JP2003249270A - Battery checker - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To decide the residual quantity of electricity of a battery correctly by electrifying an inductive load. <P>SOLUTION: In a battery checker which decides the residual quantity of electricity of the exchangeable battery 1 electrifying the inductive load 4, the terminal voltage and magnetic leakage flux of the inductive load 4 are detected, and by converting the detected magnetic leakage flux into electric current, the residual quantity of the battery 1 is decided based on the terminal voltage and the converted electric current. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a battery check device for checking the remaining capacity of a battery.

[0002]

2. Description of the Related Art A battery check current, which is smaller than a normal shutter drive current, is applied to a shutter coil,
2. Description of the Related Art There is known a battery check device that checks the remaining capacity of a battery by measuring the voltage generated across the shutter coil (for example, see Japanese Patent Laid-Open No. 2000-065907).

[0003]

However, in the conventional battery check device, the shutter coil, which is formed by winding a copper wire in a coil shape, is used as a load to pass a current, and the voltage across the shutter coil is measured. There is a problem in that the resistance value changes greatly and the determination result differs depending on whether the battery check is performed indoors or outdoors, and the remaining amount cannot be accurately determined.

It is an object of the present invention to provide a battery check device which can accurately determine the remaining battery level by energizing an inductive load.

[0005]

(1) The invention of claim 1 is applied to a battery check device for determining the remaining amount of a replaceable battery for energizing an inductive load, and a terminal voltage of the inductive load and The leakage magnetic flux is detected, the detected leakage magnetic flux is converted into a current, and the remaining amount of the battery is determined based on the terminal voltage and the converted current. (2) According to the invention of claim 2, an inductive load energized from a replaceable battery, a voltage detecting means for detecting a terminal voltage of the inductive load, and a magnetic detection for detecting a leakage magnetic flux of the inductive load. Means, conversion means for converting the leakage magnetic flux detected by the magnetic detection means into the current of the inductive load, and determining the remaining amount of the battery based on the voltage detected by the voltage detection means and the converted current by the conversion means. And a remaining amount determining means for performing the operation. (3) In the battery check device according to claim 3, an opening / closing means is provided between the battery and the inductive load to switch between energization and non-energization of the battery to the inductive load, and the voltage detection means The magnetic detection means detects the terminal voltage and the leakage magnetic flux at the time of energization and de-energization, and the remaining amount determination means determines the internal resistance of the battery based on the detected voltage and the converted current at energization and de-energization. When the calculated internal resistance exceeds the battery remaining amount determination reference value, it is determined that the battery has insufficient remaining amount. (4) In the battery check device of the fourth aspect, the magnetic detection means is a Hall element.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment in which the present invention is applied to a battery check device for a camera will be described. In addition,
The present invention is not limited to the battery check device of the camera, but is applied to the battery check device of many other devices.

FIG. 1 shows the configuration of one embodiment. The battery 1 is a power source that supplies electric power to various electric devices and circuits of the camera. Note that r0 is the internal resistance r0 of the battery 1. Microprocessor unit (hereinafter M
PU) 2 is a microcomputer and memory, A
It is composed of peripheral parts such as / D converter and controls various electric devices and circuits of the camera.

The transistor switch 3 is the battery 1
Is a switch for switching between energization and de-energization from the solenoid coil 4 to the solenoid coil 4. The MPU 2 controls ON (closed circuit) and OFF (open circuit). In this embodiment, the transistor switch 3 is used to switch between energization and de-energization of the solenoid coil 4, but a semiconductor switching element such as FET or SCR or a relay can be used instead of the transistor switch 3.

The solenoid coil 4 is a coil for locking the traveling of the shutter curtain, and is an inductive load of the battery 1. The connection point between the transistor switch 3 and the solenoid coil 4 is connected to the A / D conversion terminal of the MPU 2.

In this specification, we have inductance
Electrical devices such as solenoid coils and motors that receive power from batteries are called inductive loads. In addition, in this embodiment, the shutter driving solenoid coil 4 will be described as an example of the inductive load of the battery 1, but the inductive load of the battery 1 is not limited to the shutter driving solenoid coil 4. It may be a motor for feeding a film.

The magnetic sensor 5 is an element that detects a magnetic amount and outputs a voltage according to the magnetic amount, and is an A / D of the MPU 2.
It is connected to the conversion terminal. In this embodiment, an example in which a Hall element is used for the magnetic sensor 5 is shown, but the magnetic sensor 5 is not limited to a Hall element, and for example, a magnetoresistive element (MR element) whose resistance value changes according to the amount of magnetism, etc. Can be used. Alternatively, for example, a coil may be installed near the inductive load, and the voltage induced in the coil by the mutual induction action with the inductive load may be detected.

Next, the principle of checking the remaining amount of the battery 1 will be described. FIG. 2 shows the discharge characteristics and changes in internal resistance of a general battery. The vertical axis of the figure is the battery voltage (V)
Represents the internal resistance (Ω), and the horizontal axis represents the duration (h). The discharge characteristic in the figure shows the voltage change under no load, and the discharge characteristic shows the voltage change under load. The broken line shows the change in the internal resistance of the battery. As is clear from these characteristics, the internal resistance sharply increases at the time when the battery voltage sharply decreases, and it is considered that the remaining amount of the battery is insufficient at the time when the internal resistance sharply increases. Therefore, the remaining amount of the battery can be determined almost accurately by monitoring the internal resistance of the battery.

In FIG. 1, the terminal voltage E of the solenoid coil 4 in the state where the switch 3 is turned off, that is, the state where the solenoid coil 4 is not energized is input to the MPU 2 via the A / D conversion terminal. Next, the terminal voltage EL of the solenoid coil 4 in the state in which the switch 3 is turned on, that is, the electric power of the battery 1 is supplied to the solenoid coil 4 and the current i = IL flows in the solenoid coil 4, is set to the A / D conversion terminal. Via MPU2. The internal resistance r0 of the battery 1 is expressed by the following equation.

## EQU1 ## r0 = (E-EL) / IL

That is, if the current IL during energization can be detected in addition to the terminal voltage E during energization of the solenoid coil 4 and the terminal voltage EL during energization, the internal resistance r0 of the battery 1 can be calculated by Equation 1. it can. Therefore, in this embodiment, the leakage magnetic flux of the solenoid coil 4 is detected to detect the current IL flowing through the solenoid coil 4.

FIG. 3 shows the characteristics of the current and the leakage magnetic flux flowing in a general inductive load such as a coil and a motor. As is clear from this characteristic diagram, the current flowing through the inductive load and the leakage magnetic flux are in a proportional relationship. Therefore, if the leakage magnetic flux of the inductive load is measured, it can be converted into the current flowing through the inductive load.

FIG. 4 shows a method for detecting the leakage magnetic flux of the solenoid coil 4 according to one embodiment. When an electric current is applied to the solenoid coil 4 in the direction of the arrow, a magnetic force line, that is, a leakage magnetic flux is generated as indicated by a broken line. If this magnetic flux leakage is detected by the magnetic sensor 5, the current value IL flowing through the solenoid coil 4 can be known from the characteristic diagram shown in FIG.

Then, the terminal voltage E when the solenoid coil 4 is not energized, the terminal voltage EL when it is energized, and the current IL when it is energized are substituted into equation 1 to calculate the internal resistance r0 of the battery 1. By repeatedly obtaining the internal resistance r0 of the battery 1 in such a procedure and constantly monitoring the internal resistance r0, as shown in FIG.
If a point in time at which the battery rapidly increases is found, it can be determined that the battery 1 has run out of remaining capacity at that point.

FIG. 5 is a flow chart showing a battery check program executed by the MPU 2. The operation of the embodiment will be described with reference to this flowchart. In step 1, the switch 3 is turned off to bring the solenoid coil 4 into the non-energized state, and in step 2, the terminal voltage E of the solenoid coil 4 when not energized is taken in from the A / D conversion terminal.

In step 3, the output voltage of the magnetic sensor 5 is fetched from the A / D conversion terminal and stored in advance as table data from the characteristic diagram of the voltage-converted leakage magnetic flux with respect to the current of the solenoid coil 4 shown in FIG. The current value B corresponding to the detected voltage value corresponding to the leakage magnetic flux is calculated by looking up.
The current i does not flow when the solenoid coil 4 is not energized, and the current value B detected in step 3 is the offset of the magnetic sensor 5.

In step 4, the switch 3 is turned on to supply the solenoid coil 4 with the current from the battery 1. In the following step 5, the terminal voltage EL of the solenoid coil 4 when energized is taken in from the A / D conversion terminal. In step 6, the output voltage of the magnetic sensor 5 is fetched from the A / D conversion terminal, and the current value BL corresponding to the detected voltage value corresponding to the leakage magnetic flux is looked up from the table data shown in FIG. Then, in step 7, the switch 3 is turned off.

Next, in step 8, the solenoid coil 4
The internal resistance r0 of the battery 1 is calculated by the following equation using the terminal voltage E and the current value B when the current is not applied and the terminal voltage EL and the current value BL when the current is applied.

## EQU00002 ## r0 = (E-EL) / (B-BL) In Expression 2, (B-BL) is a value for correcting the offset of the magnetic sensor 5 when not energized to obtain a correct energizing current IL. .

Battery 1 calculated in step 9
The internal resistance r0 of is compared with the battery residual amount determination reference value. This battery residual amount determination reference value is an internal resistance value determined to be insufficient battery residual amount obtained from the residual amount characteristic of the battery 1 shown in FIG. 2 described above. When the internal resistance r0 of the battery 1 is larger than the battery residual amount judgment reference value, the routine proceeds to step 10, where it is judged that the battery 1 has no residual amount and the battery residual amount warning display is performed. On the other hand, when the internal resistance r0 of the battery 1 is less than or equal to the battery residual amount determination reference value, the process proceeds to step 11 and the battery 1
The battery level warning is not displayed because it is determined that the remaining battery level is left.

As described above, when the battery 1 is checked with the solenoid coil 4 as a load, the magnetic sensor 5 detects the leakage magnetic flux of the solenoid coil 4 and converts the detected leakage magnetic flux into a current flowing through the solenoid coil 4. Therefore, the internal resistance r0 of the battery 1 is calculated and the remaining amount of the battery 1 is determined.
It is possible to accurately determine the internal resistance r0 of the battery 1 without being affected by the operating environment temperature, and it is possible to accurately determine the remaining amount of the battery 1.

Correspondence between the constituent elements of the claims and the constituent elements of the embodiment is as follows. That is,
The solenoid coil 4 constitutes an inductive load, the MPU 2 constitutes a voltage detecting means, a converting means and a remaining amount determining means, the magnetic sensor 5 constitutes a magnetic detecting means, and the transistor switch 3 constitutes an opening / closing means. Note that each component is not limited to the above configuration as long as the characteristic function of the present invention is not impaired.

[0025]

As described above, according to the present invention, the remaining amount of the battery can be accurately determined without being affected by the ambient temperature of use.

[Brief description of drawings]

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

FIG. 2 is a diagram showing a discharge characteristic and a change in internal resistance of a general battery.

FIG. 3 is a diagram showing a relationship between a current flowing through a coil and a leakage magnetic flux.

FIG. 4 is a diagram showing a method for detecting leakage magnetic flux of a coil.

FIG. 5 is a flowchart showing a battery check program according to an embodiment.

[Explanation of symbols]

1 battery 2 Microprocessor unit (MPU) 3 transistor switch 4 solenoid coil 5 Magnetic sensor

Continued front page    F-term (reference) 2G016 CA04 CB01 CB06 CB11 CB12                       CC01 CC03 CC04 CC06 CC12                       CC16 CC27 CC28 CD02 CD03                       CD04 CD06 CD13 CD15 CE00                 2H100 DD02                 5H030 AA06 AS18 AS20 FF41 FF42                       FF44

Claims (4)

[Claims] 1. A battery check device for determining the remaining amount of a replaceable battery for energizing an inductive load, the terminal voltage of the inductive load and the leakage magnetic flux being detected, and the detected leakage magnetic flux being converted into a current. Then, the battery check device is characterized in that the remaining amount of the battery is determined based on the terminal voltage and the converted current. 2. An inductive load energized from a replaceable battery, voltage detection means for detecting a terminal voltage of the inductive load, magnetic detection means for detecting a leakage magnetic flux of the inductive load, and the magnetic A conversion unit that converts the leakage magnetic flux detected by the detection unit into a current of the inductive load, and a remaining amount determination unit that determines the remaining amount of the battery based on the detected voltage by the voltage detection unit and the converted current by the conversion unit. A battery check device comprising: 3. The battery check device according to claim 2, wherein opening / closing means is provided between the battery and the inductive load to switch between energization and non-energization of the battery to the inductive load. The voltage detecting means and the magnetism detecting means detect the terminal voltage and the leakage magnetic flux at the time of energization and de-energization, and the remaining amount judging means determines the battery based on the detected voltage and the converted current at energization and de-energization. The battery check device is characterized in that the internal resistance of the battery is calculated, and if the calculated internal resistance exceeds a battery remaining capacity determination reference value, the battery is judged to have insufficient remaining capacity. 4. The battery check device according to claim 2, wherein the magnetic detection means is a Hall element.