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

Abstract

To speedily shift to a state where power consumption is reduced in a case where a predetermined condition is established.SOLUTION: A secondary battery protection integrated circuit comprises a power supply terminal, a ground terminal, a monitor terminal, an input terminal, a resistance element which is disposed between the monitor terminal and the power supply terminal, and a control circuit. The control circuit sets a first state where the resistance element is disconnected from the power supply terminal or the monitor terminal, sets a second state where the monitor terminal is connected to the power supply terminal by the resistance element having a first resistance value when a signal is inputted to the input terminal in the first state, sets a third state where the monitor terminal is connected to the power supply terminal by the resistance element having a second resistance value higher than the first resistance value and power consumption is lower than that in the first state when a potential of the monitor terminal becomes higher than a first potential which is lower than a potential of the power supply terminal in the second state.SELECTED DRAWING: Figure 1

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, when over-discharge is detected in a state where a charger is not connected, a current detection terminal is pulled up to a power supply terminal almost simultaneously with the over-discharge detection, and a secondary battery protection integrated circuit in which an operation mode transitions from an over-discharge protection mode to a standby mode is known. By transitioning 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 being further discharged by the current consumption of the secondary battery protection integrated circuit. In this secondary battery protection integrated circuit, when the potential of the current detection terminal rises above a standby threshold value in the over-discharge protection mode, it is determined that the charger is not connected, and the operation mode is switched from the over-discharge protection mode to the standby mode (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, due to the influence of the impedance of a load or the like that receives power supply from the secondary battery, if it takes time until the potential of the current detection terminal reaches the standby threshold value, the transition to the standby mode where power consumption is reduced may be delayed.

[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 where power consumption is reduced when a predetermined condition is satisfied.

Means for Solving the Problems

[0006] The secondary battery protection integrated circuit of the first aspect is a secondary battery protection integrated circuit used for protecting a secondary battery, 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, a control circuit, and includes the control circuit sets 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, it sets to a second state in which the monitoring terminal is connected to the power supply terminal by the resistance element having a first resistance value, when the potential of the monitoring terminal in the second state becomes higher than a first potential lower than the potential of the power supply terminal, it connects the monitoring terminal to the power supply terminal by the resistance element having a second resistance value higher than the first resistance value, and sets to a third state in which the power consumption is lower than that in the first state.

[0007] The secondary battery protection integrated circuit of the second aspect is a secondary battery protection integrated circuit used for protecting a secondary battery, 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, a control circuit, and includes the control circuit sets 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, it sets to a second state in which the monitoring terminal is connected to the ground terminal by the resistance element having a first resistance value, When the potential of the monitoring terminal becomes lower than a first potential that is higher than the potential of the ground terminal in the second state, the monitoring terminal is connected to the ground terminal by 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 is set.

[0008] The secondary battery protection integrated circuit according to the third aspect is A secondary battery protection integrated circuit used for protecting a secondary battery, 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, A control circuit, And includes The control circuit Sets 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 drops below a predetermined detection voltage in the first state, the monitoring terminal is connected to the power supply terminal by 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 is set. When the potential of the monitoring terminal becomes higher than a first potential that is lower than the potential of the power supply terminal in the fourth state, the monitoring terminal is connected to the power supply terminal by 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 is set.

[0009] The secondary battery protection integrated circuit according to the fourth aspect is A secondary battery protection integrated circuit used for protecting a secondary battery, 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 ground terminal, A control circuit, comprising, The control circuit sets the resistance element to a first state in which it is disconnected from the ground terminal or the monitoring terminal, when the power supply voltage between the power supply terminal and the ground terminal in the first state drops below a predetermined detection voltage, the monitoring terminal is connected to the power supply terminal by the resistance element having a first resistance value, and a signal for stopping the discharge of the secondary battery is output from the control terminal to set a fourth state, when the potential of the monitoring terminal in the fourth state becomes lower than a first potential higher than the potential of the ground terminal, the monitoring terminal is connected to the ground terminal by 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 is set.

Advantages of the Invention

[0010] According to the present disclosure, when a predetermined condition is satisfied, it is possible to quickly transition to a state in which the power consumption is reduced.

Brief Description of the Drawings

[0011]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

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

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

[0014] The electronic device 300 is a device connected to the battery device 401. The electronic device 300 may be a charger 301 that charges the battery device 401, or a load 302 that operates with the power supplied from the battery device 401. Specific examples of such loads include mobile phones, smartphones, tablet devices, earphones, and the like. The electronic device 300 is not limited to these devices.

[0015] The battery device 401 may be externally attached to the load 302 or built into the load 302. The battery device 401 is, for example, a battery pack that is detachably housed in the load 302 and can supply power to the load 302 while being connected to the load 302. The battery device 401 and the electronic device 300 are mutually connected via a plurality of terminals (a positive power supply terminal (terminal P+) and a negative power supply terminal (terminal P−)) shown in FIG. 1. For example, the terminal P+ and the terminal P− are electrically connected to the charger 301 when charging the secondary battery 210.

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

[0017] The secondary battery 210 is an example of a rechargeable battery. The secondary battery 210 supplies power to a load 302 connected to a terminal P+ and a terminal P-. The secondary battery 210 can be charged by a 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.

[0018] The battery protection device 601 is an example of a secondary battery protection device that operates using the secondary battery 210 as a power source. The battery protection device 601 protects the secondary battery 210 from overcharging etc. by controlling the charging of the secondary battery 210, and protects the secondary battery 210 from over-discharging etc. by controlling the discharging of the secondary battery 210. The battery protection device 601 includes, for example, a terminal P+, a terminal P-, a terminal LPP, a terminal B+, a terminal B-, resistor elements R21, R23, R24, capacitors C21, C24, a power supply line 201, a ground line 202, a switch circuit 203, and a protection IC (Integrated Circuit) 101.

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

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

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

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

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

[0024] In the case of FIG. 1, 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 the ground line 202 to be conductive or cut off, and are inserted in series with the ground line 202. The charging control transistor TR1 and the discharging control transistor TR2 are, for example, N-channel type MOSFETs (Metal Oxide Semiconductor Field Effect Transistors).

[0025] 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 switch element inserted in series with the ground line 202 such that the forward direction of the parasitic diode D1 coincides with the direction in which the discharging current of the secondary battery 210 flows.

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

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

[0028] The protection IC101 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 IC101 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 IC101 detects abnormal discharge (such as over-discharge, overcurrent in the discharge direction (discharge overcurrent), etc.) by the detection circuit 222, it protects the secondary battery 210 from abnormal discharge by turning off the discharge control transistor TR2.

[0029] The protection IC101 includes, for example, a charging control terminal (terminal COUT), a discharge control terminal (terminal DOUT), a detection terminal (terminal VM), a power supply terminal (terminal VDD), a ground terminal (terminal VSS), and an input terminal (terminal LP). These terminals are external connection terminals for connecting the internal circuit of the protection IC101 to the outside of the protection IC101, for example.

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

[0031] Terminal VM is an example of a monitoring terminal used for monitoring the potential of terminal P-, and is connected to terminal P-. Terminal VM is used, for example, by control circuit 221 in protection IC 101 to monitor the presence or absence of the connection of electronic device 300 (load 302 or charger 301). Terminal VM is connected between switch circuit 203 and terminal P- via resistor element R23 to ground line 202. Terminal VM is electrically connected to ground line 202 on the side opposite to secondary battery 210 with respect to switch circuit 203.

[0032] Terminal VM may be used to detect overcharge current or over-discharge current flowing through secondary battery 210.

[0033] Terminal VDD is the power supply terminal of protection IC 101, and is connected to the positive electrode 211 of secondary battery 210 and power supply line 201 via resistor element R21. Terminal VSS is the ground terminal of protection IC 101, and is connected to the negative electrode 212 of secondary battery 210. Capacitor C21 is connected between terminal VDD and terminal VSS. Terminal VSS is connected to ground line 202 between switch circuit 203 and negative electrode 212. In this example, terminal VSS is connected to ground line 202 between discharge control transistor TR2 and negative electrode 212.

[0034] Terminal LP is a terminal to which signal S transmitted from an external device such as electronic device 300 is input via terminal LPP, and is electrically connected to terminal LPP. Resistor element R24 is inserted in series in the signal path between terminal LP and terminal LLP. Capacitor C24 is connected between terminal LP and ground line 202. Resistor element R24 and capacitor C24 function as a low-pass filter that attenuates the noise superimposed on signal S.

[0035] Signal S is a signal indicating that an external device such as electronic device 300 requests a transition to a power consumption reduction mode such as low power mode LPM with respect to protection IC 101 (details will be described later).

[0036] The protection IC 101 may include a terminal CS1 as an example of a monitoring terminal used to monitor the charging current or discharging current flowing through the secondary battery 210. The terminal CS1 is connected to the ground line 202 between the terminal B- and the switch circuit 203 (the source of the discharge control transistor TR2). When the terminal CS1 is provided, one end of the resistor element R22 inserted in series with the ground line 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 an overcharging current or an over-discharging current flowing through the secondary battery 210 by detecting the potential difference between the terminal VSS and the terminal CS1. The resistor element R22 functions as a sense resistor for detecting the current flowing through the secondary battery 210.

[0037] As an example of a monitoring terminal used to monitor the charging current or discharging current flowing through the secondary battery 210, the protection IC 101 may include a terminal CS2 instead of the terminal CS1. The terminal CS2 is connected to the ground line 202 between the terminal P- and the switch circuit 203 (the source of the charging control transistor TR1). When the terminal CS2 is provided, one end of the resistor element R25 inserted in series with the ground line 202 is connected to the terminal CS2, the other end is connected to the terminal P-, and is also connected to the terminal VM via the resistor element R23. The detection circuit A223 in the protection IC 101 can detect an overcharging current or an over-discharging current flowing through the secondary battery 210 by detecting the potential difference between the terminal CS2 and the terminal VM. The resistor element R25 functions as a sense resistor for detecting the current flowing through the secondary battery 210.

[0038] The protection IC 101 includes a detection circuit 222, a control circuit 221, a resistor element Rpu, and switches 11, 12.

[0039] 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 an overcharge detection voltage Vdet1, and generates an overcharge detection signal indicating that overcharging of the secondary battery 210 has been detected when the power supply voltage Vdd is higher than the overcharge detection voltage Vdet1.

[0040] 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 when the potential difference ΔV2 is lower than the charging overcurrent detection voltage Vdet4 based on the terminal VSS or the terminal CS2, it generates a charging overcurrent detection signal indicating that the charging overcurrent of the secondary battery 210 has been detected. 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 based on the terminal VSS, or the voltage of the terminal VM based on the terminal CS2, is lower than the charging overcurrent detection voltage Vdet4.

[0041] The control circuit 221 has a charging control circuit 221a that controls the charging of the secondary battery 210. When the overcharging of the secondary battery 210 is continuously 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 continuously detected by the detection circuit 222 for a predetermined detection delay time tVdet4, 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.

[0042] By turning off the charging control transistor TR1, the control circuit 221 prohibits the current in the charging direction of the secondary battery 210 from flowing through the ground wire 202. As a result, the charging of the secondary battery 210 stops, so that the protection IC101 can protect the secondary battery 210 from overcharging or charging overcurrent.

[0043] The detection circuit 222 includes an over-discharge detection circuit that detects over-discharge of the secondary battery 210 by monitoring the power supply voltage Vdd between the terminal VDD and the terminal VSS. The over-discharge detection circuit compares the power supply voltage Vdd with the over-discharge detection voltage Vdet2, and when the power supply voltage Vdd is lower than the over-discharge detection voltage Vdet2, generates an over-discharge detection signal indicating that over-discharge of the secondary battery 210 has been detected.

[0044] The detection circuit 222 includes a discharge over-current detection circuit that detects a discharge over-current 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 over-current detection circuit compares the potential difference ΔV2 with the discharge over-current detection voltage Vdet3, and when the potential difference ΔV2 is higher than the discharge over-current detection voltage Vdet3 with respect to the terminal VSS or the terminal CS2, generates a discharge over-current detection signal indicating that a discharge over-current of the secondary battery 210 has been detected. In other words, the discharge over-current detection circuit generates a discharge over-current detection signal when the voltage of the terminal VM or the terminal CS1 with respect to the terminal VSS, or the voltage of the terminal VM with respect to the terminal CS2, is higher than the discharge over-current detection voltage Vdet3.

[0045] The control circuit 221 has a discharge control circuit 221b that controls the discharge of the secondary battery 210. When over-discharge of the secondary battery 210 is continuously 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 a discharge over-current of the secondary battery 210 is continuously 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.

[0046] By turning off the discharge control transistor TR2, the control circuit 221 prohibits the current flowing in the direction of discharging the secondary battery 210 from flowing into the ground line 202. As a result, the discharge of the secondary battery 210 stops, so that the protection IC 101 can protect the secondary battery 210 from over-discharge or discharge over-current.

[0047] The detection circuit 222 includes a signal detection circuit 21 that detects a signal S input from the terminal LP. When the input of the signal S requesting a transition to a power consumption reduction mode such as the low power mode LPM is detected, the signal detection circuit 21 outputs a signal detection signal indicating that the input of the signal S from the terminal LP has been detected to the control circuit 221.

[0048] 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 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 a standby threshold and is set to, for example, VDD - 0.9 [V].

[0049] The resistor element Rpu is a pull-up resistor arranged between the terminal VM and the terminal VDD. The resistance value of the resistor element Rpu varies according to a signal PU2 generated by the control circuit 221. A configuration in which the resistance value of the resistor element Rpu changes according to an input signal such as the signal PU2 may be a known configuration. For example, the resistor element Rpu may have a configuration that selectively switches a resistor corresponding to the content of the signal PU2 from a plurality of resistors having different resistance values.

[0050] The switch 11 switches whether to pull up and connect the terminal VM to the terminal VDD by the resistor element Rpu according to a 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 on the pull-up line between the terminal VM and the resistor element Rpu.

[0051] Switch 12 switches whether to cut off the power supply to some specific detection circuits A223 in the detection circuit 222 according to the signal Stb generated by the control circuit 221. Examples of some specific detection circuits A223 (circuits targeted for power supply cut-off) include an overcharge detection circuit that detects overcharging, a charging overcurrent detection circuit that detects charging overcurrent, an overdischarge detection circuit that detects overdischarge, a discharging overcurrent detection circuit that detects discharging overcurrent, or the signal detection circuit 21 that detects signal S, etc. Switch 12 may be arranged to be able to cut off the power supply path between the circuit targeted for power supply cut-off and the terminal VSS, or may be arranged to be able to cut off the power supply path between the circuit targeted for power supply cut-off and the terminal VDD.

[0052] The control circuit 221 sets to the first state S11 in which the resistor element Rpu is disconnected from the terminal VDD or the terminal VM by turning off the switch 11 with the signal PU1. The first state S11 indicates a state in which the operation mode of the protection IC 101 is the normal operation mode.

[0053] 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. Thereby, in the first state S11, charging or discharging of the secondary battery 210 becomes possible.

[0054] In the first state S11, the control circuit 221 turns off the switch 11. Thereby, the impedance between the terminal VM and the terminal VDD becomes high impedance (HiZ). In the first state S11, the control circuit 221 turns on the switch 12 with the signal Stb. Thereby, since power is supplied to the detection circuit 222, the detection circuit 222 becomes operable.

[0055] When the control circuit 221 detects the input of signal S by the signal detection circuit 21 in the first state S11, it turns on the switch 11 by the signal PU1. By turning on the switch 11, the control circuit 221 sets the second state S12 in which the terminal VM is pull-up connected to the terminal VDD by the resistance element Rpu having the first resistance value R1. The second state S12 indicates a state where the operation mode of the protection IC101 is the low power mode LPM.

[0056] In the second state S12, the control circuit 221 outputs a signal (for example, a signal of high level "H") for permitting the charging of the secondary battery 210 from the terminal COUT, and outputs a signal (for example, a signal of low level "L") for stopping the discharging of the secondary battery 210 from the terminal DOUT. As a result, the discharge control transistor TR2 is turned off, so the discharging of the secondary battery 210 stops. Consequently, the 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 suppress the power consumption of the protection IC101 itself by setting an internal circuit that is unnecessary in operation in the second state S12 to the sleep mode.

[0057] The control circuit 221 sets the resistance value of the resistance element Rpu in the second state S12 to the first resistance value R1 (for example, 25 kΩ) by the signal PU2. In the second state S12, since the terminal VM is pull-up connected to the terminal VDD by the resistance element Rpu having the first resistance value R1, the potential of the terminal VM starts to rise toward the potential of the terminal VDD.

[0058] When the control circuit 221 detects by the comparison circuit 22 that the potential of the terminal VM in the second state S12 is higher than the first potential Vstb, it sets the third state S13 in which the terminal VM is connected to the terminal VDD by making the resistance element Rpu have a second resistance value R2 higher than the first resistance value R1. The third state S13 indicates a state where the operation mode of the protection IC101 is the standby mode in which the power consumption of the protection IC101 is lower than that in the first state S11 (normal operation mode).

[0059] In the third state S13, the control circuit 221 outputs a signal (for example, a signal of low level "L") for stopping the discharge of the secondary battery 210 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. As a result, a decrease in the remaining capacity of the secondary battery 210 is suppressed, and power consumption of the battery device 401 is suppressed.

[0060] In the third state S13, the control circuit 221 turns off the switch 12 by the signal Stb, thereby cutting off the power supply to a part of the specific detection circuit A223 in the detection circuit 222. The control circuit 221 suppresses the power consumption of the protection IC 101 itself by cutting off the power supply to the internal circuits whose operation is unnecessary in the third state S13. The control circuit 221 may further suppress the power consumption of the protection IC 101 itself by cutting off the power supply to the charge control circuit 221a in the third state S13.

[0061] 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 by the signal PU2. The second resistance value R2 is preferably 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 pull-up connected to the terminal VDD by 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 to the potentials of the terminal VDD and the terminals P +, B +. As a result, in the standby mode (the third state S13), the power consumption of the protection IC 101 and the battery device 401 can be stably suppressed.

[0062] As described above, in the first embodiment, the first resistance value R1 of the resistor element Rpu that pull-up connects the terminal VM to the terminal VDD in the second state S12 is smaller than the second resistance value R2 of the resistor element Rpu that pull-up connects the terminal VM to the terminal VDD in the third state S13. In the second state S12, since the terminal VM is pull-up connected to the terminal VDD by the resistor element Rpu having the relatively small first resistance value R1, the rate at which the potential of the terminal VM rises in the second state S12 is less affected by the external impedance of the electronic device 300 or the like. Therefore, in the second state S12, the potential of the terminal VM rapidly rises toward the potential of the terminal VDD. Further, after pulling up the potential of the terminal VM to a predetermined value, the potential of the terminal VM can be stabilized by setting the resistor element Rpu to the second resistance value R2 higher than the first resistance value R1.

[0063] FIG. 2 is a diagram showing an example of the operation waveform of the 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 one-dot broken line is the potential of the terminal VM, and the broken line is the potential of the terminal LP. The bar graphs of DOUT and COUT below the graph indicate the signals output from the terminals DOUT and COUT of the protection IC 101. The bar graph of IC MODE indicates the operation mode of the protection IC. The bar graph of Pull-Up VM indicates the state in which the control circuit 221 controls the resistor element Rpu. In the low power mode LPM (second state S12), since the terminal VM is pull-up connected to the terminal VDD by the resistor element Rpu having the relatively small first resistance value R1, the potential of the terminal VM rapidly rises toward the potential of the terminal VDD. Therefore, since the potential of the terminal VM rapidly exceeds the first potential Vstb, the operation mode of the protection IC 101 rapidly transitions from the low power mode LPM (second state S12) to the standby mode (third state S13). As a result, the time of operating in the operation mode that consumes more power than the standby mode is shortened, so that the effect of reducing the power consumption is enhanced.

[0064] When transitioning to the standby mode (third state S13), the terminal VM is pull-up connected to the terminal VDD by a resistance element Rpu having a second resistance value R2 that is greater than the first resistance value R1. As a result, the potential of the terminal VM gradually rises toward the potential of the terminal VDD after exceeding the first potential Vstb. In this way, the speed at which the potential of the terminal VM rises toward the potential of the terminal VDD is faster in the case of the first resistance value R1 than in the case where the resistance value of the resistance element Rpu is the second resistance value R2.

[0065] On the other hand, FIG. 3 is a diagram showing an example of the operation waveform of the secondary battery protection integrated circuit according to the first comparative form. In the first comparative form, the resistance element Rpu in the low power mode LPM is set to the same resistance value (in this example, 1 MΩ) as the resistance element Rpu in the standby mode. In the case of this form, the rising speed of the potential of the terminal VM after transitioning to the low power mode LPM (second state S12) is gentle immediately after rising as shown in FIG. 3 under the influence of an external impedance such as the electronic device 300. For this reason, there is a possibility that the transition from the low power mode LPM (second state S12) to the standby mode (third state S13) may be delayed.

[0066] FIG. 4 is a diagram showing an example of the state transition of the secondary battery protection integrated circuit according to the first embodiment. Next, with reference to FIGS. 1 and 2, an operation example of the protection IC101 shown in FIG. 1 will be described. In each state, the state of the protection IC, the outputs of the terminals COUT and DOUT, the state of the resistance element Rpu connected to the terminal VM, and the operation state of the OTP (Over Temperature Protection) are shown from the top.

[0067] In the normal operation mode (first state S11) of FIG. 4, the control circuit 221 outputs a signal (for example, a signal of high level "H") for permitting charging of the secondary battery 210 from the terminal COUT, and outputs a signal (for example, a signal of high level "H") for permitting discharging of the secondary battery 210 from the terminal DOUT. In the first state S11, the control circuit 221 sets the impedance between the terminal VM and the terminal VDD to high impedance (HiZ) by turning off the switch 11.

[0068] When the signal S is an active-high signal, 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 that the input of the signal S from the terminal LP has been detected to the control circuit 221. Alternatively, when the signal S is an active-low signal, 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 that the input of the signal S from the terminal LP has been detected to the control circuit 221.

[0069] When the signal detection signal is continuously detected for a predetermined delay time tVdetlp (see Figure 2), the control circuit 221 transitions the operation mode from the normal operation mode (the first state S11) to the low power mode LPM (the second state S12).

[0070] When the control circuit 221 transitions to the low power mode LPM (the second state S12) in Figure 4, it outputs a signal (for example, a high-level "H" signal) permitting the charging of the secondary battery 210 from the terminal COUT, and outputs a signal (for example, a low-level "L" signal) stopping the discharging of the secondary battery 210 from the terminal DOUT. In the second state S12, the control circuit 221 turns on the switch 11 to pull up and connect the terminal VM to the terminal VDD by a resistance element Rpu having a first resistance value R1 (for example, 25 kΩ). The control circuit 221 may suppress the power consumption of the protection IC101 itself by setting an internal circuit (for example, an OTP (Over Temperature Protection) circuit, etc.) that is unnecessary for operation in the second state S12 to the sleep mode.

[0071] When the potential of terminal VM is lower than the first potential Vstb and higher than the ground potential, i.e., the second potential Vrellp (e.g., VSS + 0.7 [V]) in the second state S12 and does not exceed the second potential Vrellp within a predetermined time tVrellp, the control circuit 221 transitions the operation mode from the second state S12 to the first state S11. In the second state S12, in order to rapidly increase the potential of terminal VM toward the potential of terminal VDD, terminal VM is pull-up connected to terminal VDD by a resistance element Rpu having a relatively small first resistance value R1 (e.g., 25 kΩ). However, for some reason such as a fault, if the rate of increase in the potential of terminal VM becomes slow and the potential of 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 an abnormality occurs and terminal VM ultimately does not exceed the first potential Vstb, it does not transition to any state while remaining in the second state S12, 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, the system can be made to a state where power can be supplied from the secondary battery 210 to the system 501, enabling a recovery operation by the system 501.

[0072] When the potential of terminal VM exceeds the second potential Vrellp (e.g., VSS + 0.7 [V]) within a predetermined time tVrellp in the second state S12, the control circuit 221 does not transition the operation mode from the second state S12 to the first state S11. Thereby, after determining that there is no abnormality, the operation mode can be latched in the second state S12 so that the operation mode does not return to the first state S11 even if noise occurs.

[0073] When the potential of terminal VM becomes higher than the first potential Vstb (e.g., VDD - 0.9 [V]) in the second state S12, the control circuit 221 transitions the operation mode from the low power mode LPM (the second state S12) to the standby mode (the third state S13).

[0074] When the control circuit 221 transitions to the standby mode (the third state S13) in FIG. 4, it 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 third state S13, the control circuit 221 leaves the terminal COUT unrestricted (either an H or an L signal can be output). In the third state S13, the control circuit 221 pull-up connects the terminal VM to the terminal VDD by a resistance element Rpu having a second resistance value R2 (in this example, 1 MΩ). The control circuit 221 may suppress the power consumption of the protection IC 101 itself by putting an internal circuit (e.g., an OTP (Over Temperature Protection) circuit, etc.) that is unnecessary for operation in the second state S12 into the sleep mode.

[0075] On the other hand, in the normal operation mode (the first state S11) in FIG. 4, 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 transitions the operation mode from the normal operation mode (the first state S11) to the over-discharge protection mode UVP (the 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.

[0076] When the control circuit 221 transitions to the over-discharge protection mode UVP (the fourth state S14), it outputs a signal (e.g., a signal of high level "H") for permitting 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 to pull-up connect the terminal VM to the terminal VDD by a resistance element Rpu having a second resistance value R2 (in this example, 1 MΩ). The control circuit 221 may suppress the power consumption of the protection IC 101 itself by putting an internal circuit (e.g., an OTP (Over Temperature Protection) circuit, etc.) that is unnecessary for operation in the fourth state S14 into the sleep mode.

[0077] When the potential of terminal VM becomes higher than the first potential Vstb (e.g., VDD - 0.9 [V]) in the fourth state S14, the control circuit 221 transitions the operating mode from the over-discharge protection mode UVP (the fourth state S14) to the standby mode (the third state S13). The first potential Vstb, which is the transition 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, which is the transition threshold from the low-power mode LPM (the second state S12) to the standby mode (the third state S13). If the transition threshold for mode transition is the same between both transition routes, the mode transition determination circuit can be shared between both transition routes, so that the circuit area can be reduced.

[0078] When the potential of terminal VM in the third state S13 drops below a third potential (e.g., VDD / 2) that is lower than the potential of terminal VDD, the control circuit 221 determines that the charger 301 is connected and transitions from the third state S13 to the fourth state S14.

[0079] In the fourth state S14, the control circuit 221 determines whether or not the condition that the power supply voltage Vdd is higher than a predetermined return voltage Vrel2 and the potential of terminal VM is equal to or lower than a fourth potential Vreluvp (e.g., VSS + 0.7 [V]) is satisfied within a predetermined time tVrel2. When the condition is satisfied, the control circuit 221 determines that charging by the correctly connected charger 301 has started, and transitions the operating mode from the fourth state S14 not to the second state S12 but to the first state S11. As a result, when returning from the over-discharge protection mode to the normal operating mode, it is possible to quickly transition to the normal operating mode without going through the low-power mode LPM. Also, the fourth potential Vreluvp and the second potential Vrellp can be set to the same potential. As a result, the determination potential can be shared, so that the circuit area can be reduced.

[0080] In the first embodiment, when the control circuit 221 detects the input of signal S by the signal detection circuit 21 in the first state S11, it sets the second state S12 in which the terminal VM is pull-up connected to the terminal VDD by the resistor element Rpu having the first resistance value R1. However, as a first modification of the first embodiment, when the detection circuit 222 detects that the power supply voltage Vdd is lower than the over-discharge detection voltage Vdet2 in the first state S11, the control circuit 221 may set the fourth state S14 in which the terminal VM is pull-up connected to the terminal VDD by the resistor element Rpu having the first resistance value R1.

[0081] FIG. 9 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 resistor element Rpu is the first resistance value R1 in the fourth state S14 of FIG. 4. In the fourth state S14 of FIG. 9, the control circuit 221 pull-up connects the terminal VM to the terminal VDD by the resistor element Rpu having the first resistance value R1 (for example, 25 kΩ). In the over-discharge protection mode (the fourth state S14), since the terminal VM is pull-up connected to the terminal VDD by the resistor 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, since the potential of the terminal VM rapidly exceeds the first potential Vstb (in this example, VDD - 0.9 [V]), the operation mode of the protection IC101 rapidly transitions from the over-discharge 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, so the effect of reducing the power consumption is enhanced.

[0082] Regarding other contents of the first modification of the first embodiment, since they are the same as those of the first embodiment, the above description of the first embodiment is incorporated by reference and omitted.

[0083] FIG. 5 is a circuit block diagram showing an example of a system including a secondary battery protection integrated circuit according to the second embodiment. In the second embodiment, the description of the same configuration, operation, and effects as those in the above-described embodiment 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-side power line 201.

[0084] The system 502 shown in FIG. 5 includes a battery device 402 and an electronic device 300. The battery device 402 includes a secondary battery 210 and a battery protection device 602. The battery protection device 602 is a component including, for example, a substrate on which at least the protection IC 102 is mounted. The protection IC 102 includes, for example, a charge control terminal (terminal COUT), a discharge control terminal (terminal DOUT), a detection terminal (terminal VP), a power supply terminal (terminal VDD), a ground terminal (terminal VSS), 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 in the first embodiment.

[0085] The protection IC 102 may include a terminal CS1 as an example of a monitoring terminal used for monitoring a charging current or a discharging current flowing through the secondary battery 210. The terminal CS1 is connected to the power line 201 between the terminal B+ and the switch circuit 203 (the source of the charge control transistor TR1). When the terminal CS1 is provided, one end of the resistance element R22 inserted in series with the power 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 a charging overcurrent or a 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. When the resistance element R22 is arranged, the resistance element R21 can be omitted.

[0086] The protection IC 102 may include a terminal CS2 instead of a terminal CS1 as an example of a monitoring terminal used for monitoring a charging current or a discharging current flowing through the secondary battery 210. The terminal CS2 is connected to the power line 201 between the terminal P+ and the switch circuit 203 (the source of the discharge control transistor TR2). When the terminal CS2 is provided, one end of a resistance element R25 inserted in series with the power line 201 is connected to the terminal CS2, the other end is connected to the terminal P+, and is connected to the terminal VP via the resistance element R23. The detection circuit A223 in the protection IC 102 can detect an overcharging current or an over-discharging current flowing through the secondary battery 210 by detecting a potential difference between the terminal CS2 and the terminal VP. The resistance element R25 functions as a sense resistor for detecting a current flowing through the secondary battery 210.

[0087] The detection circuit 222 includes an overcharge detection circuit that detects overcharging of the secondary battery 210 by monitoring a power supply voltage Vdd between the terminal VDD and the terminal VSS. The overcharge detection circuit compares the power supply voltage Vdd with an overcharge detection voltage Vdet1, and generates an overcharge detection signal indicating that overcharging of the secondary battery 210 has been detected when the power supply voltage Vdd is higher than the overcharge detection voltage Vdet1.

[0088] The detection circuit 222 includes a charging overcurrent detection circuit that detects a charging overcurrent of the secondary battery 210 by monitoring a 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 a charging overcurrent detection voltage Vdet4, and generates a charging overcurrent detection signal indicating that a charging overcurrent of the secondary battery 210 has been detected when the potential difference ΔV1 is higher than the charging overcurrent detection voltage Vdet4 based on the terminal VDD or the terminal CS2. 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 based on the terminal VDD, or the voltage of the terminal VP based on the terminal CS2, is higher than the charging overcurrent detection voltage Vdet4.

[0089] The detection circuit 222 includes an over-discharge detection circuit that detects over-discharge of the secondary battery 210 by monitoring the power supply voltage Vdd between the terminal VDD and the terminal VSS. The over-discharge detection circuit compares the power supply voltage Vdd with the over-discharge detection voltage Vdet2, and when the power supply voltage Vdd is lower than the over-discharge detection voltage Vdet2, generates an over-discharge detection signal indicating that over-discharge of the secondary battery 210 has been detected.

[0090] The detection circuit 222 includes a discharge over-current detection circuit that detects a discharge over-current 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 discharge over-current detection circuit compares the potential difference ΔV1 with the discharge over-current detection voltage Vdet3, and when the potential difference ΔV1 is lower than the discharge over-current detection voltage Vdet3 with respect to the terminal VDD or the terminal CS2, generates a discharge over-current detection signal indicating that a discharge over-current of the secondary battery 210 has been detected. In other words, the discharge over-current detection circuit generates a discharge over-current detection signal when the voltage of the terminal VP or the terminal CS1 with respect to the terminal VDD, or the voltage of the terminal VP with respect to the terminal CS2, is lower than the discharge over-current detection voltage Vdet3.

[0091] 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 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].

[0092] The resistance element Rpd is a pull-down resistor disposed between the terminal VP and the terminal VSS. The resistance value of the resistance element Rpd varies according to a signal PU2 generated by the control circuit 221. A configuration in which the resistance value of the resistance element Rpd changes according to an input signal such as the signal PU2 may be a known configuration. For example, the resistance element Rpd may have a configuration that selectively switches a resistor corresponding to the content of the signal PU2 from a plurality of resistors having different resistance values.

[0093] Switch 11 switches whether to pull down the terminal VP to the terminal VSS by the resistor element Rpd according to the signal PU1 generated by the control circuit 221. Switch 11 is connected in series with the resistor element Rpd. Switch 11 may be arranged on the pull-down line between the resistor element Rpd and the terminal VSS, or may be arranged on the pull-down line between the terminal VP and the resistor element Rpd.

[0094] The control circuit 221 sets the first state S11 in which the resistor element Rpd is disconnected from the terminal VSS or the terminal VP by turning off the switch 11 with the signal PU1. The first state S11 indicates a state in which the operation mode of the protection IC102 is the normal operation mode.

[0095] In the first state S11, the control circuit 221 outputs a signal (for example, a signal of high level "H") for permitting charging of the secondary battery 210 from the terminal COUT, and outputs a signal (for example, a signal of high level "H") for permitting discharging of the secondary battery 210 from the terminal DOUT. Thereby, in the first state S11, charging or discharging of the secondary battery 210 becomes possible.

[0096] In the first state S11, the control circuit 221 turns off the switch 11. Thereby, the impedance between the terminal VP and the terminal VSS becomes high impedance (HiZ). In the first state S11, the control circuit 221 turns on the switch 12 with the signal Stb. Thereby, since power is supplied to the detection circuit 222, the detection circuit 222 becomes operable.

[0097] When the input of the signal S is detected by the signal detection circuit 21 in the first state S11, the control circuit 221 turns on the switch 11 with the signal PU1. By turning on the switch 11, the control circuit 221 sets the second state S12 in which the terminal VP is pulled down to the terminal VSS by the resistor element Rpd having the first resistance value R1. The second state S12 indicates a state in which the operation mode of the protection IC101 is the low power mode LPM.

[0098] In the second state S12, the control circuit 221 outputs a signal (e.g., a signal of high level "H") that permits charging of the secondary battery 210 from the terminal COUT, and outputs a signal (e.g., a signal of low level "L") that stops discharging of the secondary battery 210 from the terminal DOUT. As a result, the discharge control transistor TR2 turns off, so that the discharging of the secondary battery 210 stops. Consequently, the decrease in the remaining capacity of the secondary battery 210 is suppressed, and the power consumption of the battery device 402 is suppressed. The control circuit 221 may suppress the power consumption of the protection IC 102 itself by setting an internal circuit that is unnecessary in the second state S12 to the sleep mode.

[0099] 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) by the signal PU2. In the second state S12, since the terminal VP is pull-down connected to the terminal VSS by the resistance element Rpd having the first resistance value R1, the potential of the terminal VP starts to decrease toward the potential of the terminal VSS.

[0100] When the control circuit 221 detects by the comparison circuit 22 that the potential of the terminal VP in the second state S12 is lower than the first potential Vstb, the control circuit 221 sets the third state S13 in which the resistance element Rpd is changed to a second resistance value R2 higher than the first resistance value R1 to connect the terminal VP to the terminal VSS. The third state S13 indicates a 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).

[0101] In the third state S13, the control circuit 221 outputs a signal (e.g., a signal of low level "L") that stops discharging of the secondary battery 210 from the terminal DOUT. As a result, in the third state S13, following the second state S12, the discharging of the secondary battery 210 stops. Consequently, the decrease in the remaining capacity of the secondary battery 210 is suppressed, and the power consumption of the battery device 402 is suppressed.

[0102] In the third state S13, the control circuit 221 turns off the switch 12 by the signal Stb, thereby cutting off the power supply to some specific detection circuits A223 in the detection circuit 222. The control circuit 221 suppresses the power consumption of the protection IC 102 itself by cutting off the power supply to the internal circuits that are unnecessary in the third state S13. The control circuit 221 may further suppress the power consumption of the protection IC 102 itself by cutting off the power supply to the charge control circuit 221a in the third state S13.

[0103] The control circuit 221 sets the resistance value of the resistance element Rpd in the third state S13 to a second resistance value R2 (for example, 1 MΩ) higher than the first resistance value R1 by the signal PU2. The second resistance value R2 is preferably sufficiently higher than the resistance value of the resistance element R23 (for example, 1 kΩ). In the third state S13, since the terminal VP is pull - down connected to the terminal VSS by the resistance element Rpd having a relatively large second resistance value R2, the potentials of the terminal VP and the terminal P+ can be stabilized to 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.

[0104] As described above, in the second embodiment, the first resistance value R1 of the resistance element Rpd that pull - down 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 pull - down connects the terminal VP to the terminal VSS in the third state S13. In the second state S12, since the terminal VP is pull - down connected to the terminal VSS by the resistance element Rpd having a relatively small first resistance value R1, the rate at which the potential of the terminal VP decreases in the second state S12 is less affected by the external impedance such as the electronic device 300. Therefore, in the second state S12, the potential of the terminal VP rapidly decreases toward the potential of the terminal VSS. Further, after the potential of the terminal VP is lowered to a predetermined value, the potential of the terminal VP can be stabilized by setting the resistance element Rpd to a second resistance value R2 higher than the first resistance value R1.

[0105] FIG. 6 is a diagram showing an example of the operation waveforms of the secondary battery protection integrated circuit according to the second embodiment. The vertical axis of the graph represents potential, and the horizontal axis represents time. The solid line represents the potential of terminal VDD, the one-dot chain line represents the potential of terminal VP, and the broken line represents the potential of terminal LP. The bar graphs of DOUT and COUT below the graph indicate the signals output from terminals DOUT and COUT of the protection IC 102. The bar graph of IC MODE indicates the operation mode of the protection IC. The bar graph of Pull-Down VP indicates the state in which the control circuit 221 controls the resistor element Rpd. In the low power mode LPM (second state S12), since the terminal VP is pull-down connected to the terminal VSS by the resistor element Rpd having a relatively small first resistance value R1, the potential of the terminal VP rapidly decreases toward the potential of the terminal VSS. Therefore, since the potential of the terminal VP rapidly falls below the first potential Vstb, the operation mode of the protection IC 102 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 enhanced.

[0106] When transitioning to the standby mode (third state S13), the terminal VP is pull-down connected to the terminal VSS by the resistor element Rpd having a second resistance value R2 larger than the first resistance value R1. Thereby, after the potential of the terminal VP falls below the first potential Vstb, it gradually decreases toward the potential of the terminal VSS. Thus, the speed at which the potential of the terminal VP decreases toward the potential of the terminal VSS is faster in the case of the first resistance value R1 than in the case of the second resistance value R2 of the resistor element Rpd.

[0107] On the other hand, FIG. 7 is a diagram showing an example of the operation waveform of the secondary battery protection integrated circuit according to the second comparative form. The second comparative form is a form in which the resistance element Rpd in the low power mode LPM is set to the same resistance value (1 MΩ in this example) as the resistance element Rpd in the standby mode. In the case of this form, the potential drop rate of the terminal VP after the transition to the low power mode LPM (the second state S12) is gentle immediately after the drop as shown in FIG. 7 due to the influence of the external impedance of the electronic device 300 or the like. For this reason, there is a possibility that the transition from the low power mode LPM (the second state S12) to the standby mode (the third state S13) may be delayed.

[0108] FIG. 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 FIGS. 5 and 6, an operation example of the protection IC102 shown in FIG. 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 resistance element Rpd connected to the terminal VP, and the operation state of the OTP (Over Temperature Protection) are shown from the top.

[0109] In the normal operation mode (the first state S21) of FIG. 8, the control circuit 221 outputs a signal (for example, a signal of a high level "H") for permitting the charging of the secondary battery 210 from the terminal COUT, and outputs a signal (for example, a signal of a high level "H") for permitting the discharging of the secondary battery 210 from the terminal DOUT. In the first state S21, the control circuit 221 sets the impedance between the terminal VP and the terminal VSS to high impedance (HiZ) by turning off the switch 11.

[0110] When the signal S is an active-high signal, for example, when the potential of the terminal LP is higher than a predetermined detection threshold value Vdetlp, the signal detection circuit 21 outputs a signal detection signal indicating that the input of the signal S from the terminal LP has been detected to the control circuit 221. Alternatively, when the signal S is an active-low signal, for example, when the potential of the terminal LP is lower than a predetermined detection threshold value Vdetlp, the signal detection circuit 21 outputs a signal detection signal indicating that the input of the signal S from the terminal LP has been detected to the control circuit 221.

[0111] When the signal detection signal is continuously detected for a predetermined delay time tVdetlp (see FIG. 6), the control circuit 221 transitions the operation mode from the normal operation mode (the first state S21) to the low power mode LPM (the second state S22).

[0112] When the control circuit 221 transitions to the low power mode LPM (the second state S22) in FIG. 8, it outputs a signal (for example, a signal of high level "H") for permitting charging of the secondary battery 210 from the terminal COUT, and outputs a signal (for example, a signal of low level "L") for stopping discharging of the secondary battery 210 from the terminal DOUT. In the second state S22, the control circuit 221 turns on the switch 11 to pull-down and connect the terminal VP to the terminal VSS by a resistance element Rpd having a first resistance value R1 (for example, 25 kΩ). The control circuit 221 may suppress the power consumption of the protection IC 102 itself by setting an internal circuit (for example, an OTP (Over Temperature Protection) circuit, etc.) that is unnecessary for operation in the second state S22 to the sleep mode.

[0113] When the potential of terminal VP is higher than the first potential Vstb and lower than the power supply potential, specifically the second potential Vrellp (e.g., VDD - 0.7 [V]), and does not fall below it within a predetermined time tVrellp in the second state S22, the control circuit 221 transitions the operation mode from the second state S22 to the first state S21. In the second state S22, in order to rapidly lower the potential of terminal VP towards the potential of terminal VSS, terminal VP is pull - down connected to terminal VSS by a resistance element Rpd having a relatively small first resistance value R1 (e.g., 25 kΩ). However, for some reason, if the rate of decrease in the potential of terminal VP becomes slow and 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, if an abnormality occurs such that terminal VP ultimately does not fall below the first potential Vstb, it does not transition to any state while remaining in the second state S22, 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 IC102 to the first state S21. As a result, the system can be made to a state where power can be supplied from the secondary battery 210 to the system 502, enabling the system 502 to perform a recovery operation.

[0114] When the potential of terminal VP falls below the second potential Vrellp (e.g., VDD - 0.7 [V]) within a predetermined time tVrellp in the second state S22, the control circuit 221 does not transition the operation mode from the second state S22 to the first state S21. Thus, after determining that there is no abnormality, the operation mode can be latched in the second state S22 so that even if noise occurs, the operation mode does not return to the first state S21.

[0115] When the potential of terminal VP becomes lower than the first potential Vstb (e.g., VSS + 0.9 [V]) in the second state S22, the control circuit 221 transitions the operation mode from the low - power mode LPM (second state S22) to the standby mode (third state S23).

[0116] When the control circuit 221 transitions to the standby mode (the third state S23) in FIG. 8, it 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 third state S23, the control circuit 221 makes the terminal COUT irrelevant (either a signal of H or L can be output). In the third state S23, the control circuit 221 pull-down connects the terminal VP to the terminal VSS through a resistance element Rpd having a second resistance value R2 (in this example, 1 MΩ). The control circuit 221 may suppress the power consumption of the protection IC 102 itself by setting an internal circuit (e.g., an OTP (Over Temperature Protection) circuit, etc.) that is unnecessary for operation in the second state S22 to the sleep mode.

[0117] On the other hand, in the normal operation mode (the first state S21) in FIG. 8, 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 transitions 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.

[0118] When the control circuit 221 transitions to the over-discharge protection mode UVP (the fourth state S24), it outputs a signal (e.g., a signal of high level "H") for permitting 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 S24, the control circuit 221 turns on the switch 11 to pull-down connect the terminal VP to the terminal VSS through a resistance element Rpd having a second resistance value R2 (in this example, 1 MΩ). The control circuit 221 may suppress the power consumption of the protection IC 102 itself by setting an internal circuit (e.g., an OTP (Over Temperature Protection) circuit, etc.) that is unnecessary for operation in the fourth state S24 to the sleep mode.

[0119] When the potential of terminal VP becomes lower than the first potential Vstb (e.g., VSS + 0.9 [V]) in the fourth state S24, the control circuit 221 transitions the operation mode from the over-discharge protection mode UVP (the fourth state S24) to the standby mode (the third state S23). The first potential Vstb, which is the transition threshold from the over-discharge protection mode UVP (the fourth state S24) to the standby mode (the third state S23), is the same as the first potential Vstb, which is the transition threshold from the low-power mode LPM (the second state S22) to the standby mode (the third state S23). When the transition thresholds for mode transitions are the same between both transition routes, the mode transition determination circuit can be shared between both transition routes, so the circuit area can be reduced.

[0120] When the potential of terminal VP rises above the third potential (e.g., VDD / 2), which 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 transitions from the third state S23 to the fourth state S24.

[0121] In the fourth state S24, the control circuit 221 determines whether or not the conditions that the power supply voltage Vdd is higher than the predetermined return voltage Vrel2 and the potential of terminal VP is equal to or higher than the fourth potential Vreluvp (e.g., VDD - 0.7 [V]) are satisfied within the predetermined time tVrel2. When the control circuit 221 determines that the conditions are satisfied, it determines that charging by the correctly connected charger 301 has started, and transitions the operation mode from the fourth state S24 not to the second state S22 but to the first state S21. Thereby, when returning from the over-discharge protection mode to the normal operation mode, it is possible to quickly transition to the normal operation mode without passing through the low-power mode LPM. Also, the fourth potential Vreluvp and the second potential Vrellp can be set to the same potential. As a result, the determination potential can be shared, so the circuit area can be reduced.

[0122] In the second embodiment, when the signal detection circuit 21 detects the input of the signal S in the first state S21, the control circuit 221 sets the second state S22 in which the terminal VP is pulled down to the terminal VSS by the resistance element Rpd having the first resistance value R1. However, as a first modification of the second embodiment, when the detection circuit 222 detects that the power supply voltage Vdd is lower than the over-discharge detection voltage Vdet2 in the first state S21, the control circuit 221 may set the fourth state S24 in which the terminal VP is pulled down to the terminal VSS by the resistance element Rpd having the first resistance value R1.

[0123] FIG. 10 is a diagram showing an example of the state transition of the secondary battery protection integrated circuit according to the 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 FIG. 8. In the fourth state S24 of FIG. 10, the control circuit 221 pulls down the terminal VP to the terminal VSS by the resistance element Rpd having the first resistance value R1 (for example, 25 kΩ). In the over-discharge protection mode (the fourth state S24), since the terminal VP is pulled down to the terminal VSS by the resistance element Rpd having a relatively small first resistance value R1 (for example, 25 kΩ), the potential of the terminal VP rapidly decreases toward the potential of the terminal VSS. For this reason, since the potential of the terminal VP rapidly falls below the first potential Vstb (in this example, VSS + 0.9 [V]), the operation mode of the protection IC102 rapidly transitions from the over-discharge 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, so the effect of reducing the power consumption is enhanced.

[0124] Regarding other contents of the first modification of the second embodiment, since they are the same as those of the second embodiment, the above description of the second embodiment is incorporated by reference and omitted.

[0125] As described above, the embodiments have been explained. However, the above embodiments are presented as examples, and the present invention is not limited by the above embodiments. The above embodiments can be implemented in various other forms, and various combinations, omissions, replacements, changes, etc. can be made without departing from the gist of the invention. These embodiments and their modifications are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalent scope thereof.

[0126] For example, the arrangement positions of the charge control transistor TR1 and the discharge control transistor TR2 may be mutually replaced with respect to the positions shown in the figure. The switch circuit 203 may be incorporated in the protection IC.

Explanation of Reference Numerals

[0127] 11, 12 Switches 21 Signal detection circuit 22 Comparison circuit 101, 102 Protection ICs 201 Power supply line 202 Ground line 203 Switch circuit 210 Secondary battery 211 Positive electrode 212 Negative electrode 221 Control circuit 222 Detection circuit 300 Electronic device 301 Charger 302 Load 401, 402 Battery devices 501, 502 Systems 601, 602 Battery protection devices Rpd, Rpu Resistance elements TR1 Charge control transistor TR2 Discharge control transistor

Claims

1. A secondary battery protection integrated circuit used for protecting a secondary battery, 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, a control circuit, and comprising: The control circuit sets 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, sets a second state in which the monitoring terminal is connected to the power supply terminal by the resistance element having a first resistance value, when the potential of the monitoring terminal in the second state becomes higher than a first potential which is lower than the potential of the power supply terminal, connects the monitoring terminal to the power supply terminal by the resistance element having a second resistance value which is higher than the first resistance value, and sets a third state in which the power consumption is lower than that in the first state. A secondary battery protection integrated circuit.

2. further comprising a detection circuit for detecting overcharge, charging overcurrent, overdischarge or discharging overcurrent of the secondary battery, The third state is a state in which power supply to the detection circuit is cut off. The secondary battery protection integrated circuit according to claim 1.

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

4. The control circuit can control so as not to transition from the second state to the first state when the potential of the monitoring terminal in the second state exceeds the second potential within the predetermined time. The secondary battery protection integrated circuit according to claim 3.

5. The rate at which the potential of the monitoring terminal rises is faster in the case where the resistance value of the resistance element is the first resistance value than in the case where the resistance value is the second resistance value. The secondary battery protection integrated circuit according to any one of claims 1 to 4.

6. further comprising a control terminal, The control circuit sets a fourth state in which a signal for stopping discharge of the secondary battery is output from the control terminal when the power supply voltage between the power supply terminal and the ground terminal in the first state drops below a predetermined detection voltage. The secondary battery protection integrated circuit according to any one of claims 1 to 4.

7. The control circuit connects the monitoring terminal to the power supply terminal by the resistance element having the second resistance value in the fourth state. The secondary battery protection integrated circuit according to claim 6.

8. The secondary battery protection integrated circuit according to claim 7, wherein when the potential of the monitoring terminal becomes higher than the first potential in the fourth state, the control circuit makes a transition from the fourth state to the third state.

9. The secondary battery protection integrated circuit according to claim 6, wherein when the potential of the monitoring terminal in the third state drops below a third potential that is lower than the potential of the power supply terminal, the control circuit makes a transition from the third state to the fourth state, and when the power supply voltage is higher than a predetermined return voltage and the potential of the monitoring terminal is equal to or lower than a fourth potential that is lower than the first potential in the fourth state, the control circuit can make a transition from the fourth state to the first state without making a transition to the second state.

10. A secondary battery protection integrated circuit used for protecting a secondary battery, 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, a control circuit, and comprising: The control circuit sets 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, sets a second state in which the monitoring terminal is connected to the ground terminal by the resistance element having a first resistance value, and when the potential of the monitoring terminal in the second state becomes lower than a first potential that is higher than the potential of the ground terminal, connects the monitoring terminal to the ground terminal by the resistance element having a second resistance value that is higher than the first resistance value, and sets a third state in which the power consumption is lower than that in the first state.

11. The secondary battery protection integrated circuit according to claim 10, further comprising a detection circuit for detecting overcharge, overcharge current, overdischarge, or over-discharge current of the secondary battery, wherein 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, wherein when the potential of the monitoring terminal in the second state does not fall below a second potential that is higher than the first potential within a predetermined time, the control circuit makes a transition from the second state to the first state.

13. The secondary battery protection integrated circuit according to claim 12, wherein when the potential of the monitoring terminal in the second state falls below the second potential within the predetermined time, the control circuit can control so as not to make a transition from the second state to the first state.

14. The rate at which the potential of the monitoring terminal decreases is faster when the resistance value of the resistance element is the first resistance value than when it is the second resistance value, for the secondary battery protection integrated circuit according to any one of claims 10 to 13.

15. Further comprising a control terminal, When the power supply voltage between the power supply terminal and the ground terminal decreases below a predetermined detection voltage in the first state, the control circuit sets to a fourth state in which a signal for stopping the discharge of the secondary battery is output from the control terminal, for the secondary battery protection integrated circuit according to any one of claims 10 to 13.

16. In the fourth state, the control circuit connects the monitoring terminal to the ground terminal by the resistance element having the second resistance value, for the secondary battery protection integrated circuit according to claim 15.

17. When the potential of the monitoring terminal becomes lower than the first potential in the fourth state, the control circuit transitions from the fourth state to the third state, for the secondary battery protection integrated circuit according to claim 16.

18. When the potential of the monitoring terminal rises above a third potential higher than the potential of the ground terminal in the third state, the control circuit transitions from the third state to the fourth state, and when the power supply voltage is higher than a predetermined return voltage and the potential of the monitoring terminal is higher than a fourth potential higher than the first potential in the fourth state, the control circuit can transition from the fourth state to the first state without transitioning to the second state, for the secondary battery protection integrated circuit according to claim 15.

19. A secondary battery protection integrated circuit used for protecting a secondary battery, 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, A control circuit, Comprising, The control circuit, Sets 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 decreases below a predetermined detection voltage in the first state, the control circuit connects the monitoring terminal to the power supply terminal by the resistance element having the first resistance value and sets to 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 becomes higher than a first potential that is lower than the potential of the power supply terminal in the fourth state, the monitoring terminal is connected to the power supply terminal by the resistance element having a second resistance value higher than the first resistance value, and a secondary battery protection integrated circuit that sets a third state in which the power consumption is lower than that in the first state.

20. Further comprising a detection circuit for detecting overcharge, overcharge current, 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. The secondary battery protection integrated circuit according to claim 19.

21. The speed at which the potential of the monitoring terminal rises is faster when the resistance value of the resistance element is the first resistance value than when it is the second resistance value. The secondary battery protection integrated circuit according to claim 19 or 20.

22. A secondary battery protection integrated circuit used for protecting a secondary battery, 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 ground terminal, A control circuit, Comprising, The control circuit, Sets 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 drops below a predetermined detection voltage in the first state, the monitoring terminal is connected to the power supply terminal by the resistance element having a first resistance value, and a signal for stopping the discharge of the secondary battery is output from the control terminal. Set to the fourth state, When the potential of the monitoring terminal becomes lower than a first potential that is higher than the potential of the ground terminal in the fourth state, the monitoring terminal is connected to the ground terminal by the resistance element having a second resistance value higher than the first resistance value, and a secondary battery protection integrated circuit that sets a third state in which the power consumption is lower than that in the first state.

23. Further comprising a detection circuit for detecting overcharge, overcharge current, 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. The secondary battery protection integrated circuit according to claim 22.

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

25. The secondary battery protection integrated circuit according to any one of claims 1, 10, 19, 22, And a switch provided in a current path connected to the secondary battery. A secondary battery protection device that protects the secondary battery by controlling the switch.

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

Images