JPH07260905A - Residual capacity detection device for battery - Google Patents

Abstract

PURPOSE:To detect the accurate residual capacity of a battery by measuring the voltage thereof. CONSTITUTION:The voltage of a battery 20 is first inputted to a microcomputer 40 via a sub-power supply 30. The microcomputer 40 is internally provided with a memory 40a for saving a relationship between battery voltage and battery residual capacity for every temperature and mode. Also, immediately after turning on power and before the operation of a body load 10, and in suspension mode where the body load 10 falls in standby state, consumption current is fixed and the battery voltage and residual capacity have a good correlation. Thus, the microcomputer 40 measures the voltage of the battery 20 at such a time for turning on power as well as in the suspension mode, and detects battery residual capacity on the basis of the contents of the memory 40a.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for detecting the remaining battery level by the battery voltage detected in a fixed current consumption state.

[0002]

2. Description of the Related Art Conventionally, battery-driven electronic devices such as notebook personal computers (hereinafter referred to as personal computers) have been in widespread use, and rechargeable batteries have been used. In such a device, if the battery remaining amount can be known, it is possible to know how long the battery can be used without being charged. For this reason, there is known one that can display the remaining battery level.

In order to display the remaining battery amount, it is necessary to measure the remaining battery amount, and as the measuring method, there are voltage measurement of the battery, integration of charge / discharge amount, and the like.

[0004]

Here, the voltage measurement of the battery is easy as a method, but the voltage of the nickel-hydrogen battery, the nickel-cadmium battery, etc. does not change unless the remaining amount of the battery becomes considerably small. Therefore, in the case of such a battery, there is a problem that the voltage measurement cannot accurately measure the remaining battery level. Further, since the battery voltage is affected by temperature, there is a problem that accurate measurement cannot be performed even when the temperature changes.

On the other hand, the cumulative discharge amount of the battery can be measured relatively accurately from the charge / discharge current after full charge. However, in the integral type battery remaining amount detection, the content of the detected battery remaining amount must be retained even when the power is turned off, and power must be continuously supplied to the memory that retains data when the power is turned off. There was a problem that it did not happen.

If the power is turned on / off or the suspend mode and the normal operation mode are frequently switched, the change in the current amount due to the mode change is large, the accuracy of the battery remaining amount detection due to the integration is deteriorated, and the battery is not fully charged. If the device is used for a long time, the difference between the detection result and the actual battery remaining amount becomes large.

Further, in the current integration type battery remaining amount detection, there is a problem that it is very difficult to judge the initial state of the battery for a device in which the battery is frequently replaced.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a battery remaining amount detecting device capable of accurately detecting the battery remaining amount by measuring the voltage of the battery. To do.

[0009]

DISCLOSURE OF THE INVENTION The present invention comprises a main body portion for achieving the main function of an electronic device, a manual power switch operated by an operator, and an on / off detecting means for detecting the on / off state of the power switch, A battery remaining amount detecting device for detecting a battery remaining amount in a battery-powered electronic device including a processing unit that performs a process for supplying power to the main body portion when detecting the turning on of a power switch, The relationship between the voltage detection means for detecting the voltage of the battery at the time of power-on during the operation of the processing unit and before the start of the power supply to the main body portion, the battery voltage at the time of power-on, and the remaining amount of the battery. A plurality of memories each storing a predetermined temperature for each predetermined temperature, and the remaining battery capacity is detected based on the battery voltage detected at power-on.

Further, the present invention has both a normal mode for achieving a normal function of an electronic device and a suspend mode for limiting the power consumption to a specific one such as maintaining the stored contents of a memory and keeping the power consumption at a low level. A battery remaining amount detecting device in a battery-driven electronic device having a mode, wherein the relationship between the voltage detecting means for detecting the battery voltage in the suspend mode, the battery voltage in the suspend mode, and the battery remaining amount is determined at predetermined temperatures. And a memory for storing a plurality of them in advance, and the remaining battery capacity is detected based on the battery voltage detected in the suspend mode.

Further, a current integration remaining amount detecting means for detecting the battery charging / discharging current and for accumulating the charging / discharging current to detect the battery remaining amount, and for detecting in the power-on state or the suspend mode. A correction unit that corrects the remaining battery amount detected by the current integration remaining amount detecting unit according to the remaining battery amount.

Further, comparing means for comparing the remaining battery amount detected at the power-on or the suspend mode with the remaining battery amount detected by the current integration remaining amount detecting means, and the comparison result of the comparing means, When the battery remaining amount detected at power-on or in the suspend mode is larger than the battery remaining amount obtained by the current integration remaining amount detecting means, the correction of the battery remaining amount by the correcting means is prohibited. And

[0013]

As described above, when the power switch is turned on and the device starts operating, the processing section performs a process for starting the operation of the main body. The current consumption at this time is fixed, such as that associated with the operation of this processing unit. The voltage of the battery in the state where the current consumption is fixed has a good correlation with the remaining amount of the battery. Therefore, even in the case of a nickel-hydrogen battery or a nickel-cadmium battery, which has a small voltage change due to a decrease in the remaining battery amount, the remaining amount can be accurately detected from the battery voltage. In particular, since the temperature of the battery 20 is also measured and the data for detecting the remaining amount is stored for each temperature, the battery 20
The accuracy of the remaining amount detection from the voltage of can be made quite high.

Also in the suspend mode, the members that receive power supply are limited. Therefore, the current consumption is fixed. Therefore, as in the case described above, highly accurate battery remaining amount detection can be performed.

Further, the remaining battery amount can be constantly updated by detecting the remaining battery amount by integrating the battery current. Then, by updating the remaining battery level by detecting the remaining battery level by detecting the battery voltage during power-on or in suspend mode,
Very accurate battery level detection can be performed.

Further, when the battery remaining amount detected by the battery voltage detection is larger than the battery remaining amount obtained by the integration, by inhibiting the correction of the battery remaining amount, the data on the battery remaining amount does not increase. Therefore, it is possible to prevent the battery remaining amount during use of the device from increasing and the battery remaining amount display being felt strange.

[0017]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing the overall configuration of the present invention, and a main body load (main body portion) 10 is a portion including circuits and the like for performing various operations of a notebook computer. An LCD (liquid crystal display) 12 is connected to the main body load 10 to perform various displays. The suspend switch 14 is a switch that is turned on manually or automatically when a key is not operated for a predetermined time, and when the suspend switch 14 is turned on, the main unit load 1
0 shifts to suspend mode. In this suspend mode, the main unit load 10 supplies electric power only to a specified member such as an internal memory to minimize the electric power amount,
It will be in a standby state.

The battery 20 is a rechargeable nickel-hydrogen battery (may be another type of battery such as nickel-cadmium), and the positive electrode is connected to the contact 22a.
The negative electrode is connected to b. Since the contact 22a is connected to the main body load 10 via the switch 24, the power of the battery 20 is supplied to the main body load 10 by turning on the switch 24. Here, when charging is performed, the main unit load 10 is disconnected, and an AC adapter (not shown) is connected instead of the main unit load 10. As a result, the DC power from the AC adapter is supplied to the battery 20 for charging.

A sub power source 30 is connected to the positive electrode of the battery 20 via a contact 22a. This sub power supply 30
Outputs a predetermined constant voltage, for example, generates a constant voltage of 5V from the battery 20 of 9V and supplies this to various circuits of 5V drive. Also, this sub power supply 3
A manual power switch 31 is connected to 0,
A signal for turning on / off the switch 31 is output. Further, as will be described later, another switch is provided inside, and the voltage of the battery 20 can be output by turning on this switch.

The contact 22b on the negative side of the battery 20
Is connected to the ground via the current detection circuit 42.
The current detection circuit 40 outputs the current flowing therethrough as a voltage value, and includes, for example, a current detection resistor having a predetermined low resistance value. Therefore, when the main body load 10 is operating, a voltage corresponding to the current flowing from the positive electrode of the battery 20 to the main body load 10 is obtained, and when charging, the adapter 20 connected to the switch 24 instead of the main body load 10 charges the battery 20. A voltage corresponding to the current is obtained.

However, the voltage thus obtained (the voltage on the upper side of the current detection resistor) has the opposite sign between the charge and discharge. The negative voltage requires a complicated circuit for subsequent comparison processing and the like. For this reason, in the present embodiment, a predetermined positive voltage is added to the upper voltage of the current detection resistor, and the positive voltage is always output as the detection value. For this addition, it is preferable to connect a voltage dividing resistor for dividing the output voltage of the sub power source 30 to the upper side of the current detecting resistor.

The signal of the detected value of the battery current, which is the output of the current detection circuit, and the power switch on / off signal, which is the output of the sub power supply 30 for turning on / off the power switch 31, are supplied to the microcomputer 40. Further, the suspend mode output signal for the transition of the main unit load 10 to the suspend mode due to the above-mentioned turning on of the suspend switch 14 is also supplied to the microcomputer 40.

The microcomputer 40 performs various processes according to the supplied signals and outputs control signals and the like.
The integrated battery remaining amount of the battery 20 is calculated by integrating the detected charging / discharging current of the battery 20, the power supply control to the main body load 10 by the on / off control of the switch 24, the on / off control of the switch built in the sub power source 30, and the like are performed. Further, the remaining battery amount calculated by the microcomputer 40 is supplied to the LCD 12 via the interface 44 and displayed here. Here, this display may be performed in response to a predetermined key operation, or may be performed always in a predetermined portion, and any mode thereof may be used. It is also preferable to generate an alarm when the remaining amount becomes low. As the alarm, it is possible to employ generation of an alarm sound or blinking of an LED.

The microcomputer 40 has a memory 40a.
Is built in. The memory 40a stores the relationship between the battery voltage and the remaining amount thereof, and has a map for each mode and each temperature. That is, the memory 40a
2, the relationship between the battery voltage and the remaining battery level is stored for each temperature and each mode.

Such data is, for example, (1) at power-on, 0 to 10 ° C. (battery data at 0 ° C.) (2) at power-on, 11 to 20 ° C. (battery data at 15 ° C.) (3) At power-on, 21 to 35 ° C (when battery data is 30 ° C) (4) At power-on, 26 to 65 ° C (when battery data is 45 ° C) (5) In suspend mode, 0 to 10 ° C (when battery data is 0 ° C) (6) In suspend mode, 11 to 20 ° C (when battery data is 15 ° C) (7) In suspend mode, 21 to 35 ° C (when battery data is 30 ° C) (8) In suspend mode, 26 to 65 ° C (battery) Data at 45 ° C.), each curve is divided into 16 parts, and 16 kinds of remaining amount data are associated with each other and stored as a table in the memory 40a. Therefore, the remaining battery amount is obtained according to the measured voltage and temperature of the battery 20 during power-on or in the suspend degree mode. And
Using this data as the initial value of the remaining battery amount, the remaining battery amount is detected by the above current integration. In addition,
Each curve is for one temperature, and the predetermined range of the detected temperature is made to correspond to one temperature curve.

Here, the sub power supply 30 has a circuit as shown in FIG. 3 in addition to the constant voltage output of 5V. That is, the upper side of the manual power switch 31 has the terminal 22a.
Is connected to the positive electrode side of the battery 20 via. The lower side of the power switch 31 is connected to the ground via two resistors 33 and 34 connected in series. Then, a power switch ON / OFF signal for ON / OFF information of the power switch 31 is output to the microcomputer 40 from the connection point of the resistors 33 and 34. Microcomputer 40
Detects that the power switch 31 is on because the voltage at the connection point between the resistors 33 and 34 is at a high level.

The upper side of the resistor 33 (power switch 3
The voltage on the lower side of 1 goes through the diode 35 to the signal VCC
Is input to the microcomputer 40. Microcomputer 40
Detects the voltage of the battery 20 with this signal Vcc.

Further, the upper side and the lower side of the power switch 31 are connected via a switch 32 and a diode 35. Therefore, even if the power switch 31 is turned off by turning on the switch 32, the battery 2
A voltage of 0 is output as signal Vcc.

Next, the operation of the battery remaining amount detecting apparatus of this embodiment will be described with reference to FIGS. First, the operation at power-on will be described based on FIG. When the use of the personal computer is started, the power switch 31 is turned on (S11). As a result, the midpoint voltage of the resistors 33 and 34 becomes high level, and this is input to the microcomputer 40 as a power switch on / off signal. Microcomputer 4
0 starts the operation in response to the high level of the power switch on / off signal (S12) and turns on the switch 32 in the sub power supply 30 (S13). Here, once the power switch 31 is turned on, the power switch 31 sequentially switches between on-off and off-on. Therefore, the power switch 31 immediately returns to off. But,
Even if the power switch 31 is turned off by turning on the switch 32, the voltage of the battery 20 is input to the microcomputer 40 as the signal Vcc. Further, since the diode 35 is provided, the current is supplied to the resistors 33 and 34 by the power switch 3
Turned off by turning off 1. Therefore, the microcomputer 40
The next time the power switch 31 is turned on, the next time the power switch 31 is turned on, the microcomputer 40
Recognize the power off command.

After turning on the switch 32, the microcomputer 40
Is supplied to the battery 20 by the signal Vcc from the sub power supply 30.
Is detected (S14). This voltage detection is performed, for example, by A / D converting the supplied signal Vcc. Then, it is determined whether this voltage Vcc is 6 V or higher (S
15). If the battery voltage is 6 V or less,
It means that the voltage of the battery 20 is insufficient for the operation of the personal computer. Therefore, the microcomputer 40 stops the power supply to the main body load 10 (starting the main body load 10), turns off the switch 32, and ends the processing (S16).

On the other hand, in S14, the battery voltage is 6
If it is equal to or higher than V, the microcomputer 40 detects the temperature of the battery 20 at that time by the temperature sensor 48 (S17). Then, based on the detected temperature and the voltage of the battery 20 detected in S14, the corresponding battery remaining amount (at the time of power-on) is read from the memory 40a and stored in the internal register as the initial battery remaining amount ( S18).

In this way, the battery remaining amount detection at the time of power-on is completed, so the switch 24 is turned on (S1).
9) The power supply to the main body load 10 is started. By this, the main body load 10 starts its operation. For example, after performing a predetermined process according to the procedure stored in the internal ROM, an application program or the like is executed to perform various processes.

At this time, in this embodiment, the microcomputer 40 receives a signal about the amount of current from the current detection circuit 42,
By multiplying this current amount by time (time for one cycle of this processing of the microcomputer 40), the discharge amount for that time is calculated (S20). Then, the obtained discharge amount is S1
Subtracted from the initial remaining amount stored in 8 (S21),
The current battery remaining amount is calculated, and the battery remaining amount data stored in the register is updated. When the detected value of the current detection circuit 42 is affected by the temperature, the temperature may be measured and a predetermined compensation may be performed.

Next, the obtained remaining amount is compared with a predetermined alarm level (S22). If it is equal to or higher than the alarm level, there is no problem in operating as it is, so the timer is activated (S23), the process returns to S20, and the process is repeated. As a result, the battery remaining amount data stored in the register is always the remaining amount of the battery 20 at that time. Therefore, the remaining battery amount can be displayed based on the data in this register. By the operation of the timer, the time of one cycle of this processing is determined to be an appropriate time.

The operation when the remaining battery level is below the alarm level will be described with reference to FIG. S2
If the remaining battery level obtained in 2 is below the alarm level, an alarm is generated (S30).
This alarm causes, for example, the LED to blink. Then, the battery voltage monitoring mode is entered (S3
1). That is, when the remaining amount of the battery 20 becomes equal to or less than the predetermined value, it is determined whether or not the body load 10 can continue to operate thereafter, when the voltage value of the battery 20 is the predetermined final voltage EV.
(For example, 6V) or less is determined.

Therefore, the microcomputer 40 compares the input battery voltage Vcc with the final voltage EV (S3).
2). Then, if it is equal to or higher than the final voltage EV, the timer is operated (S33), and this process is repeated until the voltage of the battery 20 becomes equal to or lower than the final voltage EV.

On the other hand, when the voltage of the battery 20 reaches the final voltage EV in S32, the operation of the main body load 10 is disabled, so the switch 32 is turned off (S3).
At the same time as 4), the switch 24 is turned off (S35), and the process ends.

Further, in place of the main body load 10, at the time of charging when an AC adapter is connected, the remaining battery amount is calculated by adding the charged amount. Further, even when the battery 20 is replaced, the above processing may be performed.

Next, detection of the remaining battery level in the suspend mode will be described with reference to FIG. When the suspend switch 14 is turned on to enter the suspend mode, the microcomputer 40 performs the following process as an interrupt process. The microcomputer 40 first recognizes the voltage and temperature of the battery 20. Then, the data in the memory 40a is read out based on the voltage and the temperature, and the remaining battery level is obtained (S41).

The remaining battery amount obtained from the memory 40a is compared with the remaining amount value by integration stored in the internal register (S43). Then, it is determined whether they are the same (S44), and if they are different, the remaining amount value obtained by the integration is corrected by the battery remaining amount value obtained from the memory 40a (S45). When corrected in S45 and S
If it is the same in 44, the timer is activated (S4
6) After a lapse of a predetermined time, it is determined whether or not the suspend mode is released (S47). If not, the process returns to S41 and repeats the processing. As a result, during the suspend mode, the battery remaining amount is measured by measuring the voltage of the battery 20 every predetermined time. Then, in the case of release in S47, this processing is ended. When the suspend mode is released, it is also preferable to return once to S41 and measure the remaining amount by measuring the voltage of the battery 20.

As described above, according to the present embodiment, the voltage of the battery 20 is measured immediately before the power switch 31 is turned on, before the main body load 10 is activated (when the power is on), and in the suspend mode. Only the microcomputer 40 and its peripheral circuits are operating at the time of power-on, and the current consumption amount is almost constant. In addition, the circuits that operate in the suspend mode are limited, and the current consumption is almost constant. The voltage of the battery 20 in such a state that the amount of consumed current is fixed has a good correlation with the remaining amount of the battery. Therefore, the remaining amount can be accurately detected even if the change in the voltage due to the decrease in the remaining amount of the battery such as the nickel hydrogen battery or the nickel cadmium battery is small.
In particular, since the temperature of the battery 20 is also measured and the data for detecting the remaining amount is stored for each temperature, the accuracy of the remaining amount detection from the voltage of the battery 20 can be made quite high.

Further, according to this embodiment, when the main body load 10 is started by turning on the power switch 31, it is possible to obtain the remaining battery amount at that time. Therefore, it is not necessary to store data on the remaining battery level when the power is turned off (when the operation is stopped due to the turning off of the power switch 31). Therefore, it is not necessary to back up the memory, and it is possible to save power. The remaining battery level is detected by measuring the voltage of the battery 20 only when the personal computer is placed under a specific condition (power-on, suspend mode). However, since the remaining amount can be detected by integrating the amount of current during normal operation, the remaining battery amount can always be detected accurately.

Here, in the present invention, the remaining battery level is always known. Therefore, if necessary, the remaining battery level can be displayed on the LCD 12 or the like. On the other hand, as described above, when the remaining amount is detected by measuring the battery voltage and the detected value is different from the remaining amount by the current integration,
The remaining amount is corrected. Therefore, although the displayed remaining amount data is changed, if the remaining amount measured by the battery voltage is larger than the remaining amount data obtained by integrating the current, this correction may increase the remaining amount.

However, it seems strange to the user that the remaining battery level increases. Therefore, in such a case, the display of the remaining amount should not be corrected. That is, a display register for storing the data to be displayed on the LCD 12 is provided separately from the remaining amount data register updated by the above-mentioned accumulated remaining amount data. And
When the detected remaining amount data is stored in the remaining amount data register and the detected remaining amount data exceeds the display remaining amount data, rewriting of the display register is prohibited.
Then, the content of the remaining amount register is updated by the subsequent integration of the discharge current, and the remaining amount data in the remaining amount register decreases. And. When the data in the remaining amount register becomes the same as the data in the display register, the data in the remaining amount register and the display register are made the same. Note that only the display register may be rewritten.

In this way, when the remaining battery amount is detected by measuring the battery voltage under the specific condition,
It is possible to prevent the displayed battery level from increasing.

[0046]

As described above, according to the battery remaining amount detecting apparatus of the present invention, the battery voltage can be accurately measured by the battery voltage immediately after the power switch is turned on or when the current consumption in the suspend mode is fixed. The remaining battery level can be detected. In particular, since the temperature of the battery 20 is also measured and the data for detecting the remaining amount is stored for each temperature, the accuracy of the remaining amount detection from the voltage of the battery 20 can be made quite high.

Also in the suspend mode, the members that receive power supply are limited. Therefore, the current consumption is fixed. Therefore, as in the case described above, highly accurate battery remaining amount detection can be performed.

Further, the remaining battery amount can be constantly updated by detecting the remaining battery amount by integrating the battery current. Then, by updating the remaining battery level by detecting the remaining battery level by detecting the battery voltage during power-on or in suspend mode,
Very accurate battery level detection can be performed.

Further, when the battery remaining amount detected by the battery voltage detection is larger than the battery remaining amount obtained by the integration, by inhibiting the correction of the battery remaining amount, the data on the battery remaining amount does not increase. Therefore, it is possible to prevent the battery remaining amount during use of the device from increasing and the battery remaining amount display being felt strange.

[Brief description of drawings]

FIG. 1 is a block diagram showing an overall configuration of an embodiment.

FIG. 2 is a diagram showing a relationship between a battery voltage stored in a memory and a battery remaining amount.

FIG. 3 is a diagram showing a circuit of a sub power supply 30.

FIG. 4 is a flowchart showing an operation at power-on.

FIG. 5 is a flowchart showing an operation when an alarm occurs.

FIG. 6 is a flowchart showing an operation in a suspend mode.

[Explanation of symbols]

 10 main body load 12 LCD 20 battery 30 sub power supply 40 microcomputer 42 current detection circuit

Claims (4)

[Claims] 1. A main body part for achieving a main function of an electronic device, a manual power switch operated by an operator, an on / off detecting means for detecting on / off of the power switch, and a case where the on / off of the power switch is detected. And a processing unit that performs processing for supplying power to the main body, and a battery remaining amount detecting device that detects a remaining battery amount in a battery-driven electronic device including: Then, at the time of power-on before the start of the power supply to the main body part, a plurality of voltage detection means for detecting the voltage of the battery, the relationship between the battery voltage at the time of power-on and the remaining battery level are set in advance at predetermined temperatures. A battery remaining amount detecting device having a memory for storing and detecting the remaining battery amount based on the battery voltage detected at power-on. 2. A battery having both a normal mode for achieving a normal function of an electronic device and a suspend mode for limiting the power consumption to a specific one such as maintaining the stored contents of a memory and keeping the power consumption at a low level. A battery remaining amount detecting device in a driving electronic device, comprising: a voltage detecting unit for detecting a battery voltage in the suspend mode; a plurality of relations between the battery voltage in the suspend mode and the battery remaining amount; A battery remaining amount detecting device, comprising: a memory, which detects the remaining battery amount based on the battery voltage detected in the suspend mode. 3. The device according to claim 1, further comprising: a current integration remaining amount detection that detects a battery remaining amount by detecting a charging / discharging current of the battery and integrating the current to detect a battery remaining amount. And a correction unit that corrects the remaining battery amount detected by the current integration remaining amount detecting unit according to the remaining battery amount detected at the time of power-on or in the suspend mode. . 4. The device according to claim 3, further comprising a comparing means for comparing the battery remaining amount detected at the power-on time or the suspend mode with the battery remaining amount detected by the current integration remaining amount detecting means. In the comparison result of the comparing means, if the battery remaining amount detected at the power-on or in the suspend mode is larger than the battery remaining amount obtained by the current accumulated remaining amount detecting means, A battery remaining amount detecting device characterized by prohibiting correction of the battery remaining amount.