JPH11215717A - Power supply unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize the display of the remaining electrical energy of a battery and/or the stopping control of an appliance which are scarcely affected through operating environments, by altering the displays of the residual energy of the battery and/or the stopping control characteristic of the appliance, based on the temperature information fed from a temperature sensor provided in or near the battery. SOLUTION: A controlling microcomputer 24 for a camera main body 20 controls the photographing, recording, reproducing, and displaying functions of a video camera in accordance with the indications fed from an operating panel 28. Also, inputting via a signal terminal 22 a temperature-information signal fed from a temperature sensor 12 of a battery package 10, the microcomputer 24 recognizes the temperature state of a battery 11, based on the temperature-information signal to control a power supply circuit 23, responding to the temperature characteristic of the battery 11. That is, memorizing in advance the relation between the temperature and discharge voltage characteristic of the battery 11 (its temperature characteristic), the microcomputer 24 performs the display of the resmaining electrical energy of the battery 11 and the stopping control of an appliance, with reference to this temperature characteristic. Thereby, the effects of the temperature change in the operating environment of the appliance on it can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power supply device for a device using a battery as a power supply, and more particularly to a measure for improving the usability.

[0002]

2. Description of the Related Art Generally, in a device using a battery as a power supply, the output voltage of the battery connected to the device gradually decreases when power is consumed (discharged) by operation of the device, and the battery is supplied stably. The output voltage sharply drops after the discharge end voltage at which the discharge cannot be performed. In order to prevent the circuit operation of the device from becoming unstable due to such an output voltage drop phenomenon, these devices detect a voltage near the discharge end voltage of the battery (hereinafter, referred to as a lower limit operating voltage value). It has a function to stop the operation of the device.

On the other hand, batteries use a chemical reaction, so that the output voltage has a temperature-dependent characteristic. In general, the output voltage tends to decrease in a low-temperature environment. When the device and the battery are combined and operated under different ambient temperature environments, the output voltage of the battery decreases as the temperature of the use environment decreases. Since the lower limit operating voltage value at which the circuit of the device can be maintained in a stable operation state is set to a fixed state, there is a problem (market complaint) that the operable time of the device is shortened in a low temperature environment.

In order to avoid such a market complaint, in an apparatus using a battery as a power supply, for example, an 8 mm video camera (VM-H200L) manufactured by Hitachi, Ltd.
In the instruction manual, add a supplementary explanation that the usable time will be shortened when the operating temperature decreases, such as "Please note that the operating time will be shorter when using in cold regions." Alerts the user.

[0005]

In the prior art, the lower limit operation which is a criterion for stopping the operation of a device by monitoring the power supply voltage and avoiding the device from operating in an unstable manner is avoided. The voltage value is a fixed value, and the device does not consider that the output voltage of the battery used in combination with the temperature changes with temperature. When the output voltage falls below the reference value, the device stops its operation, and there is a problem that the power stored in the battery cannot be used effectively.

[0006] A battery installed in a device consumes power stored in the battery when the load, which is the device, is turned on. The battery has a characteristic that the output voltage is reduced as the power stored inside is consumed. The time-battery output voltage characteristics (hereinafter referred to as discharge voltage characteristics) are as shown in the characteristic diagram of FIG.

Such a battery-powered device is designed to operate normally within the voltage ranges of sections A, B, and C where the battery having the discharge voltage characteristic 1 can supply power stably. I have. The voltage at the boundary between the section C and the section D is the discharge end voltage value V1 of the battery, and the section D is a section in which the battery itself cannot guarantee stable power supply. Therefore,
Devices are also areas where stable operation cannot be guaranteed. Therefore, in order to guarantee stable operation, the device is designed to set the lower limit operating voltage V2 of the power supply voltage as a monitoring reference value so as to perform control to stop the operation immediately before reaching the discharge end voltage value V1. Has been made. In general, the lower limit operating voltage value V2 is slightly higher than the discharge end voltage value V1 when the battery combined with the device is used in a normal temperature (reference temperature) environment. The power stored in the battery is sufficiently extracted and used.

If the discharge voltage characteristic when the temperature of the use environment is normal temperature is represented by a characteristic curve 1, the discharge voltage characteristic curve 1a at a low temperature and a discharge voltage characteristic curve 1b at a high temperature when the use environment changes. Is changed, and the battery cannot supply power stably.
Is a voltage value V1a at a low temperature and a voltage value V1b at a high temperature.
Changes to

On the other hand, since the lower limit operating voltage value V2 to be monitored is fixedly set in the device in order to guarantee the stable operation of the device, when the operating environment of the battery is low, the battery becomes stable. Long before reaching the voltage value V1a, which is the limit at which power can be supplied to the
2, the operation is stopped. In this case, the battery has room to discharge in a stable state up to the discharge end voltage V1a, and when the output voltage of the battery reaches the lower limit operating voltage value V2 due to the setting on the device side, Since the discharge (use of the battery) is terminated, the power stored in the battery cannot be sufficiently used, which is uneconomical. In this state, the user recognizes that the operation time of the device (= life of the battery) is short.

When the operating environment is high temperature, the lower limit operating voltage V2 at which the device stops operating is fixed.
The device has a lower limit operating voltage V that is lower than the discharge end voltage value V1b at which the battery can supply stable power.
The operation is continued up to 2. This voltage value V1b
The range from V2 to V2 is a region in which the battery cannot supply stable power, and there is a high risk that a malfunction that causes the device to malfunction may occur.

On the other hand, in a device using a battery as a power source, the remaining capacity of the battery is displayed as a guide for battery replacement and charging. However, since the remaining capacity display control is performed with reference to the output voltage of the battery, it is difficult to accurately display the remaining capacity under the current situation where the output voltage is affected by the environmental temperature as described above. It is.

It is an object of the present invention to provide a control function for monitoring the output voltage of a battery and stopping the operation of the device in order to prevent the operation of the device from becoming unstable. To mitigate the effects of change.

Another object of the present invention is to provide a device having a control function of monitoring the output voltage of a battery and stopping the operation of the device in order to prevent the operation of the device from becoming unstable. An object of the present invention is to make it possible to use the stored power effectively.

Still another object of the present invention is to realize a remaining battery capacity display in which accuracy is not greatly reduced due to the influence of environmental temperature.

[0015]

SUMMARY OF THE INVENTION The present invention relates to a power supply device for an apparatus using a battery as a power supply. By providing a control means for changing the equipment stop control characteristic, the remaining battery level display and / or the equipment stop control, which are less affected by the use environment, are realized.

Specifically, the control means performs control processing by comparing the output voltage of the battery with a criterion value, and has a control characteristic of increasing the criterion value as the temperature increases.

Further, the control means stores a discharge voltage characteristic at a reference temperature, a judgment reference value, and a temperature coefficient for calculating a judgment reference value corresponding to each temperature.

The temperature detector utilizes a detector provided to acquire battery temperature information for battery charge control.

[0019]

1 to 3 show an embodiment of the present invention.
This will be described with reference to FIG.

FIG. 1 is a block diagram of a video camera according to an embodiment of the present invention. Reference numeral 10 denotes a battery pack, and reference numeral 20 denotes a camera body to which power is supplied from the battery pack 10.

The battery pack 10 includes a rechargeable battery 11 that recovers power generation capability by charging, a temperature detector 12 that generates an electric signal (temperature information signal) corresponding to the temperature of the battery 11, and a power terminal 13a. , 13b and a temperature information signal terminal 14.

The temperature detector 12 is a thermistor that provides temperature information of the battery 11 when charging and discharging the battery 11 to a charging device (not shown) and a camera body 20 in the form of an electric signal. The temperature detector 12 may be provided to generate an electric signal related to the temperature of the battery 11;
By providing the battery pack 10 in the case, the object can be achieved.

The battery pack 10 can be formed integrally with the camera body 20.

The camera body 20 includes a power supply terminal 21a, which receives power from the power supply terminals 13a, 13b of the battery pack 10,
21b, a temperature information signal terminal 22 for inputting a temperature information signal from the temperature information signal terminal 14, a power supply circuit 23,
It includes a control microcomputer 24, a photographing / recording / reproducing unit 25, a display control circuit 26, an LCD display 27, and an operation panel 28.

The power supply circuit 23 includes power supply terminals 21a and 2a.
The output voltage of the battery 11 received via the power supply 1b is controlled to a predetermined value and supplied to the control microcomputer 24, the photographing / recording / reproducing unit 25, the display control circuit 26, and the display 27.

The control microcomputer 4 controls photographing, recording, reproducing and displaying functions of the video camera in accordance with an instruction from the operation panel 28, and executes power supply control which refers to a battery temperature, which is a feature of the present invention.

In the power supply control, the control microcomputer 24
Based on the temperature information signal input from the temperature detector 12 via the temperature information signal terminal 22, the temperature condition of the battery 11 is recognized, and the power supply circuit 23 is controlled according to the temperature characteristics of the battery 11. The control microcomputer 24 stores in advance the relationship (temperature characteristic) between the temperature of the battery 11 and the discharge voltage characteristic, and executes the display of the remaining capacity of the battery 11 and the control of the device stop by referring to the temperature characteristic.

FIG. 2 shows the control characteristics of the control microcomputer 24 for displaying the remaining battery capacity and stopping the equipment. The control microcomputer 24 holds (stores) the discharge voltage characteristic curve 1 at the reference temperature of the battery 11, the judgment reference value Vx, and the temperature coefficient α for the display of the remaining battery capacity and the device stop control. In the discharge voltage characteristic curve 1, V1 is a discharge end voltage value, V2 is a lower limit operation voltage value, V3 and V4 are remaining capacity distinction voltage values,
These voltage values V2 to V4 are the judgment reference values Vx at the reference temperature, respectively.

The control microcomputer 24 obtains a voltage value output from the battery 11 and a temperature detection signal output from the temperature detector 12, compares the battery output voltage with a judgment reference value Vx, and executes various control processes. I do. If the output voltage of the battery 11 is equal to or more than the determination reference value V4 in the usage environment at the reference temperature, the remaining capacity display control corresponding to the section A is performed. If it is between the judgment reference values V4 and V3, the remaining capacity display control corresponding to the section B is performed, and if it is between the judgment reference values V3 and V2, the section C is displayed.
Is performed, and if the value is equal to or less than the determination reference value V2, device stop control is performed.

When the use environment is low temperature, the judgment reference values V2 to V4 are multiplied by a temperature coefficient α (α <1) to correct the judgment reference values V2 to V4 to judgment reference values V2a to V4a.
The output voltage of the battery 11 is changed from the corrected reference value V2a to the reference value V2a.
The remaining capacity display control and the equipment stop control are performed as compared with V4a.

When the use environment is high temperature, the judgment reference values V2 to V4 are multiplied by a temperature coefficient α (α> 1), and the judgment reference values V2 to V4 are corrected to the judgment reference values V2b to V4b.
The output voltage of the battery 11 is changed from the corrected reference value V2b to
The remaining capacity display control and the equipment stop control are performed as compared with V4b.

The battery remaining capacity display and the device stop control as described above may cause an unstable operation of the device because the output voltage of the battery 11 follows the temperature characteristic that changes depending on the temperature. In order to avoid this, it is possible to reduce the influence of the temperature change of the use environment in the control function of stopping the operation and effectively use the power stored in the battery. A decrease in accuracy due to the influence can be reduced.

FIG. 3 is a control processing flowchart executed by the control microcomputer 24 in the video camera shown in FIG.

When the power switch is turned on (step 301), the control microcomputer 24 detects whether or not the battery 11 is connected (step 302), and turns off the power switch if the battery 11 is not connected (step 327).

When the battery 11 is connected, the temperature information signal from the temperature detector 12 is taken in to detect the temperature of the battery 11 (step 303). If the temperature is equal to or higher than 0 ° C. (step 304), the output voltage of the battery 11 is detected (step 308). If the temperature is not equal to or higher than 0 ° C., the function of the battery 11 is reduced at a low temperature.
5) Perform low temperature use display processing (step 306),
Judgment reference value V in remaining capacity display and equipment stop control processing
A temperature coefficient α for correcting 2 to V4 is set (step 307).

The detected battery output voltage is equal to the judgment reference value V2 ×
It is determined whether it is equal to or more than α (V2 = 5.8v) (= V2, V2a, V2b) (Step 309). If not, there is no remaining battery capacity to drive the device normally. (Step 325), the power switch is turned off to stop the operation of the video camera (Step 32).
7).

The detected battery output voltage is equal to the judgment reference value V2 ×
If α or more (step 309), dew condensation detection (step 310), mechanical mode detection (step 311), mechanical state processing (step 312), remote control (step 313), RAM data development (step 314), operation key data Capture (step 315), interrupt processing (step 316) ... IC control communication processing (step 3
17) The control processing for exhibiting the original functions of the video camera such as photographing, recording, and monitor display is performed.

Thereafter, the battery output voltage is detected again (step 318), and this battery output voltage is determined by the judgment reference value V.
Compare with x. The battery output voltage is equal to the judgment reference value V4 × α (V
If 4 = 7.3v) or more (step 319), it is displayed that the remaining battery charge is in the section A '(step 322). The battery output voltage is the reference value V4 × α to V
When it is between 3 × α (V3 = 6.8 V) (step 320), it is displayed that the remaining battery charge is in the section B ′ (step 323). When the battery output voltage is between the determination reference values V3 × α to V2 × α (V2 = 5.8 V) (step 321), it is displayed that the remaining battery charge is in the section C ′ (step S321). 324).

Then, the battery output voltage is equal to the judgment reference value V2 ×
If α has not been reached, there is no remaining battery capacity to drive the video camera normally, so after saving various data (step 325), the power switch is turned off to stop the operation of the video camera (step 327).

[0040]

According to the present invention, the operation characteristics of a control function for monitoring the output voltage of a battery and stopping the operation of the device in order to prevent the operation of the device from becoming unstable are changed to the battery (use environment). , The influence of a temperature change in the use environment can be reduced. Therefore,
The electric power stored in the battery can be used effectively.

Further, since the reference value for determining the remaining capacity of the battery is changed in accordance with the temperature of the battery (operating environment), it is possible to realize a remaining battery capacity display in which the accuracy is not greatly reduced due to the influence of the environmental temperature. it can.

Such a power supply device is a video camera or M
It is extremely effective for portable devices used in a wide range of environments such as PEG cameras.

[Brief description of the drawings]

FIG. 1 is a block diagram of a video camera according to an embodiment of the present invention.

FIG. 2 is a control characteristic diagram of a battery remaining capacity display and a device stop in the video camera shown in FIG.

FIG. 3 is a flowchart of a control process including a remaining battery capacity display and a device stoppage executed by a control microcomputer in the video camera shown in FIG. 1;

FIG. 4 is a control characteristic diagram of a battery remaining capacity display and a device stop in a conventional video camera.

[Explanation of symbols]

10: Battery pack, 11: Battery, 12: Temperature detector, 2
0: camera body, 24: control microcomputer, 25: photographing / recording / reproducing unit, 26: display control circuit, 27: LCD display.

Claims (4)

[Claims] 1. A power supply device for a device using a battery as a power supply, wherein a control means for changing a battery remaining capacity display and / or a device stop control characteristic according to temperature information from a battery or a temperature detector installed near the battery. A power supply device comprising: 2. The control device according to claim 1, wherein the control means performs the control process by comparing the output voltage of the battery with a criterion, and increases the criterion value as the temperature increases. And power supply. 3. The apparatus according to claim 1, wherein said control means stores a discharge voltage characteristic at a reference temperature, a judgment reference value, and a temperature coefficient for calculating a judgment reference value corresponding to each temperature. Power supply. 4. The power supply device according to claim 1, wherein the temperature detector uses a detector provided to acquire battery temperature information for battery charge control.