JP2000065907A - Battery checker and motor-operated apparatus provided with the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent real operation of actuators from being hindered, even if the actuators are driven in reality before it at the time of a battery check. SOLUTION: A battery checker is so constituted that the battery of a motor- operated apparatus may be checked by causing currents to flow into the actuators 6-1, 6-3, 6-5 of the motor-operated apparatus. On this occasion, checking currents which is caused to flow into the actuators 6-1, 6-3, 6-5 for a battery check are made smaller than driving currents which are caused to flow into actuators 6-2, 6-4, 6-6 to drive the actuators.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for checking a battery by supplying a current to an actuator such as a coil or a motor.

[0002]

2. Description of the Related Art Many electric devices are powered by a power source (battery).
Various operations are performed by supplying electric energy to an actuator such as a coil or a motor. In such an electric device, it is desirable to actually drive the actuator to detect the power supply voltage and perform a battery check in order to guarantee the operation. Particularly in the case of using a battery in a portable device or the like, the battery check is important. As described above, the battery is checked by energizing the actuator or a dummy load corresponding thereto. For example, in the case of a camera, an actuator such as a shutter coil or a film feed motor is energized in advance, and it is determined whether the battery is actually consumed from the voltage drop at that time and hinders subsequent shooting. are doing.

Some of these devices can change electric energy applied to a driving actuator. For example, in a camera, the value of a current flowing through a shutter coil is changed to control the opening speed of a shutter (constant current control), the driving speed of a film feed motor is made constant, and controllability is stabilized. (PWM control or direct constant voltage control).

[0004] Incidentally, in these battery checks, depending on the characteristics of the battery or the characteristics of the power supply filter, it is generally required that a short time is required until the power supply voltage starts to drop from the start of energization and stabilizes. It is.

[0005]

However, in some of these devices, when the actuator is actually driven at the time of checking the battery, the subsequent operation is hindered. For example, in a camera that checks the battery by energizing the shutter coil, the shutter may be opened by energizing the shutter during the battery check, resulting in an improper double-exposure photograph exposed to film and out of focus. There is.

Further, in a camera which performs a battery check by energizing a film feed motor,
There is a possibility that the film may move due to the power supply to the motor during the battery check, the interval between the film frames may not be secured, or the film may be stretched.

Further, in a camera that performs a battery check by energizing a zoom motor, a zoom position shift similarly occurs, which may cause a shift in focus, an exposure value, or a zoom tension.

Incidentally, in order to solve the above problem, it is conceivable to energize the actuator in a direction opposite to that during the main operation when checking the battery. However, in this case, an extra circuit for conducting electricity in the reverse direction is required, which increases costs and requires extra space for mounting the circuit. Further, the problem is not solved for an actuator which is originally controlled by bidirectional energization, for example, an actuator which uses a film feed motor or a zoom motor as a load for battery check. further,
In order to solve the above problem, a method of shortening the energizing time to the actuator at the time of battery check may be considered. However, in this case, as described above, since a predetermined time is required to measure the operation guarantee voltage, if only the time is shortened, it becomes difficult to detect an appropriate guarantee voltage. In order to solve this problem, it is conceivable to change the constant of the power supply filter. However, if the constant of the filter is changed, an appropriate filter effect cannot be obtained, and high-precision measurement and control cannot be performed. It is also conceivable to use a battery with good response characteristics or a battery with a small voltage drop, but this increases the cost of the battery itself and reduces the degree of freedom in designing the device.

Therefore, the present invention can design a battery by selecting a necessary battery suitable for the apparatus without interfering with the main operation after the battery check, without requiring an extra circuit or the like. Another object of the present invention is to provide a battery check device capable of accurately detecting the guaranteed voltage of the device.

[0010]

In order to achieve the above object, according to the present invention, in a battery check device for checking a battery of an electric device by supplying a current to an actuator of the electric device, the battery check is carried out. The check current flowing through the actuator is made smaller than the drive current flowing through the actuator for driving the actuator.

Then, an expected battery voltage when a drive current is supplied to the actuator is obtained based on the check current, and a warning operation is performed when the expected battery voltage is lower than a predetermined voltage.

According to such a battery check device, the actuator is not driven when the battery is checked, so that the subsequent operation is not hindered. Further, since no current is supplied to the actuator in the reverse direction, no extra circuit or the like is required. Further, since the energization time to the actuator at the time of battery check is not shortened, it is possible to select a necessary battery suitable for the device, perform design and accurately detect the guaranteed voltage of the device.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS (First Embodiment) FIG. 1 shows a configuration of a camera (electric device) according to a first embodiment of the present invention. In FIG. 1, reference numeral 1 denotes a power supply circuit including a battery (battery) for supplying power to a camera control device, actuators 6-1, 6-3, 6-5, and the like.

Reference numeral 2 denotes a power supply filter circuit which is connected to the power supply circuit 1 and suppresses ripples in the power supply to reduce fluctuations in power supply when the actuator is driven, thereby protecting the actuator from external noise.

Reference numeral 3 denotes a CPU for performing calculations and control of the camera,
Reference numeral 4 denotes a start switch, and reference numeral 5 denotes a volatile or nonvolatile storage circuit connected to the CPU 3 and having various parameters, control data, branch data, and the like.

Reference numeral 6 denotes an actuator drive circuit, which includes a shutter coil 6-1, a constant current drive circuit 6-2 for driving the shutter coil 6-1 at a constant current, a film feed motor 6
-3, a PWM drive circuit 6-4 for driving the feed motor 6-3 by PWM, a zoom motor 6-5, and a zoom motor 6-
5 includes a constant voltage driving circuit 6-6 for driving the constant voltage driving circuit 5 at constant voltage. The output from the power supply filter circuit 2 is supplied to the actuator drive circuit 6.

Reference numeral 7 denotes a power supply voltage detection circuit for detecting a power supply voltage (battery voltage) output from the power supply filter circuit 2, and 8 denotes that the battery can be operated when the battery is OK or the remaining battery power is low or the current battery power remains. This is a display circuit for displaying the state of the apparatus including battery check information indicating that the apparatus cannot be operated.

Next, the operation of the camera thus configured will be described with reference to the flowchart of FIG. 2 and the waveform diagram of FIG.

In the flow of FIG. 2, first, the CPU 3 determines whether or not the start switch 4 has been turned on (# 20).
1). When the start switch 4 is turned on, the CPU 3 determines whether each of the actuators 6-1, 6-3, 6-5 in the actuator drive circuit 6 is an energized load at the time of battery check.
Current for battery check against
Check current) and voltage values (#
202).

Here, the case where the shutter coil 6-1 is used as a battery check load will be described.

In step # 202, the CP current is set in order to set a check current value to be supplied to the shutter coil 6-1.
U3 controls the constant current drive circuit 6-2 to select and set the comparison voltage value so as to have a predetermined current value (# 202).
The check current value corresponds to I1 in FIG. 3 and is a value that does not open the shutter even when the shutter coil 6-1 is energized, that is, a current value smaller than a current value necessary for driving the shutter.

Next, in order to perform a battery check,
Power supply to the shutter coil 6-1 is started (# 20)
3). Further, since the operation is delayed by the time constant of the power supply filter circuit 2, the CPU 3 operates a timer to measure the time until the power supply voltage (VBAT) becomes a voltage corresponding to the load applied to the shutter (# 20
4). This timer is provided inside the CPU 3.

When the power supply to the shutter coil 6-1 is started, the power supply voltage VBAT gradually decreases as shown in part A of FIG.

Then, the CPU 3 determines whether a predetermined time longer than the predetermined time has elapsed (# 205).
After a lapse of a predetermined time, the value V1 of the power supply voltage (VBAT) at that time is measured through the power supply voltage detection circuit 7 (# 20).
6). Thereafter, the shutter energization is stopped (# 20)
7).

Next, the power supply voltage value V1 measured in step # 206 is corrected (# 208). This correction is based on the energizing current (driving current) I2 in the main operation step # 211 and the energizing current I1 in the previous battery check.
And the power supply VB of the above device
This is to correct a voltage difference (ΔV in FIG. 3) obtained by multiplying the combined resistance by the AT wiring resistance. That is, when the above contents are expressed by an equation, the difference is ΔV = {R (internal resistance of battery) + R (resistance of power supply wiring)} ×
{I (actuator drive current) −I (current at battery check)}, and the corrected power supply voltage value (battery check voltage) V is the power supply voltage value V measured at step # 206.
It is a value obtained by subtracting ΔV from 1.

V (battery check voltage) = V1
−ΔV = V2 In other words, the corrected power supply voltage value corresponds to the power supply voltage value that drops during the actual main operation.

Next, the minimum power supply voltage value (predetermined voltage) including a margin for guaranteeing the operation when the actuator is driven is read from the storage circuit 5 (# 209). Then, the minimum power supply voltage value read from the storage circuit 5 is compared with the corrected battery check voltage (# 210). If the battery check voltage is equal to or higher than a predetermined voltage constant, the main operation of the camera (photographing operation) is performed. ) (# 211).

On the other hand, when the battery check voltage is lower than the predetermined voltage, the shutter cannot perform the normal operation, and does not shift to the main operation. The display circuit 8 displays a battery capacity shortage or the like, or a warning sound from a sounding body (not shown). Is issued (# 212), and the operation is terminated.

According to the camera having the above-described battery check function, the battery check can be performed without hindering the photographing operation after the battery check. In addition, there is no need for an extra circuit or the like for reverse energization of the actuator.Furthermore, it is possible to design by selecting the necessary battery suitable for the camera, and accurately detect the operation guarantee voltage of the camera. Appropriate processing can be performed.

In the above-described embodiment, the case where the shutter coil is used as a load for battery check has been described. However, the load for battery check is set to a film feed motor or a zoom motor, and PWM control is performed for these controls.
The control / constant voltage control may be used to set a check current for generating a PWM value or a drive voltage value at which the motors do not operate at the time of battery check. In addition, an actuator other than that described in the above embodiment, which can change the drive current and the voltage between the time of the battery check and the time of the main operation, may be used as the battery check load.

Furthermore, in the above embodiment, the case where the battery check voltage is corrected and then compared with the operation guarantee voltage data in the storage circuit has been described. For example, the battery check voltage is not corrected and the operation guarantee voltage of the storage circuit is not corrected. The data may be corrected in advance, and the value may be compared with the battery check voltage.

In the case where a plurality of actuators are driven during this operation, a battery check is performed using the actuator having the heaviest load among the actuators. Accordingly, the operation of all actuators driven during the main operation can be guaranteed.

Further, even when the actuator that is energized at the time of battery check is different from the actuator with the heaviest load among the actuators driven during the main operation, in step # 208, ΔV = ｛R (internal resistance of battery) + R (power supply Wiring resistance)｝ ×
A similar effect can be obtained by performing the correction using the formula {I (actuator drive current) -I (current at battery check)}.

In the above embodiment, the case where the battery is checked in the camera has been described. However, the present invention can be applied to all electric devices having an actuator driven by energization.

[0035]

As described above, according to the present invention,
Since the actuator is not driven during the battery check, the battery check can be performed without hindering the subsequent main operation. Also, when the battery is checked, the actuator is not energized in the reverse direction.
This eliminates the need for an extra circuit or the like for conducting current in the reverse direction, thereby preventing an increase in cost and an increase in the size of the device.

Further, since the power supply time to the actuator at the time of battery check is not shortened, it is possible to select a necessary battery suitable for the device, perform design and accurately detect the guaranteed voltage of the device. .

[Brief description of the drawings]

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

FIG. 2 is an operation flowchart of the camera.

FIG. 3 is a graph showing a fluctuation of a power supply voltage in the camera.

[Explanation of symbols]

 1: Power supply circuit 2: Power supply filter circuit 3: CPU 4: Start switch 5: Storage circuit 6: Actuator drive circuit 6-1: Shutter coil 6-2: Constant current drive circuit 6-3: Film feed motor 6-4 : PWM drive circuit 6-5: Zoom motor 6-6: Constant voltage drive circuit 7: Power supply voltage detection circuit 8: Display circuit

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 2G016 CA00 CA04 CB11 CB12 CB13 CB21 CC01 CC04 CC06 CC10 CC27 CC28 CD02 CD03 CE00 2H002 BC07 HA14 HA21 2H100 DD02 5H030 AA08 AS11 AS18 BB21 FF42 FF44

Claims (7)

[Claims] 1. A battery check device for checking a battery of an electric device by passing a current to an actuator of the electric device, wherein a check current passed to the actuator for battery check is supplied to the actuator for driving the actuator. A battery check device, wherein the drive current is made smaller than a drive current flowing through the battery check device. 2. The battery check device according to claim 1, wherein an expected battery voltage when the drive current is supplied to the actuator is obtained based on the check current. 3. The anticipated battery voltage is obtained based on a battery voltage when the check current flows through the actuator and a difference between the check current and the drive current. The battery check device as described. 4. The predicted battery voltage is calculated by subtracting a difference voltage obtained based on a difference between the check current and the drive current from a battery voltage when the check current is supplied to the actuator. The battery check device according to claim 3, wherein the battery check device is determined. 5. The battery check according to claim 4, wherein the difference voltage is obtained by a product of a difference between the check current and the drive current and a sum of a battery internal resistance and a battery wiring resistance. apparatus. 6. The battery check device according to claim 1, wherein a warning operation is performed when the expected battery voltage is lower than a predetermined voltage. 7. An electric device comprising the battery check device according to claim 1.