JP3503765B2 - Voltage measuring device - Google Patents

Description

Detailed Description of the Invention

[0001]

[Table of Contents] The present invention will be described in the following order. Industrial applications Conventional technology (Fig. 2) Problems to be Solved by the Invention (FIGS. 3 and 4) Means for Solving the Problems (FIG. 1) Action (Fig. 1) Example (Fig. 1) The invention's effect

[0002]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a voltage measuring device, and is suitable for application to, for example, a voltage measuring device for a terminal voltage of a battery used in a video tape recorder integrated with a camera.

[0003]

2. Description of the Related Art Conventionally, when a dry battery, for example, is used as a battery used in an electronic device such as a video tape recorder with a built-in camera, a predetermined amount is required as the electric capacity decreases due to long-term use. A phenomenon occurs in which the output voltage value sharply decreases after a lapse of time. For this reason, in this type of electronic device, the electric capacity of the dry battery is reduced, and the output voltage value of the dry battery is a predetermined voltage value required to drive the entire electronic device (hereinafter, this is referred to as battery end value).
In the following cases, the dry battery is displayed on the display screen as the end of use (hereinafter referred to as battery end).

That is, as shown in FIG. 2, by applying a predetermined voltage to the circuit impedance 2 in the camera-integrated video tape recorder 1, a camera unit (not shown) and a VTR unit corresponding to the circuit impedance 2 are applied. The voltage measuring unit 3 measures the output voltage value of the dry battery 4 as a driving battery while driving (not shown) or the like.

First, when the operator attaches the dry battery 4 to a predetermined battery pack (not shown) and then operates the power switch 5 to the power-on state, the voltage measuring unit 3 causes CP
U6 switches the switch circuit 7 to the ON state. As a result, a direct current is supplied from the dry battery 4 to the circuit impedance 2. At that time, the voltage detection circuit 8 detects the terminal voltage of the circuit impedance 2 and outputs the detection result to the CPU 6. The CPU 6 controls the on / off operation of the switch circuit 7 based on the detection result of the voltage detection circuit 8, and
On the display screen (not shown) of the display unit 21, the remaining capacity or the battery end of the dry battery 4 is displayed.

In the voltage detecting circuit 8, when the value of the terminal voltage of the circuit impedance 2 is larger than a predetermined battery end value, the CPU 6 keeps the switch circuit 7 in the ON state and displays it. The remaining electric capacity of the dry battery 4 is displayed on the display screen of the section 9. on the other hand,
In the voltage detection circuit 8, when the value of the terminal voltage of the circuit impedance 2 is smaller than the predetermined battery end value, the CPU 6 switches the switch circuit 7 to the off state, and displays it on the display screen of the display unit 9. Display the battery end.

[0007]

Generally, unlike other batteries such as nickel-cadmium battery and lithium battery, dry batteries generally have a constant open-circuit voltage at the beginning of use regardless of the remaining capacity. There is a feature that indicates the value of. For this reason, in the configuration of FIG. 2, when the electric capacity of the dry battery 4 is sufficiently filled, as shown in FIG. 3, when the output voltage value of the dry battery 4 is the open circuit voltage value V _OCV , the switch circuit at time t ₁ . When 7 is switched to the ON state, the output voltage gradually decreases over several tens of minutes to several hours and reaches the battery end value V _END at time t ₂ .

On the other hand, when the electric capacity of the dry battery 4 is small, as shown in FIG. 4, when the output voltage value of the dry battery 4 is at the open circuit voltage value V _OCV , the switch circuit 7 is turned on at time t ₁ . After just a few seconds, the output voltage value suddenly drops and becomes less than the battery end value V _{END at} time t ₂ . At this time, the switch circuit 7 is switched to the off state, but the output voltage value of the dry battery 4 returns to a value close to the open circuit voltage value V _OCV again after a lapse of a predetermined time based on the above-mentioned characteristics of the dry battery 4.

For this reason, the CPU 6 switches the switch circuit 7 to the ON state again at the time t ₃ , but after a lapse of just a few seconds, the output voltage value drops sharply again and becomes less than the battery end value V _END . As a result, the CPU 6 repeats the ON / OFF operation of the switch circuit 7 many times within a predetermined time after the use of the dry battery 4 is started (hereinafter, this is referred to as hunting).

The present invention has been made in consideration of the above points, and it is possible to accurately know the remaining amount of electric capacity of a battery and to measure a voltage that can prevent malfunction at the start of use or during use of the battery. It is intended to propose a device.

[0011]

In order to solve such a problem, according to the present invention, a voltage detection circuit 1 for detecting a terminal voltage of a battery 4 which supplies a power supply voltage to a first load circuit 2.
In the voltage measurement device 11 having the battery 7, the battery detection circuit 14 for detecting whether or not the battery 4 is a dry battery is connected in parallel to the first load circuit 2, and the voltage detection circuit 17 has the first
Only when the battery 4 is a dry battery based on the detection result of the second load circuit 16 which receives a predetermined load current from the battery 4 before detecting the terminal voltage of the load circuit 2 of FIG. The first control circuit 13 that switches the load circuit 16 of No. 2 to the state in which it can be connected to the battery 4, and the voltage detection circuit 1
Based on the detection result obtained by detecting the terminal voltage of the second load circuit 16, the first load circuit 2 is switched to the state in which it can be connected to the battery 4, and the second load circuit 16 is connected. The second control circuit 13 to be released is provided.

Further, in the present invention, the second control circuit 1
3 determines whether the terminal voltage of the second load circuit 16 satisfies the drive voltage suitable for the first load circuit 2.

Further, in the present invention, a display means 9 for displaying the detection result is provided.

[0014]

[Function] Only when the battery 4 is detected as a dry battery,
By detecting the terminal voltage of the second load circuit 16 by allowing the second load circuit 16 to be supplied with a predetermined load current from the battery 4 before detecting the terminal voltage of the first load circuit 2. Based on the obtained detection result, the first load circuit 2 is switched to a state in which it can be connected to the battery 4, and
By disconnecting the load circuit 16 and displaying the detection result on the display unit 9, the remaining amount of the electric capacity of the battery 4 can be accurately known, and the malfunction of the battery 4 at the start of use or at the time of use Can be prevented in advance.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to the drawings.

In FIG. 1 in which parts corresponding to those in FIG. 2 are designated by the same reference numerals, reference numeral 10 indicates a camera-integrated video tape recorder as a whole, in which a voltage measuring section 11 is provided in place of the conventional voltage measuring section 3. ing.

First, in the voltage measuring section 11, when the dry battery 4 is attached to a predetermined battery pack (not shown), a direct current is output from a predetermined DC power source (not shown), and D
It is supplied to the CPU 13 via the C / DC converter 12. At that time, the sensor 14 detects whether or not the drive battery in the battery pack is the dry battery 4, and the detection result is CP
Output to U13. Incidentally, a protrusion that can be contacted only by the dry battery 4 is provided at a predetermined position in the battery pack, and the sensor 14
Is configured to detect whether or not the dry battery 4 is in contact with the protrusion. As a result, the sensor 14 cannot detect, for example, a nickel-cadmium battery or a lithium battery other than the dry battery 4.

The CPU 13 controls the on / off operation of the switch circuit 15 based on the detection result of the sensor 14. Here, in the sensor 14, when the driving battery in the battery pack is the dry battery 4, the CPU 1
In No. 3, a direct current is supplied from the dry cell 4 to the dummy impedance 16 by switching on the switch circuit 15.

In this state, the voltage detection circuit 17 detects the terminal voltage of the dummy impedance 16, and when the predetermined period elapses, the value of the terminal voltage becomes a stable value and is accurately detected. Thereafter, the CPU 13 controls the on / off operation of the switch circuit 18 in accordance with the operation of the power switch 5 by the operator based on the detection result of the voltage detection circuit 17, and the dry battery 4 on the display screen (not shown) of the display unit 9. It is designed to display the remaining capacity of the battery or the battery end.

In the voltage detection circuit 17, when the value of the terminal voltage of the dummy impedance 16 is larger than the predetermined battery end value, the CPU 13 causes the display screen of the display unit 9 to display the remaining capacity of the electric capacity. Is displayed. After that, when the operator operates the power switch 5 in the power-on state, the CPU 13 correspondingly causes the switch circuit 1 to operate.
5 is turned off and the switch circuit 18 is turned on. This allows the dry battery 4 to be turned into DC / D
A direct current is supplied to the circuit impedance 2 via the C converter 12, and thus the camera unit, the VTR unit, etc. corresponding to the circuit impedance 2 can be driven.

On the other hand, in the voltage detection circuit 17, when the value of the terminal voltage of the dummy impedance 16 shows a value smaller than the predetermined battery end value, the CPU 13 switches the switch circuit 15 to the off state and the switch circuit 18 as well. Is turned off, and the battery end is displayed on the display screen of the display unit 9. As a result, even if the operator thereafter operates the power switch 5 to the power-on state, no current is supplied to the circuit impedance 2.
Thus, the entire video tape recorder 10 with a built-in camera is not driven.

In the above structure, the voltage measuring unit 11 is provided with the dummy impedance 16, and when the direct current is supplied from the dry cell 4 to the dummy impedance 16, the value of the terminal voltage of the dummy impedance 16 is a predetermined battery end value. If it is larger than the above value, the remaining amount of the electric capacity is displayed on the display screen of the display unit 9 and the operator can operate the power switch 5 in the power-on state. As a result, when the operator operates the power switch 5 in the power-on state, the dummy impedance 16 is disconnected and the circuit impedance 2 is connected. As a result, a direct current is supplied from the dry battery 4 to the circuit impedance 2, and thus the camera unit, the VTR unit, etc. corresponding to the circuit impedance 2 can be driven.

On the other hand, when a direct current is supplied from the dry battery 4 to the dummy impedance 16 and the value of the terminal voltage of the dummy impedance 16 is smaller than a predetermined battery end value, the connection of the dummy impedance 16 is released. At the same time, the circuit impedance 2 is not connected, and the battery end is displayed on the display screen of the display unit 9. As a result, even if the operator thereafter operates the power switch 5 to the power-on state, no current is supplied to the circuit impedance 2, and thus hunting that occurs when the electric capacity of the dry battery 4 is low can be effectively prevented.

According to the above structure, the voltage measuring unit 11 is provided with the dummy impedance 16, and the current is supplied to the dummy impedance 16 to detect the terminal voltage thereof before the current is supplied from the dry battery 4 to the circuit impedance 2. By controlling whether or not the operator can operate the power switch 5 in the power-on state based on the detection result, the remaining amount of the electric capacity of the dry battery 4 is accurately detected, and the circuit impedance is determined according to the remaining amount. The supply of current to 2 can be controlled. As a result, it is possible to effectively prevent hunting that occurs when the electric capacity of the dry battery 4 is low. Further, by displaying the remaining amount of the electric capacity of the dry battery 4 on the display screen, the operator can visually confirm the display, and thus can prevent malfunction of the dry battery 4 at the start of use or during use.

In the above-described embodiment, the case where the dummy impedance 16 is used to detect the remaining amount of the electric capacity of the dry battery 4 has been described, but the present invention is not limited to this.
It may be applied to other batteries having a characteristic that causes hunting. By the way, if other batteries are, for example, nickel-cadmium batteries and lithium batteries, hunting does not occur. Therefore, when these batteries are used, the dummy impedance 16 is not necessary.

Further, in the above-mentioned embodiment, the case where the present invention is applied to the camera-integrated video tape recorder has been described, but the present invention is not limited to this, and is widely applied to electronic devices such as audio tape recorders and optical disc devices. It is suitable for application.

[0027]

As described above, according to the present invention, only when the battery is detected to be a dry battery, the second load circuit detects a predetermined voltage from the battery before detecting the terminal voltage of the first load circuit. The load current is supplied, and the first load circuit is switched to a state in which the battery can be connected to the second load circuit based on the detection result obtained by detecting the terminal voltage of the second load circuit. By disconnecting the circuit and displaying the detection result on the display means, the remaining amount of the electric capacity of the battery can be accurately known, and a malfunction at the start of use or during use of the battery can be prevented. .

[Brief description of drawings]

FIG. 1 is a connection diagram showing a video tape recorder with a built-in camera according to an embodiment of the present invention.

FIG. 2 is a connection diagram showing a conventional camera-integrated video tape recorder.

FIG. 3 is a characteristic curve diagram for explaining a change in terminal voltage of a conventional dry battery.

FIG. 4 is a characteristic curve diagram for explaining a change in terminal voltage of a conventional dry battery.

[Explanation of symbols]

1, 10 ... Video tape recorder with integrated camera, 2 ...
... Circuit impedance, 3,11 ... Voltage measuring unit, 4 ...
… Dry batteries, 5 …… Power switch, 6, 13 …… CPU,
7, 15, 18 ... Switch circuit, 8,17 ... Voltage detection circuit, 9 ... Display unit, 12 ... DC / DC converter, 14 ... Sensor, 16 ... Dummy impedance.

Continuation of the front page (56) Reference JP-A-62-52619 (JP, A) JP-A-6-351164 (JP, A) JP-A-6-205539 (JP, A) JP-A-5-328637 (JP , A) JP 4-17531 (JP, A) JP 3-203523 (JP, A) JP 2-218978 (JP, A) JP 64-69224 (JP, A) JP 63-110918 (JP, A) JP 3-11937 (JP, A) JP 4-24567 (JP, A) JP 5-323002 (JP, A) JP 5-297082 (JP, A) Actual Kai 4-72840 (JP, U) Actual Kai 2-140477 (JP, U) (58) Fields investigated (Int.Cl. ⁷ , DB name) H02J 7/00 302

Claims (3)

(57) [Claims] 1. A power supply voltage is applied to a first load circuit.
Voltage measurement with a voltage detection circuit that detects the terminal voltage of the battery
In the fixed device,Battery detection circuit that detects whether or not the battery is a dry battery
When, The battery is a dry battery based on the detection result of the battery detection circuit.
Connect the second load circuit to the battery only if
A first control circuit for switching to a possible state, It is connected in parallel to the first load circuit and detects the voltage.
Before the circuit detects the terminal voltage of the first load circuit,
The second load circuit that receives the specified load current from the battery.
Road, The voltage detection circuit detects the terminal voltage of the second load circuit.
Based on the detection result obtained by issuing
A state in which the load circuit of No. 1 can be connected to the above batteryCut offReplace
Together with disconnecting the second load circuitSecondcontrol
A voltage measuring device comprising a circuit. 2. The second control circuit determines whether or not a terminal voltage of the second load circuit satisfies a drive voltage suitable for the first load circuit. The voltage measuring device according to. 3. The voltage measuring device according to claim 1, further comprising display means for displaying the detection result.