JPH08336242A - Electronic apparatus - Google Patents

Abstract

PURPOSE: To obtain an electronic apparatus employing a plurality of batteries as a power supply in which the data can be protected against destruction due to abrupt removal of battery. CONSTITUTION: Battery packs 1, 2 are connected, respectively, with a switch means comprising FETs 3, 4, and a switch means comprising FETs 5, 6. One switch means is normally turned on to feed power sequentially. Detectors for detecting the opening/closing of battery cover are provided and when the detector for the currently operating battery detects the open cover state and removal of that battery is presumed, a plurality of batteries are temporarily subjected to OR connection thus sustaining the processing or retreating the data.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electronic device having a plurality of main batteries as a power source.

[0002]

2. Description of the Related Art In a conventional electronic device having a plurality of power sources such as a main battery, the voltage is detected to estimate the remaining capacity of the battery and the presence or absence of the battery is detected to switch the battery. Further, the battery has a plurality of output terminals, one of which is used to supply power, and the other of which is used to detect whether or not the battery is installed.

[0003]

However, the former method has a drawback that the main power source of the electronic device is turned off at the same time when the potential drops, and the latter method causes a slight time lag. However, there was a problem that the power was cut off while the data currently being processed could not be saved.

[0004]

SUMMARY OF THE INVENTION The present invention is to solve the above problems and provides a plurality of main batteries as main power sources, a main circuit section, and switches connected to respective output terminals of the plurality of main batteries. Means, an electric power control means for individually controlling the switch means, a voltage detecting means for measuring the voltage of the main battery, and a plurality of parts provided in a portion accommodating the main battery corresponding to the plurality of main batteries. In an electronic device having a lid and a plurality of lid detectors that detect opening and closing of the lid, the power control means selects one main battery from the plurality of main batteries, and the electronic device is selected. When electric power is being supplied to the main circuit section, the open state of the lid of the corresponding main battery is detected, the control means turns on the plurality of switch means to OR-connect the plurality of main batteries. Preparative an electronic device according to claim.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below based on an embodiment. FIG. 1 is a schematic diagram of a handheld or laptop type small computer device as an electronic device of the present invention, which includes a battery pack 1 as a battery power source, a battery pack 2, a backup sub-battery 18, and a power control means. Battery control unit 7, sub CP
U7a, A / D converter 8 of voltage detection means, main C
Main circuit unit 9 including PU 9a and peripheral circuits, display unit 1
0, IO unit 16, RAM / RTC (random access memory / real-time clock) 17, voltage regulator 24, DC-DC converter 30, and the like. The battery control unit 7 has a sub CPU 7a and monitors the power supply even when the main circuit unit 9 is stopped.

Field effect transistors (hereinafter referred to as FET) 3, FET 4, FET 5, and FET 6 are FET switches that are a kind of switching elements for turning on / off the power supply of the battery pack, and are connected in parallel with the FETs. The diodes 3a, 4a, 5a, 6a that are present are F
It is a parasitic diode existing inside the ET. But FE
Diode 4 in parallel with T4 and FET6
As a and 6a, a diode having a low forward voltage and a large current capacity can be used as required. The FET can be replaced with another bipolar transistor, a relay, or the like.

When the start switch 25, which is the power switch of the apparatus, is turned on, the battery control unit 7 detects this, and the battery pack 1 or the battery pack 2 passes through a predetermined FET, a voltage regulator 24, and a DC-DC converter 30. Then, electric power is supplied to each circuit and a predetermined operation can be executed.

As a power source, in addition to the batteries 1 and 2, A
A C adapter 21 is provided and connected to the battery output terminal 37 via the input terminal 21a and the diode 23 so that power can be supplied to the circuit section. AC adapter 2
When 1 is connected, a detection signal is output from the adapter detection circuit 22 and the gate circuit 26 is connected to the control terminals of the FETs 4 and 6,
An OFF signal is supplied via 27, and the power supply from the battery is cut off. This detection signal is also transmitted to the battery control unit, and the detection operation of the A / D converter corresponds to this.

Battery output terminal 37 and sub-battery 18
Are connected via diodes 34 and 35, and from this connection point 36, the battery control unit 7, A / D converter 8 and R
Power is supplied to each circuit such as the AM / RTC 17. During the operation of the device, the electric potential is not high on the output terminal side 37, so that no power is supplied from the sub-battery. When the normal operation of the device is stopped, electric power is supplied to each circuit such as the battery control unit 7, the A / D converter 8 and the RAM / RTC 17, and the voltage check and the start switch ON monitoring are being performed. The current consumption is much lower than during normal operation. The A / D converter 8 is connected to the output terminals of the batteries 1 and 2 and is configured to be able to individually measure the respective potentials. The A / D converter 8 is often configured as a one-chip CPU integrally with the sub CPU 7a.

When the battery pack 1 and the battery pack 2 are removed and the main power supply is stopped, the operation of the sub CPU 7a is stopped and the sub battery 18 can hold the data in the RAM / RTC 17. At this time, generally, the sub CPU 7a is in the suspend mode. Reference numeral 20 is a voltage comparison circuit for monitoring the power supply of the device, separately from the A / D converter 8, and the potentials at the voltage dividing points of the resistors 31, 32 are compared with each other with reference to the potential generated by the Zener diode 33. Output of comparator 2
It is output from 0a.

Reference numerals 28 and 29 are transistors for turning on / off the current of the AC adapter 21, and are battery packs 1, 2
It is used to control the charging of the battery.

Reference numeral 11 designates a buzzer which sounds various alarms,
Reference numerals 2 and 13 denote LEDs provided at portions corresponding to the battery packs 1 and 2, and reference numerals 14 and 15 respectively denote lid detection switches that engage with a lid of a battery storage unit, which will be described in detail later, to detect an open / closed state of the lid. Show.

FIG. 2 is a schematic view of the apparatus as viewed from the front.
The battery pack 1 and the battery pack 2 are built in at the position on the back side of the device, and the structure is such that the back lid can be opened and closed to be taken out. Reference numerals 40, 41, 42, and 43 respectively indicate the operating state and the remaining amount of the battery pack, and the display unit 1
0 is displayed above.

FIG. 3 is a schematic view of the apparatus as viewed from the back and side, and FIG. 4 is a schematic view showing the structure when the lid of the battery pack is opened. The structure around the battery will be described using this. There is a lid 45 for the battery pack 1 and a lid 46 for the battery pack 2, and when the lid is opened, the battery pack 1 and the battery pack 2 can be mounted therein. When the lid 45 for the battery pack 1 is opened, the battery pack 1, the LED 12 and the lid detection switch 14 for the battery pack 1 are provided as shown in FIG. The lid detection switch is a battery attachment detection means for detecting attachment / detachment of the battery pack, and detects opening / closing of the battery lid.

When the lid 45 for the battery pack 1 is opened, the lid detection switch 14 for the battery pack 1 operates. When the lid for the battery pack 2 is opened, although not shown in the figure, the LED 13 can be seen as in FIG. 4, and the lid detection switch 15 for the battery pack 2 is activated.

Next, the details of the present invention will be described with reference to FIG. The FETs 3 and 4 are connected in series and connected to the output terminal of the battery pack 1, and the FETs 5 and 6 are similarly connected to the output terminal of the battery pack 2.

These four FETs have a gate terminal which is a control terminal and can be turned on / off independently by the battery control unit 7.

Since a FET normally contains a parasitic diode, a current flows from the anode of the parasitic diode to the cathode through the parasitic diode even when the FET is turned off. Therefore, in order to prevent this, when using an FET as a switching element, it is often the case that two parasitic diodes of the FET are connected in series so that their anodes or cathodes face each other to realize a complete switching function. However, in this case, two FETs connected in series are controlled to be turned on or off at the same time.
However, in the embodiment of the present invention, since each FET can be turned on and off independently, if the FET 3 or 5 is turned on and the FET 4 or 6 is turned off, the FET 3 or 5 passes through the diode 4a or 6a. The power is supplied, and if both are off, the power supply from the battery is completely stopped, and it is possible to flexibly cope with various power supply modes.

In this embodiment, when the A / C adapter is not connected, the FETs are turned on and off by the following combinations. To supply power from the battery pack 1 to the circuit, turn on FET3 and FET4 and turn FET5 and FET6 on.
Turn off. (This is called a single coupling mode.) When supplying power from the battery pack 2 to the circuit, the FET is used.
3. Turn off FET4 and turn on FET5 and FET6.
In order to supply electric power to the circuit from the battery pack 1 and the battery pack 2 by the diode OR, FET3, F
ET5 is turned on and FET4 and FET6 are turned off. (This is referred to as a parallel coupling mode.) These three kinds of states can be realized by controlling four FETs independently, and the actual operation will be described in detail below.

When the start switch 25 is pressed and the apparatus is activated, first, the battery control section 7 turns on the FETs 3 and 5 in order to supply electric power from the plurality of main batteries, and the FETs 4 and 4,
Turn off 6 to OR the battery. This is for the following reasons.

That is, if the batteries 1 and 2 are removed, the sub CPU 9a is in the suspended state. (In this embodiment, at this time, since the power is not supplied from the voltage regulator 24, the main CPU 9
a is completely stopped. Therefore, the start switch releases the suspended state of the sub CPU 9a and activates the battery control unit. At this time, since it is not known which battery can supply power, power is supplied from both batteries by OR coupling. To start.

With this configuration, it is not necessary to constantly supply electric power to the battery control unit to maintain the operating state, it is possible to stand by in the suspended state, and the electric power of the sub-battery is used immediately after the power is turned on. Immediately after the power supply is started immediately, the A / D converter and the like are operated and the check program is executed. As a result, since the backup sub-battery 18 does not drive the A / D converter, it can be made as small in capacity as possible, and it is possible to select one having a small current consumption.

Next, the battery to be used is determined by the following procedure. When both battery packs are attached and both battery pack lids are closed, the battery control unit 7 turns on FET3 and FET4 to supply electric power from the battery pack 1 to the circuit, and turns on FET5 and FE.
Turn off T6. Also, when the battery pack lid is closed and only one of the battery packs is installed, the two FETs for supplying power to the circuit from the installed battery pack are turned on and the other battery pack is turned on. The FET is turned off to power the circuit from the FET.

Similarly, when the battery pack lid is closed and two battery packs are mounted together, but if one of the battery packs is not fully charged, power is supplied from the charged battery pack to the circuit. Supply. For example, when supplying power from the battery pack 1 to the circuit, FET
3. Turn on FET4 and turn off FET5 and FET6.
On the contrary, when power is supplied from the battery pack 2 to the circuit, FET3 and FET4 are turned off and FET5 and FET6 are turned on. Whether the battery is installed or not is fully charged is determined by measuring the terminal voltage of the battery pack by the A / D converter 8 and reading the A / D converted value by the battery control unit 7. The battery control unit 7 compares both potentials, selects the one with the higher potential, and supplies it to the main circuit unit. At this time, if the potential of the battery not selected is already lower than the predetermined potential,
This is transmitted to the main circuit section, and the user is notified by means such as display or warning.

In this way, the battery to be used is determined, and this power is supplied to the main circuit section 9, display section 10 and IO section 16
Etc. and the device operates.

Next, the battery switching operation will be described. When two battery packs are installed,
It is assumed that the FET 3 and FET 4 are turned on, the FET 5 and FET 6 are turned off, the battery pack 1 is selected, and power is supplied from the battery pack 1 to the circuit. During operation of the device, the battery control unit 7 regularly checks the use state of the battery pack such as electric potential or attachment / detachment. The main circuit unit 9 receives the operating state of the battery pack and the voltage of the battery pack from the battery control unit 7, and displays the state on the display unit 10. There are two types of information displayed on the display unit 10. The first information is which one of the two battery packs supplies the voltage to the circuit, and the second information is how much the voltage of each battery pack is. In this method, as shown in FIG. 2, the physical position of each battery pack and the position of the display of the operating state of the battery pack correspond to each other, and the user can easily determine which display represents the state of which battery pack. I understand.

As an example of the display, the display showing the operation is shown in FIG.
It is indicated by a circle on the LCD like the operation displays 30 and 31 of
The voltage of the battery is displayed by bar graphs 32 and 33 in five stages. When the first selected battery pack 1 supplies power to the device, the voltage of the battery pack gradually decreases. Here, the operating state of the battery is displayed on the display unit 10 of the LCD, but it is also possible to display the battery state using a device such as an LED.

Here, the voltage and the remaining capacity of the battery will be described.

FIG. 7 is a diagram showing, as an example, the relationship between the open terminal voltage and the remaining capacity of a set of two lithium ion batteries, where the vertical axis represents the voltage and the horizontal axis represents the remaining capacity in%.

This voltage value is an open terminal voltage, and when a current flows, a voltage drop occurs due to internal resistance and the potential drops. Further, it is known that the voltage hardly changes even if the temperature changes due to the characteristics of the lithium-ion battery, and thus it has a feature that there is almost no need to perform temperature correction unlike the NiCd battery. By using this feature, the remaining capacity of the battery can be detected very reliably by measuring the open circuit voltage. Also, when knowing the exact potential, to measure the open circuit voltage,
The battery is temporarily switched to the other battery, and the battery to be measured is detected in the released state, that is, the current value is 0. To measure the approximate remaining capacity, find the average value of the current consumption used in the main circuit in advance, find the drop voltage from this current value and internal resistance, and correct this amount, generally, In the handheld computer, the current consumption does not fluctuate so much as it is limited to a predetermined operation mode, so that the potential can be measured fairly accurately. The battery control unit 7 compares the reference voltage Vref1 with a predetermined reference voltage, and if the open circuit voltage drops to 6.8V, for example, when the voltage of the battery pack 1 can be judged to be dangerous for continuing the operation of the circuit, FET3 and FET3 and FET4 is turned off and FET5 and F
ET6 is turned on to supply power from the battery pack 2 to the circuit. This operation of the battery control unit 7 is transmitted to the main circuit unit 9, and the main circuit unit 9 displays the new state on the display unit 10. That is, the display unit 10 displays that the battery pack 2 is operating.

When the voltage of the battery pack 2 drops and is compared with a predetermined reference voltage Vref2 in the same manner, and it becomes dangerous to continue the operation of the device any more, the main circuit portion 9 causes the battery control portion 7 Based on the information, it is displayed on the display unit 10 that both the battery pack 1 and the battery pack 2 have insufficient voltage. If the voltage is not sufficient, for example, no square element of the bar graph of FIG. 2 is displayed. To more strongly warn of insufficient voltage, control such as blinking the right half or the left half of the display unit 10 corresponding to the position of the battery pack may be performed.
The reference voltages Vref1 and Vref2 may be the same when the battery 1 and the battery 2 have similar capacities and types,
When different types and capacities are used, different reference voltages may be used accordingly. The user needs to stop the operation promptly if the remaining voltages of the two batteries are not sufficient. Otherwise, the voltage supplied to the circuit may be lowered and the device may malfunction or the data in the RAM / RTC 17 may be destroyed.

In the present invention, as a countermeasure against this, the following control is executed. First, the two battery packs are discharged and the user is informed of the occurrence of the state on the display unit 10. Then, the user stops the operation of the apparatus even after a certain time (for example, 1 minute) has elapsed. If not, the main circuit unit 9 executes a predetermined data saving process or the like to stop the operation of the circuit and enter the suspending mode. When the operation of the circuit is stopped, the current consumption of the device is much smaller than that during the operation, and the device continues the suspended state of the main CPU for a predetermined period. The discharge is continued and the potential gradually decreases thereafter. In this state, the minimum operation of the battery control unit 7, for example, the opening of the lid and the check of the attachment / detachment of the battery are executed. When the detection voltage is determined by the Zener diode 33 and the resistors 31 and 32, the output of the comparator 20a is inverted from the H level to the L level, whereby the sub CPU is also suspended and the FET
3, 4, 5, and 6 are turned off, the power supply from the batteries 1 and 2 is stopped, and the power is switched to the backup battery 18. In this state, RAM / RTC
The power of the backup battery is consumed for the backup of 17.

When the user recognizes that the remaining voltage is low in both batteries and operates the power switch, the main circuit section 9 performs a predetermined data saving process based on whether the resume function is set or not. Stop the operation of. At this time, if the remaining voltage of the battery pack that has been supplying power to the circuit during the operation up to that time is sufficient, power is continuously supplied from the battery pack to the battery control unit even when the operation is stopped. In this case, the reference voltage when power supply is stopped may be lower than the reference voltage during normal operation. During normal operation, a relatively high potential is required because a constant voltage is supplied to the main circuit section 9 by a DC / DC converter or the like, but 3V is required for the operation of the battery control section and the backup of the RAM / RTC 17. This is because a low potential may be supplied.

The above process will be described below with reference to the battery supply control. If the battery 1 used at the beginning is not at a level higher than the predetermined reference voltage Vref3, it is determined that the voltage of both batteries is not sufficient, and F
ET3 and FET3, 5 are turned on, FET4, 6 are turned off, and the output of the two battery packs is FET4 and FET.
The parasitic diode of 6 is used to output by the diode OR. When the outputs of the battery pack 1 and the battery pack 2 are OR-coupled by the diodes in parallel with the FET 4 and the FET 6, these diodes supply power to the circuit from the higher voltage of the two battery packs.

For example, when the voltage of the battery pack 1 is higher than the voltage of the battery pack 2, the diode in parallel with the FET 4 is turned on and the diode in parallel with the FET 6 is reverse biased and cut off. In this state, only the battery pack 1 is discharged and the battery pack 2 is not discharged, so that the voltage of the battery pack 1 gradually decreases and the voltage of the battery pack 1 becomes equal to the voltage of the battery pack 2. Then, the diode in parallel with the two FETs 4 and the diode in parallel with the FET 6 are turned on at the same time to supply power from the two batteries to the circuit. Further, since the diode is included, it is possible to prevent current from flowing from a battery having a high voltage to a battery having a low voltage.

Since the reference voltage Vref3 is used to check whether the other battery is charged and recovered, it is set higher than the level for checking the remaining voltage.

The two battery co discharged user after remove either the battery to replace the fully charged battery pack the battery pack. In such a case, since the output of the battery is diode-OR-coupled regardless of which battery pack is removed first, the battery control unit 7 does not control the FET according to the insertion / extraction state of the battery. It is possible to continue supplying power to the circuit while the operation of the device is stopped.

Further, if two battery packs are diode-OR-coupled, power is supplied to the circuit from the battery having the higher voltage, while the power is supplied to the circuit that is not operating with the total capacity of the two battery packs. Can be supplied. By doing so, the backup battery 18
It is possible to prevent unnecessary discharge from the. Since the backup battery 18 usually uses a lithium primary battery in many cases, it is necessary to replace the backup battery 18 when discharged. Therefore, the backup battery 1
It is of great significance to minimize the chance of discharging from No. 8.

The above description is for the case where the voltage of the two batteries drops together and the battery pack is replaced while the device is not operating. However, when the device is stopped and then the device is operated again, the device performs it. Since the work being performed must be interrupted, the work efficiency is reduced. Therefore, if the battery pack can be replaced even when the device is operating, the device can be used continuously without interruption. In order to replace the battery pack during operation, it is necessary to continue operating the device with the other battery even if the battery to be replaced is removed from the device. Therefore, in the above description, the voltage of the battery pack 1 drops and the battery pack 2
It is necessary to replace the battery pack 1 during the period from the switching to the power supply from 1 to the time when the voltage of the battery pack 2 drops.

For example, when the voltage of the battery pack 1 drops while the device is operating with the battery pack 1, the battery control unit 7 cuts off the power supply from the battery pack 1 to the circuit and supplies the power from the battery pack 2 to the circuit. The main circuit unit 9 receives this state change from the battery control unit 7, and the display unit 10 displays information that the battery pack 2 supplies power because the voltage of the battery pack 1 has dropped. The user sees this information and replaces the battery pack.

When the user intends to replace the battery pack when the voltage of the battery pack supplying power to the device is sufficient and the voltage of the other battery pack is low (in the most probable situation) Yes, if the battery with the lower voltage is replaced, the battery pack can be replaced while the device is operating. By repeating this operation, the battery pack can be replaced without interrupting the operation of the device.

The operation described above will be described with reference to a flowchart. In FIG. 5, when the battery pack is first attached and the operation is started, the battery control unit 7 is initialized, and the FET3 and FET5 are first turned on as in step S10.
4, the FET 6 is turned off to execute the parallel combination mode in which the two battery packs are diode-OR-coupled. In the initial state, it is unknown which battery is attached or which voltage is present in which battery, so that diode OR coupling is performed and power is supplied from both battery packs. Subsequently, the battery control unit 7 measures the voltage of the battery pack 1 using the A / D converter 8 in step S12. If the voltage of the battery pack 1 is sufficient, the FET3 and FET4 are turned on as in step S20 and FE
T5, FET6 is turned off to execute the single combined mode for supplying power from the battery pack 1 to the circuit.

In step S12, the battery pack 1
If the voltage is insufficient, then the voltage of the battery pack 2 is measured in step S14. If the voltage of the battery pack 2 is sufficient, the FET3 and FET4 are turned off and the FET5 and FET6 are turned on as in step S18 to turn on the battery pack 2
Power the circuit from. If the voltage of both battery packs is not sufficient, the same parallel coupling mode set in step S10 is maintained to prevent the device from operating. However, since the charged battery pack is eventually inserted, the process returns to step S12 and the voltage of the battery pack is constantly measured even if the voltages of both battery packs are not sufficient. When the voltage is supplied to the circuit from one of the battery packs in steps S20 and S18, the device becomes operable. In step S22, the voltage of the currently selected battery is measured.

When the voltage of the battery pack drops, the voltages of other battery packs are checked next (step S2).
4). If the voltage of another battery pack is sufficient, the battery pack is switched. In step S26, the process continuously returns to step S22 to measure the voltage of the selected battery pack. If the voltage of another battery pack is not sufficient in step S24, the device cannot continue to operate. If the device is operating in step S28, the user is notified that the battery voltage is not sufficient, and then the device operation is stopped. If the device is stopped in step S28, the process skips step S30 of stopping the operation of the device and proceeds to step S32. In step S32, the voltage of both battery packs is not sufficient, so FET3, FE
T5 is turned on, FET4 and FET6 are turned off, and the output of the battery pack is diode-OR-coupled to power supply mode 2
To execute. Then, the process returns to step S12 again to check the voltage of the battery pack.

By supplying power from a plurality of batteries at the same time at the start of the normal operation of the apparatus such as turning on the power, the reliability of the start is ensured. That is, at the time of start, the detection function or the calculation function of the CPU is stopped, and first, a predetermined initialization process is always required, and at this time, power is supplied to all or a plurality of batteries by the OR circuit. Is extremely effective.

Next, consideration will be given to measures for avoiding trouble while the apparatus is in use. If the user accidentally tries to replace the battery pack that is supplying power to the device, the voltage supplied at the moment when the battery pack that supplies power to the device is removed will cause a serious trouble. May occur.

In order to avoid this in the present invention, the following control is executed. The main circuit unit 9 displays on the display unit 10 which battery pack is operating and which battery pack has a voltage drop, so that the user can know the battery pack to be replaced. However, if the lid of the battery pack that is supplying power to the circuit is opened by mistake, the battery control unit 7 will replace the wrong battery pack by the lid detection switch 14 for the battery pack 1 or the lid detection switch 15 for the battery pack 2. The buzzer 11 is sounded when it knows that. By ringing the buzzer, the user can know that he is about to replace the battery pack that is powering the circuit. At the same time, there is a battery pack LED 12 or a battery pack 2 LED 13 which can be seen by the user when the battery pack lid is opened. Each LED is mounted at a position where it is easy to see which battery pack corresponds to which LED.

For example, if the user accidentally opens the lid for the battery pack 2 while trying to replace the battery pack 2 while power is being supplied from the battery pack 2 to the circuit, the battery control unit 7 sends this to the battery pack. The buzzer 11 is made to ring by detecting it by the lid detection switch 15 for 2.
At the same time, the LED 13 for the battery pack 2 is turned on to inform the user that the battery pack 2 is in use. By lighting the buzzer and the LED, the user knows that the wrong battery pack is about to be replaced, and stops the battery replacement. If these LEDs are constantly lit, a current of 10 to 20 mA for illuminating the LEDs is wastefully consumed, so that the battery control unit 7 is lit for a fixed time (for example, 1 minute) only when the user battery pack lid is opened. Controlled by. As a result, it is possible to minimize the useless flow of current from the battery pack.

In some cases, the user may mistakenly replace the battery even if the double or triple warning is given as described above. In that case, malfunction of the device is prevented by the following method. For example, if the user accidentally opens the lid that covers the battery pack 2 while supplying power from the battery pack 2 to the circuit, the battery control unit detects that the battery pack 2 is about to be replaced. Then, first, FET3 and FET5 are turned on, and FET4 and FET6
Is turned off and the battery packs are OR-connected to enter the parallel connection mode. Next, the voltage of the battery pack 1 is detected, and if this potential is at a level at which the device can be operated, that is, higher than the reference voltage 1, the FET3 and FET4 are turned on and the FET is turned on.
5. The FET 6 is turned off to switch the power supply from the battery pack 1 to the circuit. As a result, the operation of the device can be continued with the other battery pack.

In the parallel coupled mode, when the circuit consumes a large amount of power while the device is operating, the parasitic diode causes a large voltage drop due to the forward voltage of the diode, and the voltage actually supplied to the circuit is the battery voltage. It is about 0.7 to 1 V lower than the voltage. In such a case, a type with a large power consumption of the electronic device may not be able to supply a sufficient voltage for continuing the circuit operation.

In consideration of this, the FET 4
Also, a Schottky barrier diode is connected in parallel with the FET 6. The Schottky barrier diode has a low forward voltage of 0.2 to 0.4 V and can supply a higher voltage to the circuit than when a parasitic diode is used.

If the two battery packs are diode-OR-coupled in this manner, the circuit pack can be supplied with electric power from the battery pack with a higher voltage, so that the circuit pack can be erroneously supplied with electric power. Even if the battery pack is removed, the circuit does not malfunction due to the interruption of power supply to the circuit.

If the user is mistakenly trying to replace the battery pack 2 and the battery pack 1 is not installed or the voltage of the battery pack 1 is not sufficient to operate the device, the battery control unit 7 Detects that the lid of the battery pack 2 has been opened by the lid detection switch 15 for the battery pack 2, performs a saving operation of predetermined data, and stops the operation of the circuit. In this way, even if the battery pack 1 is accidentally removed, the circuit operation is stopped and the circuit does not malfunction.

FIG. 6 is a flow chart when the battery pack lid is opened. When the lid for the battery pack is opened, a switch interlocking with the lid is activated, and the sub CPU 7a
An interrupt signal is generated at. When the interrupt signal is generated, it is first checked in step S50 which battery pack lid is open. Next, in step S52, FET3, F
The ET5 is turned on, the FET4 and the FET6 are turned off, and the output of the battery pack is diode-OR-coupled to prevent erroneous operation. In step S54, it is confirmed whether power is being supplied to the device from the battery pack with the lid opened. If power is not being supplied to the device from the battery pack with the lid opened, the operation of the device is not affected even if the battery pack is removed, so the state of the FET is returned to the original state in step S66 and the interrupt process is returned.

When power is supplied to the apparatus from the battery pack with the lid open, the operation of the apparatus suddenly stops when the battery pack is removed. Therefore, switch the battery pack or operate the apparatus. Need to stop. Therefore, in step S56, the buzzer sounds and the corresponding LED is turned on to warn the user. Then, in step S58, it is confirmed whether the voltage of the other battery pack is sufficient. If the voltage of the other battery pack is insufficient, the operation cannot be continued if the battery pack with the open lid is removed, and therefore a predetermined data saving process is executed in step S64 to stop the operation of the apparatus. Even if the voltage of other batteries is sufficient, step S60
If it is confirmed that the lid of the other battery pack is open, the operation of the device cannot be guaranteed to continue even if the battery pack is switched to another battery pack. Therefore, in step S64, the operation of the device is stopped and interrupt processing is performed. Return from.

If the voltage of the other battery pack is sufficient and the lid is closed, the battery pack can be switched. Therefore, the process proceeds to step S62, the battery pack is switched to another battery pack, and the interrupt processing is returned. In the above embodiment, the case where the number of battery packs is two has been described, but the case where the number of battery packs is three or more can be realized with the same configuration. Although the battery pack has been described as a lithium-ion secondary battery, it can be also realized by a nickel-cadmium battery, a nickel-hydrogen battery, a lead storage battery, or the like. (However, accurate residual quantity detection by voltage measurement is possible only for lithium-ion batteries and lead-acid batteries)

[0057]

As described above, according to the present invention, in an electronic device having a plurality of batteries, the removal of the batteries is detected in advance, and the plurality of batteries are temporarily OR-coupled to generate electric power. By supplying the power supply, it is possible to realize a battery control circuit capable of continuing the process being executed at that time and ensuring a data save time.

[Brief description of drawings]

FIG. 1 is a schematic diagram of a battery controller and a computer device in one embodiment of the present invention.

FIG. 2 is a diagram showing a display unit of the apparatus of the embodiment.

FIG. 3 is a view showing the back surface of the apparatus of the embodiment.

FIG. 4 is a diagram when the battery lid is removed in the device of the embodiment.

FIG. 5 is a flowchart showing control during normal operation in the apparatus of the embodiment.

FIG. 6 is a flow chart showing control when the battery lid is opened in the device of the embodiment.

FIG. 7 is a diagram showing a relationship between an open circuit voltage and a remaining capacity of a lithium ion battery used in the present invention.

[Explanation of symbols]

 1, 2: Battery pack 3, 4, 5, 6: FET 7: Battery control unit 8: A / D converter 9: Main circuit unit 10: Display unit 11: Buzzer 14: Lid detection switch for battery pack 15: Lid detection switch for battery pack 16: IO unit 17: RAM / RTC 18: Sub battery for backup

Claims (1)

[Claims] 1. A plurality of main batteries as main power sources, a main circuit section, switch means connected to respective output terminals of the plurality of main batteries, and power control means for individually controlling the switch means. , A voltage detecting means for measuring the voltage of the main battery, a plurality of lids provided in a portion accommodating the main battery corresponding to the plurality of main batteries, and detecting opening / closing of the lids corresponding to the lids. In an electronic device having a plurality of lid detectors, the power control means selects one main battery from the plurality of main batteries and supplies power to the main circuit unit of the electronic device. An electronic device having a control means for turning on the plurality of switch means and OR-connecting the plurality of main batteries when the open state of the lid of the main battery is detected.