words, the detection circuit 222 generates a charge overcurrent detection signal when the voltage of the terminal CS (or the terminal VM) is lower than the charge overcurrent detection voltage Vdet4 with respect to the terminal VSS.

[0040] The control circuit 221 has a charge control circuit 221a that controls the charging of the secondary battery 210. When overcharging of the secondary battery 210 is continuously detected by the detection circuit 222 for a predetermined detection delay time d1, the charge control circuit 221a outputs a signal (for example, a low-level gate control signal) for switching the charge control transistor TR1 from on to off from the terminal COUT. When an overcharge current of the secondary battery 210 is continuously detected by the detection circuit 222 for a predetermined detection delay time d4, the charge control circuit 221a outputs a signal (for example, a low-level gate control signal) for switching the charge control transistor TR1 from on to off from the terminal COUT.

[0041] By turning off the charge control transistor TR1, the control circuit 221 prohibits the current flowing in the charging direction of the secondary battery 210 from flowing to the ground line 202. As a result, the charging of the secondary battery 210 stops, so that the protection IC101 can protect the secondary battery 210 from overcharging or overcharge current.

[0042] The detection circuit 222 detects over-discharge of the secondary battery 210 by monitoring the power supply voltage Vdd between the terminal VDD and the terminal VSS. The detection circuit 222 compares the power supply voltage Vdd with the over-discharge detection voltage Vdet2, and generates an over-discharge detection signal indicating that over-discharge of the secondary battery 210 has been detected when the power supply voltage Vdd is lower than the over-discharge detection voltage Vdet2.

[0043] The detection circuit 222 detects a discharge overcurrent of the secondary battery 210 by monitoring the potential difference ΔV2 between the terminal VSS and the terminal CS (or the terminal VM). The detection circuit 222 compares the potential difference ΔV2 with the discharge overcurrent detection voltage Vdet3, and generates a discharge overcurrent detection signal indicating that a discharge overcurrent of the secondary battery 210 has been detected when the potential difference ΔV2 is higher than the discharge overcurrent detection voltage Vdet3 with respect to the terminal VSS. In other words, the detection circuit 222 generates a discharge overcurrent detection signal when the voltage of the terminal CS (or the terminal VM) is higher than the discharge overcurrent detection voltage Vdet3 with respect to the terminal VSS.

[0044] The control circuit 221 has a discharge control circuit 221b that controls the discharge of the secondary battery 210. When the over-discharge of the secondary battery 210 is continuously detected by the detection circuit 222 for a predetermined detection delay time d2, the discharge control circuit 221b outputs a signal (for example, a low-level gate control signal) for switching the discharge control transistor TR2 from on to off from the terminal DOUT. When the over-discharge current of the secondary battery 210 is continuously detected by the detection circuit 222 for a predetermined detection delay time d3, the discharge control circuit 221b outputs a signal (for example, a low-level gate control signal) for switching the discharge control transistor TR2 from on to off from the terminal DOUT.

[0045] By turning off the discharge control transistor TR2, the control circuit 221 prohibits the current flowing in the direction of discharging the secondary battery 210 from flowing to the ground line 202. As a result, the discharge of the secondary battery 210 stops, so that the protection IC101 can protect the secondary battery 210 from over-discharge or over-discharge current.

[0046] The first selection circuit 231 changes the overcharge detection voltage Vdet1 according to the resistance value of the resistance element R1 externally connected to the terminal SEL1. Thus, by changing the resistance value of the resistance element R1 externally attached to the protection IC101, the overcharge detection voltage Vdet1 can be easily changed. By using the resistance element R1 externally attached to the protection IC101, it becomes easy to change the specification of the overcharge detection voltage Vdet1 in a state where the protection IC101 is mounted on the substrate.

[0047] The first selection circuit 231 changes the overcharge detection voltage Vdet1 to a voltage value corresponding to the resistance value of the resistance element R1 externally connected to the terminal SEL1 according to, for example, a correspondence relationship preset in the first selection circuit 231. In this case, if the resistance value of the resistance element R1 externally connected to the terminal SEL1 is changed to a specified resistance value, the protection IC101 can be commonly used for products with different required specifications of the overcharge detection voltage Vdet1 (for example, the battery protection device 601 or the battery device 401). As a result, for example, the simplification of inventory management and the reduction of production man-hours are realized.

[0048] The first selection circuit 231 has a first potential change circuit that changes the potential of terminal SEL1 (first selection potential VSEL1) according to the resistance value of the resistance element R1 externally connected to terminal SEL1, and the overcharge detection voltage Vdet1 may be changed to a voltage value corresponding to the first selection potential VSEL1. Thereby, if the resistance value of the resistance element R1 externally attached to the protection IC101 is changed, the first selection potential VSEL1 changes, so that the overcharge detection voltage Vdet1 can be easily changed. The first selection circuit 231 changes the overcharge detection voltage Vdet1 to a voltage value corresponding to the first selection potential VSEL1 according to, for example, a correspondence relationship preset in the first selection circuit 231.

[0049] The first selection circuit 231 changes the overdischarge detection voltage Vdet2 according to the resistance value of the resistance element R2 externally connected to terminal SEL1. When the first selection circuit 231 changes the overdischarge detection voltage Vdet2, it is the same as the case where the first selection circuit 231 changes the overcharge detection voltage Vdet1, so the description thereof is omitted by referring to the above description.

[0050] The second selection circuit 232 changes the charge overcurrent detection voltage Vdet4 according to the resistance value of the resistance element R2 externally connected to terminal SEL2. Thereby, if the resistance value of the resistance element R2 externally attached to the protection IC101 is changed, the charge overcurrent detection voltage Vdet4 can be changed. By using the resistance element R2 externally attached to the protection IC101, even when the protection IC101 is mounted on the substrate, it becomes easy to change the specification of the charge overcurrent detection voltage Vdet4.

[0051] The second selection circuit 232 changes the charge overcurrent detection voltage Vdet4 to a voltage value corresponding to the resistance value of the resistance element R2 externally connected to terminal SEL2 according to, for example, a correspondence relationship preset in the second selection circuit 232. In this case, if the resistance value of the resistance element R2 externally connected to terminal SEL2 is changed to a specified resistance value, the protection IC101 can be commonly used for products with different required specifications of the charge overcurrent detection voltage Vdet4 (for example, the battery protection device 601 or the battery device 401, etc.). Thereby, for example, simplification of inventory management and reduction of production man-hours are realized.

[0052] The second selection circuit 232 has a second potential change circuit that changes the potential (second selection potential VSEL2) of the terminal SEL2 according to the resistance value of the resistance element R2 externally connected to the terminal SEL2, and the charging overcurrent detection voltage Vdet4 may be changed to a voltage value corresponding to the second selection potential VSEL2. Thereby, if the resistance value of the resistance element R2 externally attached to the protection IC 101 is changed, the second selection potential VSEL2 changes, so that the charging overcurrent detection voltage Vdet4 can be easily changed. The second selection circuit 232 changes the charging overcurrent detection voltage Vdet4 to a voltage value corresponding to the second selection potential VSEL2 according to, for example, a correspondence relationship preset in the second selection circuit 232.

[0053] The second selection circuit 232 changes the discharge overcurrent detection voltage Vdet3 according to the resistance value of the resistance element R2 externally connected to the terminal SEL2. When the second selection circuit 232 changes the discharge overcurrent detection voltage Vdet3, it is the same as the case where the second selection circuit 232 changes the charging overcurrent detection voltage Vdet4, so the description thereof is omitted by referring to the above description.

[0054] FIG. 2 is a diagram for explaining a configuration example of the first selector in the first selection circuit. The first selection circuit 231 includes the first selector 241 as a component. The first selector 241 is a circuit that selects one selection signal corresponding to the resistance value of the resistance element R1 externally connected to the terminal SEL1 from a plurality of different selection signals S11, S12, S13 when the first read signal ΦREAD1 is in an active state. The plurality of different selection signals S11, S12, S13 are selection signal candidates preset in the first decoder 271 in the first selector 241.

[0055] The first selector 241 includes a first potential change circuit 251 that changes the potential of the terminal SEL1 (first selection potential VSEL1) according to the resistance value of the resistance element R1 externally connected to the terminal SEL1 by the reference resistance Rx and the switch LD2. The reference resistance Rx is inserted in series in the current path between the first selection terminal SEL1 and the terminal VDD. When the switch LD2 is turned on by the first read signal ΦREAD1, the first selection terminal SEL1 is pull-up connected to the terminal VDD by the reference resistance Rx, so the first selection potential VSEL1 changes according to the resistance value of the resistance element R1.

[0056] The first selector 241 includes a first encoder 261. The first encoder 261 is a circuit that encodes the first selection potential VSEL1 and outputs a code (LV11, LV12, LV13, LV14) corresponding to the resistance value of the resistance element R1. The first encoder 261 has a plurality of series resistors inserted in series between the terminal VDD and the terminal VSS, and a plurality of comparators that compare the first selection potential VSEL1 with a plurality of potentials V1, V2, V3, V4. The plurality of different potentials V1, V2, V3, V4 are generated by voltage division by those plurality of series resistors when the switch LD1 is turned on by the first read signal ΦREAD1.

[0057] The first selector 241 includes a first decoder 271. The first decoder 271 is a circuit that converts the code (LV11, LV12, LV13, LV14) into a selection signal and an error signal ERROR. The first decoder 271 outputs selection signals S11, S12, S13 and an error signal ERROR that are the result of selecting the code (LV11, LV12, LV13, LV14). The selection signals S11, S12, S13 and the error signal ERROR output from the first decoder 271 are held in the latch circuit LT.

[0058] FIG. 3 is a table for explaining an operation example of the first selector. The first selector 241 becomes operable when the first read signal ΦREAD1 is in an active state (in this example, when it is at a high level "H"). In the operable state, the first selector 241 outputs from the first decoder 271 the result of selecting the first selection potential VSEL1 corresponding to the resistance value of the resistance element R1 externally connected to the terminal SEL1. In the first selector 241, when the first read signal ΦREAD1 transitions from the active state to the inactive state (in this example, a low level "L"), the selected result is held in the latch circuit LT.

[0059] For example, when the first selection potential VSEL1 is higher than the potential of the terminal VSS and equal to or lower than the potential V1, or higher than the potential V4 and equal to or lower than the potential of the terminal VDD, the first selector 241 selects the error signal ERROR, and the error signal ERROR is held in the latch circuit LT. When the first selection potential VSEL1 is higher than the potential V1 and equal to or lower than the potential V2, the first selector 241 holds the selected selection signal S11 in the latch circuit LT. In this way, the first selector 241 selects a selection signal according to the correspondence shown in FIG. 3, and the selection signal is held in the latch circuit LT.

[0060] The current supplied to the first selector 241 is cut off when the first read signal ΦREAD1 is in the inactive state. Thereby, since the current consumption of the first selector 241 is reduced, the power consumption of the protection IC 101 is suppressed. In the case of FIG. 2, when the first read signal ΦREAD1 is in the inactive state, the switches LD1 and LD2 turn off, so the current flowing through the reference resistor Rx and the plurality of series resistors is reduced.

[0061] For example, when over-discharge of the secondary battery 210 is detected, the above control circuit 221 activates the first read signal ΦREAD1, and when over-discharge of the secondary battery 210 is not detected, the first read signal ΦREAD1 is deactivated. Thereby, the first selector 241 operates only during a specific period in which over-discharge is detected and stops during other periods, so that the effect of suppressing the power consumption of the protection IC 101 is improved. Also, the first read signal ΦREAD1 can be a pulse signal having an active state shorter than the time during which over-discharge is detected when over-discharge is detected. As a result, the effect of suppressing the power consumption of the protection IC 101 can be effectively improved.

[0062] The first selection circuit 231 outputs an error signal ERROR when the resistance value of the resistance element R1 is higher than a first predetermined value (in this example, when the first selection potential VSEL1 is higher than the potential V4 and equal to or lower than the potential of the terminal VDD). Alternatively, the first selection circuit 231 outputs an error signal ERROR when the resistance value of the resistance element R1 is lower than a second predetermined value (in this example, when the first selection potential VSEL1 is higher than the potential of the terminal VSS and equal to or lower than the potential V1). Thereby, it is possible to detect an abnormality such as the absence of the externally attached resistance element R1 or a short circuit of the terminal SEL1 in the protection IC 101.

[0063] For example, when the error signal ERROR is output, the above control circuit 221 outputs a signal for stopping the charging of the secondary battery 210 from the terminal COUT, outputs a signal for stopping the discharging of the secondary battery 210 from the terminal DOUT, or performs both. Thereby, safety against an abnormality of the resistance element R1 is ensured.

[0064] FIG. 4 is a diagram for explaining a configuration example of a second selector in the second selection circuit. The second selection circuit 232 includes a second selector 242 as a component. The second selector 242 is a circuit that selects one selection signal corresponding to the resistance value of a resistance element R2 externally connected to a terminal SEL2 from a plurality of different selection signals S21, S22, and S23 when a second read signal ΦREAD2 is in an active state. The plurality of different selection signals S21, S22, and S23 are selection signal candidates preset in a second decoder 272 in the second selector 242. The second read signal ΦREAD2 may be the same signal as or different from the first read signal ΦREAD1.

[0065] The second selector 242 includes a second potential change circuit 252 that changes the potential (second selection potential VSEL2) of the terminal SEL2 according to the resistance value of the resistance element R2 externally connected to the terminal SEL2 by a reference resistor Rx and a switch LD2. The reference resistor Rx is inserted in series in a current path between the second selection terminal SEL2 and a terminal VDD. When the switch LD2 is turned on by the second read signal ΦREAD2, the second selection terminal SEL2 is pull-up connected to the terminal VDD by the reference resistor Rx, so the second selection potential VSEL2 changes according to the resistance value of the resistance element R2.

[0066] The second selector 242 includes a second encoder 262. The second encoder 262 is a circuit that encodes the second selection potential VSEL2 and outputs a code (LV21, LV22, LV23, LV24) corresponding to the resistance value of the resistance element R2. The second encoder 262 has a plurality of series resistors inserted in series between a terminal VDD and a terminal VSS, and a plurality of comparators that compare the second selection potential VSEL2 with a plurality of potentials V1, V2, V3, and V4. The plurality of different potentials V1, V2, V3, and V4 are generated by voltage division by those plurality of series resistors when a switch LD1 is turned on by the second read signal ΦREAD2.

[0067] The second selector 242 includes a second decoder 272. The second decoder 272 is a circuit that converts a code (LV21, LV22, LV23, LV24) into selection signals and an error signal ERROR. The second decoder 272 outputs selection signals S21, S22, S23 and an error signal ERROR that are the results of decoding the code (LV21, LV22, LV23, LV24). The selection signals S21, S22, S23 and the error signal ERROR output from the second decoder 272 are held in the latch circuit LT.

[0068] Figure 5 is a table for explaining an operation example of the second selector. The second selector 242 becomes operable when the second read signal ΦREAD2 is in an active state (in this example, when it is at a high level "H"). In the operable state, the second selector 242 outputs from the second decoder 272 the result of selecting a second selection potential VSEL2 corresponding to the resistance value of the resistive element R2 externally connected to the terminal SEL2. In the second selector 242, when the second read signal ΦREAD2 transitions from the active state to the inactive state (in this example, to a low level "L"), the selected result is held in the latch circuit LT.

[0069] For example, when the second selection potential VSEL2 is higher than the potential of the terminal VSS and equal to or lower than the potential V1, or higher than the potential V4 and equal to or lower than the potential of the terminal VDD, the second selector 242 selects the error signal ERROR, and the error signal ERROR is held in the latch circuit LT. When the second selection potential VSEL2 is higher than the potential V1 and equal to or lower than the potential V2, the second selector 242 holds the selected selection signal S21 in the latch circuit LT. In this way, the second selector 242 selects a selection signal according to the correspondence shown in Figure 5, and the selection signal is held in the latch circuit LT.

[0070] The current supplied to the second selector 242 is cut off when the second read signal ΦREAD2 is in the inactive state. As a result, the power consumption of the second selector 242 is reduced, and thus the power consumption of the protection IC 101 is suppressed. In the case of FIG. 4, when the second read signal ΦREAD2 is in the inactive state, the switches LD1 and LD2 are turned off, so that the current flowing through the reference resistor Rx and the plurality of series resistors is reduced.

[0071] For example, when over-discharge of the secondary battery 210 is detected, the control circuit 221 described above sets the second read signal ΦREAD2 to the active state, and when over-discharge of the secondary battery 210 is not detected, sets the second read signal ΦREAD2 to the inactive state. As a result, the second selector 242 operates only during a specific period in which over-discharge is detected and stops during other periods, so that the effect of suppressing the power consumption of the protection IC 101 is improved. Further, the second read signal ΦREAD2 can be a pulse signal having an active state shorter than the time during which over-discharge is detected when over-discharge is detected. As a result, the effect of suppressing the power consumption of the protection IC 101 can be effectively improved.

[0072] The second selection circuit 232 outputs an error signal ERROR when the resistance value of the resistance element R2 is higher than a first predetermined value (in this example, when the second selection potential VSEL2 is higher than the potential V4 and equal to or lower than the potential of the terminal VDD). Alternatively, the second selection circuit 232 outputs an error signal ERROR when the resistance value of the resistance element R2 is lower than a second predetermined value (in this example, when the second selection potential VSEL2 is higher than the potential of the terminal VSS and equal to or lower than the potential V1). As a result, it is possible to detect an abnormality such as the absence of the externally attached resistance element R2 or a short circuit of the terminal SEL2 in the protection IC 101.

[0073] For example, when the error signal ERROR is output, the control circuit 221 described above outputs a signal for stopping the charging of the secondary battery 210 from the terminal COUT, outputs a signal for stopping the discharging of the secondary battery 210 from the terminal DOUT, or performs both. As a result, safety against an abnormality of the resistance element R2 is ensured.

[0074] FIG. 6 is a configuration diagram showing a first example of the first selection circuit. Since the first selection circuit 231 and the second selection circuit 232 have the same configuration and function, the description of the first example of the second selection circuit 232 is omitted by referring to the description of the first example of the first selection circuit 231. The first selection circuit 231A shown in FIG. 6 is a first example of the first selection circuit 231.

[0075] When k is an integer of 2 or more, the first selection circuit 231A adjusts the overcharge detection voltage Vdet1 to any one of k kinds of voltage values. FIG. 6 illustrates the case where k = 3. The first selection circuit 231A includes a first selector 241, a trimming circuit 291, and an adjustment circuit 281.

[0076] The first selector 241 is a circuit that selects, when the first read signal ΦREAD1 is in an active state, one selection signal corresponding to the resistance value of the resistor element R1 externally connected to the terminal SEL1 from among k (in this example, 3) different selection signals S11, S12, and S13. The trimming circuit 291 has a plurality (= k × n) of trimming elements. n is an integer of 2 or more, and in this example, k = 3. The first selector 241 selects a plurality of trimming elements corresponding to the resistance value of the resistor element R1 (in this example, the first selection potential VSEL1) from among the plurality of trimming elements F11, F12, F13, F21, F22, F23, ···, Fn1, Fn2, Fn3 in the trimming circuit 291.

[0077] The trimming circuit 291 includes a plurality (= 3×n) of trimming elements F11, F12, F13, F21, F22, F23, ···, Fn1, Fn2, Fn3, a plurality (= 3×n) of switch elements N11, N12, N13, N21, N22, N23, ···, Nn1, Nn2, Nn3, and n resistors RD1, RD2, ···, RDn. The plurality of trimming elements F11, F12, F13, F21, F22, F23, ···, Fn1, Fn2, Fn3 are each connected in series to the corresponding switch elements N11, N12, N13, N21, N22, N23, ···, Nn1, Nn2, Nn3. The trimming element is, for example, a fuse element that can be cut by a laser irradiated from the outside of the protection IC101. The trimming circuit 291 may be an OTP (One Time Programmable) memory.

[0078] The adjustment circuit 281 adjusts the overcharge detection voltage Vdet1 to a voltage value corresponding to the trimming state of each of the plurality of trimming elements selected by the first selector 241. The adjustment circuit 281 includes n latch circuits LT that hold the trimming state of each of the plurality of trimming elements, a resistor RH, resistors RL (n trimming resistors R1 to Rn), and n switch elements M1 to Mn.

[0079] In the adjustment circuit 281, when the first read signal ΦREAD1 transitions from the active state to the inactive state (in this example, the low level "L"), the trimming state of each of the plurality of trimming elements selected by the first selector 241 is held by the plurality of latch circuits LT. The plurality of latch circuits LT output a signal representing their holding state.

[0080] The n switch elements M1 to Mn are each connected in parallel to the corresponding trimming resistors R1 to Rn and are turned on or off by the output of the corresponding latch circuit LT.

[0081] When the power supply voltage Vdd rises, the detection voltage VIN+ obtained by dividing the power supply voltage Vdd by the resistors RH and RL also rises. When the detection voltage VIN+ exceeds the reference voltage Vref, the output of the comparator 222a in the detection circuit 222 is inverted. The power supply voltage Vdd at the time of this inversion is defined as the overcharge detection voltage Vdet1.

[0082] FIG. 6 illustrates a case where a plurality of trimming elements corresponding to one selection signal selected by the first selector 241 among the plurality of selection signals S11, S12, S13 are selected. By changing the resistance value of the resistor RL according to the trimming state of each of the selected plurality of trimming elements, the overcharge detection voltage Vdet1 is adjusted to any one of k types (three types in this example) of voltage values.

[0083] When the selection signal S11 is selected by the first selector 241, the overcharge detection voltage Vdet1 is adjusted to, for example, 4.2 volts. When the selection signal S11 is selected, only the switch elements N11, N21, ···, Nn1 corresponding to the selection signal S11 are turned on, so the trimming elements F11, F21, ···, Fn1 are selected (become effective). Each of the trimming elements F11, F21, ···, Fn1 selected by the selection signal S11 is trimmed so that the overcharge detection voltage Vdet1 becomes 4.2 volts. The resistance value of the resistor RL is adjusted by the adjustment circuit 281 to a resistance value corresponding to the trimming state of each of the trimming elements F11, F21, ···, Fn1. As a result, the overcharge detection voltage Vdet1 is finely adjusted to 4.2 volts. If the resistance value of the resistor RL when the overcharge detection voltage Vdet1 becomes 4.2 volts is RL1, the overcharge detection voltage Vdet1 is represented by "Vdet1 = (RH + RL1) × Vref / RL1".

[0084] When the selection signal S12 is selected by the first selector 241, the overcharge detection voltage Vdet1 is adjusted to, for example, 4.3 volts. When the selection signal S12 is selected, only the switch elements N12, N22, ···, Nn2 corresponding to the selection signal S12 are turned on, so the trimming elements F12, F22, ···, Fn2 are selected (become effective). Each of the trimming elements F12, F22, ···, Fn2 selected by the selection signal S12 is trimmed so that the overcharge detection voltage Vdet1 becomes 4.3 volts. The resistance value of the resistor RL is adjusted by the adjustment circuit 281 to a resistance value corresponding to the trimming state of each of the trimming elements F12, F22, ···, Fn2. As a result, the overcharge detection voltage Vdet1 is finely adjusted to 4.3 volts. If the resistance value of the resistor RL when the overcharge detection voltage Vdet1 becomes 4.3 volts is RL2, the overcharge detection voltage Vdet1 is expressed as "Vdet1 = (RH + RL2) × Vref / RL2".

[0085] When the selection signal S13 is selected by the first selector 241, the overcharge detection voltage Vdet1 is adjusted to, for example, 4.4 volts. When the selection signal S13 is selected, only the switch elements N13, N23, ···, Nn3 corresponding to the selection signal S13 are turned on, so the trimming elements F13, F23, ···, Fn3 are selected (become effective). Each of the trimming elements F13, F23, ···, Fn3 selected by the selection signal S13 is trimmed so that the overcharge detection voltage Vdet1 becomes 4.4 volts. The resistance value of the resistor RL is adjusted by the adjustment circuit 281 to a resistance value corresponding to the trimming state of each of the trimming elements F13, F23, ···, Fn3. As a result, the overcharge detection voltage Vdet1 is finely adjusted to 4.4 volts. If the resistance value of the resistor RL when the overcharge detection voltage Vdet1 becomes 4.4 volts is RL3, the overcharge detection voltage Vdet1 is expressed as "Vdet1 = (RH + RL3) × Vref / RL3".

[0086] The first selection circuit 231A adjusts the overdischarge detection voltage Vdet2 in the same manner as in the above-described case of adjusting the overcharge detection voltage Vdet1. The second selection circuit 232 adjusts the discharge overcurrent detection voltage Vdet3 or the charge overcurrent detection voltage Vdet4 in the same manner as in the above-described case where the first selection circuit 231A adjusts the overcharge detection voltage Vdet1.

[0087] For example, with the configuration shown in FIG. 7, the second selection circuit 232 adjusts the charge overcurrent detection voltage Vdet4. The second selection circuit 232A shown in FIG. 7 is an example of the second selection circuit 232.

[0088] FIG. 8 is a configuration diagram showing a second example of the first selection circuit. Since the first selection circuit 231 and the second selection circuit 232 have the same configuration and function, the description of the second example of the second selection circuit 232 is omitted by referring to the description of the second example of the first selection circuit 231. The first selection circuit 231B shown in FIG. 8 is a second example of the first selection circuit 231. For the same configuration as the first example of the first selection circuit 231, the above description is referred to. The first selection circuit 231B includes a first selector 241, a trimming circuit 291, and an adjustment circuit 282. The first selector 241 and the trimming circuit 291 may be the same as in the case of the first selection circuit 231A.

[0089] The adjustment circuit 282 adjusts the overcharge detection voltage Vdet1 to a voltage value corresponding to the trimming state of each of the plurality of trimming elements selected by the first selector 241. The adjustment circuit 282 includes n latch circuits LT that hold the trimming state of each of the plurality of trimming elements, a resistor RH (resistor R0), resistors RL (n trimming resistors R1 to Rn), and n switch elements M1 to Mn. n is an integer of 2 or more.

[0090] In the adjustment circuit 282, when the first read signal ΦREAD1 transitions from the active state to the inactive state (in this example, the low level "L"), the trimming state of each of the plurality of trimming elements selected by the first selector 241 is held by the plurality of latch circuits LT. The plurality of latch circuits LT output a signal representing their holding state.

[0091] One end of each of the n switch elements M1 to Mn is connected to one end of the corresponding trimming resistor R1 to Rn, respectively. Each of the n switch elements M1 to Mn is turned on or off by the output of the corresponding latch circuit LT. The other ends of the n switch elements M1 to Mn are commonly connected to each other and connected to the non-inverting input terminal of the comparator 222a.

[0092] Similar to the first selection circuit 231A described above, the first selection circuit 231B finely adjusts the overcharge detection voltage Vdet1. The first selection circuit 231A adjusts the resistance value of the resistance RL by short-circuiting the trimming resistor, while the first selection circuit 231B adjusts the resistance value of the resistance RL by selecting the node between the trimming resistors. Similar to the first selection circuit 231A, in the case of the first selection circuit 231B as well, the overcharge detection voltage Vdet1 is represented by "Vdet1 = (RH + RL) × Vref / RL".

[0093] Similar to the above-described case where the first selection circuit 231B adjusts the overcharge detection voltage Vdet1, the first selection circuit 231B adjusts the overdischarge detection voltage Vdet2. Similar to the above-described case where the first selection circuit 231B adjusts the overcharge detection voltage Vdet1, the second selection circuit 232 adjusts the discharge overcurrent detection voltage Vdet3 or the charge overcurrent detection voltage Vdet4.

[0094] FIG. 9 is a configuration diagram showing a third example of the first selection circuit. Since the first selection circuit 231 and the second selection circuit 232 have the same configuration and function, the description of the third example of the second selection circuit 232 is omitted by referring to the description of the third example of the first selection circuit 231. The first selection circuit 231C shown in FIG. 9 is the third example of the first selection circuit 231. For the same configuration as the first or second example of the first selection circuit 231, the above description is referred to.

[0095] When k is an integer of 2 or more, the first selection circuit 231C adjusts the overcharge detection voltage Vdet1 to any one of k voltage values. Fig. 6 illustrates the case where k is 3. The first selection circuit 231C includes a first selector 241, a trimming circuit 273, and an adjustment circuit 283. The first selector 241 may be the same as in the case of the first selection circuit 231A.

[0096] When the first read signal ΦREAD1 is in the active state, the first selector 241 is a circuit that selects one selection signal corresponding to the resistance value of the resistor element R1 externally connected to the terminal SEL1 from among k (in this example, 3) different selection signals S11, S12, S13. The first selector 241 selects a potential corresponding to the selected one selection signal from among k (in this example, 3) different potentials V42, V43, V44, and sets the selected potential to the potential VN on the reference potential side of the comparator 222a. The first selection circuit 231C adjusts the overcharge detection voltage Vdet1 to any one of k (in this example, three) voltage values by setting the potential VN according to the selected one selection signal.

[0097] The trimming circuit 273 has k (in this example, 3) trimming elements F1, F2, F3, k (in this example, 3) resistors Rd1, Rd2, Rd3, and a trimming control circuit 273a. The plurality of resistors Rd1, Rd2, Rd3 are each connected in series to the corresponding trimming element F1, F2, F3. The trimming control circuit 273a is a circuit that decodes the trimming state of each of the k (in this example, 3) trimming elements F1, F2, F3 into 2 k (in this example, 8) signals.

[0098] The adjustment circuit 283 adjusts the overcharge detection voltage Vdet1 to a voltage value corresponding to the one selection signal selected by the first selector 241. The adjustment circuit 283 includes a resistor RVH (fixed resistors RV1, RV2, RV3), a resistor RVL (fixed resistors RV4, RV5), a resistor RX (m trimming resistors R1 to Rm), and 2 kIt has (in this example, eight) switch elements M1 to M8 and a regulator 283a. m is an integer of 2 or more.

[0099] In the first selection circuit 231C, first, the resistance RX is adjusted so that the output voltage VREG of the regulator 28 becomes a predetermined target value (for example, 1.80 volts). The adjustment of the resistance RX is performed by the switch elements M1 to M8 that are turned on or off according to the trimming states of the trimming elements F1, F2, and F3. As a result, the values of the potentials V42, V43, and V44 are determined.

[0100] The first selector 241 selects a potential corresponding to a selected one of the plurality of different potentials V42, V43, and V44, and sets the selected potential to the potential VN (the potential of the inverting input terminal) on the reference potential side of the comparator 222a. The potential VP (the potential of the non-inverting input terminal) on the comparison side of the comparator 222a is a fixed value (= Vdd × RVL / (RVH + RVL)). As a result, the overcharge detection voltage Vdet1 is adjusted as shown in FIG. 10 according to the selected selection signal.

[0101] The first selection circuit 231C adjusts the overdischarge detection voltage Vdet2 in the same manner as in the above case of adjusting the overcharge detection voltage Vdet1. The second selection circuit 232 adjusts the discharge overcurrent detection voltage Vdet3 or the charge overcurrent detection voltage Vdet4 in the same manner as in the above case where the first selection circuit 231C adjusts the overcharge detection voltage Vdet1.

[0102] FIG. 11 is a circuit block diagram showing an example of a system including a secondary battery protection integrated circuit according to the second embodiment. In the second embodiment, the description of the same configuration, operation, and effects as in the first embodiment is omitted by referring to the above description. The second embodiment is different from the first embodiment in that the selection terminal, the external resistance element, and the selection circuit are integrated into one.

[0103] The system 502 shown in FIG. 11 includes a battery device 402 and an electronic device 300. The battery device 402 includes a secondary battery 210 and a battery protection device 602. The battery protection device 602 is a component including, for example, a substrate on which at least a protection IC 102 and a resistance element R0 are mounted. The protection IC 102 includes, for example, a charge control terminal (terminal COUT), a discharge control terminal (terminal DOUT), a detection terminal (terminal VM), a power supply terminal (terminal VDD), a ground terminal (terminal VSS), a current detection terminal (terminal CS), a selection terminal (terminal SEL0), and a selection circuit 230.

[0104] The terminal SEL0 is a terminal for selecting the specifications of a first determination voltage (in this example, an overcharge detection voltage Vdet1 or an overdischarge detection voltage Vdet2) and a second determination voltage (in this example, a discharge overcurrent detection voltage Vdet3 or a charge overcurrent detection voltage Vdet4), and the resistance element R0 is externally connected thereto. The resistance element R0 is an example of a first resistance element provided outside the protection IC 102.

[0105] The selection circuit 230 changes the first determination voltage and the second determination voltage according to the resistance value of the resistance element R0 externally connected to the terminal SEL0. For example, the first determination voltage may be the overcharge detection voltage Vdet1 and the second determination voltage may be the charge overcurrent detection voltage Vdet4, or the first determination voltage may be the overdischarge detection voltage Vdet2 and the second determination voltage may be the discharge overcurrent detection voltage Vdet3. In the following description of the second embodiment, the case where the first determination voltage is the overcharge detection voltage Vdet1 and the second determination voltage is the charge overcurrent detection voltage Vdet4 will be described as a representative.

[0106] The selection circuit 230 changes the overcharge detection voltage Vdet1 and the charge overcurrent detection voltage Vdet4 according to the resistance value of the resistance element R0 externally connected to the terminal SEL0. Thus, if the resistance value of the resistance element R1 externally attached to the protection IC 102 is changed, the overcharge detection voltage Vdet1 and the charge overcurrent detection voltage Vdet4 can be easily changed. By using the resistance element R0 externally attached to the protection IC 102, it becomes easy to change the specifications of the overcharge detection voltage Vdet1 and the charge overcurrent detection voltage Vdet4 in a state where the protection IC 102 is mounted on the substrate.

[0107] The selection circuit 230 changes the overcharge detection voltage Vdet1 and the charge overcurrent detection voltage Vdet4 to a voltage value corresponding to the resistance value of the resistor element R0 externally connected to the terminal SEL0, for example, according to a correspondence relationship preset in the selection circuit 230. In this case, if the resistance value of the resistor element R0 externally connected to the terminal SEL0 is changed to a specified resistance value, the protection IC 102 can be commonly used for products with different required specifications of the overcharge detection voltage Vdet1 and the charge overcurrent detection voltage Vdet4 (for example, the battery protection device 602 or the battery device 402, etc.). Thereby, for example, simplification of inventory management and reduction of production man-hours are realized.

[0108] The selection circuit 230 may have a potential change circuit that changes the potential (selection potential VSEL0) of the terminal SEL0 according to the resistance value of the resistor element R0 externally connected to the terminal SEL0, and changes the overcharge detection voltage Vdet1 and the charge overcurrent detection voltage Vdet4 to a voltage value corresponding to the selection potential VSEL0. Thereby, if the resistance value of the resistor element R0 externally attached to the protection IC 102 is changed, the selection potential VSEL0 changes, so that the overcharge detection voltage Vdet1 and the charge overcurrent detection voltage Vdet4 can be easily changed. The selection circuit 230 changes the overcharge detection voltage Vdet1 and the charge overcurrent detection voltage Vdet4 to a voltage value corresponding to the selection potential VSEL0, for example, according to a correspondence relationship preset in the selection circuit 230.

[0109] FIG. 12 is a diagram for explaining a configuration example of a selector in the selection circuit. The selection circuit 230 includes a selector 240 as a component. The selector 240 is a circuit that selects one selection signal corresponding to the resistance value of the resistor element R0 externally connected to the terminal SEL0 from among a plurality of different selection signals S11, S12, S13, S21, S22, S23 when the read signal ΦREAD is in an active state. The plurality of different selection signals S11, S12, S13, S21, S22, S23 are selection signal candidates preset in the decoder 270 in the selector 240.

[0110] Selector 240 includes a potential change circuit 250 that changes the potential (selection potential VSEL0) of terminal SEL0 according to the resistance value of a resistance element R0 externally connected to terminal SEL0 by a reference resistor Rx and a switch LD2. The reference resistor Rx is inserted in series in the current path between terminal SEL0 and terminal VDD. When switch LD2 is turned on by a read signal ΦREAD, the selection terminal SEL1 is pull-up connected to terminal VDD by the reference resistor Rx, so the selection potential VSEL1 changes according to the resistance value of the resistance element R0.

[0111] Selector 240 includes an encoder 260. The encoder 260 is a circuit that encodes the selection potential VSEL0 and outputs a code (LV21, LV22, LV23, LV24, LV25, LV26, LV27) corresponding to the resistance value of the resistance element R0. The encoder 260 has a plurality of series resistors inserted in series between terminal VDD and terminal VSS, and a plurality of comparators that compare the selection potential VSEL0 with a plurality of potentials V1, V2, V3, V4, V5, V6, V7. The plurality of different potentials V1, V2, V3, V4, V5, V6, V7 are generated by voltage division by those plurality of series resistors when switch LD1 is turned on by the read signal ΦREAD.

[0112] Selector 240 includes a decoder 270. The decoder 270 is a circuit that converts a code (LV21, LV22, LV23, LV24, LV25, LV26, LV27) into a selection signal and an error signal ERROR. The decoder 270 outputs selection signals S11, S12, S13, S21, S22, S23 and an error signal ERROR that are the result of selecting the code (LV21, LV22, LV23, LV24, LV25, LV26, LV27). The selection signals S11, S12, S13, S21, S22, S23 and the error signal ERROR output from the decoder 270 are held in a latch circuit LT.

[0113] FIG. 13 is a table for explaining an operation example of the selector. The selector 240 becomes operable when the read signal ΦREAD is in the active state (in this example, when it is at the high level "H"). In the operable state, the selector 240 outputs from the decoder 270 the result of selecting the selection potential VSEL0 corresponding to the resistance value of the resistance element R0 externally connected to the terminal SEL0. In the selector 240, when the read signal ΦREAD transitions from the active state to the inactive state (in this example, the low level "L"), the selected result is held in the latch circuit LT. Also, the read signal ΦREAD can be a pulse signal having an active state shorter than the time when overcharge or over-discharge is detected when overcharge or over-discharge is detected. As a result, the effect of suppressing the power consumption of the protection IC 102 can be effectively improved.

[0114] For example, when the selection potential VSEL0 is higher than the potential of the terminal VSS and equal to or lower than the potential V1, or higher than the potential V7 and equal to or lower than the potential of the terminal VDD, the selector 240 selects the error signal ERROR, and the error signal ERROR is held in the latch circuit LT. When the selection potential VSEL0 is higher than the potential V1 and equal to or lower than the potential V2, the selected selection signal S11 and the selected selection signal S21 are held in the latch circuit LT. Thus, the selector 240 selects a selection signal according to the correspondence shown in FIG. 13, and the selection signal is held in the latch circuit LT. The correspondence shown in FIG. 13 is such that the overcharge detection voltage Vdet1 and the charge overcurrent detection voltage Vdet4 form a set corresponding to the resistance value of the resistance element R0.

[0115] Other parts in the selection circuit 230 according to the second embodiment may have the configurations illustrated in FIGS. 6 to 10.

[0116] FIG. 14 is a circuit block diagram showing an example of a system including a secondary battery protection integrated circuit according to the third embodiment. In the third embodiment, the description of the configuration, operation, and effects similar to those of the above-described embodiments is omitted by referring to the above description. The third embodiment is different from the first embodiment in that the switch circuit 203 is provided on the high-side power line 201. As a modification of the third embodiment, similar to the second embodiment, the selection terminal, the external resistance element, and the selection circuit may be integrated as shown in FIG. 15.

[0117] The system 503 shown in FIG. 14 includes a battery device 403 and an electronic device 300. The battery device 403 includes a secondary battery 210 and a battery protection device 603. The battery protection device 603 is a component including, for example, a substrate on which at least a protection IC 103 and resistance elements R1 and R2 are mounted. The protection IC 103 includes, for example, a charge control terminal (terminal COUT), a discharge control terminal (terminal DOUT), a detection terminal (terminal VP), a power supply terminal (terminal VDD), a ground terminal (terminal VSS), a current detection terminal (terminal CS), a first selection terminal (terminal SEL1), a second selection terminal (SEL2), a first selection circuit 231, and a second selection circuit 232. The terminal VP has the same function as the terminal VM in the first embodiment.

[0118] The detection circuit 222 detects overcharging of the secondary battery 210 by monitoring the power supply voltage Vdd between the terminal VDD and the terminal VSS. The detection circuit 222 compares the power supply voltage Vdd with an overcharge detection voltage Vdet1, and generates an overcharge detection signal indicating that overcharging of the secondary battery 210 has been detected when the power supply voltage Vdd is higher than the overcharge detection voltage Vdet1.

[0119] The detection circuit 222 detects the charging overcurrent of the secondary battery 210 by monitoring the potential difference ΔV1 between the terminal VDD and the terminal CS (or the terminal VP). The detection circuit 222 compares the potential difference ΔV1 with the charging overcurrent detection voltage Vdet4, and when the potential difference ΔV1 is higher than the charging overcurrent detection voltage Vdet4 with respect to the terminal VDD, generates a charging overcurrent detection signal indicating that the charging overcurrent of the secondary battery 210 has been detected. In other words, the detection circuit 222 generates a charging overcurrent detection signal when the voltage of the terminal CS (or the terminal VP) is higher than the charging overcurrent detection voltage Vdet4 with respect to the terminal VDD.

[0120] The detection circuit 222 detects the overdischarge of the secondary battery 210 by monitoring the power supply voltage Vdd between the terminal VDD and the terminal VSS. The detection circuit 222 compares the power supply voltage Vdd with the overdischarge detection voltage Vdet2, and when the power supply voltage Vdd is lower than the overdischarge detection voltage Vdet2, generates an overdischarge detection signal indicating that the overdischarge of the secondary battery 210 has been detected.

[0121] The detection circuit 222 detects the discharging overcurrent of the secondary battery 210 by monitoring the potential difference ΔV1 between the terminal VDD and the terminal CS (or the terminal VP). The detection circuit 222 compares the potential difference ΔV1 with the discharging overcurrent detection voltage Vdet3, and when the potential difference ΔV1 is lower than the discharging overcurrent detection voltage Vdet3 with respect to the terminal VDD, generates a discharging overcurrent detection signal indicating that the discharging overcurrent of the secondary battery 210 has been detected. In other words, the detection circuit 222 generates a discharging overcurrent detection signal when the voltage of the terminal CS (or the terminal VP) is lower than the discharging overcurrent detection voltage Vdet3 with respect to the terminal VDD.

[0122] As described above, the embodiments have been explained. However, the above embodiments are presented as examples, and the present invention is not limited by the above embodiments. The above embodiments can be implemented in various other forms, and various combinations, omissions, replacements, changes, etc. can be made without departing from the gist of the invention. These embodiments and their modifications are included in the scope and gist of the invention, and are included in the invention described in the claims and its equivalent scope.

[0123] For example, the arrangement positions of the charging control transistor TR1 and the discharging control transistor TR2 may be mutually replaced with respect to the positions shown in the figure. The switch circuit 203 may be incorporated in the protection IC.

[0124] The secondary battery protection integrated circuit may select circuit characteristics or functions different from the determination voltage by the same configuration or method as the above-described configuration or method for selecting the determination voltage such as the overcharge detection voltage Vdet1, according to the resistance value of the resistance element externally connected to the selection terminal. Examples of circuit characteristics different from the determination voltage include delay times such as the detection delay time d1.

[0125] Regarding the above embodiments, the following additional notes are further disclosed. (Additional Note 1) The first determination voltage and the second determination voltage are in a set corresponding to the resistance value of the first resistance element. (Additional Note 2) The first determination voltage can be adjusted to any one of k types of voltage values, and the number of the plurality of trimming elements is a natural multiple of k.

Explanation of Reference Numerals

[0126] 101, 102, 103 Protection IC 201 Power supply line 202 Ground line 203 Switch circuit 210 Secondary battery 211 Positive electrode 212 Negative electrode 221 Control circuit 222 Detection circuit 230 Selection circuit 231 First selection circuit 232 Second selection circuit 240 Selector 241 First selector 242 Second selector 281 Adjustment circuit 300 Electronic device 401, 402, 403 Battery device 501, 502, 503 System 601, 602, 603 Battery protection device TR1 Charge control transistor TR2 Discharge control transistor

Claims

1. A plurality of terminals including a power supply terminal, a ground terminal, a selection terminal, and a control terminal, A selection circuit that changes a first determination voltage according to a resistance value of a first resistance element externally connected to the selection terminal, A control circuit that outputs, from the control terminal, a signal for controlling charging or discharging of a secondary battery according to a result of comparing a power supply voltage between the power supply terminal and the ground terminal with the first determination voltage. A secondary battery protection integrated circuit comprising the same.

2. A plurality of terminals including a power supply terminal, a ground terminal, a selection terminal, a monitoring terminal, and a control terminal, A selection circuit that changes a second determination voltage according to a resistance value of a second resistance element externally connected to the selection terminal, A control circuit that outputs, from the control terminal, a signal for controlling charging or discharging of a secondary battery according to a result of comparing a first potential difference between the monitoring terminal and the power supply terminal or a second potential difference between the monitoring terminal and the ground terminal with the second determination voltage. A secondary battery protection integrated circuit comprising the same.

3. A plurality of terminals including a power supply terminal, a ground terminal, a first selection terminal, a second selection terminal, a monitoring terminal, and a control terminal, A selection circuit that changes a first determination voltage according to a resistance value of a first resistance element externally connected to the first selection terminal and changes a second determination voltage according to a resistance value of a second resistance element externally connected to the second selection terminal, A control circuit that outputs, from the control terminal, a signal for controlling charging or discharging of a secondary battery according to a result of comparing a power supply voltage between the power supply terminal and the ground terminal with the first determination voltage, and outputs, from the control terminal, a signal for controlling charging or discharging of the secondary battery according to a result of comparing a first potential difference between the monitoring terminal and the power supply terminal or a second potential difference between the monitoring terminal and the ground terminal with the second determination voltage. A secondary battery protection integrated circuit comprising the same.

4. A plurality of terminals including a power supply terminal, a ground terminal, a selection terminal, a monitoring terminal, and a control terminal, A selection circuit that changes a first determination voltage and a second determination voltage according to a resistance value of a first resistance element externally connected to the selection terminal; A control circuit that outputs, from the control terminal, a signal for controlling charging or discharging of the secondary battery according to a result of comparing a power supply voltage between the power supply terminal and the ground terminal with the first determination voltage, and outputs, from the control terminal, a signal for controlling charging or discharging of the secondary battery according to a result of comparing a first potential difference between the monitoring terminal and the power supply terminal or a second potential difference between the monitoring terminal and the ground terminal with the second determination voltage. A secondary battery protection integrated circuit comprising: **Claim 5** The control circuit outputs, from the control terminal, a signal for stopping charging of the secondary battery when the power supply voltage is higher than the first determination voltage. The secondary battery protection integrated circuit according to any one of claims 1, 3, and 4. **Claim 6** The control circuit outputs, from the control terminal, a signal for stopping discharging of the secondary battery when the power supply voltage is lower than the first determination voltage. The secondary battery protection integrated circuit according to any one of claims 1, 3, and 4. **Claim 7** The control circuit outputs, from the control terminal, a signal for stopping charging of the secondary battery when the first potential difference is higher than the second determination voltage with reference to the power supply terminal. The secondary battery protection integrated circuit according to any one of claims 2 to 4. **Claim 8** The control circuit outputs, from the control terminal, a signal for stopping discharging of the secondary battery when the first potential difference is lower than the second determination voltage with reference to the power supply terminal. The secondary battery protection integrated circuit according to any one of claims 2 to 4. **Claim 9** The control circuit outputs, from the control terminal, a signal for stopping discharging of the secondary battery when the second potential difference is higher than the second determination voltage with reference to the ground terminal. The secondary battery protection integrated circuit according to any one of claims 2 to 4. **Claim 10** When the second potential difference is lower than the second determination voltage with reference to the ground terminal, the control circuit outputs a signal for stopping charging of the secondary battery from the control terminal. The secondary battery protection integrated circuit according to any one of claims 2 to 4.

11. The first determination voltage includes a first detection voltage and a second detection voltage. The second determination voltage includes a third detection voltage and a fourth detection voltage. The control terminal includes a charge control terminal and a discharge control terminal. The control circuit When the power supply voltage is higher than the first detection voltage, outputs a signal for stopping charging of the secondary battery from the charge control terminal. When the power supply voltage is lower than the second detection voltage, outputs a signal for stopping discharging of the secondary battery from the discharge control terminal. When the first potential difference is lower than the third detection voltage with reference to the power supply terminal, or when the second potential difference is higher than the third detection voltage with reference to the ground terminal, outputs a signal for stopping discharging of the secondary battery from the discharge control terminal. When the first potential difference is higher than the fourth detection voltage with reference to the power supply terminal, or when the second potential difference is lower than the fourth detection voltage with reference to the ground terminal, outputs a signal for stopping charging of the secondary battery from the charge control terminal. The secondary battery protection integrated circuit according to claim 3 or 4.

12. When the resistance value of the first resistance element is higher than a first predetermined value or lower than a second predetermined value, the selection circuit outputs an error signal. When the error signal is output, the control circuit outputs a signal for stopping charging or discharging of the secondary battery from the control terminal. The secondary battery protection integrated circuit according to any one of claims 1, 3, and 4.

13. When the resistance value of the second resistance element is higher than a first predetermined value or lower than a second predetermined value, the selection circuit outputs an error signal. The secondary battery protection integrated circuit according to claim 2 or 3, wherein when the error signal is output, the control circuit outputs a signal for stopping charging or discharging of the secondary battery from the control terminal.

14. The selection circuit includes a plurality of trimming elements, a selector that selects a plurality of elements corresponding to the resistance value of the first resistance element from among the plurality of trimming elements, and an adjustment circuit that adjusts the first determination voltage to a voltage value corresponding to the trimming state of each of the plurality of elements selected by the selector, the secondary battery protection integrated circuit according to any one of claims 1, 3, and 4.

15. The selection circuit includes a plurality of trimming elements, a selector that selects a plurality of elements corresponding to the resistance value of the second resistance element from among the plurality of trimming elements, and an adjustment circuit that adjusts the second determination voltage to a voltage value corresponding to the trimming state of each of the plurality of elements selected by the selector, the secondary battery protection integrated circuit according to claim 2 or 3.

16. The selection circuit includes a selector that selects a selection signal corresponding to the resistance value of the first resistance element when a first lead signal is in an active state, a holding circuit that holds the selection signal selected by the selector, and an adjustment circuit that adjusts the first determination voltage to a voltage value corresponding to the selection signal held by the holding circuit, and cuts off current supply to the selector when the first lead signal is in an inactive state, the secondary battery protection integrated circuit according to any one of claims 1, 3, and 4.

17. The first lead signal becomes active when over-discharge of the secondary battery is detected, and becomes inactive when over-discharge of the secondary battery is not detected, the secondary battery protection integrated circuit according to claim 16.

18. The selection circuit a selector that selects a selection signal corresponding to the resistance value of the second resistance element when the second lead signal is in an active state; a holding circuit that holds the selection signal selected by the selector; and an adjustment circuit that adjusts the second determination voltage to a voltage value corresponding to the selection signal held by the holding circuit. The secondary battery protection integrated circuit according to claim 2 or 3, wherein when the second lead signal is in an inactive state, the current supply to the selector is cut off.

19. The secondary battery protection integrated circuit according to claim 18, wherein the second lead signal is a signal having an active state shorter than the time when the over-discharge of the secondary battery is detected when the over-discharge of the secondary battery is detected.

20. A battery device comprising the secondary battery protection integrated circuit according to any one of claims 1 to 4 and the secondary battery.

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