JPH08126216A - Portable electronic device and method for measuring remaining capacity of battery therein - Google Patents

Abstract

PURPOSE: To significantly prolong the life of a battery even if the discharge characteristics of a pristine battery are changed to those of the one at life-end, and this save labor required for battery change. CONSTITUTION: The load current to a load device is so controlled that a constant discharging current will be maintained until a final discharge voltage is reached. A sub-CPU 10 subjects variations in the detected voltage of a battery to arithmetic operation, and classifies the discharge characteristic of the battery under one of the first through third categories: The discharge characteristics of a pristine battery, those of a battery where a memory effect is produced, and those of a battery at life-end. According to the result of the discharge characteristic classification, the sub-CPU 10 automatically changes the reference values of the judgment of batteries' remaining capacity, stored in an SRAM 11, and compares the respective reference values of the judgment of batteries' remaining capacity, stored in the SRAM 11, with the detected voltage of the battery pack 3 to judge the remaining capacity of the battery.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a portable electronic device having a function of detecting the remaining amount of a battery by using a secondary battery as a means for supplying power, and a method of determining the remaining amount of battery in the portable electronic device.

[0002]

2. Description of the Related Art Conventionally, a method of detecting the remaining amount of a secondary battery is a method of detecting the integrated amount of discharge current by combining a dedicated IC and a one-chip microcomputer, and a fixed voltage value and a battery voltage considering the discharge voltage characteristic of the battery. There is a method of detecting a decrease in the remaining amount by comparing

The former is a change in the operating state of the device (load fluctuation).
It is possible to detect the remaining amount with high accuracy without being affected by changes in the operating environment (especially temperature), but at the same time, the cost becomes high.

In the latter case, the remaining amount detecting function can be constructed inexpensively, but the remaining amount detecting accuracy may be low due to load fluctuations and changes in the operating environment. Therefore, as an intermediate method between the two, a method of detecting the remaining battery level by comparing the slice value corresponding to the remaining level and the battery voltage using a one-chip microcomputer, or further load fluctuation (fluctuation of discharge current) or use In recent years, a method using a slice value in which the influence of the environment (mainly temperature) is corrected has been widely used.

[0005]

However, in the above-mentioned conventional example (in particular, the method other than the discharge current integration method), the slice value corresponding to each remaining amount level is determined from the experimental value based on the discharge characteristic of the new battery. Since the setting is fixed, if the battery characteristics change more than when new, the detection accuracy will deteriorate. Ni-Cd battery (NiCd), which is a typical secondary battery, and large-capacity characteristics and environmental characteristics (Cd-less)
Nickel-metal hydride batteries (NiM
In (h), there is a memory effect in which a part of the discharge voltage is reduced as shown in FIG. 11 due to partial repeated charge / discharge or long-term continuous charge. Apparent battery capacity will decrease.

FIG. 11 is a diagram for explaining the discharge characteristics of a conventional secondary battery. The horizontal axis shows the discharge time (t) and the vertical axis shows the voltage per unit cell (V).

The solid line shows the discharge characteristics of a new battery,
The broken line shows the discharge characteristic of the battery having the memory effect, and the alternate long and short dash line shows the discharge characteristic of the life end battery.

As shown in this figure, the memory effect returns to the conventional discharge characteristic when proper charging and discharging are performed again, but when the number of times of charging and discharging reaches several hundreds (2 to 3 hundreds), the internal effect of the battery is restored. As the impedance increases, a change in charge / discharge characteristics (life end characteristic) occurs as shown in FIG.

In particular, in the case of NiMh, the entire discharge voltage decreases, so when the slice value based on the discharge characteristics of a new battery is applied as it is, the battery Low is detected while the battery capacity is still sufficient. Therefore, even though the battery alone has a charge / discharge capacity of about 500 times,
The battery will be replaced after a few hundred uses.

The present invention has been made to solve the above problems, and an object of the first to eighth inventions of the present invention is to analyze the discharge characteristics of a rechargeable battery and By changing the reference value for life judgment, even if the discharge characteristic changes from a new state to a life end state, the battery life is judged according to the appropriate reference value corresponding to the current discharge characteristic, and It is an object of the present invention to provide a portable electronic device and a method for determining a battery remaining amount of the portable electronic device, which can significantly extend the life and reduce the burden of battery replacement.

[0011]

A first aspect of the present invention is a portable electronic device for driving a load device by energization from a rechargeable battery to perform predetermined data processing. Storage means for storing a plurality of battery remaining amount determination reference values for determining the state, detection means for detecting the voltage value of the battery, each battery remaining amount determination reference value stored in the storage means, and the detection means A remaining amount determining means for determining the remaining battery amount of the battery by comparing the detected voltage value of the battery, and the voltage value of the fully charged battery reaches a discharge end voltage for disconnecting the load device. Current control means for controlling the load current to the load device so as to keep the discharge current constant, and a variation state of the voltage value of the battery detected by the detection means in a state where the discharge current is constant The discharge characteristics of the battery to sense the first
To a third new battery, a battery having a memory effect, or a discharge characteristic of a life-end battery, the characteristic determining means and the first to third discharge characteristics determined by the characteristic determining means. And a changing unit for automatically changing the battery residual amount determination reference value stored in the storage unit.

According to a second aspect of the present invention, the characteristic determining means calculates a voltage change rate per unit time for each detection of a periodic battery voltage, and the calculated voltage change rate is constant from a fluctuation state. The discharge characteristic of the battery is discriminated to be one of the first to third discharge characteristics based on the battery voltage at the point where the state or the constant state changes to the variable state and the number of the change points.

According to a third aspect of the present invention, the storage means is
It is composed of a non-volatile storage medium.

According to a fourth aspect of the present invention, the changing means is
Each time the power is turned on, it is configured to determine whether or not each battery remaining amount determination reference value stored in the storage means has been rewritten and initialize each battery remaining amount determination reference value corresponding to the initial discharge characteristic of the battery. It is a thing.

According to a fifth aspect of the present invention, an instructing means for instructing the start of discharge characteristic identification processing by the characteristic determining means,
When a discharge characteristic identification process start instruction is given by the instruction means, a change state of the voltage value of the battery detected by the detection means is arithmetically processed in a state where the discharge current is constant to perform discharge processing of the battery. Is configured to be discriminated and determined to be one of the first to third discharge characteristics.

According to a sixth aspect of the present invention, the changing means is
Each battery remaining amount determination reference value stored in the storage means is changed to a battery voltage value at a point where the voltage change rate changes from a changing state to a constant state or from a constant state to a changing state depending on the actual discharge characteristics of the battery. It is configured in.

According to a seventh aspect of the present invention, in a battery remaining amount determination method for a portable electronic device, which drives a load device by energizing from a rechargeable battery to perform predetermined data processing, A setting step of setting a plurality of remaining battery level determination reference values for level determination in the storage medium,
The detection step of detecting the voltage value of the battery, and the remaining battery level of the battery to be compared by comparing each battery level determination reference value set in the storage medium with the detected voltage value of the battery. An amount determination step, a limiting step of limiting the load current to the load device so that the discharge current is kept constant until the voltage value of the fully charged battery reaches a discharge end voltage that disconnects the load device, and the discharge A characteristic determining step of performing a calculation process on a variation state of the voltage value of the battery detected in a state in which the current is constant to identify the discharge characteristic of the battery as one of the first to third discharge characteristics; And a changing step of changing the battery remaining amount determination reference value stored in the storage medium according to the first to third discharge characteristics determined by the characteristic determining step.

In an eighth aspect of the present invention, in the characteristic determining step, the rate of voltage change per unit time is calculated every time the battery voltage is detected periodically, and the calculated rate of voltage change is constant from the fluctuation state. The discharge characteristic of the battery is discriminated to be one of the first to third discharge characteristics based on the battery voltage at the point where the state or the constant state changes to the variable state and the number of the change points.

[0019]

In the first aspect of the invention, the load current for the load device is controlled so that the discharge current is kept constant until the voltage value of the battery fully charged by the current control means reaches the discharge end voltage for disconnecting the load device. In a controlled state, the characteristic determination means performs arithmetic processing on the variation state of the voltage value of the battery detected by the detection means to discriminate and determine the discharge characteristic of the battery to any one of the first to third discharge characteristics, The automatic changing unit automatically changes the battery remaining amount determination reference value stored in the storage unit according to the determined first to third discharge characteristics, and the remaining amount determining unit stores each battery remaining amount stored in the storage unit. Even when the discharge characteristic of the battery changes from the new state to the life end state by determining the remaining battery level of the battery by comparing the determination reference value and the voltage value of the battery detected by the detection means, battery It shifts the criterion of the amount, making it possible to extend the battery life in actual use.

In the second aspect of the invention, the characteristic determining means calculates a voltage change rate per unit time for each detection of the periodic battery voltage, and the calculated voltage change rate changes from a changing state to a constant state or a constant state. From the battery voltage at the point of change from the
It is possible to discriminate and determine any one of the first to third discharge characteristics, and reliably determine which state of the first to third discharge characteristic batteries the current discharge characteristic of the battery is.

In the third invention, the storage means is composed of a non-volatile storage medium, and is capable of holding a battery remaining amount determination reference value corresponding to the current discharge characteristic of the battery regardless of the power on / off state. And

In the fourth aspect of the invention, the changing means determines whether or not each battery remaining amount determination reference value stored in the storage means is rewritten each time the power is turned on, and each battery corresponding to the initial discharge characteristic of the battery. It is possible to initialize the remaining amount determination reference value and set the optimal battery remaining amount determination reference value that matches the discharge characteristics of the replaced battery when the battery is replaced.

In the fifth aspect of the invention, when the instructing means gives an instruction to start the process of identifying the discharge characteristic, the characteristic determining means indicates the voltage value of the battery detected by the detecting means while the discharge current is constant. It is possible to test the battery life at the timing intended by the user by arithmetically processing the fluctuation state and discriminating and determining the discharge characteristic of the battery as one of the first to third discharge characteristics.

In the sixth aspect of the invention, the changing means changes the battery remaining amount determination reference value stored in the storage means from a changing state to a constant state or from a constant state to a changing state in which the voltage change rate depends on the actual discharge characteristics of the battery. It is possible to change to the battery voltage value at the point of changing to, and to change to the optimum battery remaining amount determination reference value that matches the current battery discharge characteristic.

In the seventh invention, the load current for the load device is limited so that the discharge current is kept constant until the voltage value of the fully charged battery reaches the discharge end voltage for disconnecting the load device. , A variation state of the voltage value of the battery detected in a state where the discharge current is constant is arithmetically processed to discriminate and determine the discharge characteristic of the battery to any one of the first to third discharge characteristics, and the determination is performed. The battery remaining amount determination reference value stored in the storage medium is changed according to the changed first to third discharge characteristics, and each changed battery remaining amount determination reference value and the detected voltage value of the battery are To determine the remaining battery level of the battery, and even if the discharge characteristics of the battery change over time, the respective battery remaining level reference values are set to the respective battery remaining level reference values commensurate with the discharge characteristics. Shift to substantially increase battery life And executable life to control the programmable.

In the eighth aspect of the invention, in the characteristic determining step, the voltage change rate per unit time is calculated every time the battery voltage is detected periodically, and the calculated voltage change rate is changed from a changing state to a constant state or a constant state. From the battery voltage at the point of change from the
It is possible to perform the processing for reliably determining which state of the first to the third discharge characteristic battery the discharge characteristic of the current battery is, by performing the identification determination from the above to the third discharge characteristic. To do.

[0027]

FIG. 1 is a schematic configuration diagram showing an example of a portable electronic device showing an embodiment of the present invention, for example, a portable computer device.

In the figure, 1 is a main body, 2 is an AC adapter which is a means of supplying power to the main body 1, and when the AC power cannot be taken, the main body 1 is supplied with power and the rechargeable battery pack 3 is supplied. It also has a charging function.

Reference numeral 4 is a main power switch (SW) for controlling power supply from the AC adapter 2 or the battery pack 3 to the main body 1, and 5 is a power saving state (suspend) in which driving of each unit is stopped and a normal state (resume). ) Is a suspend / resume switch (SW), 6 is a battery test switch (SW) for starting a battery test mode, which will be described later, and 7 is a power LED for displaying the remaining battery level.

FIG. 2 is a block diagram for explaining the control configuration of the main body 1 shown in FIG. 1. The same parts as those in FIG. 1 are designated by the same reference numerals.

In the figure, 10 is a sub CPU, which controls battery management. As a power source, the battery pack 3 (nominal 10.8 V) and the AC adapter 2 (2
0V), the content of the SRAM 11 for storing control information around the battery is held by a minute current from the battery pack 3.

The power supply unit 13 includes a switching circuit for the two drive power supplies, a voltage conversion circuit for generating logic voltages and drive voltages for various motors from the drive power supplies, and a reset signal generation circuit for turning on the main power supply SW. , And a charge command signal 1 from the sub CPU 10 to the AC adapter 2
4 or an interface circuit such as a full charge signal 15 which informs the sub CPU 10 that the battery is in a fully charged state, and when the battery voltage becomes less than 8.5 V (discharge end voltage), In order to prevent over-discharge, a discharge termination circuit that disconnects the battery pack 3 and the load is included (not shown).

In the discharge termination circuit, the main power switch 4 is turned off.
Since the operation is performed even in the FF state, when the battery pack 3 is inserted / removed, the current to the SRAM 11 is unconditionally cut off regardless of the switch state of the main power switch 4. In the initial test of, SRAM1 held at the head of SRAM11
The checksum value of 1 and the checksum of the actual SRAM area will be different.

Battery management by the sub CPU 10 is roughly divided into remaining amount detection control, charging control, battery test control and power control.

The remaining amount detection control is performed by the AD conversion value of the battery voltage input to the AD conversion terminal 12 of the sub CPU 10 and the SRA.
The remaining level is determined by comparing the slice value held in M11 and the remaining battery level is displayed on the power LED 7.

The charging control causes the AC adapter 2 to start the charging operation via the power supply unit 13 by the charging command signal 14 when the charging condition is satisfied, and waits for the full charging signal 15 from the AC adapter 2. When the battery test switch 6 is pressed, the charging operation is started by the charge command signal 14, and after the end of charging (full charge signal 15) is detected, the AC permission signal 17 is compulsorily used from the AC adapter 2 to the battery pack 3. To the planar unit 20 and sends a constant current operation request command to the planar unit 20 side using an IFRAM 31 described later to measure the battery discharge voltage characteristic under the constant current discharge condition, and if necessary, the SRAM 11
Performs control (battery test control) to retune the slice value held in.

The power control includes a full power down process and a resume process. In the full power down process, the sub CPU 10 receives the full power down signal 21 which is a state control signal from the planar unit 20 and the DC / DC control signal is received. 19 is sent to the power supply unit 13 and unnecessary DC /
This is a process of stopping the oscillation of DCs (supply of power to the planar side), whereby the device is in a power saving state (suspend state) in which power supply to parts other than some electronic components such as the sub CPU 10 is stopped.

In the resume process, the sub CPU 10 detects the resume request signal 22 generated when the suspend / resume switch (sustain / registration SW) 5 is pressed, and the DC / DC control signal 19 supplies power to all electronic components. After restarting the supply and stabilizing the oscillation, the planar unit 2
This is a process for returning from the power saving state (suspend state) to the normal state by sending the resume permission signal 23 to the 0 side.

The interface between the planar unit 20 and the sub CPU 10 has the aforementioned power control signals (full power down signal 21, resume permission signal 2).
In addition to 3), the sub CPU 10 writes to the 1-byte memory (IFRAM) 31 directly connected to the bus line 30,
This is also performed by outputting the read request signal 32 to the planar unit 20 side.

Correspondence between the present embodiment and each means of the first to sixth inventions and their functions will be described below with reference to FIG.

The first invention is chargeable (AC adapter 2
Battery level determination criterion for determining the state of the remaining battery level in a portable electronic device that drives a load device by energization from a battery (battery pack 3) to carry out predetermined data processing. A storage unit (SRAM 11) for storing a plurality of values, a detection unit for detecting the voltage value of the battery (detected by the A / D conversion input of the sub CPU 10), and a battery remaining amount determination reference stored in the storage unit. Remaining capacity determination means (sub-CP) that compares the value (levels HM, ML, device stop level described later) with the voltage value of the battery detected by the detection means to determine the remaining battery capacity of the battery.
U10) and a current control means (planar unit) for controlling the load current to the load device so that the discharge current is kept constant until the voltage value of the fully charged battery reaches the discharge end voltage for disconnecting the load device. Two
0)), the discharge characteristic of the battery is determined by any one of the first to third discharge characteristics by arithmetically processing the fluctuation state of the voltage value of the battery detected by the detecting means in a state where the discharge current is constant. Character determination means (sub CP
U10) and changing means (sub CPU) for automatically changing the battery remaining amount reference value stored in the storage means according to the first to third discharge characteristics determined by the characteristic determining means.
10) is provided, and the load current for the load device is controlled so that the discharge current is constant until the voltage value of the battery fully charged by the planar unit 20 reaches the discharge end voltage that disconnects the load device. In this state, the sub CPU 10 arithmetically processes the detected variation of the voltage value of the battery to change the discharge characteristics of the battery from the first to the third discharge characteristics (the discharge characteristics at the time of new product, the memory effect is generated). Discharge characteristic or life end state discharge characteristic), and the sub CPU 10 automatically changes the battery remaining amount determination reference value stored in the SRAM 11 according to the determined first to third discharge characteristics. (See FIG. 10 described later), the battery remaining amount of the battery is determined by comparing each battery remaining amount determination reference value stored in the SRAM 11 with the detected voltage value of the battery pack 3. Constant and, even when the discharge characteristics of the battery has changed from new state until the life end state, to shift the criteria battery level, makes it possible to extend the battery life in actual use.

A second aspect of the invention is a characteristic determining means (sub CPU
11) is a battery voltage at the point where the voltage change rate per unit time is calculated for each periodical battery voltage detection, and the calculated voltage change rate changes from a changing state to a constant state or from a constant state to a changing state. And the discharge characteristic of the battery is discriminated from any of the first to third discharge characteristics based on the number of change points thereof, and whether the current discharge characteristic of the battery is the first to third discharge characteristic battery is determined. It is possible to make a reliable judgment.

According to a third aspect of the present invention, the storage means is composed of a non-volatile storage medium (SRAM 11) and holds a battery residual amount determination reference value corresponding to the current discharge characteristic of the battery regardless of the power on / off state. It is possible.

A fourth aspect of the invention is a changing means (sub CPU 1
0), each time the power is turned on, it is determined whether or not each battery remaining amount determination reference value stored in the storage means is rewritten, and each battery remaining amount determination reference value corresponding to the initial discharge characteristic of the battery is initialized. Thus, when the battery is replaced, it is possible to set the optimum battery remaining amount determination reference value that matches the discharge characteristics of the replaced battery.

In a fifth aspect of the present invention, when the instruction means (test switch 6) gives an instruction to start the discharge characteristic identification process, the characteristic determining means (sub CPU 10) causes the detecting means to perform the discharge current constant. The detected variation of the voltage value of the battery is arithmetically processed to discriminate the discharge characteristic of the battery from any one of the first to third discharge characteristics, and the battery life is tested at the timing intended by the user. It is possible.

A sixth aspect of the invention is a changing means (sub CPU 1
0) is a point at which the rate of change of the voltage of each battery remaining capacity determination reference value stored in the SRAM 11 changes from a fluctuating state to a constant state or from a constant state to a fluctuating state depending on the actual discharge characteristics of the battery (TV1, which will be described later) It is possible to change to the battery voltage value in the TV 2) and change to the optimum battery remaining amount determination reference value that matches the current battery discharge characteristic.

Thus, the rate of change of the discharge voltage in the constant current discharge state is monitored, and the battery characteristic is judged by sampling the polarization point and its voltage value (battery test process). By using a slice value that matches the characteristics of the battery (reference value above), even if the battery has a life end characteristic (a decrease in discharge voltage due to an increase in internal impedance), the battery operation equivalent to that of a new battery can be performed. This allows the battery, which has been replaced in several hundred cycles, to be used for a long time while maintaining the performance of the conventional battery alone.

At the same time, by completely discharging the battery to the discharge end voltage in the battery test process, it becomes possible to recover the discharge characteristics even from a temporary decrease in battery capacity due to the memory effect.

The main routine of the sub CPU 10 used in the portable computer device having the above configuration will be described with reference to FIG.

FIG. 3 is a flowchart showing an example of the main processing procedure by the sub CPU in the portable electronic device according to the present invention. Note that (1) to (14) indicate each step.

When the main power switch 4 is turned on, the logic DC / DC oscillation on the power supply unit 13 is unconditionally started, and when the logic voltage reaches 4.2 V, the reset IC on the power supply unit 13 resets. Signal is sub C
It is output to the PU 10 and the planar unit 20. Then, after reset release (1), the sub CPU 10
Execution of the program starts from the start address of the M area.

The unconditional oscillation of the logic DC / DC by the above-mentioned power supply unit 13 is limited to the width of 400 msec, and the sub CPU 10 controls the DC / DC control signal 19
To activate DC / D even after unconditional oscillation
The oscillation of C is continued and the power supply to the entire device is continued (2). Next, the initial setting regarding the input / output port and the interrupt is performed (3).

In the present embodiment, the resume signal, A, generated when the suspend / register SW5 is pressed in the suspend state
Although two external interrupts of the C adapter 2 are used, the interrupts are disabled in the initial setting and enabled in the full power down process described later.

Next, the sum check of the built-in ROM, the read / write check of the built-in RAM, and the external SRAM 1
The sum check of 1 and the blinking of the power LED 7 are also performed at the same time (4). Then, it is determined whether the checksum of the SRAM 11 has an error (5). If the error is determined, the battery pack 3 may be replaced and the contents of the SRAM 11 may be lost. A slice value used for quantity detection and a value (stored in the ROM) according to the characteristics of the new battery are set in the SRAM 11 (6). The test result is stored in the IFRAM 31, and this value is confirmed during the startup process on the planar unit 20 side.

Next, the main loop in the main routine in the present embodiment is a remaining amount detection processing routine for detecting the remaining amount of the battery, and a sub-CP from the planar unit 20 side.
The detection of the full power down signal state sent to U10 and the detection of the battery test switch 6 are executed sequentially, but a timer for taking this timing is started before entering the main loop (7).

Next, the remaining amount of the battery is detected based on the remaining amount detecting processing routine described later, and the result is displayed on the power LED 7 and also stored in the IFRAM 31 (8). Then, the full power down signal 21 is sensed (9), and if active, the process branches to a full power down processing routine described later (10).

On the other hand, if the full power down signal 21 is inactive in the determination in step (9), the battery test switch 6 is sensed, and it is determined whether or not the switch depression is detected (11). Branches to the battery test processing routine described later (12).

Subsequently, as a result of the remaining amount detection by the remaining amount detection processing routine of step (8), the battery remaining amount level is L.
In the case of the ow level (13), the battery Low described later
After executing the processing routine (14), the process branches to (8).

FIG. 4 is a flow chart showing an example of detailed procedure of the battery low processing routine shown in FIG. Note that (1) to (8) indicate each step.

This process is Low when the battery remaining amount is detected, which will be described later.
This is the procedure executed when the level is determined and the AC adapter 2 is not connected.

In this embodiment, the battery Low
The processing is to warn the user of the remaining battery level by blinking the buzzer and the power LED 7, and to request the battery low if the battery voltage of the battery pack 3 becomes less than the device stop voltage or 30 seconds elapses from the low level detection. By
This is a process of requesting the planar unit 20 side to start the transition to the suspended state of the device.

First, the battery voltage of the battery pack 3 is A / D converted (1), and this value is compared with the value corresponding to the device stop voltage held in the SRAM 11 (2). In this comparison, when the battery voltage is lower, the battery voltage may drop below the discharge end voltage (8.5 V) before the operation for 30 seconds. In this case, the discharge end circuit on the power supply unit 13 is Since the user operates and forcibly disconnects the battery pack 3 and the load, the data being processed by the user will be lost. Therefore, the process immediately shifts to the suspend process, and the process branches to step (8) described later.

On the other hand, in the determination of step (2), for example, in the case of a new battery, the device stop voltage held in the SRAM 11 is 9.7 V, but a lower value is obtained after execution of the battery test process described later. It may be held, so
When the battery voltage of the battery pack 3 is higher than the device stop voltage, the buzzer sounds for 1 second and the power LED lights in orange (3).

As a result, when the user notices the warning and presses the suspend / resume switch 5, the planar unit 20 side detects this and detects the memory, HD, LC.
The full power-down signal 21 is output after the evacuation process such as D is completed.

Next, the sub CPU 10 determines whether or not the full power down signal 21 is detected (4).
After finishing the ow process and returning to the main loop, a full power down process described later is executed.

On the other hand, if it is determined in step (4) that the sub CPU 10 has not detected the full power down signal 21, it is determined whether the AC adapter 2 is detected (5). Since the supply is guaranteed, the battery Low process ends.

On the other hand, if neither of the judgments in steps (4) and (5) is detected, the buzzer is stopped for 1 second and the power L
The ED is turned off (6).

Next, it is judged from the timer timing state whether 30 seconds have passed since the battery low process was started (7). If it is judged that the timer has not passed, the process branches to step (1). The process of is repeated.

On the other hand, if it is determined in step (7) that 30 seconds have passed, the battery low request is issued to IFR.
By writing to the AM 31 and activating the read request signal, the saving process on the planar unit 20 side and the output of the full power down signal 21 are prompted (8), and the battery Low process is ended.

On the side of the planar unit 20 which receives the battery low request, the same processing as when the depression of the suspend / resume switch 5 is detected is performed, and the full power down signal 21 is output after the save processing.

FIG. 5 is a flow chart showing an example of a detailed procedure of the full power down processing routine shown in FIG. Note that (1) to (9) indicate each step.

This process is started when the full power down signal 21 is detected in the main routine shown in FIG.

First, the DC / DC control signal 19 commands the oscillation stop of DC / DCs (DC / DC for the planar side) on the power supply unit 13 which are not used in the suspended state (1).

Next, the return from the suspend state is executed by the resume request interrupt process, which will be described later, when the resume request signal 22 generated when the user presses the suspend / register SW 5 is input to the sub CPU 10 as an interrupt. Therefore, the resume request interrupt is enabled (2).

Next, the presence or absence of the AC adapter 2 is checked (3), and if it is determined that the AC adapter 2 is not present, A
The C adapter 2 enables the plug-in interrupt (4), and the sub C
When the PU 10 enters the temporary stop state (stop mode) by itself (5), the power saving state is further achieved.

On the other hand, when returning from the stop mode, the AC adapter 2 may be inserted in addition to the resume request interrupt (9). On the other hand, in step (3), A
When the C adapter interrupt is generated, after clearing the interrupt factor and adjusting the stack pointer, the process branches to step (3) described later to start the charging process.

That is, when it is determined that the AC adapter 2 is present, after electrically connecting the battery pack 3 and the AC adapter 2 on the power supply unit 13 with the AC permission signal, the AC adapter is connected via the power supply unit 13. By outputting the charge command signal to 2, the charging of the battery pack 3 by the AC adder 2 is started (6).

Next, when the AC adapter 2 detects that the battery pack 3 is fully charged, the charging is stopped, and the sub CPU 10 outputs a full charge signal 15 output from the AC adapter 2 to the sub CPU 10 via the power supply unit 13. It is determined whether or not it is detected (7), and if NO, the process branches to step (3). When it is determined that the full charge signal 15 is detected, a status indicating full charge is recorded in the IFRAM 31 and a read request is issued. A signal is output to notify the planar unit 20 side that the battery is fully charged (8), and the process branches to step (3).

When the suspend / resume switch 5 is pressed in the suspend state (the state in which unnecessary DC / DC oscillation is stopped by the full power down process) during the full power down process, the resume request signal is issued. 22 is input to the sub CPU 10 as an interrupt,
The resume request interrupt processing routine shown in FIG. 6 is executed.

FIG. 6 is a flowchart showing an example of a detailed procedure of the resume request interrupt processing routine in the full power down processing routine shown in FIG. Note that (1) to (5) indicate each step.

After clearing the interrupt factor, adjusting the stack pointer, and masking all other external interrupts (1), the charging command signal output to the AC adapter 2 via the power supply unit 13 is withdrawn to stop charging ( 2).

Next, the DC / DC control signal 19 orders the restart of the DC / DC oscillations for all logics, which had been stopped by the DC / DC control signal 19 (3), and waits for 50msec to stabilize the oscillations (4). A resume permission signal that triggers the recovery process is output (5), and the process branches to (E1) immediately before the main loop and the series of processes is repeated.

When the planar unit 20 receives the resume permission signal 23, the operation of each I / O class is restarted from the state immediately before the full power down.

FIG. 7 is a flow chart showing an example of a detailed procedure of the battery remaining amount detection processing routine shown in FIG.
Note that (1) to (9) indicate each step.

First, one address of the slice value storage area on the SRAM 11 is set to the sub CPU 10 according to the remaining battery level stored in the internal RAM of the sub CPU 10.
To obtain the slice value (1).
Then, it is judged whether or not the remaining amount level is in the Low state (2), and if the remaining amount level is Low, it will be described later (7).
Branch to.

On the other hand, if it is determined in step (2) that the remaining amount level is High, the address where the level HM is stored is set to the pointer, and if the remaining amount level is Middle, the address where the level ML is stored is set to the pointer. The battery voltage of the battery pack 3 is A / D converted (3), and the converted value is compared with the value on the SRAM 11 indicated by the pointer (4).

The value of the slice value storage area in the SRAM 11 is the slice voltage value A for switching the remaining amount level.
A value corresponding to the D conversion value is stored.

Next, the processes of steps (3) and (4) are repeated five times (5), and it is judged whether the battery voltage conversion value of the battery pack 3 is greater than the slice value three times or more (6) and three times. If it is less than 1, the battery level is lowered by one level (9), and the process branches again to step (1) to repeat a series of processes.

On the other hand, when it is determined in step (6) that the battery voltage conversion value is greater than the slice value three times or more, the final value determined by comparing the battery voltage conversion value with the value on the SRAM 11 is determined. The status corresponding to the remaining level is recorded in the IFRAM 31 (7) and the power LED is turned on according to the remaining level (8).

As shown in FIG. 11, in the discharge characteristics of the battery, a part of the voltage decreased due to the memory effect due to repeated charging and discharging, and the entire voltage decreased due to the increase of the internal impedance of the battery with the aging. In this case, if the above-described battery low processing and remaining amount detection processing are performed with a slice value that matches the discharge characteristics of a new battery, the battery becomes a low state while leaving sufficient capacity as a single battery (apparent battery capacity decreases. To).

Therefore, as a countermeasure against this, in the present invention, a battery test mode is newly added, and the slice value on the SRAM 11 is rewritten according to the test result to extend the battery life in actual use.

The battery test process executed when the pressing of the battery test SW6 is detected in the main loop will be described with reference to FIGS.

FIG. 8 is a flow chart showing an example of detailed procedure of the battery test processing routine shown in FIG. Note that (1) to (22) indicate each step.

First, the presence or absence of the battery pack 3 and the AC adapter 2 is checked (1), and if either is not connected, I
Write a warning status (warning status) in the FRAM31 and activate the read request signal (2),
Return to the main routine.

On the other hand, when it is determined in step (1) that both are connected, the same process as the battery low process (the battery L in the IFRAM 31 is stored).
The ow request is written and the read request signal is activated) to prompt the planar unit 20 side to perform full power down processing (3).

Next, when the sub CPU 10 detects the full power down signal 21 (4), the same processing as the above full power down processing (power supply unit 1 with the AC enable signal) is performed.
After electrically connecting the battery pack 3 and the AC adapter 2 on the battery pack 3, the charging command signal is output to the AC adapter 2 via the power supply unit 13) The charging of the battery pack 3 by the AC adapter 2 is started ( 5).

Next, when the full charge signal 15 from the AC adapter 2 is detected (6), a constant current discharge command is set in the IFRAM 31 (7), and the same process as the resume interrupt process (DC / DC control signal) is performed. Then, the oscillation is restarted and the resume enable signal is output to the planar.) The full power down state is restored to the resume state (8).

At this time, the planar unit 20 side which has returned by using the resume enable signal as a trigger is
According to the setting of 1, all interrupts are prohibited and the operation state of a constant load (corresponding to 1 A) is continued.

Next, the sub CPU 10 uses a check flag, a polarization counter, a progress counter, a 10-byte ring buffer (for 10 minutes), and a 10-byte test data area (polarity) for recording the polarization data used in the processing described later. (5 poles) is initialized to “0” (9), and the AC load signal is used to cut off the electrical connection between the device load and the AC adapter 2 (10), forcing the drive power supply to AC. Switch from the adapter 2 to the battery pack 3.

Next, in order to carry out the determination processing described later, 7
A timer interrupt is started with a set value of 0 minutes (a time corresponding to 70% of the time for discharging from the full charge to the discharge end voltage (8.5V) by the constant current discharge of 1A) (11).

Next, the A / D of the battery voltage of the battery pack 3
Conversion is performed, the result is stored in the corresponding address of the 10-byte ring buffer of the sub CPU 10, and the progress counter is incremented by "1" (12).

Next, from the voltage conversion value of the battery pack 3 stored in the ring buffer, the change in voltage conversion value per minute is calculated for 10 minutes based on the latest voltage conversion value (13). Then, it is determined whether the check flag is "0" (14), and when the check flag is determined as "0", it is checked whether the change amount has changed from a variable state to a constant value (15). When the constant value of the change cannot be detected by the check, after waiting for 1 minute (18), the process branches to step (12) to repeat the series of processes.

On the other hand, when it is detected in step (15) that the change has become constant, the voltage conversion value on the ring buffer corresponding to the latest battery voltage and the elapsed counter are set to the sub CP
The data is stored in the corresponding address of the test data area of the internal RAM of U10 (16), the check flag indicating that the discharge state is stable is set to "1", and the polarization point counter is incremented by "1" (17). ) After waiting for 1 minute (18), the process branches to step (12).

In the case of the memory effect battery, since the discharge characteristic changes stepwise as shown in FIG. 11, the above-mentioned polarization point counter finally becomes a value of 3 or more.

Therefore, when the check flag is judged to be "1" in the judgment of step (14), it is checked that the change per minute changes from the constant value state to the variable value state (19). . When the variable value change value cannot be detected, after one minute of waiting (22), the process branches to step (12) to repeat the series of processes.

On the other hand, when it is detected in step (19) that the variation has changed, the voltage conversion value on the ring buffer corresponding to the latest battery voltage and the elapsed counter are set to the corresponding addresses in the test data area. It saves (20), clears the check flag to "0", increments the polarization point counter by "1" (21), waits for one minute (22), and branches to step (12).

Hereinafter, in step (11) shown in FIG. 8, the battery state is judged according to the procedure shown in FIG. 9 in the timer interrupt process 70 minutes after the start of the battery test.

FIG. 9 is a flowchart showing an example of an interrupt processing procedure based on the 70-minute timer shown in FIG.
Note that (1) to (8) indicate each step.

First, it is determined whether the above-mentioned polarization point counter is "2" (1), and if the polarization point counter is other than "2", the process unconditionally branches to step (8) described later.

On the other hand, when it is determined in step (1) that the polarization point counter is 3 or more, the battery under test is a memory effect battery whose discharge voltage changes stepwise,
When the polarization point counter is "1", the discharge is further continued. In either case, there is no need to change the slice value held in the SRAM 11, so the process branches to step (8) described below and the sub CPU 10 prohibits all interrupts and repeats an infinite loop.

As a result, the device continues the above-mentioned steady discharge (corresponding to 1 A) and the battery pack 3 is discharged up to 8.5 V at which the over-discharge prevention circuit on the power supply unit 13 operates, so that the memory effect is generated. Capacity will be restored.

On the other hand, when the polarization point counter is determined to be "2" in the determination in step (1), the voltage conversion value (TV1) corresponding to the polarization point 1 and the voltage conversion value corresponding to the polarization point 2 are obtained. While referring to (TV2) from the test data area, (2) and (3), TV3 = (TV2-discharge end voltage (8.5V)) / 2 + discharge end voltage (8.5V) is calculated (4), Each value TV1, TV2, TV3 is a sub CPU
Stored in 10 internal RAMs.

Then, the values TV1, TV2, TV3 stored in the test data area and the slice values (level H) corresponding to the respective remaining amount levels held in the SRAM 11 are stored.
M, level ML, device stop voltage) (5), and the measured value in the battery test process is 0.
It is judged whether it is lower than or equal to 05V or more (6), and if it is judged to be high, the process branches to step (8), and if it is judged to be low, the battery internal impedance increases (life end). After determining that the battery has a characteristic) and replacing the corresponding slice level value in the SRAM 11 with the measured value (7), the sub CPU 10 prohibits all interrupts and repeats an infinite loop (8).

Discharge characteristic curves and the above-mentioned test data TV1, TV2 when new battery, memory effect battery and life end characteristic battery are subjected to the above battery test processing
FIG. 10 shows an example of the value of the TV 3 and the slice value (level HM, level ML, device stop voltage) held in the SRAM 11.

FIG. 10 is a diagram showing discharge characteristics during a battery test in the portable electronic device according to the present invention. The same parts as those in FIG. 11 are designated by the same reference numerals. However, the value is not the A / D converted value of the voltage value of the battery pack 3 for convenience, and is 1
The battery voltage value per cell is displayed.

Correspondence between the present embodiment and the respective steps of the seventh and eighth inventions and the operation thereof will be described with reference to FIGS. 8, 9 and 3.
Will be described with reference to.

A seventh invention according to the present invention is a battery remaining amount determination method for a portable electronic device, which drives a load device by energization from a rechargeable battery pack 3 to perform predetermined data processing. A setting process (step (6) in FIG. 3) of setting a plurality of battery remaining amount determination reference values for level determination of the remaining amount state in the storage medium, and a detection process of detecting the voltage value of the battery (in FIG. 3). In step (8), the details of FIG. 7) are compared with each battery residual amount determination reference value set in the storage medium and the detected voltage value of the battery to compare the battery residual amount of the battery. Remaining amount determination step of determining (a limiting step of limiting the load current to the load device so that the discharge current is kept constant until the voltage value of the fully charged battery reaches the discharge end voltage for disconnecting the load device (FIG. 8 (7) ~ ( 1)), and the discharge characteristic of the battery is discriminated to be one of the first to third discharge characteristics by performing arithmetic processing on the fluctuation state of the voltage value of the battery detected in the state where the discharge current is constant. Characteristic determination step (steps (11) to (21) in FIG. 8) and the battery remaining capacity determination criteria stored in the storage medium according to the first to third discharge characteristics determined by the characteristic determination step. Change the value (SRAM1
The battery voltage value at the point where the rate of change in voltage changes from the fluctuation state to the constant state or from the constant state to the fluctuation state depending on the actual discharge characteristic (life end characteristic) of the battery remaining amount determination reference value stored in 1 (Test data TV1, TV
2) and change to the optimum battery remaining amount determination reference value that matches the current battery discharge characteristic) (FIG. 9)
Steps (1) to (7)) are executed, and even if the discharge characteristic of the battery changes over time, the reference value for determining the remaining battery level is set to the reference value for determining the remaining battery level that matches the discharge characteristic. The control is performed in a programmable manner by shifting each to substantially extend the battery life.

In an eighth aspect of the present invention, in the characteristic determining step, a voltage change rate (dV / dt) per unit time is calculated every time a periodic battery voltage is detected, and the calculated voltage change rate is calculated. From the fluctuation state to the constant state or from the constant state to the fluctuation state (polarization point) at the battery voltage and the number of points of change, the discharge characteristic of the battery is discriminated to be one of the first to third discharge characteristics, Current battery has the first discharge characteristics
Therefore, it is possible to execute the processing for surely determining which state of the third discharge characteristic battery is in a programmable manner.

In the above embodiment, the remaining amount is detected only by comparing the voltages. However, the present invention can be applied to the case of the remaining amount detection in which the discharge current is corrected to further improve the accuracy. V (voltage drop from new battery) = I (discharge current) × Z (battery internal impedance)]
It is only necessary to calculate the voltage slice value correction amount at another discharge current from the battery test result of the A steady discharge and reconstruct the slice value.

Further, in the above embodiment, the SRAM 11 which retains the contents with a small amount of power even when the power is off is used as the area for retaining the slice value. However, the interface with the planar unit 20 by the bus line (IFR) is used.
If the AM31) is configured to be bidirectionally readable and writable, a hard disk (HD) or floppy disk (F)
It is also possible to hold it in another storage device such as D).

Further, even in the case of a portable electronic device such as a portable power tool which does not have a rewritable storage device, the present invention can be applied by using a fuse or the like. In this case, a slice value that matches the new battery discharge characteristics and a slice value that matches the battery discharge characteristics after several hundreds of uses are prepared in the ROM, and the battery test process determines that the life end characteristics. For example, blow the fuse. In the remaining amount detection process, the slice value for a new battery is used when the fuse is ON, and the slice value after several hundreds of uses is used when the fuse is OFF. Further, when the battery is replaced, if the fuse is also replaced, the present invention can be applied at a relatively low cost and the battery life can be extended.

According to the above embodiment, according to the present invention, in addition to the control mode (remaining amount detection control) for detecting the remaining battery amount during use of the device by comparing the slice value and the battery voltage value, The battery voltage (V) is periodically (t) monitored by constant current discharge from the charged state, and the voltage change rate dV / dt per unit time is calculated to calculate the number of polarization points and the polarization points of the discharge characteristic curve. It has a control mode (battery test control) that detects the battery voltage value and determines the normal battery, memory effect battery, and life end battery and switches the processing.

The slice value used in the remaining amount detection control includes a slice value corresponding to the remaining amount level and a slice value for temporarily stopping the drive of the device after detection (device stop voltage corresponding value). After being stored, the contents are stored in the SRAM area where the contents are saved by a very small amount of power.

Further, in the battery test mode process according to the above FIG. 8, when the battery is recognized as a life end battery, the value corrected by the discharge voltage drop measured in the battery test control is used in the remaining amount detection control. The SRAM 11 is used as a slice value for detecting the remaining amount level and a device stop voltage value.
If it is not determined to be a life-end battery, the battery is controlled to discharge to the discharge end voltage, and the stored battery test result is the default value when the battery pack 3 is replaced. Since it is reset to (a value that matches the initial characteristics of the battery), the slice value of the remaining amount detection that was fixed in the past was made variable, and there was a change in the characteristics of the battery over time such as memory effect and life end characteristics. The battery life in actual use can be extended by adding the adjustment.

[0125]

As described above, the first aspect of the present invention
According to the invention, a state in which the load current for the load device is controlled so that the discharge current is kept constant until the voltage value of the battery fully charged by the current control means reaches the discharge end voltage for disconnecting the load device. Then, the characteristic determining means performs arithmetic processing on the variation state of the voltage value of the battery detected by the detecting means to discriminate and determine the discharge characteristic of the battery to any one of the first to third discharge characteristics, and the determination is made. First
According to the third discharge characteristic, the automatic changing unit automatically changes the battery remaining amount determination reference value stored in the storage unit, and the remaining amount determining unit stores each battery remaining amount determination reference value stored in the storage unit and Since the remaining battery level of the battery is determined by comparing the voltage value of the battery detected by the detection means, even if the discharge characteristic of the battery fluctuates from the new state to the life end state, The judgment criteria can be shifted to extend the battery life in actual use.

According to the second aspect of the invention, the characteristic determining means calculates the voltage change rate per unit time every time the battery voltage is detected cyclically, and the calculated voltage change rate changes from a changing state to a constant state or a constant state. From the battery voltage at the point where it changes from a constant state to the fluctuating state and the number of its changes,
Therefore, it is possible to reliably determine which of the first to third discharge characteristic batteries the current discharge characteristic of the battery is.

According to the third aspect of the present invention, since the storage means is composed of a non-volatile storage medium, it retains the battery residual amount determination reference value corresponding to the current discharge characteristic of the battery regardless of the power on / off state. be able to.

According to the fourth aspect of the invention, the changing means responds to the initial discharge characteristic of the battery by determining whether or not each battery residual quantity determination reference value stored in the storage means is rewritten every time the power is turned on. Since each battery remaining capacity judgment reference value is initialized,
When the battery is replaced, it is possible to set the optimum battery remaining amount determination reference value that matches the discharge characteristics of the replaced battery.

According to the fifth aspect of the invention, when the instructing means gives an instruction to start the process of identifying the discharge characteristic, the characteristic judging means detects the voltage of the battery detected by the detecting means while the discharge current is constant. Since the variation state of the value is calculated and the discharge characteristic of the battery is discriminated to be one of the first to third discharge characteristics, the battery life can be tested at the timing intended by the user.

According to the sixth aspect of the present invention, the changing means changes the battery remaining capacity determination reference value stored in the storage means from a changing state to a constant state or from a constant state when the voltage change rate depending on the actual discharge characteristics of the battery is changed. Since the battery voltage value at the point of changing to the fluctuating state is changed, it is possible to change to the optimum battery remaining amount determination reference value that matches the current battery discharge characteristic.

According to the seventh invention, the load current for the load device is limited so that the discharge current is kept constant until the voltage value of the fully charged battery reaches the discharge end voltage for disconnecting the load device. In a state, the discharge characteristic of the battery is discriminated to be any one of the first to third discharge characteristics by performing arithmetic processing on the variation state of the voltage value of the battery detected in the state where the discharge current is constant, The battery remaining amount determination reference value stored in the storage medium is changed according to the determined first to third discharge characteristics, and each changed battery remaining amount determination reference value and the detected voltage of the battery. Since the remaining battery level of the battery is determined by comparing with the value, even if the discharge characteristic of the battery changes over time and changes, each battery remaining amount determination reference value matches each discharge remaining characteristic. Each to shift the battery life substantially Control for survival to be able to execute the programmable.

According to the eighth aspect of the present invention, in the characteristic determining step, the voltage change rate per unit time is calculated every time the battery voltage is detected periodically, and the calculated voltage change rate is changed from the fluctuation state to the constant state or From the battery voltage at the point where it changes from a constant state to the fluctuating state and the number of its changes,
From the first to the third discharge characteristic battery, the processing for surely determining which state of the first to the third discharge characteristic battery the current discharge characteristic of the battery is, is executed programmable. You can

Therefore, even if the discharge characteristic fluctuates from a new state to a life end state, the battery life is substantially extended while the battery life is judged by an appropriate reference value corresponding to the current discharge characteristic. Also, it is possible to reduce the burden of battery replacement.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing an example of a portable electronic device showing an embodiment of the present invention.

FIG. 2 is a block diagram illustrating a control configuration of a main body 1 shown in FIG.

FIG. 3 is a sub CP in the portable electronic device according to the present invention.
It is a flow chart which shows an example of the main processing procedure by U.

4 is a flowchart showing an example of a detailed procedure of a battery low processing routine shown in FIG.

5 is a flowchart showing an example of a detailed procedure of a full power down processing routine shown in FIG.

6 is a flowchart showing an example of a detailed procedure of a resume request interrupt processing routine in the full power down processing routine shown in FIG.

7 is a flowchart showing an example of a detailed procedure of a battery remaining amount detection processing routine shown in FIG.

8 is a flowchart showing an example of a detailed procedure of a battery test processing routine shown in FIG.

9 is a flowchart showing an example of an interrupt processing procedure based on the 70-minute timer shown in FIG.

FIG. 10 is a diagram showing discharge characteristics during a battery test in the portable electronic device according to the present invention.

FIG. 11 is a diagram illustrating discharge characteristics of a conventional secondary battery.

[Explanation of symbols]

 2 AC adapter 3 Battery pack 4 Main power switch 5 Suspend / resume switch 6 Test switch 7 Power LED 10 Sub CPU 11 SRAM 20 Planer unit

Claims (8)

[Claims] 1. In a portable electronic device that drives a load device by energization from a rechargeable battery to perform predetermined data processing, a plurality of battery remaining amount reference values for determining the remaining battery amount state are provided. A storage means for storing, a detection means for detecting the voltage value of the battery, a battery remaining capacity determination reference value stored in the storage means and the voltage value of the battery detected by the detection means are compared. A remaining amount determination means for determining the remaining battery amount of the battery, and a load for the load device so that the discharge current is kept constant until the voltage value of the fully charged battery reaches the discharge end voltage for disconnecting the load device. A current control unit that controls a current, and a variation state of the voltage value of the battery detected by the detection unit in a state where the discharge current is constant is arithmetically processed to change the discharge characteristics of the battery from the first to the third. Characteristic determination means for discriminating and distinguishing between a new battery, a battery having a memory effect, and a discharge characteristic of a life end battery, and a first characteristic determination means for judging the characteristic.
To a changing means for automatically changing the battery residual amount determination reference value stored in the storage means according to the third discharge characteristic. 2. The characteristic determining means calculates a voltage change rate per unit time each time a periodic battery voltage is detected, and the calculated voltage change rate changes from a changing state to a constant state or from a constant state to a changing state. 2. The portable electronic device according to claim 1, wherein the discharge characteristic of the battery is discriminated to be one of the first to third discharge characteristics from the battery voltage at the changing point and the number of the changing points. 3. The portable electronic device according to claim 1, wherein the storage means is a non-volatile storage medium. 4. The changing means determines whether or not each battery residual quantity determination reference value stored in the storage means is rewritten each time the power is turned on, and each battery residual quantity determination criterion corresponding to the initial discharge characteristic of the battery. 2. The value is initialized as set forth in claim 1.
A portable electronic device as described. 5. The instructing means for instructing the start of the discharge characteristic identifying process by the characteristic determining means, and the detecting means in a state where the discharge current is constant when the instructing means starts the discharge characteristic identifying process start instruction. 2. The portable type according to claim 1, wherein the variation state of the voltage value of the battery detected by the above is arithmetically processed to discriminate and determine the discharge characteristic of the battery as one of the first to third discharge characteristics. Electronic device. 6. The changing means changes the battery remaining amount determination reference value stored in the storage means depending on the actual discharge characteristics of the battery, and the voltage change rate changes from a variable state to a constant state or from a constant state to a variable state. The portable electronic device according to claim 1, wherein the battery voltage value at the point is changed. 7. A method for determining a remaining battery level of a portable electronic device, which drives a load device by energization from a rechargeable battery to perform predetermined data processing, comprising: Setting step for setting the battery remaining amount determination reference value in the storage medium, a detection step for detecting the voltage value of the battery, and a battery remaining amount determination reference value set in the storage medium and the detected battery A remaining amount determining step of determining a battery remaining amount of the battery by comparing it with a voltage value, and a discharge current is kept constant until the voltage value of the fully charged battery reaches a discharge end voltage for disconnecting the load device. As described above, the limiting step of limiting the load current to the load device and the variation state of the voltage value of the battery detected in the state where the discharge current is constant are arithmetically processed to change the discharge characteristics of the battery from the first to the first. 3's A characteristic determination step of discriminating between any of the discharge characteristics, and a change of changing the battery remaining capacity determination reference value stored in the storage medium according to the first to third discharge characteristics determined by the characteristic determination step. A method of determining a remaining battery level of a portable electronic device, comprising: 8. The characteristic determining step calculates a voltage change rate per unit time for each detection of a periodic battery voltage, and the calculated voltage change rate changes from a changing state to a constant state or from a constant state to a changing state. 8. The battery remaining amount determination of the portable electronic device according to claim 7, wherein the discharge characteristic of the battery is discriminated to be any one of the first to third discharge characteristics from the battery voltage at the changing point and the number of the changing points. Method.