Secondary battery protection integrated circuit, secondary battery protection device, and battery device

Abstract

The invention provides a secondary battery protection integrated circuit, a secondary battery protection device, and a battery device. When a predetermined condition is satisfied, the power consumption is quickly switched to a state in which the power consumption is reduced. A secondary battery protection integrated circuit includes: a power supply terminal; a ground terminal; a monitoring terminal; an input terminal; a resistive element disposed between the monitoring terminal and the power supply terminal; and a control circuit that is set to a first state in which the resistive element is disconnected from the power supply terminal or the monitoring terminal; when a signal is input to the input terminal in the first state, the control circuit is set to a second state in which the monitoring terminal and the power supply terminal are connected by a resistive element having a first resistance value; in the second state, when the potential of the monitoring terminal is higher than a first potential lower than the potential of the power supply terminal, a third state is set in which the monitoring terminal and the power supply terminal are connected by a resistive element having a second resistance value higher than the first resistance value, and the power consumption is lower than that of the first state.

Description

Technical Field

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

[0002] Conventionally, there has been known a secondary battery protection integrated circuit that, when over-discharge is detected in a state where a charger is not connected, pulls up a current detection terminal to a power supply terminal substantially simultaneously with the detection of over-discharge, and switches an operation mode from an over-discharge protection mode to a standby mode. By switching the operation mode from the over-discharge protection mode to the standby mode, it is possible to prevent a secondary battery in an over-discharged state from further discharging due to the consumption current of the secondary battery protection integrated circuit. The secondary battery protection integrated circuit determines that the charger is not connected when the potential of the current detection terminal rises above a standby threshold value in the over-discharge protection mode, and switches the operation mode from the over-discharge protection mode to the standby mode (for example, refer to Patent Document 1).

[0003] However, due to the influence of the impedance of a load or the like that receives power supply from the secondary battery, when it takes time for the potential of the current detection terminal to reach the standby threshold value, the transition to the standby mode with reduced power consumption may be delayed.

[0004] Patent Document 1: Japanese Patent No. 6492740 Summary of the Invention

[0005] The present disclosure provides a secondary battery protection integrated circuit, a secondary battery protection device, and a battery device that can quickly transition to a state with reduced power consumption when a predetermined condition is satisfied.

[0006] A secondary battery protection integrated circuit according to a first aspect is a secondary battery protection integrated circuit for protecting a secondary battery, and includes: a power supply terminal; a ground terminal; a monitoring terminal; an input terminal; a resistance element disposed between the monitoring terminal and the power supply terminal; and a control circuit. The control circuit is set to a first state in which the resistance element is disconnected from the power supply terminal or the monitoring terminal. When a signal is input to the input terminal in the first state, the control circuit is set to a second state in which the monitoring terminal is connected to the power supply terminal through the resistance element having a first resistance value. When the potential of the monitoring terminal is higher than a first potential lower than the potential of the power supply terminal in the second state, it is set to a third state in which the monitoring terminal is connected to the power supply terminal through the resistance element having a second resistance value higher than the first resistance value, and the power consumption is lower than that in the first state.

[0007] The secondary battery protection integrated circuit of the second mode is a secondary battery protection integrated circuit for protecting a secondary battery, and includes: a power supply terminal; a ground terminal; a monitoring terminal; an input terminal; a resistance element disposed between the monitoring terminal and the ground terminal; and a control circuit. The control circuit is set to a first state in which the resistance element is disconnected from the ground terminal or the monitoring terminal. When a signal is input to the input terminal in the first state, the control circuit is set to a second state in which the monitoring terminal is connected to the ground terminal through the resistance element having a first resistance value. When the potential of the monitoring terminal is lower than a first potential higher than the potential of the ground terminal in the second state, the control circuit is set to connect the monitoring terminal to the ground terminal through the resistance element having a second resistance value higher than the first resistance value, and a third state in which the power consumption is lower than that in the first state.

[0008] The secondary battery protection integrated circuit of the third mode is a secondary battery protection integrated circuit for protecting a secondary battery, and includes: a power supply terminal; a ground terminal; a monitoring terminal; an input terminal; a control terminal; a resistance element disposed between the monitoring terminal and the power supply terminal; and a control circuit. The control circuit is set to a first state in which the resistance element is disconnected from the power supply terminal or the monitoring terminal. When the power supply voltage between the power supply terminal and the ground terminal is lower than a predetermined detection voltage in the first state, the control circuit is set to connect the monitoring terminal to the power supply terminal through the resistance element having a first resistance value, and a fourth state in which a signal for stopping the discharge of the secondary battery is output from the control terminal. When the potential of the monitoring terminal is higher than a first potential lower than the potential of the power supply terminal in the fourth state, the control circuit is set to connect the monitoring terminal to the power supply terminal through the resistance element having a second resistance value higher than the first resistance value, and a third state in which the power consumption is lower than that in the first state.

[0009] The secondary battery protection integrated circuit of the fourth method is a secondary battery protection integrated circuit for protecting a secondary battery, and includes: a power supply terminal; a ground terminal; a monitoring terminal; an input terminal; a control terminal; a resistor element disposed between the monitoring terminal and the ground terminal; and a control circuit. The control circuit is set to a first state in which the resistor element is disconnected from the ground terminal or the monitoring terminal. When the power supply voltage between the power supply terminal and the ground terminal is lower than a predetermined detection voltage in the first state, the control circuit is set to connect the monitoring terminal to the power supply terminal through the resistor element having a first resistance value, and output a signal for stopping the discharge of the secondary battery from the control terminal in a fourth state. When the potential of the monitoring terminal is lower than a first potential higher than the potential of the ground terminal in the fourth state, the control circuit is set to connect the monitoring terminal to the ground terminal through the resistor element having a second resistance value higher than the first resistance value, and a third state in which the power consumption is lower than the first state.

[0010] According to the present disclosure, when a predetermined condition is satisfied, it is possible to quickly switch to a state with reduced power consumption. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 It is a circuit block diagram showing an example of a system including the secondary battery protection integrated circuit of the first embodiment.

[0012] Figure 2 It is a diagram showing an example of the operation waveform of the secondary battery protection integrated circuit of the first embodiment.

[0013] Figure 3 It is a diagram showing an example of the operation waveform of the secondary battery protection integrated circuit of the first comparison method.

[0014] Figure 4 It is a diagram showing an example of the state transition of the secondary battery protection integrated circuit of the first embodiment.

[0015] Figure 5 It is a circuit block diagram showing an example of a system including the secondary battery protection integrated circuit of the second embodiment.

[0016] Figure 6 It is a diagram showing an example of the operation waveform of the secondary battery protection integrated circuit of the second embodiment.

[0017] Figure 7 It is a diagram showing an example of the operation waveform of the secondary battery protection integrated circuit of the second comparison method.

[0018] Figure 8This is a diagram showing an example of the state transition of the secondary battery protection integrated circuit according to the second embodiment.

[0019] Figure 9 This is a diagram showing an example of the state transition of the secondary battery protection integrated circuit according to the first modification of the first embodiment.

[0020] Figure 10 This is a diagram showing an example of the state transition of the secondary battery protection integrated circuit according to the first variation of the second embodiment. Detailed Embodiments

[0021] Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings.

[0022] Figure 1 This is a circuit block diagram showing an example of a system including the secondary battery protection integrated circuit according to the first embodiment. Figure 1 The illustrated system 501 includes a battery device 401 and an electronic device 300.

[0023] The electronic device 300 is a device connected to the battery device 401. The electronic device 300 can be a charger 301 that charges the battery device 401, or a load 302 that operates using the power supplied from the battery device 401. Specific examples of such a load include a mobile phone, a smartphone, a tablet device, and headphones. The electronic device 300 is not limited to these devices.

[0024] The battery device 401 can be external to the load 302 or can be built into the load 302. The battery device 401 is, for example, a battery pack that can be freely detached and stored in the load 302, and can supply power to the load 302 in a state of being connected to the load 302. The battery device 401 and the electronic device 300 are connected to each other via Figure 1 the illustrated plurality of terminals (a positive power supply terminal (terminal P+) and a negative power supply terminal (terminal P-)). For example, the terminal P+ and the terminal P- are electrically connected to the charger 301 when charging the secondary battery 210.

[0025] The battery device 401 includes a secondary battery 210 and a battery protection device 601.

[0026] The secondary battery 210 is an example of a battery that can be charged and discharged. The secondary battery 210 supplies power to the load 302 connected to the terminal P+ and the terminal P-. The secondary battery 210 can be charged by the charger 301 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.

[0027] 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, a terminal P+, a terminal P-, a terminal LPP, a terminal B+, a terminal B-, resistance elements R21, R23, R24, capacitors C21, C24, a power line 201, a ground line 202, a switching circuit 203, and a protection IC (Integrated Circuit) 101.

[0028] The battery protection device 601 is, for example, a component having a substrate on which at least the protection IC 101 is mounted.

[0029] The terminal P+ is an example of a load positive terminal and is connected to the power line of the electronic device 300. The terminal P is an example of a load negative terminal and is connected to the ground line of the electronic device 300. The terminal B+ is an example of a battery positive terminal and is connected to the positive electrode 211 of the secondary battery 210. The terminal B is an example of a battery negative terminal and is connected to the negative electrode 212 of the secondary battery 210.

[0030] The terminal B+ and the terminal P+ are connected by the power line 201 which is a current path on the positive side. The power line 201 is a power path connecting between the terminal B+ and the 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.

[0031] The terminal B- and the terminal P- are connected by the ground line 202 which is a current path on the negative side. The ground line 202 is a power path connecting between the terminal B- and the 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.

[0032] The switching circuit 203 is provided on the ground line 202 between the terminal B- and the terminal P-. The switching 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 cuts off the charging path of the secondary battery 210. The discharging control transistor TR2 is a semiconductor switching element that cuts off the discharging path of the secondary battery 210.

[0033] In Figure 1In this case, the charging control transistor TR1 cuts off the ground line 202 through which the charging current of the secondary battery 210 flows, and the discharging control transistor TR2 cuts off the ground line 202 through which the discharging current of the secondary battery 210 flows. The charging control transistor TR1 and the discharging control transistor TR2 are switching elements that switch between conduction and cut-off of the ground line 202, and are serially inserted into the ground line 202. The charging control transistor TR1 and the discharging control transistor TR2 are, for example, N-channel MOSFETs (Metal Oxide Semiconductor Field Effect Transistors).

[0034] The charging control transistor TR1 has a parasitic diode D1 between the drain and the source, with the direction opposite to the direction of the charging current of the secondary battery 210 being the forward direction. The charging control transistor TR1 is a switching element serially inserted into the ground line 202 such that the forward direction of the parasitic diode D1 is consistent with the flowing direction of the discharging current of the secondary battery 210.

[0035] The discharging control transistor TR2 has a parasitic diode D2 between the drain and the source, with the direction opposite to the direction of the discharging current of the secondary battery 210 being the forward direction. The discharging control transistor TR2 is a switching element serially inserted into the ground line 202 such that the forward direction of the parasitic diode D2 is consistent with the flowing direction of the charging current of the secondary battery 210.

[0036] The protection IC 101 is an example of a secondary battery protection integrated circuit for protecting the secondary battery. The protection IC 101 operates with the secondary battery 210 as the power source.

[0037] 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-discharge, 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.

[0038] The protection IC 101, for example, has 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), and an input terminal (terminal LP). 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.

[0039] 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.

[0040] The terminal VM is an example of a monitoring terminal 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 IC101 to monitor whether an electronic device 300 (load 302 or charger 301) is connected. The terminal VM is connected to the ground line 202 via a resistance element R23 between the switching 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 switching circuit 203.

[0041] The terminal VM can also be used to detect an overcharge current or an overdischarge current flowing through the secondary battery 210.

[0042] The terminal VDD is a power supply terminal of the protection IC101 and is connected to the positive electrode 211 of the secondary battery 210 and the power supply line 201 via a resistance element R21. The terminal VSS is a ground terminal of the protection IC101 and is connected to the negative electrode 212 of the secondary battery 210. A capacitor C21 is connected between the terminal VDD and the terminal VSS. The terminal VSS is connected to the ground line 202 between the switching circuit 203 and the negative electrode 212. In this example, the terminal VSS is connected to the ground line 202 between the discharging control transistor TR2 and the negative electrode 212.

[0043] The terminal LP is a terminal for inputting a signal S transmitted from an external device such as the electronic device 300 via the terminal LPP and is electrically connected to the terminal LPP. A resistance element R24 is inserted in series in the signal path between the terminal LP and the terminal LLP. A capacitor C24 is connected between the terminal LP and the ground line 202. The resistance element R24 and the capacitor C24 function as a low-pass filter for attenuating noise superimposed on the signal S.

[0044] The signal S is a signal (described in detail later) indicating that an external device such as the electronic device 300 requests the protection IC101 to switch to a power consumption reduction mode such as the low power mode LPM.

[0045] As an example of a monitoring terminal for monitoring the charging current or discharging current flowing through the secondary battery 210, the protection IC 101 may also include a terminal CS1. The terminal CS1 is connected to the ground wire 202 between the terminal B- and the switching circuit 203 (the source of the discharging control transistor TR2). When the terminal CS1 is provided, one end of the resistance element R22 serially inserted into the ground wire 202 is connected to the terminal VSS, and the other end is connected to the terminal CS1. The detection circuit A223 in the protection IC 101 can detect the overcharging current or discharging overcurrent flowing through the secondary battery 210 by detecting the potential difference between the terminal VSS and the terminal CS1. The resistance element R22 functions as a sense resistor for detecting the current flowing through the secondary battery 210.

[0046] As an example of a monitoring terminal for monitoring the charging current or discharging current flowing through the secondary battery 210, the protection IC 101 may also include a terminal CS2 instead of the terminal CS1. The terminal CS2 is connected to the ground wire 202 between the terminal P- and the switching circuit 203 (the source of the charging control transistor TR1). When the terminal CS2 is provided, one end of the resistance element R25 serially inserted into the ground wire 202 is connected to the terminal CS2, and the other end is connected to the terminal P- and connected to the terminal VM via the resistance element R23. The detection circuit A223 in the protection IC 101 can detect the overcharging current or discharging overcurrent flowing through the secondary battery 210 by detecting the potential difference between the terminal CS2 and the terminal VM. The resistance element R25 functions as a sense resistor for detecting the current flowing through the secondary battery 210.

[0047] The protection IC 101 includes a detection circuit 222, a control circuit 221, a resistance element Rpu, and switches 11 and 12.

[0048] The detection circuit 222 includes an overcharging detection circuit that detects the overcharging of the secondary battery 210 by monitoring the power supply voltage Vdd between the terminal VDD and the terminal VSS. The overcharging detection circuit compares the power supply voltage Vdd with the overcharging detection voltage Vdet1, and generates an overcharging detection signal indicating that the overcharging of the secondary battery 210 is detected when the power supply voltage Vdd is higher than the overcharging detection voltage Vdet1.

[0049] The detection circuit 222 includes a charging overcurrent detection circuit that detects the charging overcurrent of the secondary battery 210 by monitoring the potential difference ΔV2 between the terminal VSS and the terminal VM (or between the terminal VSS and the terminal CS1, or between the terminal CS2 and the terminal VM). The charging overcurrent detection circuit compares the potential difference ΔV2 with the charging overcurrent detection voltage Vdet4, and generates a charging overcurrent detection signal indicating that the charging overcurrent of the secondary battery 210 is detected when the potential difference ΔV2 is lower than the charging overcurrent detection voltage Vdet4 with the terminal VSS or the terminal CS2 as the reference. In other words, the charging overcurrent detection circuit generates a charging overcurrent detection signal when the voltage of the terminal VM or the terminal CS1 with the terminal VSS as the reference, or the voltage of the terminal VM with the terminal CS2 as the reference is lower than the charging overcurrent detection voltage Vdet4.

[0050] The control circuit 221 has a charging control circuit 221a for controlling the charging of the secondary battery 210. The charging control circuit 221a outputs a signal (e.g., a low-level gate control signal) for switching the charging control transistor TR1 from on to off from the terminal COUT when the overcharging of the secondary battery 210 is detected by the detection circuit 222 for a predetermined detection delay time tVdet1. The charging control circuit 221a outputs a signal (e.g., a low-level gate control signal) for switching the charging control transistor TR1 from on to off from the terminal COUT when the charging overcurrent of the secondary battery 210 is detected by the detection circuit 222 for a predetermined detection delay time tVdet4.

[0051] The control circuit 221 prohibits the current in the charging direction of the secondary battery 210 from flowing through the ground wire 202 by turning off the charging control transistor TR1. 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 charging overcurrent.

[0052] The detection circuit 222 includes an overdischarge detection circuit that detects the overdischarge of the secondary battery 210 by monitoring the power supply voltage Vdd between the terminal VDD and the terminal VSS. The overdischarge detection circuit compares the power supply voltage Vdd with the overdischarge detection voltage Vdet2, and generates an overdischarge detection signal indicating that the overdischarge of the secondary battery 210 is detected when the power supply voltage Vdd is lower than the overdischarge detection voltage Vdet2.

[0053] The detection circuit 222 includes a discharge overcurrent detection circuit, which detects the discharge overcurrent of the secondary battery 210 by monitoring the potential difference ΔV2 between the terminal VSS and the terminal VM (or between the terminal VSS and the terminal CS1, or between the terminal CS2 and the terminal VM). The discharge overcurrent detection circuit compares the potential difference ΔV2 with the discharge overcurrent detection voltage Vdet3, and generates a discharge overcurrent detection signal indicating that the discharge overcurrent of the secondary battery 210 is detected when the potential difference ΔV2 is higher than the discharge overcurrent detection voltage Vdet3 with the terminal VSS or the terminal CS2 as the reference. In other words, the discharge overcurrent detection circuit generates a discharge overcurrent detection signal when the voltage of the terminal VM or the terminal CS1 with the terminal VSS as the reference, or the voltage of the terminal VM with the terminal CS2 as the reference is higher than the discharge overcurrent detection voltage Vdet3.

[0054] The control circuit 221 has a discharge control circuit 221b for controlling the discharge of the secondary battery 210. When the over-discharge of the secondary battery 210 is detected by the detection circuit 222 for a predetermined detection delay time tVdet2, the discharge control circuit 221b outputs a signal (e.g., a low-level gate control signal) for switching the discharge control transistor TR2 from on to off from the terminal DOUT. When the discharge overcurrent of the secondary battery 210 is detected by the detection circuit 222 for a predetermined detection delay time tVdet3, the discharge control circuit 221b outputs a signal (e.g., a low-level gate control signal) for switching the discharge control transistor TR2 from on to off from the terminal DOUT.

[0055] The control circuit 221 prohibits the current in the discharging direction of the secondary battery 210 from flowing through the ground wire 202 by turning off the discharge control transistor TR2. 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 discharge overcurrent.

[0056] The detection circuit 222 includes a signal detection circuit 21 for detecting the signal S input from the terminal LP. When the signal detection circuit 21 detects the input of the signal S requesting a transition to a power consumption reduction mode such as the low power mode LPM, it outputs a signal detection signal indicating the detection of the input of the signal S from the terminal LP to the control circuit 221.

[0057] The detection circuit 222 includes a detection circuit A223 and a detection circuit B224. The detection circuit B224 includes a comparison circuit 22, which compares the potential of the terminal VM with a first potential Vstb lower than the potential of the terminal VDD, and outputs the result of the comparison to the control circuit 221. The first potential Vstb is also referred to as the standby threshold and is set to VDD - 0.9 [V], for example.

[0058] The pull-up resistor Rpu is a pull-up resistor configured between the terminal VM and the terminal VDD. The resistance value of the resistor element Rpu is variable according to the signal PU2 generated by the control circuit 221. The structure in which the resistance value of the resistor element Rpu changes according to an input signal such as the signal PU2 can be a known structure. For example, the resistor element Rpu may have a structure that selectively switches a resistor body corresponding to the content of the signal PU2 from a plurality of resistor bodies having different resistance values.

[0059] The switch 11 switches whether to pull up and connect the terminal VM to the terminal VDD through the resistor element Rpu according to the signal PU1 generated by the control circuit 221. The switch 11 is connected in series with the resistor element Rpu. The switch 11 may be arranged on the pull-up line between the resistor element Rpu and the terminal VDD, or may be arranged on the pull-up line between the terminal VM and the resistor element Rpu.

[0060] The switch 12 switches whether to cut off the power supply to a specific detection circuit A223 in a part of the detection circuit 222 according to the signal Stb generated by the control circuit 221. As an example of a specific detection circuit A223 (the circuit for which the power supply is to be cut off) in a part, an overcharge detection circuit for detecting overcharge, a charging overcurrent detection circuit for detecting charging overcurrent, an overdischarge detection circuit for detecting overdischarge, a discharge overcurrent detection circuit for detecting discharge overcurrent, or a signal detection circuit 21 for detecting the signal S can be cited. The switch 12 may be arranged to cut off the power supply path between the circuit for which the power supply is to be cut off and the terminal VSS, or may be arranged to cut off the power supply path between the circuit for which the power supply is to be cut off and the terminal VDD.

[0061] The control circuit 221 turns off the switch 11 through the signal PU1, thereby setting the first state S11 in which the resistor element Rpu is disconnected from the terminal VDD or the terminal VM. The first state S11 indicates a state in which the operation mode of the protection IC 101 is the normal operation mode.

[0062] In the first state S11, the control circuit 221 outputs a signal (for example, a signal of high level “H”) that permits charging of the secondary battery 210 from the terminal COUT, and outputs a signal (for example, a signal of high level “H”) that permits discharging of the secondary battery 210 from the terminal DOUT. Thus, in the first state S11, charging or discharging of the secondary battery 210 can be performed.

[0063] The control circuit 221 turns off switch 11 in the first state S11. As a result, a high impedance (HiZ) is formed between terminal VM and terminal VDD. The control circuit 221 turns on switch 12 through signal Stb in the first state S11. As a result, since power is supplied to the detection circuit 222, the detection circuit 222 can operate.

[0064] When the input of signal S is detected by the signal detection circuit 21 in the first state S11, the control circuit 221 turns on switch 11 through signal PU1. By turning on switch 11, the control circuit 221 sets the second state S12 in which terminal VM is pulled up to terminal VDD through the resistor element Rpu having the first resistance value R1. The second state S12 indicates the state in which the operation mode of the protection IC 101 is the low power mode LPM.

[0065] In the second state S12, the control circuit 221 outputs a signal (e.g., a high level “H” signal) that permits the charging of the secondary battery 210 from terminal COUT, and outputs a signal (e.g., a low level “L” signal) that stops the discharging of the secondary battery 210 from terminal DOUT. As a result, the discharge control transistor TR2 turns off, so the discharging of the secondary battery 210 stops. As a result, a decrease in the remaining capacity of the secondary battery 210 is suppressed, and the power consumption of the battery device 401 is suppressed. The control circuit 221 may also set an internal circuit that does not need to operate to the sleep mode in the second state S12, thereby suppressing the power consumption of the protection IC 101 itself.

[0066] The control circuit 221 sets the resistance value of the resistor element Rpu in the second state S12 to the first resistance value R1 (e.g., 25 kΩ) through signal PU2. In the second state S12, since terminal VM is pulled up to terminal VDD through the resistor element Rpu having the first resistance value R1, the potential of terminal VM starts to rise toward the potential of terminal VDD.

[0067] When the comparison circuit 22 detects that the potential of terminal VM is higher than the first potential Vstb in the second state S12, the control circuit 221 sets the third state S13 in which terminal VM is connected to terminal VDD by making the resistor element Rpu have a second resistance value R2 higher than the first resistance value R1. The third state S13 indicates the state in which the operation mode of the protection IC 101 is the standby mode in which the power consumption of the protection IC 101 is lower than that in the first state S11 (normal operation mode).

[0068] In the third state S13, the control circuit 221 outputs a signal for stopping the discharge of the secondary battery 210 (for example, a signal of low level "L") from the terminal DOUT. As a result, in the third state S13, following the second state S12, the discharge of the secondary battery 210 stops. Consequently, a decrease in the remaining capacity of the secondary battery 210 is suppressed, and power consumption of the battery device 401 is suppressed.

[0069] In the third state S13, the control circuit 221 opens the switch 12 through the signal Stb, thereby cutting off the power supply to a specific detection circuit A223, which is a part of the detection circuit 222. The control circuit 221 cuts off the power supply to internal circuits that do not need to operate in the third state S13, thereby suppressing the power consumption of the protection IC 101 itself. The control circuit 221 may also cut off the power supply to the charge control circuit 221a in the third state S13, thereby further suppressing the power consumption of the protection IC 101 itself.

[0070] The control circuit 221 sets the resistance value of the resistance element Rpu in the third state S13 to a second resistance value R2 (for example, 1 MΩ) higher than the first resistance value R1 through the signal PU2. Preferably, the second resistance value R2 is sufficiently higher than the resistance value of the resistance element R23 (for example, 1 kΩ). In the third state S13, since the terminal VM is pulled up to the terminal VDD through the resistance element Rpu having the relatively large second resistance value R2, the potentials of the terminal VM and the terminal P- can be stabilized at the potentials of the terminal VDD and the terminals P+, B+. As a result, in the standby mode (third state S13), the power consumption of the protection IC 101 and the battery device 401 can be stably suppressed.

[0071] In this way, in the first embodiment, the first resistance value R1 of the resistance element Rpu that pulls up the terminal VM to the terminal VDD in the second state S12 is smaller than the second resistance value R2 of the resistance element Rpu that pulls up the terminal VM to the terminal VDD in the third state S13. In the second state S12, since the terminal VM is pulled up to the terminal VDD through the resistance element Rpu having the relatively small first resistance value R1, the rising speed of the potential of the terminal VM in the second state S12 is less likely to be affected by an external impedance such as the electronic device 300. Therefore, in the second state S12, the potential of the terminal VM rapidly rises to the potential of the terminal VDD. Moreover, after the potential of the terminal VM is increased to a predetermined value, by making the resistance element Rpu have a second resistance value R2 higher than the first resistance value R1, the potential of the terminal VM can be stabilized.

[0072] Figure 2FIG. is an example of an operation waveform of a secondary battery protection integrated circuit according to the first embodiment. The vertical axis of the graph is potential, and the horizontal axis is time. The solid line is the potential of the terminal VDD, the dotted line is the potential of the terminal VM, and the dashed line is the potential of the terminal LP. The bar graphs of DOUT and COUT below the graph represent the signals output from the terminals DOUT and COUT of the protection IC101. The bar graph of the IC mode represents the operation mode of the protection IC. The bar graph of the pull-up VM represents the state of the control circuit 221 controlling the resistance element Rpu. In the low power mode LPM (second state S12), the terminal VM is pulled up to the terminal VDD by the resistance element Rpu having a relatively small first resistance value R1, so the potential of the terminal VM rapidly rises toward the potential of the terminal VDD. Therefore, the potential of the terminal VM rapidly exceeds the first potential Vstb, and thus, the operation mode of the protection IC101 rapidly changes from the low power mode LPM (second state S12) to the standby mode (third state S13). As a result, the time of operating in an operation mode that consumes more power than the standby mode is shortened, so the effect of reducing power consumption is improved.

[0073] When switching to the standby mode (third state S13), the terminal VM is pulled up to the terminal VDD by the resistance element Rpu having a second resistance value R2 larger than the first resistance value R1. Thereby, after the potential of the terminal VM exceeds the first potential Vstb, it slowly rises toward the potential of the terminal VDD. Thus, regarding the speed at which the potential of the terminal VM rises toward the potential of the terminal VDD, the case where the resistance value of the resistance element Rpu is the first resistance value R1 is faster than the case where the resistance value of the resistance element Rpu is the second resistance value R2.

[0074] On the other hand, Figure 3 FIG. is an example of an operation waveform of a secondary battery protection integrated circuit according to the first comparison method. The first comparison method is a method in which the resistance element Rpu in the low power mode LPM is set to the same resistance value (1 MΩ in this example) as the resistance element Rpu in the standby mode. In the case of this method, the rising speed of the potential of the terminal VM after shifting to the low power mode LPM (second state S12) is affected by the external impedance of the electronic device 300 or the like, as Figure 3 shown, it is slow just after rising. Therefore, the transition from the low power mode LPM (second state S12) to the standby mode (third state S13) may be delayed.

[0075] Figure 4 FIG. is an example of the state transition of the secondary battery protection integrated circuit according to the first embodiment. Next, referring to Figure 1 and Figure 2 , for Figure 1An example of the operation of protecting IC101 will be described. In each state, the state of the protection IC, the outputs of terminal COUT and terminal DOUT, the state of the resistor element Rpu connected to terminal VM, and the operation state of OTP (Over Temperature Protection) are shown from the top.

[0076] In Figure 4 the normal operation mode (first state S11), the control circuit 221 outputs a signal (e.g., a high-level "H" signal) that permits charging of the secondary battery 210 from terminal COUT, and outputs a signal (e.g., a high-level "H" signal) that permits discharging of the secondary battery 210 from terminal DOUT. In the first state S11, the control circuit 221 makes the impedance between terminal VM and terminal VDD high impedance (HiZ) by turning off switch 11.

[0077] When the signal detection circuit 21 determines that signal S is a high-level active signal, for example, when the potential of terminal LP is higher than a predetermined detection threshold Vdetlp, the signal detection circuit 21 outputs a signal detection signal indicating that the input of signal S from terminal LP has been detected to the control circuit 221. Alternatively, when the signal detection circuit 21 determines that signal S is a low-level active signal, for example, when the potential of terminal LP is lower than a predetermined detection threshold Vdetlp, the signal detection circuit 21 outputs a signal detection signal indicating that the input of signal S from terminal LP has been detected to the control circuit 221.

[0078] When the control circuit 221 detects the signal detection signal after a predetermined delay time tVdetlp (refer to Figure 2 ), it changes the operation mode from the normal operation mode (first state S11) to the low power mode LPM (second state S12).

[0079] When transitioning to Figure 4 the low power mode LPM (second state S12), the control circuit 221 outputs a signal (e.g., a high-level "H" signal) that permits charging of the secondary battery 210 from terminal COUT, and outputs a signal (e.g., a low-level "L" signal) that stops discharging of the secondary battery 210 from terminal DOUT. In the second state S12, the control circuit 221 connects terminal VM to terminal VDD in a pull-up manner using a resistor element Rpu having a first resistance value R1 (e.g., 25 kΩ) by turning on switch 11. The control circuit 221 may also put internal circuits that do not require operation (e.g., the OTP (Over Temperature Protection) circuit, etc.) into a sleep mode in the second state S12, thereby suppressing the power consumption of the protection IC101 itself.

[0080] When the potential of the terminal VM in the second state S12 does not exceed a second potential Vrellp (e.g., VSS + 0.7 [V]) that is lower than the first potential Vstb and higher than the ground potential within a predetermined time tVrellp, the control circuit 221 switches the operation mode from the second state S12 to the first state S11. In the second state S12, in order to rapidly raise the potential of the terminal VM toward the potential of the terminal VDD, the terminal VM is pull-up connected to the terminal VDD through a resistor element Rpu having a relatively small first resistance value R1 (e.g., 25 kΩ). However, if for some reason such as a fault, the rate of increase in the potential of the terminal VM slows down and the potential of the terminal VM does not exceed the second potential Vrellp within the predetermined time tVrellp, the operation mode can be returned from the second state S12 to the first state S11. For example, if the terminal VM ultimately does not exceed the first potential Vstb due to an abnormality, the second state S12 is maintained without transferring to any state, and the power supply from the secondary battery 210 to the system 501 is interrupted and cannot be restored. When such an abnormality is detected, the control circuit 221 can return the protection IC 101 to the first state S11. As a result, a state is achieved in which power can be supplied from the secondary battery 210 to the system 501, and a recovery operation can be performed by the system 501.

[0081] When the potential of the terminal VM in the second state S12 exceeds the second potential Vrellp (e.g., VSS + 0.7 [V]) within the predetermined time tVrellp, the control circuit 221 does not switch the operation mode from the second state S12 to the first state S11. Thereby, on the basis of determining that there is no abnormality, the operation mode can be locked in the second state S12, and the operation mode will not return to the first state S11 even if noise occurs.

[0082] When the potential of the terminal VM in the second state S12 is higher than the first potential Vstb (e.g., VDD - 0.9 [V]), the control circuit 221 switches the operation mode from the low power mode LPM (second state S12) to the standby mode (third state S13).

[0083] When transferring to Figure 4In the standby mode (third state S13), the control circuit 221 outputs a signal (e.g., a signal of low level "L") for stopping the discharge of the secondary battery 210 from the terminal DOUT. The control circuit 221 regardless of the terminal COUT in the third state S13 (any one of H and L signals can be output). In the third state S13, the control circuit 221 pulls up the terminal VM to the terminal VDD through a resistor element Rpu having a second resistance value R2 (1 MΩ in this example). The control circuit 221 can also put an internal circuit (e.g., an OTP (Over Temperature Protection) circuit, etc.) that does not need to operate in the second state S12 into the sleep mode to suppress the power consumption of the protection IC101 itself.

[0084] On the other hand, in Figure 4 In the normal operation mode (first state S11), when the over-discharge of the secondary battery 210 is continuously detected by the detection circuit 222 for a predetermined detection delay time tVdet2, the control circuit 221 switches the operation mode from the normal operation mode (first state S11) to the over-discharge protection mode UVP (fourth state S14). The detection circuit 222 detects the over-discharge of the secondary battery 210 when the power supply voltage Vdd between the terminal VDD and the terminal VSS is lower than the over-discharge detection voltage Vdet2.

[0085] When switched to the over-discharge protection mode UVP (fourth state S14), the control circuit 221 outputs a signal (e.g., a signal of high level "H") for allowing the charging of the secondary battery 210 from the terminal COUT, and outputs a signal (e.g., a signal of low level "L") for stopping the discharge of the secondary battery 210 from the terminal DOUT. In the fourth state S14, the control circuit 221 turns on the switch 11, and thus pulls up the terminal VM to the terminal VDD through a resistor element Rpu having a second resistance value R2 (1 MΩ in this example). The control circuit 221 can also put an internal circuit (e.g., an OTP (Over Temperature Protection) circuit, etc.) that does not need to operate in the fourth state S14 into the sleep mode to suppress the power consumption of the protection IC101 itself.

[0086] When the potential of terminal VM is higher than the first potential Vstb (e.g., VDD - 0.9 [V]) in the fourth state S14, the control circuit 221 converts the operation mode from the over-discharge protection mode UVP (the fourth state S14) to the standby mode (the third state S13). The first potential Vstb as the conversion threshold from the over-discharge protection mode UVP (the fourth state S14) to the standby mode (the third state S13) is the same as the first potential Vstb as the conversion threshold from the low power mode LPM (the second state S12) to the standby mode (the third state S13). When the conversion threshold for mode conversion is the same between two conversion routes, the decision circuit for mode conversion can be shared between the two conversion routes, so that the circuit area can be reduced.

[0087] When the potential of terminal VM is lower than the third potential (e.g., VDD / 2) which is lower than the potential of terminal VDD in the third state S13, the control circuit 221 determines that the charger 301 is connected and converts from the third state S13 to the fourth state S14.

[0088] In the fourth state S14, the control circuit 221 determines whether the condition that the power supply voltage Vdd is higher than the predetermined recovery voltage Vrel2 and the potential of terminal VM is equal to or lower than the fourth potential Vreluvp (e.g., VSS + 0.7 [V]) holds within the predetermined time tVrel2. When this condition holds, the control circuit 221 determines that the charging has started by the correctly connected charger 301, and converts the operation mode from the fourth state S14 to the first state S11 without converting to the second state S12. Thus, when returning from the over-discharge protection mode to the normal operation mode, it is possible to quickly switch to the normal operation mode without passing through the low power mode LPM. In addition, the fourth potential Vreluvp and the second potential Vrellp can be made the same potential. As a result, the determination potential can be made general, so that the circuit area can be reduced.

[0089] In addition, in the first embodiment, when the input of the signal S is detected by the signal detection circuit 21 in the first state S11, the control circuit 221 is set to connect the terminal VM to the terminal VDD through the resistor element Rpu having the first resistance value R1 in the second state S12. However, as a first modification of the first embodiment, when the power supply voltage Vdd is detected to be lower than the over-discharge detection voltage Vdet2 by the detection circuit 222 in the first state S11, the control circuit 221 may be set to connect the terminal VM to the terminal VDD through the resistor element Rpu having the first resistance value R1 in the fourth state S14.

[0090] Figure 9This is a diagram showing an example of the state transition of the secondary battery protection integrated circuit according to the first modification of the first embodiment. The first modification of the first embodiment is different from the first embodiment in that the resistance value of the resistance element Rpu is the first resistance value R1 in the fourth state S14 of Figure 4 . In the fourth state S14 of Figure 9 , the control circuit 221 pulls up the terminal VM to the terminal VDD through the resistance element Rpu having the first resistance value R1 (for example, 25 kΩ). In the overdischarge protection mode (the fourth state S14), since the terminal VM is pulled up to the terminal VDD through the resistance element Rpu having a relatively small first resistance value R1 (for example, 25 kΩ), the potential of the terminal VM rapidly rises toward the potential of the terminal VDD. Therefore, the potential of the terminal VM rapidly exceeds the first potential Vstb (in this example, VDD - 0.9 [V]), and thus the operation mode of the protection IC101 rapidly changes from the overdischarge protection mode (the fourth state S14) to the standby mode (the third state S13). As a result, the time of operating in an operation mode that consumes more power than the standby mode is shortened, and thus the effect of reducing power consumption is improved. Figure 4 The fourth state S14 of Figure 4 is different from the first embodiment in that the resistance value of the resistance element Rpu is the first resistance value R1. In the fourth state S14 of Figure 9 , the control circuit 221 pulls up the terminal VM to the terminal VDD through the resistance element Rpu having the first resistance value R1 (for example, 25 kΩ). In the overdischarge protection mode (the fourth state S14), since the terminal VM is pulled up to the terminal VDD through the resistance element Rpu having a relatively small first resistance value R1 (for example, 25 kΩ), the potential of the terminal VM rapidly rises toward the potential of the terminal VDD. Therefore, the potential of the terminal VM rapidly exceeds the first potential Vstb (in this example, VDD - 0.9 [V]), and thus the operation mode of the protection IC101 rapidly changes from the overdischarge protection mode (the fourth state S14) to the standby mode (the third state S13). As a result, the time of operating in an operation mode that consumes more power than the standby mode is shortened, and thus the effect of reducing power consumption is improved. Figure 9 In the fourth state S14 of Figure 9 , the control circuit 221 pulls up the terminal VM to the terminal VDD through the resistance element Rpu having the first resistance value R1 (for example, 25 kΩ). In the overdischarge protection mode (the fourth state S14), since the terminal VM is pulled up to the terminal VDD through the resistance element Rpu having a relatively small first resistance value R1 (for example, 25 kΩ), the potential of the terminal VM rapidly rises toward the potential of the terminal VDD. Therefore, the potential of the terminal VM rapidly exceeds the first potential Vstb (in this example, VDD - 0.9 [V]), and thus the operation mode of the protection IC101 rapidly changes from the overdischarge protection mode (the fourth state S14) to the standby mode (the third state S13). As a result, the time of operating in an operation mode that consumes more power than the standby mode is shortened, and thus the effect of reducing power consumption is improved.

[0091] The other content of the first modification of the first embodiment is the same as that of the first embodiment, and thus the description of the first modification is omitted by referring to the above description of the first embodiment.

[0092] Figure 5 This is a circuit block diagram showing an example of a system including the secondary battery protection integrated circuit according to the second embodiment. In the second embodiment, the description of the same structure, operation, and effect as those of the above embodiments is omitted by referring to the above description. The second embodiment is different from the first embodiment in that the switch circuit 203 is provided on the high-potential side power supply line 201.

[0093] Figure 5 The system 502 shown has 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 at least a substrate on which the protection IC102 is mounted, for example. The protection IC102 includes 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), an input terminal (terminal LP), a detection circuit 222, a control circuit 221, a resistance element Rpd, and switches 11 and 12. The terminal VP has the same function as the terminal VM of the first embodiment.

[0094] As an example of a monitoring terminal for monitoring the charging current or discharging current flowing through the secondary battery 210, the protection IC 102 may also include a terminal CS1. The terminal CS1 is connected to the power supply line 201 between the terminal B+ and the switching circuit 203 (the source of the charging control transistor TR1). When the terminal CS1 is provided, one end of the resistance element R22 serially inserted into the power supply line 201 is connected to the terminal VDD, and the other end is connected to the terminal CS1. The detection circuit A223 in the protection IC 102 can detect the overcharging current or discharging overcurrent flowing through the secondary battery 210 by detecting the potential difference between the terminal VDD and the terminal CS1. The resistance element R22 functions as a sense resistor for detecting the current flowing through the secondary battery 210. In addition, when the resistance element R22 is arranged, the resistance element R21 can be omitted.

[0095] As an example of a monitoring terminal for monitoring the charging current or discharging current flowing through the secondary battery 210, the protection IC 102 may also include a terminal CS2 instead of the terminal CS1. The terminal CS2 is connected to the power supply line 201 between the terminal P+ and the switching circuit 203 (the source of the discharging control transistor TR2). When the terminal CS2 is provided, one end of the resistance element R25 serially inserted into the power supply line 201 is connected to the terminal CS2, and the other end is connected to the terminal P+ and connected to the terminal VP via the resistance element R23. The detection circuit A223 in the protection IC 102 can detect the overcharging current or discharging overcurrent flowing through the secondary battery 210 by detecting the potential difference between the terminal CS2 and the terminal VP. The resistance element R25 functions as a sense resistor for detecting the current flowing through the secondary battery 210.

[0096] The detection circuit 222 includes an overcharge detection circuit that detects overcharging of the secondary battery 210 by monitoring the power supply voltage Vdd between the terminal VDD and the terminal VSS. The overcharge detection circuit compares the power supply voltage Vdd with the overcharge detection voltage Vdet1, and when the power supply voltage Vdd is higher than the overcharge detection voltage Vdet1, generates an overcharge detection signal indicating that overcharging of the secondary battery 210 is detected.

[0097] The detection circuit 222 includes a charging overcurrent detection circuit that detects the charging overcurrent of the secondary battery 210 by monitoring the potential difference ΔV1 between the terminal VDD and the terminal VP (or between the terminal VDD and the terminal CS1, or between the terminal CS2 and the terminal VP). The charging overcurrent detection circuit compares the potential difference ΔV1 with the charging overcurrent detection voltage Vdet4, and generates a charging overcurrent detection signal indicating that the charging overcurrent of the secondary battery 210 is detected when the potential difference ΔV1 is higher than the charging overcurrent detection voltage Vdet4 with the terminal VDD or the terminal CS2 as the reference. In other words, the charging overcurrent detection circuit generates a charging overcurrent detection signal when the voltage of the terminal VP or the terminal CS1 with the terminal VDD as the reference, or the voltage of the terminal VP with the terminal CS2 as the reference is higher than the charging overcurrent detection voltage Vdet4.

[0098] The detection circuit 222 includes an overdischarge detection circuit that detects the overdischarge of the secondary battery 210 by monitoring the power supply voltage Vdd between the terminal VDD and the terminal VSS. The overdischarge detection circuit compares the power supply voltage Vdd with the overdischarge detection voltage Vdet2, and generates an overdischarge detection signal indicating that the overdischarge of the secondary battery 210 is detected when the power supply voltage Vdd is lower than the overdischarge detection voltage Vdet2.

[0099] The detection circuit 222 includes a discharging overcurrent detection circuit that detects the discharging overcurrent of the secondary battery 210 by monitoring the potential difference ΔV1 between the terminal VDD and the terminal VP (or between the terminal VDD and the terminal CS1, or between the terminal CS2 and the terminal VP). The discharging overcurrent detection circuit compares the potential difference ΔV1 with the discharging overcurrent detection voltage Vdet3, and generates a discharging overcurrent detection signal indicating that the discharging overcurrent of the secondary battery 210 is detected when the potential difference ΔV1 is lower than the discharging overcurrent detection voltage Vdet3 with the terminal VDD or the terminal CS2 as the reference. In other words, the discharging overcurrent detection circuit generates a discharging overcurrent detection signal when the voltage of the terminal VP or the terminal CS1 with the terminal VDD as the reference, or the voltage of the terminal VP with the terminal CS2 as the reference is lower than the discharging overcurrent detection voltage Vdet3.

[0100] The detection circuit 222 includes a detection circuit A223 and a detection circuit B224. The detection circuit B224 includes a comparison circuit 22 that compares the potential of the terminal VP with a first potential Vstb that is higher than the potential of the terminal VSS, and outputs the result of the comparison to the control circuit 221. The first potential Vstb is also referred to as a standby threshold and is set to, for example, VSS + 0.9 [V].

[0101] The resistor element Rpd is a pull-down resistor configured between the terminal VP and the terminal VSS. The resistance value of the resistor element Rpd is variable according to the signal PU2 generated by the control circuit 221. The structure in which the resistance value of the resistor element Rpd changes according to an input signal such as the signal PU2 can be a known structure. For example, regarding the resistor element Rpd, it can have the following structure: selectively switch a resistor body corresponding to the content of the signal PU2 from among a plurality of resistor bodies having different resistance values.

[0102] The switch 11 switches whether to pull down and connect the terminal VP to the terminal VSS through the resistor element Rpd according to the signal PU1 generated by the control circuit 221. The switch 11 is connected in series with the resistor element Rpd. The switch 11 can be arranged on the pull-down line between the resistor element Rpd and the terminal VSS, or can be arranged on the pull-down line between the terminal VP and the resistor element Rpd.

[0103] The control circuit 221 disconnects the switch 11 according to the signal PU1, thereby setting the first state S11 in which the resistor element Rpd is disconnected from the terminal VSS or the terminal VP. The first state S11 represents the state in which the operation mode of the protection IC102 is the normal operation mode.

[0104] In the first state S11, the control circuit 221 outputs a signal (for example, a high-level “H” signal) that permits charging of the secondary battery 210 from the terminal COUT, and outputs a signal (for example, a high-level “H” signal) that permits discharging of the secondary battery 210 from the terminal DOUT. Thus, in the first state S11, charging or discharging of the secondary battery 210 can be performed.

[0105] The control circuit 221 disconnects the switch 11 in the first state S11. As a result, a high impedance (HiZ) is formed between the terminal VP and the terminal VSS. The control circuit 221 closes the switch 12 through the signal Stb in the first state S11. As a result, since power is supplied to the detection circuit 222, the detection circuit 222 can operate.

[0106] When the input of the signal S is detected by the signal detection circuit 21 in the first state S11, the control circuit 221 closes the switch 11 through the signal PU1. By closing the switch 11, the control circuit 221 sets the second state S12 in which the terminal VP is pulled down and connected to the terminal VSS through the resistor element Rpd having the first resistance value R1. The second state S12 represents the state in which the operation mode of the protection IC101 is the low power mode LPM.

[0107] In the second state S12, the control circuit 221 outputs a signal (e.g., a signal with a high level "H") that permits the charging of the secondary battery 210 from the terminal COUT, and outputs a signal (e.g., a signal with a low level "L") that stops the discharging of the secondary battery 210 from the terminal DOUT. Thereby, the discharge control transistor TR2 is turned off, and thus the discharging of the secondary battery 210 stops. As a result, a decrease in the remaining capacity of the secondary battery 210 is suppressed, and power consumption of the battery device 402 is suppressed. The control circuit 221 may also put an internal circuit that does not require operation into a sleep mode in the second state S12, thereby suppressing power consumption of the protection IC 102 itself.

[0108] The control circuit 221 sets the resistance value of the resistance element Rpd in the second state S12 to the first resistance value R1 (e.g., 25 kΩ) via the signal PU2. In the second state S12, since the terminal VP is pulled down and connected to the terminal VSS through the resistance element Rpd having the first resistance value R1, the potential of the terminal VP starts to drop toward the potential of the terminal VSS.

[0109] When it is detected by the comparison circuit 22 in the second state S12 that the potential of the terminal VP is lower than the first potential Vstb, the control circuit 221 sets the resistance element Rpd to a second resistance value R2 higher than the first resistance value R1, thereby setting to the third state S13 in which the terminal VP is connected to the terminal VSS. The third state S13 indicates a state in which the operation mode of the protection IC 101 is a standby mode in which the power consumption of the protection IC 101 is lower than that in the first state S11 (normal operation mode).

[0110] In the third state S13, the control circuit 221 outputs a signal (e.g., a signal with a low level "L") that stops the discharging of the secondary battery 210 from the terminal DOUT. Thereby, in the third state S13, following the second state S12, the discharging of the secondary battery 210 stops. As a result, a decrease in the remaining capacity of the secondary battery 210 is suppressed, and power consumption of the battery device 402 is suppressed.

[0111] In the third state S13, the control circuit 221 turns off the switch 12 via the signal Stb, thereby cutting off the power supply to a specific detection circuit A223 in a part of the detection circuit 222. The control circuit 221 cuts off the power supply to an internal circuit that does not require operation in the third state S13, thereby suppressing power consumption of the protection IC 102 itself. The control circuit 221 may also cut off the power supply to the charge control circuit 221a in the third state S13, thereby further suppressing power consumption of the protection IC 102 itself.

[0112] The control circuit 221 sets the resistance value of the resistance element Rpd in the third state S13 to a second resistance value R2 (e.g., 1 MΩ) higher than the first resistance value R1 through the signal PU2. Preferably, the second resistance value R2 is sufficiently higher than the resistance value of the resistance element R23 (e.g., 1 kΩ). In the third state S13, the terminal VP is pulled down and connected to the terminal VSS through the resistance element Rpd having a relatively large second resistance value R2, so that the potentials of the terminal VP and the terminal P+ can be stabilized at the potentials of the terminal VSS and the terminals P-, B-. Thereby, in the standby mode (the third state S13), the power consumption of the protection IC 102 and the battery device 402 can be stably suppressed.

[0113] Thus, in the second embodiment, the first resistance value R1 of the resistance element Rpd that pulls down and connects the terminal VP to the terminal VSS in the second state S12 is smaller than the second resistance value R2 of the resistance element Rpd that pulls down and connects the terminal VP to the terminal VSS in the third state S13. In the second state S12, since the terminal VP is pulled down and connected to the terminal VSS through the resistance element Rpd having a relatively small first resistance value R1, the rate of decrease in the potential of the terminal VP in the second state S12 is not easily affected by the external impedance of the electronic device 300 or the like. Therefore, in the second state S12, the potential of the terminal VP rapidly decreases toward the potential of the terminal VSS. And after the potential of the terminal VP is decreased to a predetermined value, by setting the resistance element Rpd to a second resistance value R2 higher than the first resistance value R1, the potential of the terminal VP can be stabilized.

[0114] Figure 6 It is a diagram showing an example of the operation waveform of the secondary battery protection integrated circuit according to the second embodiment. The vertical axis of the graph is potential, and the horizontal axis is time. The solid line is the potential of the terminal VDD, the dotted line is the potential of the terminal VP, and the dashed line is the potential of the terminal LP. The bar graphs of DOUT and COUT below the graph represent the signals output from the terminals DOUT and COUT of the protection IC 102. The bar graph of the IC mode represents the operation mode of the protection IC. The bar graph of pulling down VP represents the state in which the control circuit 221 controls the resistance element Rpd. In the low power mode LPM (the second state S12), since the terminal VP is pulled down and connected to the terminal VSS through the resistance element Rpd having a relatively small first resistance value R1, the potential of the terminal VP rapidly drops toward the potential of the terminal VSS. Therefore, the potential of the terminal VP rapidly becomes lower than the first potential Vstb, so that the operation mode of the protection IC 102 rapidly switches from the low power mode LPM (the second state S12) to the standby mode (the third state S13). As a result, the time of operating in an operation mode that consumes more power than the standby mode is shortened, so that the effect of reducing power consumption is improved.

[0115] When transitioning to the standby mode (third state S13), the terminal VP is pulled down and connected to the terminal VSS through a resistor element Rpd having a second resistance value R2 greater than the first resistance value R1. As a result, after the potential of the terminal VP becomes lower than the first potential Vstb, it slowly decreases toward the potential of the terminal VSS. In this way, the rate at which the potential of the terminal VP decreases toward the potential of the terminal VSS is faster when the resistance value of the resistor element Rpd is the first resistance value R1 than when the resistance value of the resistor element Rpd is the second resistance value R2.

[0116] On the other hand, Figure 7 is a diagram showing an example of the operation waveform of the secondary battery protection integrated circuit representing the second comparison method. The second comparison method is a method in which the resistor element Rpd in the low power mode LPM is set to the same resistance value (1 MΩ in this example) as the resistor element Rpd in the standby mode. In this case, the rate of decrease in the potential of the terminal VP after transitioning to the low power mode LPM (second state S12) is affected by the external impedance of the electronic device 300 or the like, and is slow from just after the decrease as Figure 7 shown. Therefore, the transition from the low power mode LPM (second state S12) to the standby mode (third state S13) may be delayed.

[0117] Figure 8 is a diagram showing an example of the state transition of the secondary battery protection integrated circuit according to the second embodiment. Next, with reference to Figure 5 and Figure 6 , the operation example of the protection IC102 shown in Figure 5 will be described. In each state, the state of the protection IC, the outputs of the terminals COUT and DOUT, the state of the resistor element Rpd connected to the terminal VP, and the operation state of the OTP (Over Temperature Protection) are shown from the top.

[0118] In Figure 8 the normal operation mode (first state S21), the control circuit 221 outputs a signal (for example, a high level "H" signal) that permits charging of the secondary battery 210 from the terminal COUT, and outputs a signal (for example, a high level "H" signal) that permits discharging of the secondary battery 210 from the terminal DOUT. In the first state S21, the control circuit 221 makes the impedance between the terminal VP and the terminal VSS high impedance (HiZ) by turning off the switch 11.

[0119] When the signal S is a signal with active high level, for example, when the potential of the terminal LP is higher than a predetermined detection threshold Vdetlp, the signal detection circuit 21 outputs a signal detection signal indicating the detection of the input of the signal S from the terminal LP to the control circuit 221. Alternatively, when the signal S is a signal with active low level, for example, when the potential of the terminal LP is lower than a predetermined detection threshold Vdetlp, the signal detection circuit 21 outputs a signal detection signal indicating the detection of the input of the signal S from the terminal LP to the control circuit 221.

[0120] When the control circuit 221 detects the signal detection signal for a continuous predetermined delay time tVdetlp (refer to Figure 6 ), it switches the operation mode from the normal operation mode (the first state S21) to the low power mode LPM (the second state S22).

[0121] When the control circuit 221 switches to Figure 8 the low power mode LPM (the second state S22), it outputs a signal (for example, a signal with high level “H”) that allows the charging of the secondary battery 210 from the terminal COUT, and outputs a signal (for example, a signal with low level “L”) that stops the discharging of the secondary battery 210 from the terminal DOUT. In the second state S22, the control circuit 221 connects the terminal VP to the terminal VSS by pulling it down through a resistor element Rpd having a first resistance value R1 (for example, 25 kΩ) by turning on the switch 11. The control circuit 221 can also put an internal circuit that does not need to operate (such as an OTP (OverTemperature Protection) circuit, etc.) into the sleep mode in the second state S22, thereby suppressing the power consumption of the protection IC102 itself.

[0122] When the potential of terminal VP in the second state S22 does not fall below a second potential Vrellp (e.g., VDD - 0.7 [V]) that is higher than the first potential Vstb and lower than the power supply potential within a predetermined time tVrellp, the control circuit 221 changes the operation mode from the second state S22 to the first state S21. In the second state S22, in order to rapidly reduce the potential of terminal VP toward the potential of terminal VSS, the terminal VP is pulled down and connected to the terminal VSS through a resistance element Rpd having a relatively small first resistance value R1 (e.g., 25 kΩ). However, for some reason, the rate of decrease in the potential of terminal VP slows down. In the case where the potential of terminal VP does not fall below the second potential Vrellp within the predetermined time tVrellp, the operation mode can be returned from the second state S22 to the first state S21. For example, in the case where the terminal VP does not ultimately fall below the first potential Vstb due to an abnormality, the second state S22 is maintained without being changed to any other state, and the power supply from the secondary battery 210 to the system 502 is interrupted and cannot be restored. When such an abnormality is detected, the control circuit 221 can return the protection IC 102 to the first state S21. As a result, a state is achieved in which power can be supplied from the secondary battery 210 to the system 502, and a recovery operation can be performed through the system 502.

[0123] When the potential of terminal VP in the second state S22 falls below the second potential Vrellp (e.g., VDD - 0.7 [V]) within the predetermined time tVrellp, the control circuit 221 does not change the operation mode from the second state S22 to the first state S21. Thereby, based on the determination that there is no abnormality, the operation mode can be locked in the second state S22 so that the operation mode does not return to the first state S21 even if noise occurs.

[0124] When the potential of terminal VP in the second state S22 is lower than the first potential Vstb (e.g., VSS + 0.9 [V]), the control circuit 221 changes the operation mode from the low power mode LPM (second state S22) to the standby mode (third state S23).

[0125] The control circuit 221 upon transitioning to Figure 8In the standby mode (the third state S23), a signal for stopping the discharge of the secondary battery 210 (for example, a signal with a low level "L") is output from the terminal DOUT. The control circuit 221 regardless of the terminal COUT in the third state S23 (either an H or an L signal can be output). In the third state S23, the control circuit 221 pulls down the terminal VP to be connected to the terminal VSS through a resistance element Rpd having a second resistance value R2 (1 MΩ in this example). The control circuit 221 can also put an internal circuit (for example, an OTP (Over Temperature Protection) circuit, etc.) that does not need to operate in the second state S22 into a sleep mode, thereby suppressing the power consumption of the protection IC 102 itself.

[0126] On the other hand, in Figure 8 In the normal operation mode (the first state S21), when the over-discharge of the secondary battery 210 is detected by the detection circuit 222 for a continuous predetermined detection delay time tVdet2, the control circuit 221 switches the operation mode from the normal operation mode (the first state S21) to the over-discharge protection mode UVP (the fourth state S24). The detection circuit 222 detects the over-discharge of the secondary battery 210 when the power supply voltage Vdd between the terminal VDD and the terminal VSS is lower than the over-discharge detection voltage Vdet2.

[0127] When switched to the over-discharge protection mode UVP (the fourth state S24), the control circuit 221 outputs a signal for allowing the charging of the secondary battery 210 (for example, a signal with a high level "H") from the terminal COUT, and outputs a signal for stopping the discharge of the secondary battery 210 (for example, a signal with a low level "L") from the terminal DOUT. In the fourth state S24, the control circuit 221 turns on the switch 11, thereby pulling down the terminal VP to be connected to the terminal VSS through a resistance element Rpd having a second resistance value R2 (1 MΩ in this example). The control circuit 221 can also put an internal circuit (for example, an OTP (Over Temperature Protection) circuit, etc.) that does not need to operate in the fourth state S24 into a sleep mode, thereby suppressing the power consumption of the protection IC 102 itself.

[0128] When the potential of terminal VP is lower than the first potential Vstb (e.g., VSS + 0.9 [V]) at the lower end of the fourth state S24, the control circuit 221 switches the operation mode from the over-discharge protection mode UVP (fourth state S24) to the standby mode (third state S23). The first potential Vstb, which is the conversion threshold from the over-discharge protection mode UVP (fourth state S24) to the standby mode (third state S23), is the same as the first potential Vstb, which is the conversion threshold from the low power mode LPM (second state S22) to the standby mode (third state S23). When the conversion threshold for mode conversion is the same between the two conversion routes, the decision circuit for mode conversion can be shared between the two conversion routes, thus reducing the circuit area.

[0129] When the potential of terminal VP rises above the third potential (e.g., VDD / 2) that is higher than the potential of terminal VSS in the third state S23, the control circuit 221 determines that the charger 301 is connected and switches from the third state S23 to the fourth state S24.

[0130] In the fourth state S24, the control circuit 221 determines whether the condition that the power supply voltage Vdd is higher than the predetermined recovery voltage Vrel2 and the potential of terminal VP is equal to or higher than the fourth potential Vreluvp (e.g., VDD - 0.7 [V]) holds within the predetermined time tVrel2. When this condition holds, the control circuit 221 determines that charging has started by the correctly connected charger 301, and switches the operation mode from the fourth state S24 to the first state S21 without switching to the second state S22. Thus, when returning from the over-discharge protection mode to the normal operation mode, it is possible to quickly shift to the normal operation mode without passing through the low power mode LPM. In addition, the fourth potential Vreluvp and the second potential Vrellp can be made the same potential. As a result, the determination potential can be made general-purpose, thus reducing the circuit area.

[0131] In addition, in the second embodiment, when the input of the signal S is detected by the signal detection circuit 21 in the first state S21, the control circuit 221 is set to the second state S22 in which the terminal VP is pulled down and connected to the terminal VSS through the resistor element Rpd having the first resistance value R1. However, as a first modification of the second embodiment, when the power supply voltage Vdd is detected to be lower than the over-discharge detection voltage Vdet2 by the detection circuit 222 in the first state S21, the control circuit 221 may be set to the fourth state S24 in which the terminal VP is pulled down and connected to the terminal VSS through the resistor element Rpd having the first resistance value R1.

[0132] Figure 10This is a diagram showing an example of the state transition of a secondary battery protection integrated circuit according to a first modification of the second embodiment. The first modification of the second embodiment is different from the second embodiment in that the resistance value of the resistance element Rpd is the first resistance value R1 in the fourth state S24 of Figure 8 . In the fourth state S24 of Figure 10 , the control circuit 221 connects the terminal VP to the terminal VSS by pulling it down through the resistance element Rpd having the first resistance value R1 (for example, 25 kΩ). In the overdischarge protection mode (the fourth state S24), since the terminal VP is connected to the terminal VSS by pulling it down through the resistance element Rpd having the relatively small first resistance value R1 (for example, 25 kΩ), the potential of the terminal VP rapidly drops toward the potential of the terminal VSS. Therefore, the potential of the terminal VP rapidly becomes lower than the first potential Vstb (in this example, VSS + 0.9 [V]), and thus the operation mode of the protection IC102 rapidly changes from the overdischarge protection mode (the fourth state S24) to the standby mode (the third state S23). As a result, the time of operating in an operation mode that consumes more power than the standby mode is shortened, and thus the effect of reducing power consumption is improved. Figure 8 The fourth state S24 of Figure 8 is different from the second embodiment in that the resistance value of the resistance element Rpd is the first resistance value R1. Figure 10 In the fourth state S24 of Figure 10 , the control circuit 221 connects the terminal VP to the terminal VSS by pulling it down through the resistance element Rpd having the first resistance value R1 (for example, 25 kΩ). In the overdischarge protection mode (the fourth state S24), since the terminal VP is connected to the terminal VSS by pulling it down through the resistance element Rpd having the relatively small first resistance value R1 (for example, 25 kΩ), the potential of the terminal VP rapidly drops toward the potential of the terminal VSS. Therefore, the potential of the terminal VP rapidly becomes lower than the first potential Vstb (in this example, VSS + 0.9 [V]), and thus the operation mode of the protection IC102 rapidly changes from the overdischarge protection mode (the fourth state S24) to the standby mode (the third state S23). As a result, the time of operating in an operation mode that consumes more power than the standby mode is shortened, and thus the effect of reducing power consumption is improved.

[0133] Regarding other aspects of the first modification of the second embodiment, since they are the same as those of the second embodiment, the description is omitted by reference to the above description of the second embodiment.

[0134] As described above, the embodiments have been described, but the above embodiments are presented as examples, and the present invention is not limited to the above embodiments. The above embodiments can be implemented in various other ways, and various combinations, omissions, substitutions, 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 scope of the invention described in the patent protection scope and its equivalents.

[0135] For example, the arrangement positions of the charge control transistor TR1 and the discharge control transistor TR2 can also be mutually replaced with respect to the positions shown in the figure. The switch circuit 203 can also be built in the protection IC.

[0136] Description of reference numerals

[0137] 11, 12 Switches

[0138] 21 Signal detection circuit

[0139] 22 Comparison circuit

[0140] 101, 102 Protection ICs

[0141] 201 Power supply line

[0142] 202 Ground line

[0143] 203 Switching Circuit

[0144] 210 Secondary Battery

[0145] 211 Positive Electrode

[0146] 212 Negative Electrode

[0147] 221 Control Circuit

[0148] 222 Detection Circuit

[0149] 300 Electronic Device

[0150] 301 Charger

[0151] 302 Load

[0152] 401, 402 Battery Device

[0153] 501, 502 System

[0154] 601, 602 Battery Protection Device

[0155] Rpd, Rpu Resistance Element

[0156] TR1 Charge Control Transistor

[0157] TR2 Discharge Control Transistor.

Claims

1. A secondary battery protection integrated circuit for protecting a secondary battery, characterized in that: The secondary battery protection integrated circuit comprises: Power terminal; Ground terminal; Monitoring terminal; Input terminal; a resistor element disposed between the monitoring terminal and the power supply terminal; as well as Control circuit, The control circuit is set to a first state in which the resistor element is disconnected from the power supply terminal or the monitoring terminal, When a signal is input to the input terminal in the first state, the control circuit is set to a second state in which the monitoring terminal is connected to the power supply terminal via the resistor element having a first resistance value. When in the second state the potential of the monitoring terminal is higher than a first potential lower than the potential of the power supply terminal, the control circuit is set to a third state in which the monitoring terminal is connected to the power supply terminal via the resistor element having a second resistance value higher than the first resistance value, and power consumption is lower than that of the first state.

2. The secondary battery protection integrated circuit according to claim 1, characterized in that: The secondary battery protection integrated circuit further comprises a detection circuit, which detects overcharge, charging overcurrent, overdischarge or discharge overcurrent of the secondary battery. The third state is a state in which power supply to the detection circuit is cut off.

3. The secondary battery protection integrated circuit according to claim 1, characterized in that: When the potential of the monitoring terminal does not exceed a second potential lower than the first potential within a predetermined time in the second state, the control circuit switches from the second state to the first state.

4. The secondary battery protection integrated circuit according to claim 3, characterized in that: When the potential of the monitoring terminal exceeds the second potential within the predetermined time in the second state, the control circuit can control not to switch from the second state to the first state.

5. The secondary battery protection integrated circuit according to any one of claims 1 to 4, characterized in that: When the resistance value of the resistor element is the first resistance value, the rate at which the potential of the monitoring terminal rises is faster than when the resistance value of the resistor element is the second resistance value.

6. The secondary battery protection integrated circuit according to any one of claims 1 to 4, characterized in that: The secondary battery protection integrated circuit also has a control terminal. When the power supply voltage between the power supply terminal and the ground terminal is lower than a predetermined detection voltage in the first state, the control circuit is set to a fourth state in which a signal for stopping discharge of the secondary battery is output from the control terminal.

7. The secondary battery protection integrated circuit according to claim 6, characterized in that: In the fourth state, the control circuit connects the monitoring terminal to the power supply terminal via the resistance element having the second resistance value.

8. The secondary battery protection integrated circuit according to claim 7, characterized in that: When the potential of the monitoring terminal is higher than the first potential in the fourth state, the control circuit switches from the fourth state to the third state.

9. The secondary battery protection integrated circuit according to claim 6, characterized in that: When the potential of the monitoring terminal in the third state is lower than a third potential that is lower than the potential of the power supply terminal, the control circuit switches from the third state to the fourth state, and when the power supply voltage in the fourth state is higher than a predetermined recovery voltage and the potential of the monitoring terminal is below a fourth potential that is lower than the first potential, the control circuit can switch from the fourth state to the first state without switching to the second state.

10. A secondary battery protection integrated circuit for protecting a secondary battery, characterized in that: The secondary battery protection integrated circuit comprises: Power terminal; Ground terminal; Monitoring terminal; Input terminal; a resistor element disposed between the monitoring terminal and the ground terminal; as well as Control circuit, The control circuit is set to a first state in which the resistance element is disconnected from the ground terminal or the monitoring terminal, When a signal is input to the input terminal in the first state, the control circuit is set to a second state in which the monitoring terminal is connected to the ground terminal via the resistor element having a first resistance value. When the potential of the monitoring terminal in the second state is lower than the first potential higher than the potential of the ground terminal, the control circuit is set to a third state in which the monitoring terminal is connected to the ground terminal via the resistor element having a second resistance value higher than the first resistance value, and power consumption is lower than the first state.

11. The secondary battery protection integrated circuit according to claim 10, characterized in that: The secondary battery protection integrated circuit further comprises a detection circuit, which detects overcharge, charging overcurrent, overdischarge or discharge overcurrent of the secondary battery. The third state is a state in which power supply to the detection circuit is cut off.

12. The secondary battery protection integrated circuit according to claim 10, characterized in that: When the potential of the monitoring terminal does not fall below a second potential higher than the first potential within a predetermined time in the second state, the control circuit switches from the second state to the first state.

13. The secondary battery protection integrated circuit according to claim 12, characterized in that: When the potential of the monitoring terminal is lower than the second potential within the predetermined time in the second state, the control circuit can control not to switch from the second state to the first state.

14. The secondary battery protection integrated circuit according to any one of claims 10 to 13, characterized in that: When the resistance value of the resistor element is the first resistance value, the speed at which the potential of the monitoring terminal drops is faster than when the resistance value of the resistor element is the second resistance value.

15. The secondary battery protection integrated circuit according to any one of claims 10 to 13, characterized in that: The secondary battery protection integrated circuit also has a control terminal. When the power supply voltage between the power supply terminal and the ground terminal is lower than a predetermined detection voltage in the first state, the control circuit is set to a fourth state in which a signal for stopping discharge of the secondary battery is output from the control terminal.

16. The secondary battery protection integrated circuit according to claim 15, characterized in that: In the fourth state, the control circuit connects the monitoring terminal to the ground terminal via the resistance element having the second resistance value.

17. The secondary battery protection integrated circuit according to claim 16, characterized in that: When the potential of the monitoring terminal is lower than the first potential in the fourth state, the control circuit switches from the fourth state to the third state.

18. The secondary battery protection integrated circuit according to claim 15, characterized in that: When the potential of the monitoring terminal in the third state rises to a third potential higher than the potential of the ground terminal, the control circuit switches from the third state to the fourth state. In the fourth state, when the power supply voltage is higher than a predetermined recovery voltage and the potential of the monitoring terminal is greater than a fourth potential higher than the first potential, the control circuit can switch from the fourth state to the first state without switching to the second state.

19. A secondary battery protection integrated circuit for protecting a secondary battery, characterized in that: The secondary battery protection integrated circuit comprises: Power terminal; Ground terminal; Monitoring terminal; Input terminal; Control terminals; a resistor element disposed between the monitoring terminal and the power supply terminal; as well as Control circuit, The control circuit is set to a first state in which the resistor element is disconnected from the power supply terminal or the monitoring terminal, When the power supply voltage between the power supply terminal and the ground terminal is lower than a predetermined detection voltage in the first state, the control circuit is set to a fourth state in which the monitoring terminal is connected to the power supply terminal via the resistor element having a first resistance value and a signal for stopping the discharge of the secondary battery is output from the control terminal. When the potential of the monitoring terminal in the fourth state is higher than the first potential lower than the potential of the power supply terminal, the control circuit is set to a third state in which the monitoring terminal is connected to the power supply terminal via the resistor element having a second resistance value higher than the first resistance value, and power consumption is lower than that of the first state.

20. The secondary battery protection integrated circuit according to claim 19, characterized in that: The secondary battery protection integrated circuit further comprises a detection circuit, which detects overcharge, charging overcurrent, overdischarge or discharge overcurrent of the secondary battery. The third state is a state in which power supply to the detection circuit is cut off.

21. The secondary battery protection integrated circuit according to claim 19 or 20, characterized in that: When the resistance value of the resistor element is the first resistance value, the rate at which the potential of the monitoring terminal rises is faster than when the resistance value of the resistor element is the second resistance value.

22. A secondary battery protection integrated circuit for protecting a secondary battery, characterized in that: The secondary battery protection integrated circuit comprises: Power terminal; Ground terminal; Monitoring terminal; Input terminal; Control terminals; a resistor element disposed between the monitoring terminal and the ground terminal; as well as Control circuit, The control circuit is set to a first state in which the resistance element is disconnected from the ground terminal or the monitoring terminal, When the power supply voltage between the power supply terminal and the ground terminal is lower than a predetermined detection voltage in the first state, the control circuit is set to a fourth state in which the monitoring terminal is connected to the power supply terminal via the resistor element having a first resistance value and a signal for stopping the discharge of the secondary battery is output from the control terminal. When the potential of the monitoring terminal in the fourth state is lower than the first potential higher than the potential of the ground terminal, the control circuit is set to a third state in which the monitoring terminal is connected to the ground terminal via the resistor element having a second resistance value higher than the first resistance value, and power consumption is lower than that of the first state.

23. The secondary battery protection integrated circuit according to claim 22, characterized in that: The secondary battery protection integrated circuit further comprises a detection circuit, which detects overcharge, charging overcurrent, overdischarge or discharge overcurrent of the secondary battery. The third state is a state in which power supply to the detection circuit is cut off.

24. The secondary battery protection integrated circuit according to claim 22 or 23, characterized in that: When the resistance value of the resistor element is the first resistance value, the speed at which the potential of the monitoring terminal drops is faster than when the resistance value of the resistor element is the second resistance value.

25. A secondary battery protection device, characterized in that: have: The secondary battery protection integrated circuit according to any one of claims 1, 10, 19, and 22; and a switch provided in a current path connected with the secondary battery, The secondary battery is protected by controlling the switch.

26. A battery device, characterized in that: have: The secondary battery protection integrated circuit according to any one of claims 1, 10, 19, and 22; the secondary battery; and a switch provided in a current path connected with the secondary battery, The secondary battery protection integrated circuit protects the secondary battery by controlling the switch.

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