JP7474316B2 - Battery checking device, battery checking method, and camera - Google Patents

Description

The present invention relates to a battery checking device, a battery checking method, and a camera.
This application claims priority based on Japanese Patent Application No. 2020-029462, filed in Japan on February 25, 2020, the contents of which are incorporated herein by reference.

A method has been known for evaluating the battery voltage drop under specified load conditions and predicting the remaining battery charge in electronic devices that use batteries as their power source (see Patent Document 1).

Japanese Patent Publication No. 2006-153819

In electronic devices that use a battery as a power source, the battery supplies a low-level primary voltage to a boost circuit, and the secondary voltage boosted by the boost circuit is supplied to loads such as a microcomputer, a motor, and a sensor. In a normal battery check, the voltage level dropped by the load is measured, and the battery condition is determined based on whether or not the voltage level exceeds a predetermined value.
However, when a boost circuit outputs different voltages to multiple loads, the protection circuit of the boost circuit may be activated when some of the loads are driven, causing the boost circuit to stop. If the boost circuit stops operating during a battery check, the battery voltage level hardly drops at all, making it very difficult to determine the battery condition based on the voltage level.

According to a first aspect of the present invention, a battery checking device applicable to an electronic device that supplies power from a power source to multiple loads via a boost circuit is provided. The battery checking device has a voltage measuring unit that measures the voltage of the power source of the electronic device, and a load driving unit that drives multiple loads of the electronic device with power supplied from the power source via the boost circuit. The battery checking device executes a first determination step of measuring a voltage V1 of the power source by the voltage measuring unit during a period in which the first load is driven by the load driving unit, and determining whether the measured voltage V1 is equal to or greater than a predetermined value, and a second determination step of measuring a voltage V2 of the power source by the voltage measuring unit during a period in which the second load that consumes more power than the first load is driven by the load driving unit, and determining whether the measured voltage V2 is smaller than the voltage V1.

According to a second aspect of the present invention, a battery check method applicable to an electronic device that supplies power from a power source to a plurality of loads via a boost circuit is provided. The battery check method includes a first determination step of measuring a voltage V1 of the power source during a period in which a first load is driven by power supplied from the power source via the boost circuit and determining whether the measured voltage V1 is equal to or greater than a predetermined value, and a second determination step of measuring a voltage V2 of the power source during driving during a period in which a second load that consumes more power than the first load is driven by power supplied from the power source via the boost circuit and determining whether the measured voltage V2 is smaller than the voltage V1.

According to a third aspect of the present invention, there is provided a camera including a power source, a boost circuit connected to the power source, a first load connected to the boost circuit, a second load connected to the boost circuit and consuming more power than the first load, and a battery check unit for determining the state of the power source. The battery check unit has a voltage measurement unit for measuring the voltage of the power source, and a load drive unit for driving the load with power supplied from the power source via the boost circuit. The battery check unit determines the state of the power source by executing a first determination step in which, during a period in which the first load is driven by the load drive unit, the voltage measurement unit measures the voltage V1 of the power source and determines whether the measured voltage V1 is equal to or greater than a predetermined value, and a second determination step in which, during a period in which the load drive unit drives the second load, the voltage measurement unit measures the voltage V2 of the power source and determines whether the measured voltage V2 is smaller than the voltage V1.

According to aspects of the present invention, a battery checking device, a battery checking method, and a camera are provided that can accurately determine the deterioration state of a battery and enable reliable operation of electronic devices.

FIG. 1 is a block diagram showing the main parts of a camera according to an embodiment of the present invention. FIG. 2 is a circuit diagram showing the main part of the camera according to an embodiment of the present invention. FIG. 3 is a flowchart of a battery checking method according to an embodiment of the present invention. FIG. 4 is a waveform diagram relating to a battery check operation in one embodiment of the present invention.

Hereinafter, one embodiment of the present invention will be described with reference to FIGS.
This embodiment is an example of a camera 1 in which a battery check function for determining the state of the battery 2 is incorporated in the microcomputer 3 .

As shown in Figure 1, the camera 1 of this embodiment comprises a battery 2, a microcomputer 3 that controls the entire camera 1, a shutter drive motor 4 that constitutes a shutter drive mechanism 21 (see Figure 2), a film transport motor 5 that constitutes a film transport mechanism 22 (see Figure 2), a boost circuit 6 that supplies power to a strobe (not shown), a boost circuit 7 that supplies power to the microcomputer 3, a boost circuit 8 that supplies power to the shutter drive mechanism and the film transport mechanism, a motor driver 9 that drives the shutter drive motor 4, a motor driver 10 that drives the film transport motor 5, and a release switch 11 that provides shutter timing.

Battery 2 is the driving power source for the entire camera 1. Battery 2 is connected to three boost circuits 6 to 8. Battery 2 supplies power to each part of camera 1 directly or via boost circuits 6 to 8. As battery 2, an alkaline dry battery, a size AA lithium battery, a CR-V3 battery, a Ni-MH battery, or the like is used.

The power of the battery 2 is supplied to the microcomputer 3 via a boost circuit 7. The power of the battery 2 is supplied to motor drivers 9 and 10 via a boost circuit 8. The motor driver 9 drives the shutter drive motor 4 with the power supplied from the boost circuit 8. The motor driver 10 drives the film transport motor 5 with the power supplied from the boost circuit 8.

The microcomputer 3 controls three boost circuits 6, 7, and 8, and two motor drivers 9 and 10. The microcomputer 3 receives input from a release switch 11 and a signal that monitors the primary voltage of the battery 2. In this embodiment, the microcomputer 3 is supplied with power from the battery 2 via the boost circuit 7. When the camera 1 is in operation, the microcomputer 3 receives a supply of voltage boosted by the boost circuit 7, and controls the boost circuits 6 to 8 and the drive of the motor drivers 9 and 10. When the camera 1 is not in operation, the microcomputer 3 transitions to a hibernation state to reduce current consumption. In the hibernation state, the microcomputer 3 is supplied with the primary voltage of the battery 2 that is not boosted.

2 shows only the circuits necessary for the battery check operation in camera 1. The positive terminal of battery 2 is connected to power supply line VB, and the negative terminal of battery 2 is connected to ground line GND. Resistors R11 and R12 are connected in series between power supply line VB and ground line GND. The wiring connecting resistors R11 and R12 is connected to input terminal P0 of microcontroller 3.

The microcontroller 3 is connected to the power supply line VB via a boost circuit 7. The ground terminal of the microcontroller 3 is connected to the ground line GND. The microcontroller 3 has an AD converter 31 built in. Although not shown, the microcontroller 3 includes a CPU (Central Processing Unit), memory (RAM (Random Access Memory), ROM (Read Only Memory)), I/O, a timer, etc., which are connected via an internal bus. The AD converter 31 is part of the I/O, and converts an analog signal input from the input terminal P0 into a digital value and outputs it. The microcontroller 3 has a first output terminal P1, a second output terminal P2, and a third output terminal P3 that control the system of the camera 1.

A boost circuit 8 is connected to the power supply line VB via a coil L1. In this embodiment, the boost circuit 8 is a boost IC capable of outputting multiple voltages. The ground terminal of the boost circuit 8 is connected to the ground line GND. The boost circuit 8 drives the coil L1 to boost the primary voltage of the power supply line VB and output it to the power supply line VDD.

The resistor R21, the capacitor C1, the shutter drive mechanism 21, and the film transport mechanism 22 are connected to the power supply line VDD extending from the output terminal of the boost circuit 8. One terminal of the resistor R21 is connected to the power supply line VDD, and the other terminal of the resistor R21 is connected to one terminal of the resistor R22, one terminal of the resistor R23, and the voltage feedback terminal of the boost circuit 8. The other terminal of the resistor R22 is connected to the ground line GND. The other terminal of the resistor R23 is connected to the collector terminal of the transistor TR3. The emitter terminal of the transistor TR3 is connected to the ground line GND. The base terminal of the transistor TR3 is connected to the third output terminal P3 of the microcomputer 3. The resistor R21, the resistor R22, the resistor R23, and the transistor TR3 are a circuit that controls the output voltage of the boost circuit 8.

Capacitor C1 is connected between the power supply line VDD and the ground line GND. Capacitor C1 is disposed between the boost circuit 8 and the film transport mechanism 22. Capacitor C1 stores the current supplied from the boost circuit 8 and stably maintains the secondary voltage boosted by the boost circuit 8.

The shutter drive mechanism 21 includes a shutter drive motor 4 and a motor driver 9. The ground terminal of the shutter drive mechanism 21 is connected to the collector terminal of the transistor TR1. The emitter terminal of the transistor TR1 is connected to the ground line GND. The base terminal of the transistor TR1 is connected to the first output terminal P1 of the microcomputer 3.

The film transport mechanism 22 includes a film transport motor 5 and a motor driver 10. The ground terminal of the film transport mechanism 22 is connected to the collector terminal of the transistor TR2. The emitter terminal of the transistor TR2 is connected to the ground line GND. The base terminal of the transistor TR2 is connected to the second output terminal P2 of the microcomputer 3.

The shutter drive mechanism 21 and the film transport mechanism 22 are driven by the power of the battery 2 and act as a load on the battery 2 during operation. In this embodiment, the shutter drive mechanism 21 is a first load that consumes relatively little power, and the film transport mechanism 22 is a second load that consumes more power than the shutter drive mechanism 21.

The microcontroller 3 can obtain the power supply voltage of the battery 2, which is divided by resistors R11 and R12, via the input terminal P0. The voltage input to the microcontroller 3 from the input terminal P0, i.e., the voltage between the terminals of resistor R12, is converted to a digital value by the AD converter 31. The digital value output from the AD converter 31 is held in the memory of the microcontroller 3. In other words, the microcontroller 3 has a voltage measurement unit that measures the power supply voltage of the battery 2.

The microcomputer 3 controls the driving of the shutter driving mechanism 21 and the film transport mechanism 22 via the first output terminal P1 and the second output terminal P2.
When driving the shutter driving mechanism 21, the microcomputer 3 controls the transistor TR1 to be in the on state and the transistor TR2 to be in the off state via the first output terminal P1 and the second output terminal P2. When driving the film transport mechanism 22, the microcomputer 3 controls the transistor TR1 to be in the off state and the transistor TR2 to be in the on state via the first output terminal P1 and the second output terminal P2.

That is, the microcomputer 3 has a load driving section that drives the shutter driving mechanism 21 and the film transport mechanism 22, which are loads on the battery 2, with power supplied via the boost circuit 8. Therefore, the microcomputer 3 of the camera 1 incorporates a battery check section that includes a voltage measurement section and a load driving section.

The microcontroller 3 controls the secondary voltage output from the boost circuit 8 by controlling the transistor TR3 via the third output terminal P3. By controlling the transistor TR3, the voltage input to the voltage feedback terminal of the boost circuit 8 can be adjusted. When the transistor TR3 is in the off state, the secondary voltage divided by the resistors R21 and R22 is input to the voltage feedback terminal of the boost circuit 8. On the other hand, when the transistor TR3 is in the on state, the resistor R23 is connected in parallel to the resistor R22, so that the voltage input to the voltage feedback terminal of the boost circuit 8 drops. This causes the secondary voltage output from the boost circuit 8 to rise.

In the case of the camera 1 of this embodiment, in normal shooting operation, during the period when the shutter drive mechanism 21 is driven, the transistor TR3 is controlled to the on state, and a relatively high secondary voltage is output from the boost circuit 8. On the other hand, during the period when the film transport mechanism 22 is driven in normal shooting operation, the transistor TR3 is controlled to the off state, and a relatively low secondary voltage is output from the boost circuit 8.

Next, the battery check operation in the camera 1 of this embodiment will be described with reference to FIGS.
3, in the camera 1 of this embodiment, a battery check operation is started by turning on the release switch 11. That is, when the operator performs a photographing operation on the camera 1, a battery check is executed before the photographing process is started inside the camera 1.

When the release switch 11 is turned on in the camera 1, a battery check operation including a first determination step S1 and a second determination step S2 is executed.
The first determination step S1 includes a step S11 of reversely energizing the shutter drive motor 4, a step S12 of measuring the voltage V1 of the battery 2, and a step S13 of determining the state of the battery 2 by comparing the voltage V1 with a specified value.
The second determination step S2 includes a step S21 of energizing the film transport motor 5, a step S22 of measuring the voltage V2 of the battery 2, and a step S23 of determining the state of the battery 2 by comparing the voltage V2 with the voltage V1.

As shown in FIG. 4, when the release switch 11 is input, the microcomputer 3 controls the transistor TR1 to the on state and drives the shutter drive mechanism 21 (step S11). At this time, the microcomputer 3 reversely energizes the shutter drive motor 4 via the motor driver 9. That is, a voltage in the opposite direction to that during shooting is applied to the shutter drive motor 4. The reversely energized shutter drive motor 4 drives in the direction to close the shutter. Therefore, the shutter will not open during the battery check operation and the film will not be exposed. In addition, the period during which electricity is applied to the shutter drive motor 4 is very short, and does not affect the subsequent shooting operation of the camera 1.

The microcomputer 3 measures the voltage V1 of the battery 2 while the shutter drive mechanism 21 is being driven (step S12). That is, the microcomputer 3 acquires the terminal voltage of the resistor R12 input from the input terminal P0 as a digital value via the AD converter 31. As shown in FIG. 4, when the shutter drive motor 4 is energized, the current flowing through the boost circuit 8 and the shutter drive mechanism 21 increases, and the voltage of the battery 2 decreases accordingly. The microcomputer 3 acquires the voltage V1 of the battery 2, which has decreased due to the increase in current, as a digital value D1 equivalent to the voltage V1.

The microcomputer 3 compares the digital value D1 corresponding to the acquired voltage V1 with a specified value stored in advance in memory (step S13). The specified value to be compared is a digital value obtained by converting the voltage of the battery 2 when the battery 2 has a sufficient capacity for the operation of the camera 1.
If the comparison shows that the digital value D1 is below the specified value, the microcomputer 3 determines that the battery 2 has deteriorated and the voltage is insufficient, and stops the shooting operation. The microcomputer 3 proceeds to a battery NG operation in step S4. In the battery NG operation, the microcomputer 3, for example, blinks or lights up an LED installed on the housing of the camera 1. This makes it possible to prompt the operator to replace the battery 2.

In step S13, if the digital value D1 corresponding to the voltage V1 is equal to or greater than the specified value, the microcomputer 3 proceeds to the second determination step S2.
In the second determination step S2, the microcomputer 3 controls the transistor TR2 to be in the on state, and drives the film transport mechanism 22 (step S21). At this time, the microcomputer 3 executes the supply of electricity to the film transport motor 5 via the motor driver 10. The supply of electricity to the film transport motor 5 is for a very short time, and the film in the camera 1 does not move.
At this time, the microcomputer 3 controls the transistor TR3 to be in an on state, thereby increasing the voltage output from the boost circuit 8. This makes it possible to accurately execute the determination process in step S23, which will be described later.

The microcomputer 3 measures the voltage V2 of the battery 2 while the film transport mechanism 22 is driven (step S22). That is, the microcomputer 3 acquires the terminal voltage of the resistor R12 input from the input terminal P0 as a digital value via the AD converter 31. As shown in FIG. 4, when the film transport motor 5 is energized, the current flowing through the boost circuit 8 and the film transport mechanism 22 increases, and the voltage of the battery 2 decreases accordingly. The microcomputer 3 acquires a digital value D2 equivalent to the voltage V2 of the battery 2 that has decreased due to the increase in current.

The microcomputer 3 compares the digital value D2 corresponding to the acquired voltage V2 with the digital value D1 corresponding to the voltage V1 acquired in step S12 (step S23). If the comparison result shows that the digital value D2 is lower than the digital value D1, the microcomputer 3 determines that the power supply voltage of the battery 2 is at a level at which shooting is possible, and proceeds to the battery OK operation of step S3. In step S3, the microcomputer 3 executes the shooting operation. That is, the shutter is operated by the shutter drive mechanism 21 to expose the film, and the exposed film is transported by the film transport mechanism 22.

In this embodiment, in step S21, the microcomputer 3 controls the transistor TR3 to be on, thereby increasing the voltage supplied to the film transport mechanism 22. This allows a relatively large voltage drop in the battery 2 caused by current flow to the film transport mechanism 22. Therefore, even if the battery 2 has sufficient capacity, the voltage V2 can be reduced. This ensures a relatively large difference between the digital values D1 and D2 in step S23, allowing accurate determination of the magnitude of the digital values D1 and D2.
The amount of decrease in voltage V2 due to an increase in current consumption varies depending on the load configuration, driving conditions, etc. Therefore, if the difference between voltage V2 and voltage V1 is large enough that the output voltage from boost circuit 8 does not need to be increased, a voltage equivalent to that for normal shooting operation may be supplied to film transport mechanism 22 in step S21.

On the other hand, if digital value D2 is equal to or greater than digital value D1 in step S23, this means that almost no voltage drop occurred in battery 2 when electricity was applied to film transport mechanism 22 in step S21, as shown in the right diagram of Figure 4.
When the remaining charge of the battery 2 is low, even if the shutter drive mechanism 21 can be driven, the film transport mechanism 22, which consumes a large amount of power, may not be able to be driven. In such a case, a load is placed on the boost circuit 8 as the boost circuit 8 attempts to increase the primary voltage of the weakened battery 2. When a certain level of load is placed on the boost circuit 8, a protection circuit built into the boost circuit 8 operates, causing the boost circuit 8 to stop boosting. As a result, the voltage of the battery 2 hardly drops, and the measured voltage V2 becomes large.
Furthermore, the conditions under which the protection circuit of the boost circuit 8 operates are influenced not only by the degree of deterioration of the battery 2, but also by the type and brand of the battery 2, fluctuations in the operating state of the load, and fluctuations in environmental temperature, etc. For this reason, it is also difficult to accurately estimate the value of voltage V2 at which the protection circuit operates.
In contrast, in this embodiment, the stop of the operation of the boost circuit 8 can be detected with high accuracy by comparing the digital value D1 corresponding to the voltage V1 with the digital value D2 corresponding to the voltage V2.

If digital value D2 is equal to or greater than digital value D1, microcomputer 3 stops the shooting operation and proceeds to the battery NG operation in step S4. In the battery NG operation, microcomputer 3 causes, for example, an LED installed on the housing of camera 1 to blink or light up. This makes it possible to prompt the operator to replace battery 2.

According to the camera 1 of this embodiment having the above configuration, the state of the battery 2 is determined by executing the first determination step S1 and the second determination step S2, so that a state in which some of the mechanisms of the camera 1 do not operate can be avoided. This makes it possible to prevent problems such as the shutter operating while the exposed film is not transported. Therefore, according to the camera 1 of this embodiment, the deterioration state of the battery 2 can be accurately grasped, and the shooting operation can be reliably performed.

In the above embodiment of the camera 1, a battery check is performed when the shutter is released. However, the battery check may be started in conjunction with an operation other than the release input. For example, the battery check may be started by operating a battery check switch installed on the body of the camera 1.

In this embodiment, the microcomputer 3 of the camera 1 has a battery check unit. However, the battery check function of the above embodiment can be installed in electronic devices other than cameras.
In addition, the device having the battery check function of the above embodiment may be configured as a battery check device that can be connected to an electronic device. That is, a device that includes a voltage measurement unit that measures the voltage of the power supply of the electronic device and a load drive unit that drives the load of the electronic device and can execute the first determination step S1 and the second determination step S2 may be configured as the battery check device. By configuring the device having the battery check function of the above embodiment as an independent battery check device, it becomes easier to apply it to various electronic devices.
Furthermore, the configurations described in this specification can be combined as appropriate within the scope of not being mutually contradictory.

According to the aspects of the present invention, a battery checking device, a battery checking method, and a camera are provided that can accurately determine the deterioration state of a battery and enable reliable operation in electronic devices. Therefore, the present invention has industrial applicability.

1 Cameras 6, 7, 8 Boost circuit 21 Shutter drive mechanism 22 Film transport mechanism S1 First determination step S2 Second determination step V1, V2 Voltage

Claims (9)

A battery checking device applicable to an electronic device that supplies power from a power source to a first load and a second load via a boost circuit, comprising:
a voltage measuring unit that measures a voltage of the power supply of the electronic device;
a load driving unit that drives the first load and the second load of the electronic device using power supplied from the power source via the boost circuit;
having
a first determination step of measuring a voltage V1 of the power supply by the voltage measurement unit during a period in which the first load is driven by the load drive unit, and determining whether the measured voltage V1 is equal to or greater than a predetermined value;
a second determination step of measuring a voltage V2 of the power supply by the voltage measurement unit during a period in which the second load, which consumes more power than the first load, is driven by the load drive unit, and determining whether the measured voltage V2 is smaller than the measured voltage V1;
Execute
Battery check device. In the second determination step, a voltage supplied from the boost circuit to the second load is controlled to a voltage higher than a voltage supplied to the second load during a normal operation of the electronic device.
2. The battery checking device according to claim 1. 1. A battery checking method applicable to an electronic device that supplies power from a power source to a first load and a second load through a boost circuit, comprising:
a first determination step of measuring a voltage V1 of the power supply during a period in which the first load is driven by the power supplied from the power supply via the boost circuit, and determining whether the measured voltage V1 is equal to or greater than a predetermined value;
a second determination step of measuring a voltage V2 of the power supply during a period in which the second load, which consumes more power than the first load, is driven by the power supplied from the power supply via the boost circuit, and determining whether the measured voltage V2 is smaller than the measured voltage V1;
including,
How to check the battery. In the second determination step, a voltage supplied from the boost circuit to the second load is controlled to a voltage higher than a voltage supplied to the second load during a normal operation of the electronic device.
The battery checking method according to claim 3. Power supply,
a boost circuit connected to the power supply;
a first load connected to the boost circuit;
a second load connected to the boost circuit and consuming a larger amount of power than the first load;
a battery check unit that determines the state of the power source;
A camera comprising:
the battery check unit includes a voltage measurement unit that measures a voltage of the power source, and a load drive unit that drives the first load and the second load with power supplied from the power source via the boost circuit,
The battery check unit includes:
a first determination step of measuring a voltage V1 of the power supply by the voltage measurement unit during a period in which the first load is driven by the load drive unit, and determining whether the measured voltage V1 is equal to or greater than a predetermined value;
a second determination step of measuring a voltage V2 of the power supply by the voltage measurement unit during a period in which the second load is driven by the load drive unit, and determining whether the measured voltage V2 is smaller than the measured voltage V1;
determining a state of the power source by executing
camera. The battery check unit includes:
In the second determination step, the voltage supplied from the boost circuit to the second load is controlled to a voltage higher than a voltage supplied to the second load during normal operation of the camera .
The camera according to claim 5. the first load is a shutter drive mechanism that drives a shutter;
7. The camera according to claim 5 or 6. the second load is a film transport mechanism that transports a film;
A camera according to any one of claims 5 to 7. The battery check unit executes the first determination step and the second determination step during a release operation.
A camera according to any one of claims 5 to 8.

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