JP2000041341A - Power supply control method and electronic equipment driven by secondary battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power supply control method and electronic equipment driven by a secondary battery capable of safely operating without stopping instantaneously power supply of an equipment main unit, when a high load accessory is connected to the electronic equipment driven by the secondary battery. SOLUTION: An accessory detection part 54 detects the connection of an accessory 10. An end voltage correction part 51 corrects end voltage of a battery by using a correction value from an end voltage correction ROM 43. A battery voltage detection part 53 detects voltage of the battery. A comparator 52 compares an end voltage preset value or its correction value with battery detection value detected by the battery voltage detection part 53. An end processing part 56 performs an end process in accordance with a comparison result in the comparator 52. This end processing part 56 performs not only simply to disconnect power supply but also to conduct necessary suspending processes such as ending a recording process, when it is halfway in recording.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power supply control method when a high-load accessory is connected to an electronic device main body driven by a secondary battery, and to a secondary battery-driven electronic device.

[0002]

2. Description of the Related Art Conventionally, in an electronic device driven by a secondary battery (hereinafter, referred to as a battery), a voltage for determining the end of battery operation (hereinafter, referred to as a battery) is determined by a change in power or the presence or absence of accessories.
Without changing the battery end voltage), the power was turned off when the voltage became constant.

[0003]

By the way, there is no problem in an apparatus having a constant power, but in an electronic apparatus to which an accessory of a type supplying power from a main body is connected, a large current flows to the accessory side. In some cases, the battery voltage may drop momentarily, exceeding the power supply capability, and the power supply may suddenly drop. In this case, since the power is turned off without performing a proper power-off procedure of the device, there is a possibility that the inside of the device may be adversely affected. For example, when such a state occurs in a video camera recorder, a digital still camera, or the like, there is a possibility that the recording medium may be damaged or destroyed.

Therefore, the battery end voltage is usually set higher than the operation limit voltage of the battery with a margin rather than being used to the very end of the battery capacity. In general, it is safer to set the battery end voltage higher as the power consumption increases and the instantaneous rush current increases.

[0005] However, if the battery end voltage is set to a high value in accordance with a high load for safety and when an accessory is connected, the battery can be operated even when operated at a low load or when there is no accessory. However, the power is turned off, and the battery energy cannot be sufficiently extracted.

The present invention has been made in view of the above-mentioned circumstances, and when a high-load accessory is connected to a rechargeable battery-powered electronic device, the power supply of the device main body does not stop instantaneously and can be safely performed. An object of the present invention is to provide a power supply control method and a secondary battery-driven electronic device that can be operated.

It is another object of the present invention to provide a power supply control method and a secondary battery-driven electronic device in which accessories are not attached to the secondary battery-driven electronic device and sufficient energy of the battery can be taken out even at a low load. And

[0008]

In order to solve the above-mentioned problems, a power supply control method according to the present invention is a power supply control method for a secondary battery-driven electronic device driven by a secondary battery. Accessory detecting step, an operation end voltage correcting step of correcting an operation end determining voltage of the secondary battery based on a detection result of the accessory connection in the accessory detecting step, and a voltage detection of detecting a voltage of the secondary battery And a termination processing step of comparing the operation termination determination voltage corrected in the termination voltage correction step with the voltage detected in the voltage detection step, and performing termination processing of the secondary battery according to the comparison result. Prepare.

Here, the operation end voltage correction step is performed based on the result of the accessory type detection in addition to the accessory connection detection result in the accessory detection step.
When a high-load accessory is connected, the operation end determination voltage is corrected to be higher.

[0010] The secondary battery-driven electronic device according to the present invention comprises:
In order to solve the above-mentioned problems, in a secondary battery-driven electronic device driven by a secondary battery, an accessory detecting means for detecting connection of an accessory, and the secondary battery based on a connection detection result from the accessory detecting means. End voltage correction means for correcting the operation end determination voltage, secondary battery voltage detection means for detecting the voltage of the secondary battery, operation end determination voltage corrected by the end voltage correction means, and the secondary battery voltage Comparing means for comparing with the secondary battery voltage detected by the detecting means, and termination processing means for performing termination processing of the secondary battery according to the comparison result of the comparing means.

In this case, there is provided an accessory type determining means for determining the type of the connected accessory, and the accessory detecting means and the accessory type determining means comprise:
When it is determined that a high-load accessory is connected, the end voltage correcting means corrects the operation end determination voltage of the secondary battery to a higher value.

Therefore, even when a high-load accessory is used, the power can be safely turned off without suddenly turning off during operation.

In addition, during high-load operation, the power supply can be safely turned off while the battery has sufficient capacity, and during low-load operation, the apparatus can be operated to the limit of the battery capacity.

[0014]

Embodiments of the present invention will be described below with reference to the drawings.

First, a specific example of a secondary battery (battery) driven electronic device is shown in FIG. This specific example is a video camera recorder 1 which is driven by a battery 2 and can connect a floppy disk adapter 10 shown in FIG. Here, the battery 2 is a lithium ion battery or the like.

A floppy disk adapter 10 is a floppy disk drive 11 for recording and reading video data on a floppy disk (not shown).
By inserting the memory slot connection portion 13 connected by the cable 12 into the card slot portion 3 of the video camera recorder 1, for example, an image captured by the video camera recorder 1 or a magnetic tape attached An already recorded image can be recorded.

Since power is supplied to the floppy disk adapter 10 from the battery 2 of the video camera recorder 1, the power load on the main body greatly changes depending on whether or not the floppy disk adapter 10 is connected. As such a high-load accessory, a video light, a flash light, or the like may be considered.

FIG. 3 shows the overall circuit configuration of the video camera recorder 1. This video camera recorder 1
An imaging unit 21 for imaging a subject, a line-in signal processing circuit 22 for performing processing for line-in, and an interface for signals from the imaging unit 21 and the line-in signal processing circuit 22 and an I / F / image MI for performing image mixing processing
An X circuit 23 is provided.

The video camera recorder 1 includes a recording / reproducing signal processing circuit 24 of a DV system according to the digital video standard for home use, a display device 26 such as a liquid crystal display for displaying information signals, and an information device. A recording unit 25 for recording signals on a recording medium such as a DV tape.

Here, the recording section 25 records the information signal from the DV recording / reproducing signal processing circuit 24 on a DV tape, and conversely, the information signal recorded by the DV recording / reproducing signal processing circuit 24 from the DV tape. read out.

Further, the video camera recorder 1 is a
EG / Motion JPEG compression / decompression circuit 29 and PCMC
IA (personal computer memory card international
association) I / O / ATA (AT attachment) I / F
A processing circuit 30 is also provided.

Here, the PCMCIA standard is PCMCIA standard.
This is a so-called PC card interface standard defined by the IA. AT is a so-called PC / AT
A standard for connecting a compatible processor and a hard disk.

The JPEG / Motion JPEG compression / decompression circuit 29 decompresses a JPEG standard still image or an encoded image of a Motion JPEG standard moving image into an image signal, and converts a still image or a moving image image signal into the above standard code. This is a circuit that compresses the image. The JPEG / Motion JPEG compression / decompression circuit 29 is used for the I / F / image MIX circuit 23 or P / P
The above processing is performed on the image signal or the encoded image from the CMCIA I / O / ATA I / F processing circuit 30.

The PCMCIA I / O / ATA I / F processing circuit 30 is a circuit that provides an interface between the coded image from the JPEG / Motion JPEG compression / decompression circuit 29 and the floppy disk adapter 10.
Specifically, the PCMCIA I /
Since the O standard or the ATA I / F standard is used, a conversion process or the like corresponding to the above standard is performed.

Then, this video camera recorder 1
An operation key block 27 for performing an input operation on the video camera recorder 1 is provided, and a control circuit 28 for controlling each part of the video camera recorder 1, particularly, a power supply control method according to the present invention. As the control circuit 28, for example, a microcomputer including a CPU, a RAM, a ROM, and the like is used. The execution of the power control method by the microcomputer serving as the control circuit 28 will be described later.

In the video camera recorder 1, usually,
The recording unit 25 is used to record an imaging signal from the imaging unit 21 and a line-in signal on a DV tape. In the case of this recording, the DV signal subjected to the recording signal processing by the DV recording / reproducing signal processing circuit 24 is recorded on a DV tape.

When recording the signal via the imaging unit 21 and the line-in signal processing unit 22 on a floppy disk, the JPEG / Motion JPEG compression / expansion circuit 29 performs a compression process on a JPEG for a still image and a Motion JPE for a moving image.
G, and performs PCMCIA I / O or ATA signal processing I / F processing of the PCMCIA I / O / ATA I / F processing circuit 30, sends data to the floppy disk drive 11 through the memory slot connection unit 13, and sends data to the floppy disk drive 11. To record.

When an image or the like recorded on a DV tape is downloaded to a floppy disk by the recording unit 25, the data recorded on the DV tape is transferred to the floppy disk according to the key operation of the operation key block 27 and the control of the control circuit 28. The data is sent to the adapter 10 and recorded on a floppy disk.

Next, FIG. 4 shows a configuration of a main part 5 having a control circuit 28 for executing the power supply control method. This main part is hereinafter referred to as main part 5 of the video camera recorder.

A specific example of the power supply control method executed by the video camera main part 5 is to detect the connection when the floppy disk adapter 10 which is a high-load accessory is connected to the video camera recorder 1 driven by the battery 2. This is a power supply control method in which the value of the operation end determination voltage in the battery 2 is corrected, and when the voltage of the battery 2 reaches the corrected voltage value, the battery end processing is performed.

In the power supply control method of the video camera recorder, in the operation end voltage correction step, in addition to the correction of the battery operation end voltage depending on the presence or absence of the floppy disk adapter 10, communication between the battery and the main body is performed as described later. Thereby, a correction value of the operation end determination voltage according to the characteristics of the battery cell is obtained.

Further, the power supply control method of the video camera recorder determines a condition when a high-load accessory is connected, and when the condition is satisfied, corrects the battery operation end determination voltage to a higher value. Good.

That is, a specific example of this power supply control method is as follows.
An accessory detection step of detecting an accessory connection, an operation end voltage correction step of correcting an operation end determination voltage of the secondary battery based on a result of the accessory connection detection in the accessory detection step, and a voltage of the secondary battery And comparing the operation end determination voltage corrected in the end voltage correction step with the voltage detected in the voltage detection step, and performing the end processing of the secondary battery according to the comparison result. And a termination processing step.

The main part 5 of the video camera recorder which executes the power control method of the video camera recorder is composed of a microcomputer 41 and a microcomputer 4.
A power control unit 42 for controlling the power supply to the accessory 10 based on the control of 1; an end voltage correction ROM 43 storing a correction value used when correcting an operation end voltage (end voltage) inside the microcomputer 41; It has. The accessory 10 is assumed to be a floppy disk adapter 10.

As shown in FIG. 5, the microcomputer 41 includes an accessory detector 54 for detecting the connection of the accessory 10, an accessory type determiner 55 for determining the type of the connected accessory, and the end voltage correction ROM 43. An end voltage corrector 51 that corrects the end voltage of the battery using the correction value, a battery voltage detector 53 that detects the voltage of the battery, and an end voltage set value or the correction value and the battery voltage detector 53 detect Comparator 52 for comparing with battery detection voltage
And an end processing unit 56 that performs an end process via the power supply control unit 42 in FIG. 4 according to the comparison result in the comparator 52. The end processing unit 56 performs not only the power-off but also a necessary evacuation process such that the recording process is terminated during the recording.

The microcomputer 41 measures the voltage and remaining amount of the battery 2 by using the battery voltage detecting section 53, and when the voltage of the battery 2 becomes lower than the battery end voltage (the minimum voltage value at which the main body can safely operate). ,
The end processing unit 56 is caused to perform end processing via the power supply control unit 2.

In normal use, the battery end voltage is set with a margin with respect to the operation limit voltage of the video camera recorder 1 body. However, when the floppy disk adapter 10 is connected as an external accessory as described above, or when the external accessory is connected and the operation is switched from off to on, the load on the main body increases and the voltage of the battery 2 increases. It drops sharply. In the worst case, it is conceivable that the voltage of the battery 2 instantaneously becomes higher than the operation limit voltage of the main body, and the main body stops momentarily. In this case, since the power is turned off without performing a proper power-off procedure of the apparatus, there is a possibility that the inside of the apparatus may be adversely affected. Video camera recorder 1
In such a state, there is a possibility that the recording medium may be damaged or destroyed.

In order to prevent this, it is generally necessary to increase the margin of the battery end voltage with respect to the operation limit voltage of the main body. The relationship between the operation limit voltage and the battery end voltage will be described with reference to FIG.

As shown in FIG. 6, normally, the operation end voltage of the device is set with a margin with respect to the operation limit voltage of the device. This is because the end processing of the operation is performed between the time when the device reaches the end voltage and the time when the device is turned off.

If this margin is not set and the operation limit voltage of the apparatus is equal to the end voltage, not only is it unfriendly to the user, but also the power is suddenly cut off from the operation state, which adversely affects the inside of the apparatus. For example, in the video camera recorder, digital still camera, portable personal computer, and the like, there is a possibility that the recording medium is damaged.
Therefore, the power is turned off after the end process for safely turning off the power is performed. The end voltage is set with a margin to the operation limit voltage so that the operation can be performed for a sufficient time for the end processing. In general, the operation limit voltage of the device is substantially equal to the lower limit of the voltage range in which the battery operates as a power supply.

However, if the margin of the battery end voltage is increased, the operation time of the main body when using without the accessory is shortened.

Therefore, the microcomputer 41 shown in FIG. 5 monitors the connection of the floppy disk adapter 10 by using the accessory detecting section 54, and corrects the battery end voltage by the end voltage correcting section 51 depending on whether or not the floppy disk adapter 10 is connected. And battery 2
The operation end is determined by the voltage of. Thus, when there is no high-load accessory (floppy disk adapter) 10 (low load), the capacity of the battery is used without waste, and when the high-load accessory 10 is connected (high load), there is a sufficient margin. Ensure that the main unit operates within a safe operating voltage range.

FIG. 7 shows a discharge characteristic curve of the battery. A normal discharge curve is represented by a solid line, and a voltage effect due to accessory operation is represented by a wavy line. In normal operation, the battery end point is point a. Now, consider a state in which end voltage correction is not considered at all. If an accessory is connected and operated during normal operation near point b of the battery end, the voltage of the battery will momentarily fall below the operation limit operation of the device due to a voltage drop due to the accessory operation, and the power supply will drop.

Therefore, when the accessory is connected, the end voltage is corrected. If the amount of end voltage correction due to accessory connection is set to be equal to or greater than the voltage drop due to accessory operation near the end voltage, even if the accessory suddenly operates just before the end point c at the time of accessory connection, the battery voltage will be normal operation (Only when there is no accessory) It drops only to the vicinity of the end voltage, and the end process is performed as it is. A voltage margin for end processing can be secured.

At this time, the detection of the accessory and the voltage correction must be completed before the accessory operates. This is because, when accessories are connected and operated during operation between ca and a, the battery voltage may become lower than the operation limit voltage of the device. At this time, if the detection of the accessory and the correction of the end voltage are completed before the operation of the accessory, the voltage of the battery is equal to or lower than the end voltage, so that the end process is started and the power is safely turned off.

The battery end determination process in the main part 5 of the video camera recorder will be described below with reference to FIG. First, in step S <b> 1, the microcomputer 41 measures a power supply voltage from the battery cell 2 a of the battery 2 using the battery voltage detection unit 53.

Next, in step S2, the connection of the accessory is detected using the accessory detection unit 54. If the connection of the accessory is detected, the process proceeds to step S3, and a process for determining a battery correction voltage is started. If the connection of the accessory cannot be detected, the process proceeds to step S5.

In the process of determining the battery correction voltage in step S3, the comparator 52 compares the voltage of the battery cell 2a with the correction voltage of the accessory to determine the correction voltage. The correction voltage of the accessory is determined by the end voltage correction unit 51 using the correction value from the ROM 43 based on the detection result of the accessory connection and the type determination result of the accessory type determination unit 55.

As shown in step S4, the battery end voltage (the initial voltage) is an end voltage when no accessories are provided + a correction voltage. When the battery end voltage is determined, the process proceeds to step S5 to enter a battery end detection process based on the voltage. If the battery end is determined in step S6, the process proceeds to step S7 to perform the battery end process. Turn off.

If it is determined in step S6 that the voltage is not the battery end voltage, the process returns to step S1 and repeats from the measurement of the power supply voltage. Microcomputer 41 and battery 2
When communication is not performed between the cells, the same processing is performed assuming that the correction voltage of the cell is zero.

From the above, it can be said that the power supply control method of the video camera recorder executed by the microcomputer 41 of the main part 5 is particularly suitable for the type of accessory that operates from time to time.

Other examples include a digital still camera, a video light of a portable computer, a flash light, and a floppy disk adapter.

As another specific example, in addition to the correction of the battery operation end voltage depending on the presence or absence of the floppy disk adapter 10, as described above, communication between the battery and the main body is performed to meet the characteristics of the battery cell. A main part 6 of the video camera recorder shown in FIG. 9 that executes a power control method of the video camera recorder that obtains the correction value of the operation end determination voltage can be given. The main part 6 of the video camera recorder has a battery microcomputer 2b in addition to the battery cell 2a inside the battery 2. The state of the battery is sent to the microcomputer 41 by communication, and the video camera recorder 1 can be operated with cells having various characteristics by providing a battery end voltage according to the characteristics of the battery cell 2a.

[0054]

As described above, according to the present invention,
When a high-load accessory is connected to the secondary battery-driven electronic device, the power supply of the device main body can be safely operated without being momentarily stopped.

In addition, it is possible to sufficiently extract the energy of the battery even when the load is low without accessories attached to the secondary battery-driven electronic device.

Further, when combined with the battery characteristic determination, the battery can be used without wasting energy according to various conditions such as the type of power supply, accessories, and load, and without fear of power interruption.

[Brief description of the drawings]

FIG. 1 is an external perspective view of a video camera recorder as a specific example of a battery-driven electronic device.

FIG. 2 is an external perspective view showing a state in which a floppy disk adapter which is a high-load accessory is connected to the video camera recorder.

FIG. 3 is a block diagram showing an overall circuit configuration of the video camera recorder.

FIG. 4 is a block diagram showing a configuration of a main part of the video camera recorder that executes a specific example of the power supply control method of the present invention.

FIG. 5 is a block diagram showing a detailed configuration of a microcomputer included in a main part of the video camera.

FIG. 6 is a discharge characteristic diagram of a battery near an operation end for explaining a relationship between an operation limit voltage and a battery end voltage.

FIG. 7 is a discharge characteristic diagram of a battery.

FIG. 8 is a flowchart illustrating a battery end determination process in a main part 5 of the video camera recorder.

FIG. 9 is a block diagram showing a configuration of another specific example for executing a power supply control method of a video camera recorder that obtains a correction value of an operation termination determination voltage according to characteristics of a battery cell by performing communication between a battery and a main body. FIG.

[Explanation of symbols]

1 video camera recorder, 2 batteries, 10 floppy disk adapter, 41 microcomputer, 42 power supply control unit, 43 end voltage correction ROM,
51 end voltage correction unit, 52 comparator, 53 battery voltage detection unit, 54 accessory detection unit, 55 accessory type determination unit, 55 end processing unit

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2H002 BB01 BC01 BC07 BC11 EB00 GA73 HA06 HA07 JA07 JA08 5C022 AA00 AB40 AC69 AC73 AC78 5G003 DA02 DA14 EA06 GC05

Claims (7)

[Claims] 1. A power supply control method for a secondary battery-driven electronic device driven by a secondary battery, comprising: an accessory detection step of detecting an accessory connection; and an accessory connection detection result in the accessory detection step. An operation end voltage correction step of correcting the operation end determination voltage of the secondary battery, a voltage detection step of detecting the voltage of the secondary battery, an operation end determination voltage corrected in the operation end voltage correction step, and the voltage detection A power supply control method comprising: comparing the voltage detected in the step with the voltage detected in the step; and performing a termination processing of the secondary battery according to a result of the comparison. 2. The operation end voltage correction step is performed based on the accessory connection detection result in the accessory detection step and the discrimination result of the accessory type when the high load accessory is connected. 2. The power supply control method according to claim 1, wherein the voltage is corrected to be higher. 3. The operation end voltage correction step of obtaining a correction value of an operation end determination voltage according to characteristics of a secondary battery cell by performing communication with the secondary battery. 2. The power supply control method according to 1. 4. In a secondary battery driven electronic device driven by a secondary battery, an accessory detecting means for detecting connection of an accessory, and the operation of the secondary battery being terminated based on a connection detection result from the accessory detecting means. End voltage correction means for correcting the judgment voltage, secondary battery voltage detection means for detecting the voltage of the secondary battery, operation end judgment voltage corrected by the end voltage correction means, and the secondary battery voltage detection means A secondary-battery-driven electronic device comprising: comparison means for comparing a detected secondary battery voltage; and termination processing means for performing termination processing of the secondary battery in accordance with a comparison result of the comparison means. . 5. The secondary battery-driven electronic device according to claim 4, further comprising an accessory type determining means for determining a type of the connected accessory. 6. When the accessory detecting means and the accessory type determining means determine that a high-load accessory is connected, the end voltage correcting means corrects the operation end determination voltage of the secondary battery to a higher value. The secondary battery-driven electronic device according to claim 5, wherein 7. The ending voltage correcting unit obtains a correction value of an operation ending determination voltage according to characteristics of a secondary battery cell by performing communication with the secondary battery. 4. The secondary battery-driven electronic device according to 4.