JPH11283677A - Battery pack and method for controlling its state monitoring operation mode - Google Patents

Abstract

PROBLEM TO BE SOLVED: To properly switch a state-monitoring operation mode between a normal mode and a sleep mode when a battery pack is connected to external equipment having no communications functions. SOLUTION: A battery pack 10 has a switching circuit for stopping charge and discharge and a monitoring circuit for the state of a secondary battery. The monitoring circuit comprises a microcomputer 40 and a measuring part 30 to which power is fed only during measurements. When the current of the secondary battery is not greater than a specific value, the monitoring circuit is set in a sleep mode, and when the specified value is exceeded the circuit is set in a normal mode. In the normal mode, the power consumed internally is great since the microcomputer 40 operates at high speed and time intervals of measurements made by the measuring part 30 are short. In the sleep mode, the power consumed internally is small since the microcomputer 40 operates at low speed and the intervals of the measurements are long. The sleep mode includes a first and second sleep modes. When the battery pack 10 is not connected to external equipment, the second sleeve mode in which the intervals of the measurements are the longest is selected.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a battery pack having a monitoring circuit for monitoring the state of a secondary battery, and more particularly to a battery pack for saving power by setting the monitoring circuit to a sleep mode when the current of the battery pack is small. And a state monitoring operation mode control method.

[0002]

2. Description of the Related Art Portable electronic devices, for example, mobile phones, notebook computers, camcorders, CD players and the like are widely used. Most of these electronic devices are equipped with chargeable / dischargeable battery packs. This battery pack is packaged with a plurality of rechargeable batteries, one in series or in parallel, and supplies power to an electronic device as a load.

In recent years, lithium ion batteries have been widely used as secondary batteries. This lithium-ion battery has features such as high operating voltage, high energy density, large discharge current, long cycle life, no memory effect, and short charging time. I have. As described above, the lithium ion battery has many advantages, but special attention must be paid to short-circuiting and charging / discharging of the battery as compared with other secondary batteries.

For example, when a battery pack is detached from an external device such as an electronic device or a charger, and the power supply terminal (plus terminal, minus terminal) is short-circuited by a necklace or the like, a lithium ion battery May generate heat, explode or ignite. In addition, if the battery is discharged with an overcurrent exceeding the maximum allowable current, the temperature of the lithium ion battery rises abnormally and deteriorates irreparably, or the safety valve is activated and becomes unusable.

Conversely, when charging with overcurrent, the battery temperature rises abnormally and the battery life is shortened. Further, there is a danger that the organic electrolyte solution is decomposed to generate gas and metallic lithium which causes internal short circuit is generated.

[0006] When the battery is charged beyond the specified charge stop voltage, the organic electrolyte is decomposed, and the above-mentioned gas is generated and metallic lithium is deposited. Further, due to this overcharging, the battery characteristics may be significantly degraded, the safety valve may operate, and further, the lithium ion battery may explode or ignite.

Conversely, if the discharge is performed beyond the prescribed discharge stop voltage, the electrodes are deteriorated or the organic electrolyte is decomposed. In addition, the overdischarge causes melting of the copper current collector and the lead wire, which causes a deterioration in the performance of the lithium ion battery and a contact failure. When a plurality of lithium-ion batteries are connected in series, each battery may not be charged or discharged uniformly, and some of the batteries may be charged and discharged faster than other batteries.

In order to prevent abnormal situations such as short circuit, overcurrent, overcharge and overdischarge, a battery pack in which a lithium ion battery is packaged is provided with a charge / discharge control circuit (protection circuit). The charge / discharge control circuit includes a monitoring circuit that monitors the state of each lithium-ion battery and the connection state of electronic devices, and an ON / OFF signal based on a signal from the monitoring circuit.
And a switching circuit that regulates charging and discharging. The switching circuit comprises a charge stopping FET (field effect transistor) and a discharging stopping FET,
These are connected in series to the lithium ion battery.

The monitoring circuit determines an abnormal situation from the measuring section and a signal from the measuring section, and turns ON / OFF the switching circuit.
F. As the determination unit, a comparator or a microcomputer is used. The measuring unit includes a current measuring circuit for measuring the current of the lithium ion battery, a voltage measuring circuit for measuring the voltage of the lithium ion battery, a temperature measuring circuit for measuring the heat generation temperature of the lithium ion battery, and the like.

For example, a microcomputer determines an overcharge state, an overdischarge state, an overcurrent state, and a heat generation state based on a measurement signal from each measurement circuit. The overcurrent state and the heat generation state include those that occur during charging and those that occur during discharging. The microcomputer turns off the charging stop FET when an abnormal situation occurs during charging.
When an abnormal situation occurs during discharge, the discharge stop FET is turned off.

It is also known to connect a PTC element in series with a switching circuit in order to prevent overcurrent. This PTC element has a positive temperature coefficient whose resistance value increases with temperature. When the current increases, the temperature rises due to heat generation, so that the resistance value becomes extremely large and the flow of the current is prevented. When the temperature decreases, the resistance value returns to the original value, so that charging and discharging can be performed again.

Further, a measuring unit, a microcomputer, F
Even if ET breaks down, in order to stop charging and discharging reliably,
A fuse is provided. This fuse melts when the temperature of the battery pack becomes abnormally high or when an overcurrent that is considerably larger than the overcurrent flows, thereby breaking the connection between the battery and the power supply terminal. Because this fuse is the ultimate protection, once it is melted, the battery pack cannot be reused.

The battery pack is provided with a pair of power supply terminals for charging and discharging with an external device and a connection detection terminal for detecting a short circuit. Correspondingly, the external device is also provided with a pair of power supply terminals and connection detection terminals.

When the battery pack is normally connected to, for example, an electronic device, the plus terminal of the electronic device is connected to the plus terminal of the battery pack, and the minus terminal of the electronic device is connected to the minus terminal of the battery pack. In a normal connection state, the connection detection terminal is connected to the plus terminal in the electronic device, so that the connection detection terminal is set to “H”, and if the connection is not properly made, the connection detection terminal is set to “L”.

When the connection detection terminal is at "H", the microcomputer turns on the two FETs to enable charging and discharging, and when at "L", turns off the two FETs.
Therefore, when the battery pack is not attached to the electronic device and is in a single unit, the two FETs are OFF, so that even if the plus terminal and the minus terminal of the battery pack come into contact with each other, no short circuit occurs. .

In an electronic device such as a notebook personal computer, if the remaining battery capacity of the battery pack becomes small and sufficient power cannot be supplied, data being input is lost. Therefore, recently, a battery pack called an intelligent battery, which includes a communication terminal and communicates with an electronic device, is commercially available. The microcomputer of the battery pack sends data on the state of the battery (battery voltage, discharge current, remaining battery capacity, availability of discharge, etc.) to the electronic device in response to a request from the electronic device. In an electronic device, the remaining battery capacity is checked, and when there is a possibility that the electronic device may not operate normally, a warning is displayed or data is automatically backed up.

The monitoring circuit operates not only when it is connected to an external device such as an electronic device or a charger, but also when it is not connected to the external device and is a single unit. Although the monitoring circuit differs depending on the circuit configuration, for example, a current of about 6 mA flows. Since the power used in this monitoring circuit is internal power consumption, the usage time of the battery pack is shortened accordingly.

Therefore, there is known a method of setting an operation mode of a monitoring circuit according to a connection detection terminal for detecting connection of an external device and a voltage of a communication terminal for communicating with the external device. (JP-A-8-308121). The operation modes include a normal mode and a low power consumption mode. In the normal mode, power is supplied to the voltage measurement circuit, the current measurement circuit, and the temperature measurement circuit to perform measurement, but in the low power consumption mode, power is not supplied to each circuit to stop the measurement. This method sets the low power consumption mode when not connected to an external device or when connected but there is no communication from the external device, and reduces the current consumed in the battery pack to save power. Is what you do.

[0019]

In the above-mentioned conventional method, the operation mode of an external device is determined based on the presence or absence of communication and the operation mode is set. Therefore, when connected to an external device having no communication function, a low power consumption mode is set. In this case, the state of the secondary battery cannot be monitored because each measurement circuit does not operate. As a result, the battery pack implementing this method cannot be used for an external device having no communication function.

Further, according to the conventional method, since the voltage, current and the like are not measured in the low power consumption mode, even if an abnormal situation occurs in the secondary battery, it cannot be detected. Therefore, appropriate measures such as communicating the abnormal situation to the electronic device or turning off the switching circuit cannot be taken.

To accurately calculate the current remaining battery capacity,
It is necessary to determine the discharge capacity by measuring the current in the low power consumption mode. However, in the conventional method, the current measurement circuit is turned off in the low power consumption mode, so that the remaining battery capacity cannot be obtained correctly.

The present invention can be used for an external device having no communication function, and can properly set a status monitoring operation mode according to the operation status of the external device, and a status monitor for the battery pack. An object of the present invention is to provide an operation mode control method.

Another object of the present invention is to provide a battery pack capable of monitoring the state of a secondary battery and measuring the current even in a sleep mode in which current consumption is small, and a method of controlling the state monitoring operation mode. It is assumed that.

[0024]

According to a first aspect of the present invention, there is provided a method for controlling a state monitoring operation mode, comprising: at least one chargeable / dischargeable secondary battery; and a state of the secondary battery. A monitoring circuit for monitoring, and a switching circuit for stopping charging and discharging by a signal from the monitoring circuit, and in a battery pack connected to an electronic device or a charger, the current of the secondary battery exceeds a specified value. When the monitoring circuit is set to the normal mode where the internal power consumption is large, and when the current of the secondary battery is
The monitoring circuit is set to a sleep mode with small internal power consumption.

According to a second aspect of the present invention, the monitoring circuit includes a voltage measuring circuit for measuring a voltage of the secondary battery, a current measuring circuit for measuring a current of the secondary battery, and a secondary battery based on the measured voltage. And a microcomputer that determines ON state and controls ON / OFF of the switching circuit. This microcomputer determines the state monitoring operation mode from the measured current, and energizes the current measurement circuit and the voltage measurement circuit only at the time of measurement. In the normal mode, the microcomputer is driven by a high-frequency clock, and in the sleep mode, the microcomputer is driven by a low-frequency clock.

In the state monitoring operation mode control method according to the third aspect, the current and voltage measurement intervals are shortened in the normal mode, and the measurement intervals are increased in the sleep mode.

In the state monitoring operation mode control method according to the fourth aspect, the battery pack includes at least one chargeable / dischargeable secondary battery, a monitoring circuit for monitoring the state of the secondary battery, and the monitoring circuit. And a switching circuit for stopping charging / discharging with the signal. The monitoring circuit is
When the current of the secondary battery exceeds the specified value, the normal mode in which the internal power consumption is large is set. When the current of the secondary battery is equal to or less than the specified value, the battery is connected to an electronic device or a charger. Sometimes, the first sleep mode in which the internal power consumption is relatively small is set. Then, when the current of the secondary battery is equal to or less than the specified value and is not connected to the electronic device or the charger, the second sleep mode in which the internal power consumption is minimized is set.

According to a fifth aspect of the present invention, the monitoring circuit includes a voltage measuring circuit for measuring a voltage of the secondary battery, a current measuring circuit for measuring a current of the secondary battery, and a secondary battery based on the measured voltage. And a microcomputer which determines ON state and controls ON / OFF of the switching circuit. The microcomputer turns on the current measuring circuit and the voltage measuring circuit only at the time of measurement, and determines the state monitoring operation mode from the measured current. In the normal mode, the microcomputer is driven by a high-frequency clock, and the interval between current and voltage measurement is short. First
In the sleep mode, the microcomputer is driven by a low-frequency clock, and the current and voltage measurement intervals are relatively long. In the second sleep mode, the microcomputer is driven by a low-frequency clock and measures at least the current at the longest measurement interval.

According to a sixth aspect of the present invention, there is provided a state monitoring operation mode control method which is connected to an electronic device or a charger and, when a communication signal is received from the electronic device or the charger, the current of the secondary battery is equal to or less than a specified value. Set to normal mode.

According to a seventh aspect of the present invention, in the state monitoring operation mode control method, when communication from the electronic device or the charger is performed during the first sleep mode, the mode is returned to the normal mode,
If the electronic device or the charger is connected during the second sleep mode, the process returns to the normal mode.

According to the present invention, there is provided a battery pack comprising: a voltage measuring circuit for measuring a voltage of a secondary battery; a current measuring circuit for measuring a current of the secondary battery; and a switching circuit for stopping charging and discharging of the secondary battery. Determining the state of the secondary battery from the measured voltage, controlling ON / OFF of the switching circuit, and determining the state monitoring operation mode from the measured current;
Further, a microcomputer for energizing the voltage measurement circuit and the current measurement circuit only at the time of measurement is provided. This microcomputer monitors the secondary battery in the sleep mode in which the internal power consumption is small when the current of the secondary battery is less than the specified value, and when the current of the secondary battery exceeds the specified value,
The secondary battery is monitored in the normal mode in which the internal power consumption is large.

In the battery pack according to the ninth aspect, in the normal mode, the microcomputer is driven by a clock having a high frequency, the current and voltage measurement intervals are short, and in the sleep mode, the microcomputer is driven by a clock having a low frequency. The current and voltage measurement intervals are long.

The battery pack according to the tenth aspect has a first sleep mode and a second sleep mode as sleep modes. The first sleep mode is set when the electronic device or the charger is connected, and the second sleep mode is set when the electronic device or the charger is not connected. The measurement interval of the second sleep mode is longer than that of the first sleep mode.

According to the eleventh aspect, the battery pack exchanges communication signals with a pair of power supply terminals for charging or discharging with an electronic device or a charger and with the electronic device or a charger. A connection terminal for receiving a connection signal from the electronic device or the charger when a pair of power terminals are normally connected to the electronic device or the charger, and measuring a voltage of the secondary battery. Voltage measurement circuit,
A current measuring circuit for measuring the current of the secondary battery, a switching circuit for stopping charging / discharging of the secondary battery, and a state of the secondary battery based on the measured voltage to determine whether the switching circuit is ON or OFF.
A microcomputer is provided for controlling OFF and for energizing the voltage measurement circuit and the current measurement circuit only during measurement. This microcomputer is in normal mode when the current of the secondary battery exceeds the specified value,
When the current of the secondary battery is equal to or less than the specified value and there is a connection signal, the first sleep mode is set. When the current of the secondary battery is equal to or less than the specified value and there is no connection signal, the second sleep mode is set. Mode. In the normal mode, the microcomputer is driven by a high-frequency clock, and the interval between current and voltage measurement is short. In the first sleep mode, the microcomputer is driven by a low-frequency clock, and the current and voltage measurement intervals are relatively long. In the second sleep mode, the microcomputer is driven by a low-frequency clock, and the current measurement interval is longest.

In a twelfth aspect of the present invention, when a communication signal is received during the normal mode, the battery pack is maintained in the normal mode even if the current of the secondary battery is less than a specified value.

In the battery pack according to the thirteenth aspect, during the first sleep mode, when receiving a communication signal from an electronic device or a charger, the battery pack is returned to the normal mode,
When the connection signal is received during the second sleep mode, the mode is returned to the normal mode.

In the battery pack according to the present invention,
The current measurement circuits include a first current measurement circuit having a small measurement range and small power consumption, and a second current measurement circuit having a large measurement range and large power consumption. The first current measurement circuit is operable in all state monitoring operation modes together with the voltage measurement circuit, and the second current measurement circuit is operable only in the normal mode.

According to a fifteenth aspect of the present invention, there is provided a battery pack, wherein a plurality of secondary batteries are connected in series, a monitoring circuit for monitoring the status of these secondary batteries, and charging / discharging is stopped by a signal from the monitoring circuit. And a switch for turning on / off the monitoring circuit, and a series voltage of a plurality of secondary batteries are measured. When the measured series voltage falls below the discharge inhibition series voltage, the switch is turned off and monitored. And a series voltage detection circuit for stopping power supply to the circuit.

[0039]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As shown in FIG. 1, a battery pack 10 is removably mounted on a portable electronic device 11 such as a notebook computer or a portable telephone, and supplies power to the electronic device 11. The battery pack 10 is connected to a charger 70 shown in FIG. 9 for charging when the remaining battery capacity is low.

In FIG. 1, the battery pack 10 is provided with a plus terminal 13, a minus terminal 14, a connection detection terminal 15, and a communication terminal 16. On the other hand, the electronic device 11 is also provided with a plus terminal 17, a minus terminal 18, a connection detection terminal 19, and a communication terminal 20. The plus terminal 13 and the minus terminal 14 are connected to the electronic device 1.
1 and a power supply terminal for charging and discharging with the charger 70.

Each terminal 13 to 16 of the battery pack 10
And the terminals 17 to 20 of the electronic device 11, when the battery pack 10 is normally loaded into the electronic device 11,
The corresponding ones are arranged to be connected.
That is, when the battery pack 10 is correctly loaded into the electronic device 11, the plus terminal 13 of the battery pack 10 becomes the plus terminal 17 of the electronic device 11, and the minus terminal 14 of the battery pack 10 becomes the minus terminal 18 of the electronic device 11. Connected to.

Similarly, the connection detection terminal 15 of the battery pack 10 is connected to the connection detection terminal 19 of the electronic device 11, and the communication terminal 16 is connected to the communication terminal 20. In addition,
When the orientation of the battery pack 10 is wrong,
In order to prevent the battery pack 10 from being loaded in the electronic device 11, it is preferable that the shape of the battery pack 10 is asymmetrical in the left-right and front-back directions.

A plurality of, for example, three lithium-ion batteries 23 are housed in the battery pack 10, and these are connected in series. Between the positive terminal of the lithium ion battery 23 connected in series and the positive terminal 13, a discharging stop FET 24, a charging stopping FET 25,
Fuse 26 is connected in series. A current measuring resistor 27 having a small resistance value is connected between the negative electrode of the lithium ion battery 23 and the negative terminal 14.

FET 24 for stopping discharge and FE for stopping charging
T25 constitutes a switching circuit for regulating charging and discharging. These FETs 24 and 25 are P-channel, and are turned on when a signal of “L” is input to the gate.
Then, when the signal of “H” is inputted, it is turned off. When normal charging and discharging are performed, both the FETs 24 and 25 are ON.

The discharge stop FET 24 forcibly stops the discharge of the battery pack 10 to prevent the electronic device 11 and the battery pack 10 from falling into a dangerous state, and to prevent a failure and a shortened life. As a case where this discharge is forcibly stopped, three lithium ion batteries 2
3 when the voltage has dropped to the discharge stop voltage, or when a current (overcurrent) greater than or equal to the overcurrent value has flowed during discharge. Here, the overcurrent value is set to a value slightly larger than the maximum allowable current value at which charging and discharging are allowed.

The charge stopping FET 25 forcibly stops charging of the battery pack 10 to prevent the battery pack 10 from falling into a dangerous state, or to prevent a failure or shortened life. The case where the charging is forcibly stopped is when any one of the three lithium ion batteries 23 reaches the charging stop voltage or when an overcurrent flows during charging.

The fuse 26 is in a dangerous state in which when the FETs 24 and 25 are not turned off due to a failure or the like, the fuse 26 is melted and disconnected when an excessive current flows, and the lithium ion battery 23 is ignited or ruptured. Avoid the risk of becoming When the fuse 26 is melted and disconnected, the battery pack 10 cannot be used. As described above, since the fuse 26 is a final security means, the excessive current value is determined to be a value considerably larger than the overcurrent value.

The positive and negative electrodes of each lithium ion battery 23 are connected to a voltage measuring circuit 30, respectively. The voltage measurement circuit 30 includes at least three operational amplifiers for obtaining a difference between two voltages, and measures voltages (VH, VM, VL) of the three lithium ion batteries 21. This voltage VH is the voltage of the lithium ion battery 23 on the positive electrode 13 side. The voltage VM is the voltage of the middle lithium ion battery 23. Voltage VL
Is the lithium ion battery 23 on the negative electrode 14 side.
Voltage.

The current measuring circuits 31 and 3 are connected to both ends of the resistor 27.
2 are connected. These current measuring circuits 31, 32
Is composed of at least one operational amplifier that performs an analog operation, and measures a current flowing through the resistor 27 during charging or discharging from a voltage across the resistor 27 and a resistance value (known) of the resistor 27.

The current measuring circuit 31 is for measuring a small current I _{1 of} about 200 mA, and its power consumption is small. On the other hand, the current measuring circuit 32 is for measuring a large current I _{0 of} about ± 7 A, and consumes a large amount of power. Thus, the two types of current measurement circuits 31, 32
Is provided, the internal power consumption can be reduced by using the current measurement circuit 31 when measuring a small current.

The overcurrent detection circuit 3 is connected between both ends of the resistor 27.
3 are connected. The overcurrent detection circuit 33 includes a comparator, and generates an “L” signal when the charging current or the discharging current exceeds the overcurrent value.

If the charge or discharge of the lithium ion battery 23 is abnormal, the battery temperature becomes considerably high, and there is a possibility that the battery will burst. Therefore, a thermistor 34 is provided to measure the temperature inside the battery pack 10.
The thermistor 34 has a property that the resistance value decreases in proportion to the temperature. The voltage at the connection point between the thermistor 34 and the resistor 44 is used as the temperature signal T.

The battery voltage is applied to the regulator 36 via the switch 35. This regulator 36 converts the battery voltage into a constant drive voltage and outputs it. The microcomputer 40 is supplied with power by the regulator 36.

The regulator 36 includes a switch 42
Is supplied to the voltage measuring circuit 30 and the current measuring circuit 31 via the analog-to-digital converter, and is further input to the AD converter 50 as the reference voltage _Vref . Further, power is supplied to the thermistor 34 via a resistor 44 having a considerably large resistance value. The current detection circuit 32 is supplied with power by the regulator 36 via the switch 43. Furthermore,
Power is supplied to the nonvolatile memory 41 via the switch 45.
These switches 42 and 43 are turned ON only at the time of measurement in order to save power. The switch 45 is turned ON only at the time of writing.

The series voltage detection circuit 37 detects that the battery voltage has dropped to the use prohibited series voltage. The series voltage detection circuit 37 turns on the switch 35 when the voltage exceeds the use prohibited series voltage, and turns off the switch 35 when the voltage drops to the use prohibited series voltage. This switch 3
When the switch 5 is turned off, the operation of the regulator 36 is stopped, so that the voltage measurement circuit 30, the current measurement circuits 31, 32, the microcomputer 40, the nonvolatile memory 41, and the thermistor 44 are not supplied with power, and the power consumed by the battery pack 10 is consumed. Is the minimum.

The microcomputer 40 includes the control unit 4
8, an operation unit 49, an AD conversion unit 50, a communication unit 51, and a clock control unit 52. The microcomputer 40 and the measuring unit allow the lithium ion battery 23
A monitoring circuit for monitoring the state of the device is configured. In the measuring section,
A voltage detection circuit 30, current measurement circuits 31, 32, a thermistor 33 and the like are included. Note that a charge / discharge control circuit is configured by the monitoring circuit and the FETs 24 and 25 that are turned ON / OFF by the monitoring circuit.

The monitoring mode of the state of the lithium ion battery by the monitoring circuit includes a normal mode in which monitoring is frequently performed, a first sleep mode in which the number of monitoring is reduced, and a second sleep mode in which monitoring is performed occasionally. The first sleep mode and the second sleep mode are for saving the internal power consumption consumed by the monitoring circuit in the battery pack 10. The second sleep mode has a greater power saving effect than the first sleep mode. When the switch 34 is turned off, the power is not supplied to the monitoring circuit, and the monitoring circuit is cut off. For convenience, this state is called a cutoff mode. Since these state monitoring operation modes are set and executed by the microcomputer 40, they can be said to be the state monitoring operation modes of the microcomputer 40.

The AD converter 50 AD converts the voltages VH, VM, VL, the current values I ₀ , I ₁ , and the temperature signal T of each lithium ion battery 23 and converts them into digital signals. These digital signals are sent to the arithmetic unit 49. The operation unit 49 takes in the measurement data from the A / D conversion unit 50, the signal from the overcurrent detection circuit 33, the connection signal from the connection detection terminal 15, and the communication data from the communication unit 51, and sets the state monitoring operation mode. The determination is made, the state of the lithium ion battery 23 is determined, and whether charging / discharging should be permitted is determined.

The control unit 48 turns ON / OFF the switches 42, 43, 45 according to the instruction from the arithmetic unit 49. In the normal mode, the switches 42 and 43 are turned ON / OFF in a short cycle. In the sleep mode, the switch 42 is turned ON / OFF in a long cycle. When the communication unit 51 writes data to the memory 41, the switch 45 is turned ON.

The control unit 48 outputs a signal for controlling charging and discharging from two terminals based on an instruction from the arithmetic unit 49. That is, when charging / discharging is permitted, a signal of “L” is sent to the OR gates 55 and 56. When stopping the discharge, a signal of “H” is sent to the OR gate 55. To stop charging, set the "H" signal to O
Send to R gate 56. Note that when the switch 35 is turned off and the power supply to the microcomputer 40 is stopped, both terminals become “L”.

The communication section 51 communicates with the electronic device 11 and the charger 70 via the communication terminal 16 to communicate with the lithium ion battery 2.
Data indicating the status of No. 3 and commands are exchanged. The command received by the communication unit 51 is sent to the calculation unit 49. The arithmetic unit 49 sends various data to the electronic device 11 and the like via the communication unit 51 according to the command. The data indicating the state of the battery output from the communication unit 51 includes:
Battery type, remaining battery capacity, battery voltage (VH, VM, VL
, The current value, the state of the switching circuit, the number of times of charging, and the like. Commands received by the communication unit 51 include:
The instruction includes a data unit (mW, AH, mV, etc.), a data request, and the like.

When the battery pack 10 is in a dangerous state, the arithmetic unit 49 voluntarily sends the dangerous information to the electronic device 11 or the like via the communication unit 51. The danger information and the data transmitted from the battery pack 10, for example, the remaining battery capacity, are displayed on the display 66 of the electronic device 11 or the like. In addition, the communication unit 51 writes the number of times of charging of the battery pack 10, the voltage of each lithium ion battery 23 at the end of charging, the content of the battery abnormality, the date and time of occurrence, and the like in the memory 41.

The clock control unit 52 includes oscillators 60 and 61
And selectively operating one of them according to the state monitoring operation mode. In the normal mode, the oscillator 60 generating a 4 MHz clock is operated, and in the first or second sleep mode, the oscillator 61 generating a 32 KHz clock is operated. The current consumption of the oscillator 60 is 3 mA, and the current consumption of the oscillator 61 is 200 μA
It is. Since the current consumption of the oscillator 61 is small, the internal power consumption in the sleep mode can be reduced. The clock control unit 52 sends the clock from the selected oscillator to the control unit 48, the operation unit 49, the communication unit 51, and the AD conversion unit 50.

The connection detection terminal 15 is connected to the regulator 36 via the resistor 58. Battery pack 1
When an external device such as the electronic device 11 or the charger 70 is connected to a normal state, the connection detection terminal 15 is “L”. When the battery pack 10 is disconnected from the external device, the connection detection terminal 15 is at "H".
These signals are sent to the arithmetic unit 49. Note that the “L” signal is referred to as a connection signal.

Next, the function of the arithmetic section 49 will be described in detail. The computing unit 49 determines that each lithium ion battery 23 is in a normal state when the following conditions are satisfied. The three conditions are that each lithium ion battery 23 is not in an overcharged state or an overdischarged state, is not in an overcurrent state, and is in a normal temperature state. When neither the overcharge state nor the overdischarge state is present, the voltage of the lithium ion battery 23 is in the chargeable / dischargeable voltage range between the discharge stop voltage and the charge stop voltage.

When the battery pack 10 is normally connected to the electronic device 11, the operation section 49 receives a connection signal from the electronic device 11 via the connection detection terminal 15.
When the connection signal is received and the respective lithium ion batteries 23 are in a normal state, the arithmetic unit 49 sends a signal for permitting charging and discharging to the control unit 48. Control unit 48
Outputs an "L" signal from the output terminal 2 and sends it to the OR gates 55 and 56 to turn on the two FETs 24 and 25.

The operation unit 49 monitors the state of each lithium ion battery 23 at a predetermined cycle from the voltage, current, and temperature measured by the measurement unit during charging and discharging of the battery pack 10.
Further, the remaining battery capacity, abnormal situation, and the like are written in the memory 41.
When any one of the lithium ion batteries 23 is out of the chargeable / dischargeable voltage range or when an overcurrent state is detected, the corresponding FET 2
One of 4, 25 is turned off.

The operation unit 49 monitors the state of each lithium ion battery 23 at a predetermined cycle even when the battery pack 10 is not being charged or discharged, that is, even when the battery pack 10 is disconnected from an external device. If an abnormality of the battery pack 10 is detected, this is written into the memory 41 as history information.

When the current measured by the current measuring circuit 31 exceeds the specified value, the microcomputer 4
0 monitors the state of each lithium ion battery 23 in the normal mode. In the normal mode, the oscillator 60 is energized, and the microcomputer 40 operates with a clock having a high frequency. In the microcomputer 40, when a clock rises, a current flows through each circuit element. Therefore, as the frequency of the clock increases, the average current consumption increases, and thus the power consumption increases.

In the normal mode, the switch 4
Since the cycle in which the switches 2 and 43 are turned on is the shortest, the number of operations of each measurement circuit supplied with power through these switches 42 and 43 increases. Therefore, the average current consumption of each measurement circuit increases, and as a result, the power consumption increases. Further, in the normal mode, the current measuring circuit 3 having large power consumption is used.
2. The oscillator 60 operates. For this reason, the self-power consumption in the normal mode is highest.

When the battery pack 10 is connected to an external device but the power of the external device is turned off,
Alternatively, in a power save state in which the screen saver of the display is activated, the current consumption of the external device is small. In this case, since the current of the battery pack 10 becomes equal to or less than the specified value, the monitoring circuit monitors the state of each lithium ion battery 23 in the first sleep mode.

In the first sleep mode, the oscillator 6
1 is energized and the microcomputer 40 operates slowly with a low frequency clock. Further, the switch 42
Is relatively long. In addition, the current measurement circuit 32 and the oscillator 60 that consume large power do not operate. For this reason, in the first sleep mode, the power consumed by the monitoring circuit is considerably smaller than in the normal mode.

Note that when connected to an external device,
When the communication unit 51 receives the communication signal, the electronic device 1
Since 1 is operating normally or in a preparation state, the microcomputer 40 monitors in the normal mode regardless of whether the current is below the specified value. Also, during the first sleep mode, when a communication signal is received or when a current exceeding a specified current flows, the mode returns to the normal mode.

When not connected to an external device and the current is equal to or less than the specified value, monitoring is performed in the second sleep mode. In the second sleep mode, the oscillator 61 operates and the microcomputer 40 operates slowly.
Further, the cycle in which the switch 42 is turned on is the longest, and the current measuring circuit 32 and the like do not operate. For this reason, the power consumed by the monitoring circuit is the smallest. When an external device is connected during the second sleep mode, or when a current exceeding a specified current flows, the mode returns to the normal mode.

The OR gate 55 is connected to the discharge stopping FET 24, and the OR gate 56 is connected to the charging stopping FET 25.
It is connected to the. This discharge stopping FET 24 has an OR
55 turns on when the output is “L”, and turns on when the output is “H”.
FF. Similarly, the charging stop FET 25 is turned on when the output of the OR gate 56 is "L", and turned off when the output of the OR gate 56 is "H".
FF. Therefore, the discharge stop FET 24 is turned on when all the input signals of the OR gate 55 are "L", and turned off when any one of the input signals is "H". O
The same applies to the R gate 56. These OR gates 55,
56, FETs 24 and 25 are powered by regulator 36.

The signals from the overcharge / overdischarge detection circuit 57 are input to the OR gates 55 and 56. Further, a signal from the connection detection terminal 15 is also input to the OR gate 55. The overcharge / overdischarge detection circuit 57 is configured by an analog IC circuit including two comparators,
Power is directly supplied by the lithium ion battery 23.

The overcharge / overdischarge detection circuit 57 stops charging / discharging when the microcomputer 40 is out of order or when an abnormal situation occurs in the lithium ion battery 23 during the suspension of the measurement. Therefore, the overcharge / overdischarge detection circuit 57 assists the microcomputer 40 and protects the battery pack 10 twice.

The overcharge / overdischarge detection circuit 57 has two output terminals at "L" when the microcomputer 40 has a chargeable / dischargeable voltage at which charging / discharging is permitted. When one of the lithium ion batteries 23 drops to a voltage slightly lower than the discharge stop voltage, a signal of “H” is sent to the OR gate 55, and when the voltage reaches a voltage slightly higher than the charge stop voltage, The signal of “H” is sent to the OR gate 56. Note that the overcharge / overdischarge detection circuit 57
Although the overdischarge threshold is slightly lower than the discharge stop voltage, and the overcharge threshold is slightly higher than the charge stop voltage,
The microcomputer may be operated simultaneously with the microcomputer 40 by using the discharge stop voltage and the charge stop voltage as these thresholds.

The electronic device 11 is provided with a system main body 65, a display 66, and the like, and is supplied with power by the battery pack 10 through the plus terminal 17 and the minus terminal 18. This system body 65 and minus terminal 1
8, a main switch 67 is provided. Further, since the connection detection terminal 19 is connected to the minus terminal 18, when the battery pack 10 is normally connected to the electronic device 11, the connection detection terminal 19 becomes “L”.

The system main body 65 receives data indicating the state of the battery from the battery pack 10 via the communication terminal 10. In addition, the display 66 displays, for example, the calculation result of the system main body 65 and the remaining battery capacity of the battery bag 10.

FIG. 2 shows an example of current consumption of the monitoring circuit in the normal mode. In the normal mode, the measurement time during which the switches 42 and 43 are ON is 100 ms. The measurement cycle is 220 mS. Switch 4
During the measurement time when the switches 2 and 43 are ON, a current of about 6 mA flows to the monitoring circuit. During this measurement, the current measurement circuit 3
2, the current consumption increases.

During the measurement pause when the switches 42 and 43 are OFF, an average current of about 400 μA flows to the monitoring circuit. The current of about 400 μA is used to operate the microcomputer 40. This microcomputer 40 consumes a large amount of current because the oscillator 60 consuming a large amount of current is operated and is operated at a high speed by a clock of 4 MHz. Therefore, in the normal mode, the current consumption of the microcomputer 40 and the measuring unit is large and the number of times of measurement is large, so that the self-power consumption of the monitoring circuit is the largest.

FIG. 3 shows an example of current consumption of the monitoring circuit in the first sleep mode. In the first sleep mode, the switch 43 remains OFF, and the current measuring circuit 32 that consumes a large amount of power does not operate. Switch 42
Turns ON at intervals of 2 seconds, and the ON time is 100 mS. During the measurement time when the switch 42 is ON, about 50
A current of 0 μA flows to the monitoring circuit. Switch 42 is OF
While the measurement is stopped, the microcomputer 40
, A small current of 150 μA on average flows.

The microcomputer 40 uses an oscillator 61 with low current consumption and operates slowly with a clock of 32 KHz, so that the average current consumption is small. In the first sleep mode, the current consumption of the microcomputer 40 and the measurement unit is small and the number of measurements is small, so that the internal power consumption of the monitoring circuit is relatively small.

FIG. 4 shows an example of current consumption of the monitoring circuit in the second sleep mode. This second sleep mode is the same as the first sleep mode except that the switch 42 is turned on at intervals of two minutes. In the second sleep mode, the current consumption of the microcomputer 40 and the measuring unit is small and the number of times of measurement is the smallest, so that the internal power consumption of the monitoring circuit is the smallest. In the cutoff mode,
Since the monitoring circuit is not operated, the power consumption of the monitoring circuit becomes zero.

The operation of the battery pack will be described with reference to FIGS. In the factory, after each lithium ion battery 23 is manufactured, it is charged to approximately half of the full charge (approximately the intermediate voltage between the charge stop voltage and the discharge stop voltage). After this charging, the three lithium ion batteries 23 are connected in series via the connection fitting. Next, the circuit board on which the circuit shown in FIG.
Mounted on

When the assembly is completed, the circuit board is supplied with power from the lithium ion battery 23, and starts monitoring by the overcharge / overdischarge detection circuit 57 and the series voltage detection circuit 37.
The overcharge / overdischarge detection circuit 57 monitors the voltage of each lithium ion battery 23. In addition, the series voltage detection circuit 37 calculates the series voltage (battery voltage) of the three lithium ion batteries 23.
To monitor.

As shown in FIG. 5, the series voltage detecting circuit 37
When the battery voltage is lower than the use prohibition voltage, the switch 35 is turned off and the power supply to the regulator 36 is stopped. In this case, the microcomputer 4
0 is cut off to enter the cutoff mode. In this cut-off mode, the monitoring circuit does not operate, so that the internal power consumption is kept to a minimum. On the other hand, when the battery voltage exceeds the use prohibition voltage, the voltage detection circuit 37 turns on the switch 35 to supply power to the regulator 36. The regulator 36 applies a predetermined voltage to the overcurrent detection circuit 33 and the microcomputer 40.

While the power supply is stopped, the microcomputer 40
Is in the cutoff mode, and at this time, the calculation unit 49 is in the reset state. The reset of the arithmetic unit 49 is released when the power supply starts when the switch 35 changes from OFF to ON. When the reset is released, the microcomputer 40 shifts from the cutoff mode to the normal mode. In this normal mode, the microcomputer 4
0 is driven by a 4 MHz clock output from the oscillator 60 and operates at a high speed. During the normal mode, the power consumption of the monitoring circuit is the largest as shown in FIG.

The overcurrent detection circuit 33 determines whether or not the charging / discharging current exceeds the overcurrent value from the magnitude of the voltage across the resistance value 27.
And outputs an “L” signal when it is large. This overcurrent state occurs only when the battery pack 10 is externally connected, and does not occur when the battery pack 10 remains alone. Therefore, in the normal mode shown in FIG. 6 and the first sleep mode shown in FIG.
When the output of No. 3 changes to “L”, the arithmetic unit 49 performs interrupt processing to stop discharging.

As shown in FIG. 6, in the normal mode,
First, the arithmetic unit 49 checks a signal from the connection detection terminal 15 to determine whether the battery pack 10 is connected to an external device. When the battery pack 10 is not connected to an external device, the voltage of the regulator 36 is applied to the connection detection terminal 15 via the resistor 58, so that the connection detection terminal 15 is at “H”. When the signal from the connection detection terminal 15 is “H”, the calculation unit 49 determines that there is no connection. In this case, the microcomputer 40 shifts from the normal mode to the second sleep mode.

In the second sleep mode, internal power consumption can be reduced, and battery consumption can be suppressed.
In addition, during the second sleep mode, the arithmetic unit 49 outputs a “H” signal indicating charge / discharge prohibition to the OR circuits 55 and 56 via the control unit 48. These OR circuits 55 and 56
Is "H", the discharge stop FET 24 and the charge stop FET 25 are off. Therefore, when the battery pack 10 remains alone, even if the metal contacts the positive terminal 13 and the negative terminal 14, the battery pack 10 will not be short-circuited.

As shown in FIG. 7, in the second sleep mode, the clock control unit 52 stops the oscillator 60,
Instead, the oscillator 61 with low power consumption is driven. With the 32 KHz clock generated by the oscillator 61, the microcomputer 40 operates slowly.

In the second sleep mode, the monitoring circuit
Perform a monitoring cycle every 2 minutes. In the first monitoring cycle, first, the arithmetic unit 49 operates an internal timer to measure time. Then, when two minutes have elapsed, the internal timer is restarted and the monitoring process is executed. In order to quickly perform this monitoring process, the arithmetic unit 49 stops the oscillator 61 via the clock control unit 52 and activates the oscillator 60 instead. Microcomputer 40
Is operated with a 4 MHz clock. Next, the operation unit 4
No. 9 turns on the switch 42 by 100 mS via the control unit 48. When the switch 42 is turned on, the voltage detection circuit 30 and the current measurement circuit 3 are controlled by the regulator 36.
1. The thermistor 33 is supplied with power. AD converter 5
Even at 0, the voltage of the regulator 35 is supplied as a reference voltage.

The voltage detection circuit 30 measures the voltages VH, VM, and VL of the three lithium ions 23, and
Send to 0. The current measuring circuit 31 measures the current IL flowing through the resistor 27 from the voltage drop caused by the resistor 27 and sends the current IL to the AD converter 50. The voltage of the thermistor 33 is sent to the AD converter 50 as a temperature signal T.

The AD converter 50 converts each measurement signal into a digital signal. After this digital conversion, the arithmetic unit 49 takes in the measurement data and temporarily stores it in a register. Next, the operation unit 49 determines whether the current stored in the register exceeds a specified value. When it is determined that the value does not exceed the specified value, the monitoring process ends, and the monitoring circuit is maintained in the second sleep mode. In this case, the oscillator 61 is driven again, and the microcomputer 40 is operated at a low speed. During the second sleep mode, the microcomputer 40 checks whether two minutes have elapsed since the start of the first monitoring cycle. When two minutes have elapsed, the internal timer is restarted, and the above-described monitoring process is performed at a high speed.

If the current IL exceeds the specified value, it means that an error such as a measurement error or a circuit failure has occurred. The arithmetic unit 49 turns on the switch 45 via the control unit 48 and writes error information into the memory 41 via the communication unit 51. This error information is used when the battery pack 10 is repaired.

When an error occurs, the microcomputer 40 shifts to the normal mode. Oscillator 60
Is driven as it is following the monitoring process, so that the microcomputer 40 operates at high speed. When the mode shifts to the normal mode, the presence / absence of connection is checked, so that the mode returns to the second sleep mode again. Then, as described above, when two minutes elapse during the second sleep mode, the monitoring process is executed.

When the current IL obtained by this measurement is equal to or smaller than the specified value, the second sleep mode continues. On the other hand, if the current IL exceeds the specified value, it means that the same error has occurred, so that the mode shifts to the normal mode without writing the error information. Therefore, unless the error does not disappear, the second sleep mode and the normal mode are alternately repeated. When an error occurs repeatedly in this way, the transition between modes may be stopped, and monitoring may be continued in either the normal mode or the second sleep mode until the error no longer occurs.

The battery pack 10 is shipped after undergoing product inspection after assembly. In this product inspection, the microcomputer 40 is set to a test mode that is not open to the user. Microcomputer 4
0 is driven by a 4 MHz clock. Then, the operation check of each circuit, the check of the charge state and the discharge state, the writing to the memory 41, and the like are performed using the inspection tool. Information to be written in the memory 41 includes the date of manufacture,
These are various parameters used for calculating the serial number and the remaining battery level. When the test mode is released, the microcomputer 40 returns to the normal mode again, and when it is determined that there is no connection, the microcomputer 40 shifts to the second sleep mode.

Battery pack 10 subjected to product inspection
Are shipped to manufacturers of electronic equipment, electric stores and the like. At the time of shipment from the factory, the second sleep mode is set, and the internal power consumption is kept low.

[0102] During the second sleep mode, the battery pack 10 is loaded into the electronic device 11. When the battery pack 10 is correctly loaded into the electronic device 11, the plus terminal 13 of the battery pack 10 is connected to the plus terminal 17 of the electronic device 11, and the minus terminal 14 of the battery pack 10 is connected to the minus terminal 18 of the electronic device 11. You.
At this time, the connection detection terminal 1 of the battery pack 10
5 is connected to the connection detection terminal 19 of the electronic device 11, and the communication terminal 16 is connected to the communication terminal 20.

Since the connection detection terminal 15 is connected to the minus terminal 14 of the battery pack 10 via the connection detection terminal 19 and the minus terminal 18 of the external device 11, the connection detection terminal 15 becomes "L". When the connection detection terminal 15 changes from “H” to “L”, the arithmetic unit 49 performs an interrupt process and shifts the microcomputer 40 from the second sleep mode to the normal mode.

When the mode shifts to the normal mode, the microcomputer 40 is operated by the clock of 4 MHz as described above. The operation unit 49 checks the presence or absence of the connection from the signal of the connection detection terminal 15. At this time, in order to prevent chattering when the battery pack 10 is mounted, it is preferable to determine that there is a connection when the signal of the connection detection terminal 15 is kept at “L” for a predetermined time.

When the connection of the electronic device 11 is confirmed, the arithmetic unit 49 outputs “L” indicating charge / discharge permission via the control unit 48.
Is output to the OR circuits 55 and 56. Here, when each lithium-ion battery 23 is in the chargeable / dischargeable voltage range between the discharge stop voltage and the charge stop voltage, the overdischarge / overcharge detection circuit 57 outputs “L” indicating charge / discharge permission. The signal is output to OR circuits 55 and 56. Further, an “L” signal from the connection detection terminal 15 is input to the OR circuit 55.

Since all of the input signals of the OR circuits 55 and 56 are “L”, the output signals are “L”. As a result, the discharge stopping FET 24 and the charging stopping FET 25
N, the lithium-ion battery 23 enters a chargeable / dischargeable state. Here, the power switch 67 of the electronic device 11 is
When N, the discharge current from the lithium battery 23 becomes FET
24, 25, the fuse 26, and the plus terminal 13 flow to the electronic device 11. The system main body 65 executes a predetermined process, and information is displayed on the display 66.

In the normal mode, the arithmetic section 49 starts an internal timer to perform a monitoring cycle every 220 ms. When the internal timer measures 220 mS, the monitoring process is started. In this monitoring process, the arithmetic unit 49 sets the switches 42 and 43 through the control unit 48 to 10
Turn ON only for 0mS. When the switch 42 is turned on, as described above, the voltage detection circuit 30, the current measurement circuit 31,
The thermistor 33 measures the voltage, the current IL, and the temperature. When the switch 43 is turned on, the current measuring circuit 32 is supplied with power and the current IH is measured.

Each measurement signal is converted into a digital signal by the AD conversion unit 50, and then is taken into the operation unit 49 and is temporarily stored in its register. Next, the arithmetic unit 49 determines whether the measured current IL stored in the register exceeds a specified value. If the measured current is less than the specified value,
This is when the power switch 67 of the first electronic device 11 is turned off, or the electronic device 11 shifts to the power save mode because there is no key operation during a predetermined time. In this case, the microcomputer 40 confirms that there is no communication from the electronic device 11, and then shifts to the first sleep mode. At this time, if there is communication, data is sent to the electronic device 11 at high speed by an interrupt process.

When the measured current is equal to or more than the specified value, or after performing communication by interrupt processing, the microcomputer 40 proceeds to voltage check. The arithmetic unit 49 determines whether the measured voltage of each lithium ion battery 23 is a charge stop voltage or a charge stop voltage. If the voltage has dropped below the discharge stop voltage, the arithmetic unit 49 sends a signal “H” indicating the stop of the discharge to the OR circuit 55 via the control unit 48. Since the OR circuit 55 outputs the signal of “H”, the discharge stopping FET 24 is turned off, and the discharge is forcibly stopped.

The measured voltage of each lithium ion battery 23 is
If the voltage is equal to or higher than the charge stop voltage, the arithmetic unit 49 sends a signal “H” indicating stop of charge to the OR circuit 56 via the control unit 48. Since the OR circuit 56 outputs a signal of “H”, the charge stop FET 25 is turned off, and the charge is forcibly stopped. Since the battery pack 10 is currently supplying power to the electronic device 11, the charging stop FET 25 is ON.

When the measured voltage of each lithium ion battery 23 is within the dischargeable voltage, the process proceeds to the temperature check. The calculation unit 49 determines whether the temperature of the battery pack 10 is equal to or higher than a specified temperature. If there is an abnormality in the lithium ion battery 23, the battery pack 10 generates heat during discharging, and the temperature rises considerably. If the temperature of the battery pack 10 exceeds the specified temperature, the calculation unit 49 sends a signal of “H” to the OR circuit 55 to forcibly turn off the discharge stop FET 24.

When the voltage and the temperature are normal, the microcomputer 40 returns to the first step in the normal mode. Here, when it is determined that there is no connection, the mode shifts to the second sleep mode. If there is a connection, since the switching circuit has already been turned on, the process directly proceeds to the determination step of 220 mS. The microcomputer 40 is
If it is determined that 220 mS has elapsed from the start of the first monitoring cycle, the internal timer is restarted, and then the second monitoring cycle is executed to perform the above-described measurement and determination monitoring processing.

During the operation of the regulator 36, the overcurrent detection circuit 33 monitors the overcurrent state. Upon detecting the overcurrent state, the overcurrent detection circuit 33 generates an “L” signal. Then, during the normal mode, the arithmetic unit 49 sets “L”
Is received, an interrupt process is performed, a signal of "H" is sent to the OR circuit 55, and the discharge stopping FET 24 is forcibly turned off.

In each monitoring cycle, when an overcurrent state is detected outside the dischargeable voltage range, at a specified temperature or higher, the microcomputer 40 forcibly turns off the discharge stopping FET 24 as described above. Then, the connection state of the electronic device 11 is checked. Battery pack 1
When 0 is removed from the electronic device 1, the mode shifts from the normal mode to the second sleep mode. On the other hand, if the electronic device 11 is still connected, as described above, 2
The process proceeds to the determination step of elapse of 20 mS, and the next monitoring cycle is executed. In this monitoring cycle, if the abnormal state that is equal to or higher than the specified temperature or the overcurrent state has been resolved, the process returns to the first step of the normal mode, checks the connection, and turns on the discharge stop FET 24. After that,
As described above, the process proceeds to the step of determining the lapse of 220 ms.

When the current exceeds the specified value while being connected to the electronic device 11, the microcomputer 4
0 selects the normal mode, and monitors each lithium ion battery in a monitoring cycle of 220 mS. Note that the normal mode is selected even if the communication is interrupted even if the value is equal to or less than the specified value.

The system body 65 of the electronic device 11
Is connected to the microcomputer 10 via the communication terminal 20.
To send a command for data request and data unit. The communication unit 51 controls the electronic device 11 during the normal mode.
When the command is received, the command is sent to the operation unit 49. The arithmetic unit 49 immediately interrupts the communication and sends out data corresponding to the request from the electronic device 11 to the electronic device 11 via the communication unit 51.

When the electronic device 11 receives, for example, data on the remaining battery capacity, the electronic device 11 displays the data on the display 6 with a graphic or a mark.
6 is displayed. Further, the microcomputer 40 calculates a power supply available time from the remaining battery capacity and the supplied current. Then, when the time during which the power can be supplied becomes short, the warning information is spontaneously sent to the electronic device 11. The electronic device 11
A warning is displayed on the display 66, and data being processed is saved. Alternatively, the electronic device 11 is shifted to the power save mode, the system main body 65 is put into the sleep state, or the display on the display 66 is stopped.

If the power switch 67 of the electronic device 11 is turned off or enters the power save mode during the normal mode, the discharge current becomes lower than the specified value, and the communication is stopped. In this case, the microcomputer 40
Shifts to the first sleep mode because monitoring in an early cycle is unnecessary.

In the first sleep mode, except during the monitoring process, the oscillator 61 operates, and the microcomputer 40 operates at a low speed with a clock of 32 KHz. Then, the monitoring process is executed every two seconds to execute the lithium ion battery 2
Monitor the status of 3. In this first sleep mode,
The self-consumption of the monitoring circuit is larger than that of the second sleep mode, but is considerably smaller than that of the normal mode.

As shown in FIG. 8, when shifting to the first sleep mode, the microcomputer 40 operates an internal timer to measure the lapse of 2 seconds. When two seconds have elapsed, the first monitoring cycle is started. And
Activate the oscillator 60 to speed up the monitoring process,
The microcomputer 40 operates at a high speed with a clock of 4 MHz.

When the monitoring process starts, first, the switch 42 is
N, voltage, current (IL), and temperature are measured. After this measurement, a current check is performed. When the power switch 67 of the electronic device 11 is turned on during the first sleep mode, or when the power save mode returns to the normal operation mode, the discharge current to the electronic device 11 becomes larger than a specified value. In this case, the microcomputer 40 shifts from the first sleep mode to the normal mode, and performs monitoring in an early cycle.

When the electronic device 11 is in the power save mode or the like, the discharge current is equal to or less than the specified value, so that the voltage check and the temperature check are performed as in the normal mode. When the voltage is equal to or lower than the discharge stop voltage or equal to or higher than the specified temperature, the microcomputer 40
Generates a discharge prohibition signal and turns off the discharge stop FET 24
Then, the mode shifts to the normal mode. Further, when an overcurrent state occurs during the first sleep mode, the discharge stop FET 24 is turned off by interrupt processing, and then a transition is made to the normal mode.

If the voltage and temperature are normal, a connection check is performed. If the battery pack 10 is removed from the electronic device 11 during the first sleep mode, it is determined that there is no connection. At this time, the microcomputer 10
Outputs a discharge stop signal and a charge stop signal, turns off the two FETs 24 and 25, and then shifts to the second sleep mode.

When it is determined that there is a connection, the monitoring process ends, and the first sleep mode is continued. The oscillator 61 is operated instead of the oscillator 60, and the microcomputer 40 is operated at a low speed. Then, it is checked whether two seconds have elapsed since the start of the first monitoring cycle. When two seconds have passed,
After restarting the internal timer as described above,
Execute the second monitoring cycle.

In the first sleep mode, if there is communication from the electronic device 11, the mode shifts to the normal mode. Then, an interrupt process is immediately executed during the normal mode, and communication with the electronic device 11 is executed.

When the microcomputer 40, the voltage measuring circuit 30 or the like is out of order, or a wrong measurement or a wrong judgment may occur. Even in such a case, since the overcharge / overdischarge detection circuit 57 is operating, when the voltage drops to a voltage slightly lower than the discharge stop voltage, the overcharge / overdischarge detection circuit 57 outputs the “L” discharge stop signal. The signal is sent to the OR circuit 55 to turn off the discharge stopping FET 24.

After the battery pack 10 has dropped to the discharge stop voltage, it may not be charged and may be left loaded in the electronic device 11. In this case, each lithium ion battery 23
Discharges further. When this discharge proceeds and the battery voltage becomes equal to or lower than the discharge inhibition series voltage, the voltage detection circuit 37 turns off the switch 35. Since the microcomputer 40 enters the cutoff mode, the current consumption of the battery pack 10 is minimized. In this shutoff mode, the output of the microcomputer 40 becomes "L". When the discharge further proceeds, all circuits such as the voltage detection circuit 37, the overdischarge / overcharge detection circuit 57, the overcurrent detection circuit 33, and the FETs 24 and 25 are turned off.

FIG. 9 shows a charger. The charger 70 includes a charging circuit 71 and a charging control circuit 72. The charging circuit 71 includes a constant voltage device that converts a commercial power supply into a charging voltage, a constant current device that regulates a current value so as not to exceed a certain value, and the like. A positive terminal 73, a negative terminal 74, and a connection detection terminal 75 are connected to the charging circuit 71. The charging control circuit 72 turns ON / OFF the charging circuit 71 and performs communication with the battery pack 10 via the communication terminal 76. Also,
The charging control circuit 71 includes a timer, and turns off the charging circuit 71 when a predetermined time has elapsed since the battery pack 10 reached a predetermined voltage.

When the battery pack 10 is detached from the electronic device 10 for charging, the microcomputer 40 turns off the FETs 24 and 25 and shifts to the second sleep mode. When the battery pack 10 is correctly loaded in the charger 70, the corresponding terminals are connected. By this connection, the microcomputer 40 is connected to the second
From the sleep mode to the normal mode, and the two FETs 24 and 25 are turned on to be in a chargeable state.

The charging control circuit 72 requests the microcomputer 40 for data on the battery voltage, charging current, temperature, and the ON / OFF state of the FET 25. When determining from the data received from the microcomputer 40 that the battery pack 10 is in a chargeable state, the charging control circuit 72 activates the charging circuit 71. The charging circuit 71 uses a constant voltage and a constant current to charge the battery pack 1.
Charge 0. At the time of this charging, the plus terminal 13, F
The charging current flows to each lithium ion battery 23 through the ETs 25 and 24.

Since the charging current exceeds the specified value during normal charging, the microcomputer 40 monitors the charging state of each lithium ion battery in the normal mode shown in FIG. In response to a request from the charge control circuit 72 of the charger 70, the microcomputer 40
Data on the charging current, the temperature, and the ON / OFF state of the FET 25 is communicated.

If any one of the lithium ion batteries 23 reaches the charge stop voltage while the battery pack 10 is being charged, the microcomputer 40 determines that the battery pack 10 is fully charged. At this time, the microcomputer 40 outputs the charging inhibition signal to the OR circuit 56.
And the charging stop FET 25 is turned off. In addition,
At the time when charging is stopped, since each lithium ion battery 23 has exceeded the discharge stop voltage, the discharge stop FET 24
Remains ON.

When the charging stop FET 25 is turned off, the microcomputer 40 sends a signal indicating full charge to the charge control circuit 72 of the charger 70. The charging control circuit 72 turns off the charging circuit 71 to stop charging. When the charge stop FET 25 is turned off, the charge current becomes equal to or less than a specified value, and the charge control circuit 72 stops communication. Therefore, the microcomputer 40
Shift to the first sleep mode.

When the temperature exceeds the specified temperature or when the overcurrent detection circuit 33 detects an overcurrent state, the microcomputer 40 turns off the charging stop FET 25.
Change to F. At this time, the micron computer 40
Since the occurrence of the abnormal state is communicated to the charger 70, the charging control circuit 72 turns off the charging circuit 71.
When this charging abnormality has occurred, the charging control circuit 72
Requests data from the battery pack 10 at predetermined time intervals, the battery pack 10 is maintained in the normal mode even if the charging current is equal to or less than the specified value.

When the microcomputer 40 determines that the charging abnormality has been resolved by the measurement of the thermistor 34 or the overcurrent detection circuit 33, the microcomputer 40 turns on the charging stop FET 25. Then, the micron computer 40 communicates to the charger 70 that the charging abnormality has been eliminated. When the communication for eliminating the charging abnormality is received, the charging circuit 71 operates to restart charging.

The over-discharge / over-charge detection circuit 5 also operates during charging.
7 is working. And the microcomputer 40
If the battery has a failure or the like, when the voltage slightly exceeds the charge stop voltage, the overdischarge / overcharge detection circuit 57 sends a signal “H” indicating the charge stop to the OR circuit 56 to stop the charge stop. FET 25 is turned off.

When charging is started from the time when the battery pack 10 is in the overdischarge state, the microcomputer 40 turns on the charge stop FET 25 but does not turn on the discharge stop FET 24. However, this discharge stopping F
In the ET 24, as is well known, a small charging current flows from the drain to the source by a parasitic diode (not shown), so that charging proceeds slowly. And
When the discharge stop voltage is exceeded, the microcomputer 40
Turns on the discharge stopping FET 24, so that charging is performed with a predetermined charging current.

A charge auxiliary circuit (not shown) is provided in parallel with the charge stopping FET. All circuits are OFF
If the battery voltage is lower enough to reach the state, the charging auxiliary circuit is turned on by the charger 70, and
A small current of about 0 mA flows through the battery pack 10, and slowly charges each lithium ion battery 23.

During this charging, the voltage detection circuit 37, the overcharge / overdischarge detection circuit 57, and the FETs 24 and 25 operate.
At this point, the FETs 24 and 25 are in the OFF state.
When the charge exceeds the discharge inhibition series voltage due to the progress of charging, the series voltage detection circuit 37 operates the regulator 36.
Thus, the reset of the microcomputer 40 is released. The microcomputer 40 is a charging FET
25 is turned on, and the discharging FET 24 is turned off.
At this point, the charging auxiliary circuit is turned off, so that charging with a slightly larger charging current is started through the charging FET 25 as described above. Further, as the charging proceeds, the discharging FET 24 turns on as described above.

When the battery pack 10 is removed from the charger 70, the microcomputer 40 shifts to the second sleep mode shown in FIG. Thereafter, when the battery pack 10 is loaded into the electronic device 11 again, the mode shifts to the normal mode as described above. When the battery pack 10 is fully charged, the charge stopping FET 25
Is OFF. This charging stop FET 25 is turned off.
Even so, a current having a value sufficient to drive the electronic device 10 flows from the drain to the source by the parasitic diode (not shown), so that the power supply to the electronic device 10 is performed normally. Then, when all the lithium ion batteries 23 become lower than the charge stop voltage, the microcomputer 40 turns on the charge stop FET 25.

FIG. 10 shows an electronic device having a built-in charger. In this electronic device 80, a power supply circuit 81,
System body 82, power switch 83, terminals 84 to 87
Is provided. The power supply circuit 81 includes a constant voltage device and a constant current device, transforms a commercial power supply, and applies a constant voltage to the system main body 82. The operation of the power supply circuit 81 is controlled by the system main body 82.

When the battery bag 10 is connected to the electronic device 80, as described above, the microcomputer 40 of the battery pack 10 is in a state determined according to the connection state, the magnitude of the charge / discharge current, and the presence / absence of an interrupt. In the monitoring operation mode, the state of each lithium ion battery 23 is monitored. When the electronic device 80 is connected to commercial power,
The system main body 82 is driven by the power supply circuit 81.
When the system body 82 is off, the battery pack 10 is charged by the power supply circuit 81. When the battery is fully charged, the charging stop FET 25 is turned off, and the charging of the battery pack 10 is stopped.
When the electronic device 80 is not connected to a commercial power supply, the electronic device 80 receives power from the battery pack 10.

As described above, when the battery pack 10 is connected to an external device, the first sleep mode with low power consumption is selected when the current value is equal to or less than the specified value. When the current exceeds the specified value, the normal mode is selected. When the interrupt process is accepted, the normal mode is selected even if the current is equal to or less than the specified value.

When the battery pack 10 is disconnected from the external device, and the current value is equal to or less than the specified value,
The second sleep mode that consumes the least power is selected. The normal mode is selected when the current value exceeds the specified value. When the interrupt processing is accepted, the normal mode is selected.

The microcomputer 40 calculates the remaining battery charge for each monitoring cycle in each mode. The discharge capacity in each monitoring cycle is obtained by multiplying the total consumption current obtained by adding the measured current and the dark current by the monitoring cycle time and the discharge correction coefficient. If this is one cycle discharge capacity, a new battery remaining capacity is obtained by subtracting one cycle discharge capacity from the battery remaining capacity immediately before read from the memory 41. The old remaining battery capacity in the memory 41 is updated with this new value.

Here, the dark current is measured by the current measuring circuits 31 and 3
2 is the consumption current not measured. In the circuit shown in FIG. 1, since the microcomputer 40 and the negative terminal of the measuring unit are connected to the negative electrode of the lithium ion battery 23, the current measuring circuits 31 and 32 provide the discharge current supplied to the electronic device 11 or The charging current supplied from the charger 70 is measured. Therefore, in the circuit shown in FIG. 1, the dark current is a current consumed by the monitoring circuit, the charge / overdischarge detection circuit 57, the voltage detection circuit 37, and the like. If the microcomputer 40 and the negative terminal of the measuring section are connected to a connection point between the negative terminal 14 and the resistor 27, the current flowing through the monitoring circuit is measured by the current measuring circuits 31 and 32, and thus the Not included in the current.

Also, during charging, the charge capacity of one cycle is similarly calculated during each monitoring cycle, and this is integrated to obtain the battery charge capacity (the same as the remaining battery capacity). The correction is performed by setting the battery charge capacity to a constant value when a predetermined battery voltage is reached.

The microcomputer 40 writes information on the number of times of full charge and the battery history in addition to the date of manufacture and the remaining battery capacity in the memory 41. The battery history includes the number of battery temperature abnormalities, the number of voltage abnormalities, the number of errors, the number of times the FETs 24 and 25 are turned off, the number of overcurrents, and the like.

When the reset of the microcomputer 40 is released, the battery history may be confirmed and the battery checked at a high speed of 4 MHz, and then the mode may be shifted to the normal mode. In checking battery history,
The battery history in the memory 41 is read. For example, the number of times when the voltage of each lithium ion 23 becomes abnormally high (voltage abnormality) is checked, and when this exceeds a predetermined value,
Judging that the battery is defective, displaying a warning and FE
T24 and 25 are maintained in the OFF state. In the battery check, each lithium ion battery 23 was 2.0 V
If there is the above, and if the voltage rises by 100 mV or more within 30 seconds, it is determined that the battery is good, and the mode is shifted to the normal mode.

Further, a liquid crystal display or an LED may be provided on the battery pack 10 to display the remaining battery capacity or display the battery abnormality.

In the battery pack of the present invention, the specified current for determining the state monitoring operation mode is, for example, 100 mA. Further, the discharge stop voltage is 2.3 V and the charge stop voltage is 4.2 V. The discharge inhibition series voltage is 6V,
The temperature at which charging and discharging are prohibited is 60 ° C. or higher. The overcurrent is 8 A, and the overcurrent at which the fuse blows is 10 A.

In the present invention, in the case of overdischarge or overcharge, the microcomputer 40 controls charging and discharging in preference to the overdischarge / overcharge detection circuit 57. Instead, the overdischarge / overcharge detection circuit 57 may be prioritized and the microcomputer 40 may be used in an auxiliary manner. In this case, the overdischarge / overcharge detection circuit 57 has a discharge stop voltage of 2.3 V and a charge stop voltage of 4.2 V. On the other hand, the microcomputer 40 determines that the discharge stop voltage is 2.
25V, and the charging stop voltage is 4.25V.

When the battery voltage drops to the discharge prohibition series voltage, the power supply of the monitoring circuit is stopped to set the cutoff mode. Alternatively, a signal from the series voltage measurement circuit 37 may be sent to the microcomputer 40 when the voltage becomes equal to or less than the discharge inhibition series voltage to set the measurement stop mode. In this case, the microcomputer 40 operates at a low speed, but stops the measurement operation by keeping the switch 43 OFF. Alternatively, the operation of the oscillator may be stopped via the clock control circuit 52 and the microcomputer 40 may be put into a freeze state to stop the operation.
In this case, the measurement naturally stops.

In the second sleep mode, the voltage measurement is omitted by stopping the power supply to the voltage measurement circuit 30.
You may simply measure the current. Conversely, it may be determined from the voltage measured in the second sleep mode whether the voltage is within the chargeable / dischargeable voltage range.

Two current measuring circuits 3 having different current consumptions
1 and 32 are provided, but a single current measuring circuit 32 having a wide measuring range may be used instead. In addition, this 1
If the overcurrent state is determined using the measurement values of the current measurement circuits 32, the overcurrent detection circuit 33 can be omitted.

Since the AD converter 50 converts the measured data one by one, instead of turning on the current measuring circuit and the voltage measuring circuit at the same time at the time of measurement, only the one to be A / D converted is turned on. The current consumption may be further reduced. FET2 as a switching circuit
4, 25, but a thyristor, a transistor, or the like can be used.

When the battery voltage drops to the discharge inhibition series voltage, the microcomputer 40 is turned off.
At F, the monitoring circuit is in the cutoff mode. Instead, the battery series voltage obtained by adding the three voltages from the voltage measurement circuit 30 is used. When the battery series voltage drops to the discharge inhibition series voltage, the microcomputer 40 is driven by a low-frequency clock, The measurement may be stopped while the switches 42 and 43 are kept OFF.

A series-parallel connection in which three batteries are connected in series to form one set and two sets are connected in parallel may be used.
In this case, the voltages of two batteries connected in parallel are measured. Further, the present invention relates to a Ni / Cd battery, Ni
/ MH battery, Zn / Br ₂ , lead storage battery and the like.

[0159]

According to the present invention, the current of the battery pack is measured, and when the current is equal to or less than the specified value, the mode shifts from the normal mode in which the power consumption is large to the sleep mode in which the power consumption is small. By properly setting the state monitoring operation mode for the external device as well, power saving of the battery pack can be achieved.

Further, the present invention monitors the state of the secondary battery by measuring the voltage and current, etc., even when the mode shifts to the sleep mode. Therefore, even when an abnormal situation occurs during the sleep mode, the present invention appropriately copes with the situation. can do. Further, since the current is measured even in the sleep mode, it is possible to accurately obtain the remaining battery capacity by calculating, for example, the discharge capacity in the sleep mode.

In the present invention, in the sleep mode,
Since the microcomputer is driven by a clock having a low frequency, the current consumption of the microcomputer itself can be reduced. Furthermore, in the sleep mode, attention is paid to the fact that an abnormal situation rarely occurs suddenly, and the average value of the current consumed by the measurement unit is reduced by reducing the number of times of measurement.

Furthermore, according to the present invention, the first sleep mode is set when the battery pack is connected to an external device, and the second sleep mode is set when the battery pack is not connected to an external device. The sleep mode can be changed in two stages. In the second sleep mode, the number of measurements is extremely smaller than in the first sleep mode, so that when the battery pack is not connected to an external device, the internal power consumption thereof can be further reduced.

Furthermore, a detection circuit for detecting the battery voltage is provided, and when the voltage drops below the discharge inhibition series voltage, the power supply to the monitoring circuit is stopped and the cutoff mode is set to eliminate internal power consumption by the monitoring circuit. Discharge that causes deterioration of the secondary battery can be suppressed.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a battery pack according to the present invention.

FIG. 2 is a waveform diagram of a current flowing in a monitoring circuit during a normal mode.

FIG. 3 is a waveform diagram of a current flowing through a monitoring circuit during a first sleep mode.

FIG. 4 is a waveform diagram of a current flowing through a monitoring circuit during a second sleep mode.

FIG. 5 is a flowchart showing a shutdown mode and reset release of the microcomputer.

FIG. 6 is a flowchart showing a normal mode.

FIG. 7 is a flowchart showing a second sleep mode.

FIG. 8 is a flowchart showing a first sleep mode.

FIG. 9 is a block diagram of a charger.

FIG. 10 is a block diagram illustrating an electronic device with a built-in charger.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Battery pack 11 Electronic device 13, 17, 73, 84 Positive terminal 14, 18, 74, 85 Minus terminal 15, 19, 73, 86 Connection detection terminal 16, 20, 76, 87 Communication terminal 23 Lithium ion battery 24 Discharge stop FET 25 Charge stop FET 30 Voltage measurement circuit 31, 32 Current measurement circuit 33 Overcurrent detection circuit 34 Thermistor 40 Microcomputer

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI H02J 7/00 302 H02J 7/00 302D

Claims (15)

[Claims] At least one chargeable / dischargeable secondary battery, a monitoring circuit for monitoring a state of the secondary battery, and a switching circuit for stopping charging / discharging by a signal from the monitoring circuit. In a battery pack connected to an electronic device or a charger, when the current of the secondary battery exceeds a specified value, the monitoring circuit is set to a normal mode in which internal power consumption is large, and the current of the secondary battery is When the value is equal to or less than a specified value, the monitoring circuit is set to a sleep mode in which the internal power consumption is small. 2. A monitoring circuit comprising: a voltage measuring circuit for measuring a voltage of a secondary battery; a current measuring circuit for measuring a current of the secondary battery; A microcomputer for controlling the OFF, the microcomputer determines the state monitoring operation mode from the measured current, and energizes the current measurement circuit and the voltage measurement circuit only at the time of measurement; 2. The state monitoring operation mode control method according to claim 1, wherein the microcomputer is driven by a high clock and the microcomputer is driven by a low frequency clock in the sleep mode. 3. The state monitoring operation mode control method according to claim 2, further comprising: shortening the current and voltage measurement intervals in the normal mode, and increasing the measurement intervals in the sleep mode. 4. At least one chargeable / dischargeable secondary battery, a monitoring circuit for monitoring a state of the secondary battery, and a switching circuit for stopping charging / discharging by a signal from the monitoring circuit. In a battery pack connected to an electronic device or a charger, when the current of the secondary battery exceeds a specified value, the monitoring circuit is set to a normal mode in which internal power consumption is large; When the current is equal to or less than the specified value and the electronic device or the charger is connected, the monitoring circuit is set to the first sleep mode in which the internal power consumption is relatively small, and the current of the secondary battery is Is less than or equal to a prescribed value, and when not connected to an electronic device or a charger, the monitoring circuit is set to a second sleep mode in which internal power consumption is minimized. Monitoring operation mode control method. 5. A monitoring circuit comprising: a voltage measuring circuit for measuring a voltage of a secondary battery; a current measuring circuit for measuring a current of the secondary battery; A microcomputer that controls OFF, the microcomputer conducts the current measuring circuit and the voltage measuring circuit only at the time of measurement, and determines the state monitoring operation mode from the measured current. In the first sleep mode, the microcomputer is driven by a low-frequency clock, and the current and voltage measurement intervals are relatively long; In sleep mode 2, the microcomputer is driven by a low-frequency clock and Without thereby measuring the current minimum, the state monitoring operation mode control method according to claim 4, wherein the measurement interval is the longest. 6. The state monitoring operation mode according to claim 5, wherein when a communication signal is received during the normal mode, the mode is maintained in the normal mode even if the current of the secondary battery is equal to or less than a specified value. Control method. 7. When there is communication from the electronic device or the charger during the first sleep mode, the communication device is returned to the normal mode, and is connected to the electronic device or the charger during the second sleep mode. 7. The state monitoring operation mode control method according to claim 6, wherein when the state monitoring operation returns to the normal mode. 8. A battery pack comprising at least one chargeable / dischargeable secondary battery and connected to an electronic device or a charger, a voltage measurement circuit for measuring a voltage of the secondary battery, and the secondary battery. A current measuring circuit that measures the current of the secondary battery; a switching circuit that stops charging and discharging of the secondary battery; determining a state of the secondary battery from the measured voltage, and controls ON / OFF of the switching circuit and performs measurement. A microcomputer for determining the state monitoring operation mode from the current and for energizing the voltage measurement circuit and the current measurement circuit only at the time of measurement, wherein the microcomputer has an internal power consumption when the current of the secondary battery is equal to or less than a specified value. Monitors the rechargeable battery in the small sleep mode, and when the rechargeable battery current exceeds the specified value, the normal mode with large internal power consumption Battery pack which is characterized by monitoring the secondary battery. 9. In the normal mode, the microcomputer is driven by a high-frequency clock, and the measurement interval of current and voltage is short. In the sleep mode, the microcomputer is driven by a low-frequency clock, and 9. The battery pack according to claim 8, wherein a voltage measurement interval is long. 10. The sleep mode includes a first sleep mode and a second sleep mode.
Is set when the electronic device or the charger is connected, the second sleep mode is set when the electronic device or the charger is not connected, and the second sleep mode is the first sleep mode. 10. The battery pack according to claim 9, wherein the measurement interval is longer than in the sleep mode. 11. A battery pack including at least one chargeable / dischargeable secondary battery and connected to an electronic device or a charger, wherein the battery pack performs charging or discharging with the electronic device or the charger. A pair of power terminals, a communication terminal for exchanging communication signals between the electronic device or the charger, and an electronic device when the pair of power terminals are normally connected to the electronic device or the charger. A connection detection terminal for receiving a connection signal from a charger, a voltage measurement circuit for measuring a voltage of the secondary battery, a current measurement circuit for measuring a current of the secondary battery, and charging of the secondary battery. A switching circuit for stopping discharge, a state of the secondary battery is determined from the measured voltage, ON / OFF of the switching circuit is controlled, and a voltage measuring circuit and a current measuring circuit are used only during measurement. A microcomputer that is energized, wherein the microcomputer is in a normal mode when the current of the secondary battery exceeds a specified value, and when the current of the secondary battery is equal to or less than the specified value and there is a connection signal, the first mode is set. When the current of the secondary battery is equal to or less than a specified value and there is no connection signal, a state monitoring operation mode is set so as to be a second sleep mode. In the first sleep mode, the microcomputer is driven by a low-frequency clock, and the current and voltage measurement intervals are relatively long, and the microcomputer is driven by a low-frequency clock. In the second sleep mode, the microcomputer is driven by a low frequency clock, and Battery pack measurement interval of the flow is characterized by the longest. 12. When the communication signal is received during the normal mode, the normal mode is maintained even when the current of the secondary battery is equal to or less than a specified value.
The battery pack described. 13. Returning to a normal mode when receiving a communication signal from an electronic device or a charger during the first sleep mode, and returning to a normal mode when receiving a connection signal during a second sleep mode. 13. The battery pack according to claim 12, wherein the battery pack is returned to a normal mode. 14. The current measurement circuit includes a first current measurement circuit having a small measurement range and small power consumption, and a second current measurement circuit having a large measurement range and large power consumption. 14. The device according to claim 13, wherein the first current measurement circuit is operable in all state monitoring operation modes together with the voltage measurement circuit, and the second current measurement circuit is operable only in the normal mode. battery pack. 15. A semiconductor device comprising: a plurality of rechargeable batteries connected in series; a monitoring circuit for monitoring the state of the rechargeable batteries; and a switching circuit for stopping charging and discharging by a signal from the monitoring circuit. In a battery pack connected to an electronic device or a charger, a switch for turning on / off the monitoring circuit and a series voltage of a plurality of secondary batteries are measured, and when the measured series voltage falls to or below a discharge inhibition series voltage. And a series voltage detection circuit for turning off the switch to stop power supply to the monitoring circuit.