JPH056781A - Battery operating type device - Google Patents

Abstract

PURPOSE:To provide a battery operating type device which allows a deeper discharge so as not to reduce the discharge capacity by memory effect, dispenses with an exclusive discharge means, thus requires no enlargement of the device for the discharge means, and also provides an advantageous cost. CONSTITUTION:The power source part of an electron steel camera which is a battery operating type device using a Ni-Cd battery 30 as a power source, and its output is outputted as the line of a power source voltage V0 through a stabilizing circuit 31, and the power sources of four systems of power source lines V1, V2, V3, V4 are supplied to determined circuit parts, respectively, through a saving circuit 32 which is a power source system control means for controlling the power supply by a CPU 1. At the time of discharge operation, any one of the power source lines V1, V2, V3, V4 is selected as a load by the CPU 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a battery-operated device, and more particularly to a battery-operated device incorporating a secondary battery as a power supply device.

[0002]

2. Description of the Related Art In recent years, rechargeable nickel-cadmium batteries have been used as power sources for various portable electronic devices such as cameras and word processors, portable razors, electric drills, and various portable measuring instruments. (Hereafter, Ni-
Secondary batteries such as Cd batteries) and lithium batteries are used. Further, this Ni-Cd battery has a long charge / discharge life and is highly popular.

However, the Ni-Cd battery may have a memory effect depending on the charging / discharging method and the discharge capacity may decrease. Regarding this memory effect, FIG.
A description will be given using 20. FIG. 19 shows an example of the discharge waveform of the Ni-Cd battery. As shown in this figure, the discharge voltage reaches the discharge end voltage Vs from the start point A through the discharge time B'point when the voltage becomes flat. Time point B, and then
The discharge voltage drops rapidly. Therefore, when used in equipment, the above-mentioned discharge end voltage Vs is used as the usage limit of the power supply voltage of equipment. Normally, the above-mentioned battery is discharged and recharged until time B, at which the discharge end voltage Vs drops.
In such a state of use, one of the batteries indicated by the area "d" is
A discharge capacity close to 00% can be utilized. In addition,
Discharging until the discharge end voltage Vs is reached is generally called "discharging at a deep discharge depth".

However, since it is desired to keep the battery in a fully charged state at all times, before and after the discharge time point B ', for example,
When in the state of point C, the state of repeating recharging, so-called,
When charging and discharging are repeated at a shallow depth of discharge, the discharge waveform becomes stepwise at point C, as shown in FIG. 20, and the discharge voltage after point C drops. Then, in a general device, the device cannot operate at this voltage, the usable discharge capacity is limited to the range of “d ′”, and the charging energy in the region indicated by “e” cannot be used.

The effect of exhibiting a phenomenon in which the discharge characteristic curve exhibits a stepwise characteristic when recharging is performed in a state where the discharge is not completed is called a "memory effect". This phenomenon is caused by the fact that a portion that does not discharge always remains inside the battery and that portion becomes inactivated. Therefore, the Ni-Cd battery exhibiting the memory effect can be restored by activating the inactivated portion. Therefore, as shown in FIG. 21, for the battery having the memory effect, once the voltage is lower than the initial termination voltage Vs,
If the discharge voltage level is lowered to the voltage Vs' corresponding to the point B and the battery is completely discharged, the discharge characteristic does not change due to the memory effect and the capacity shortage can be eliminated.

On the other hand, the Ni-Cd battery has a characteristic that the discharge capacity changes depending on the magnitude of the discharge current. FIG. 22 shows the discharge current value of one cell of the Ni-Cd battery having a nominal capacity of 600 mAH. It shows the change of the discharge capacity with the parameter. In the figure, the unit CmA that indicates the magnitude of the discharge current is the value obtained by dividing the discharge current by the value that indicates the nominal capacity, and the actual discharge current is the CmA value multiplied by the value that indicates the nominal discharge capacity. Required. Therefore, this figure shows the change in discharge capacity when discharged with a discharge current of 0.2 to 5 CmA, that is, 120 mA to 3 A. When the discharge end voltage is 1.1 V, if the discharge current is small, the discharge capacity is closer to 100%, but when the discharge current is 5 CmA, that is, 3 A, the discharge capacity drops to less than 60%. Will end up. Then, when the discharge is repeated, at the same time, the discharge capacity becomes insufficient due to the above memory effect.

For example, in the case of a camera with a strobe, a current of about 3 A is consumed when the strobe is charged. And
In the case of a Ni-Cd battery driven camera, if the flash light is repeatedly used, as described above, a large discharge capacity shortage occurs due to the memory effect.

In order to solve the above-mentioned problems, therefore, in a portable cassette tape recording / reproducing apparatus or the like which uses a Ni-Cd battery as a power source, the above-mentioned memory is provided in a power source unit, for example, an AC adapter with a charging function. A product equipped with a dedicated discharge circuit for preventing the occurrence of the effect is also commercialized.

[0009]

DISCLOSURE OF INVENTION Problems to be Solved by the Invention In the above-described conventional power source unit with a discharge function, a dedicated circuit for discharging is provided, and there is space for arrangement of the circuit and wiring. It is necessary to make it extra, and there is a problem that the device cannot be made compact enough. Further, in terms of cost, an increase in cost due to the dedicated discharge circuit cannot be avoided.

The present invention has been made in order to solve the above-mentioned problems, and enables the secondary battery for its own power source to be forcibly discharged to a relatively deep discharge depth. It is an object of the present invention to provide a battery-operated device in which the discharge capacity does not decrease due to the memory effect and the discharge means is not provided with a dedicated discharge means.

[0011]

The battery-operated device of the present invention comprises discharge means for forcibly discharging the secondary battery for its own power source to a relatively deep discharge depth before recharging. Further, the discharging means is configured to discharge a predetermined portion of a circuit of the device, which is applied to another purpose when the battery-operated device is in a normal operating state, in a forced discharge operation. It is characterized by having a power supply system control means for applying as a load.

[0012]

The secondary battery for power supply can be forcibly discharged to a comparatively deep discharge depth before recharging by the discharging means, and when the device is in the normal operation state, it is applied to other purposes. The above-mentioned forced discharge is performed through such a circuit unit.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on the illustrated embodiments. FIG. 1 is a main block configuration diagram of a recordable / reproducible electronic still camera which is a battery-operated device according to a first embodiment of the present invention. In this camera, it is assumed that the CPU 1 controls all control elements of the system. The user has an input switch group for instructing each operation, and the input switch group includes a power switch 22 for instructing the operation start of the system and a tele (T side)
A zoom switch 23 that is a bidirectional switch that gives a wide (W side) zoom driving instruction, a two-step operation trigger switch 24 that gives an instruction to execute shooting, and a mode switch 25 that gives an instruction to select a recording, reproduction, or discharge operation mode. It consists of and.

The power source of the camera uses a Ni-Cd battery 30 as its power source, and its output is output as a line of the power source voltage V0 through the stabilizing circuit 31.
Power supply lines V1 and V are connected via a power saving circuit 32 which is a power supply system control means whose power supply is controlled by
Four power sources of 2, V3 and V4 are respectively supplied to predetermined circuit parts. Further, the power supply voltage of the battery 30 is always detected by the power supply voltage detection circuit 33, and its output stops various operations such as recording and reproduction when the power supply voltage drops to the final voltage for the Ni-Cd battery 30. CPU1 for
Is input as an interrupt signal to or a signal for detecting a discharge state.

In this camera, when the power switch 22 is operated with the R side turned on by the mode switch 25 and the recording mode is selected, the preparatory operation is executed. The “recording mode” is displayed via this. Then, the strobe circuit 20 performs charging for the strobe light emitting tube 21 to emit light. When the zoom switch 23 is operated, the zoom lens 4 is driven to the tele or wide side via the zoom drive circuit 9. Then, when the first stage of the trigger switch 24 is turned on, a preparatory operation for photographing is performed. That is, a part of the subject light is incident on the photometric sensor 10 via the half mirror 5, and photometry is performed by the photometric circuit 11. Further, distance measurement information of the subject is obtained by the distance measurement circuit 13 via the distance measurement sensor 12. The photometry and distance measurement information are fetched by the CPU 1, and the diaphragm drive of the diaphragm 3 is performed via the diaphragm drive circuit 8 based on the values.
The focusing lens 2 is driven for focusing via an AF (autofocus) drive circuit 7. On the other hand, the spindle motor of the floppy disk drive device (hereinafter referred to as FDD) 17 for recording and reproducing the video signal is also activated.

Subsequently, when the second stage of the trigger switch 24 is turned on, the image signal of the subject image is recorded. First, the subject light is the focusing lens 2,
The light passes through the diaphragm 3, the zoom lens 4, and the half mirror 5 to form an image on the CCD 6, which is an image sensor. And
The image pickup signal is input to the image pickup process circuit 14. The output video signal is input to the recording circuit 15 and transmitted to the magnetic recording head section of the FDD 17 via the recording / reproducing changeover switch 16 to perform recording. Here, the CCD 6, the imaging process circuit 14, the recording circuit 15, and F
The DD 17 and the like are synchronously driven by an SSG circuit (synchronization signal generation circuit) 19 controlled by the CPU 1.

When the power switch 22 is operated to turn it on while the P side is turned on by the mode switch 25 and the reproduction mode is selected, first, the display circuit 2
"Playback mode" is displayed via 6 and FD
The spindle motor of D17 starts. Then, the recorded video signal is output via the reproduction circuit 18 to an external monitor, an installed EVF (electronic viewfinder, not shown), or the like.

Further, when the power switch 22 is operated to be turned on in the state where the D side is turned on by the mode switch 25 and the discharge mode is selected, the display circuit 2
The "discharge mode" is displayed via 6 and the discharge process is performed. This process is a process for forcibly discharging the Ni-Cd battery to a relatively deep discharge depth by an operator's instruction in order to prevent the occurrence of the memory effect that reduces the discharge capacity. As a discharge load for this discharge process, a circuit portion applied to a purpose other than discharge in a normal state, that is, a recording / reproducing operation state, for example, a strobe circuit 20, CPU1, a power supply voltage detection circuit which is a light load 33, the switches 22 to 25, the display circuit 26, and the zoom drive circuit 9 in a state where the motor is not driven are selected. The selection of the zoom drive circuit 9 is made by a switch built in the power saving circuit 32 of the power supply system control means, which is a switch SW1 for setting the power supply line V1 in the power supply state. In this case, the interrupt at the time of power supply voltage drop is prohibited, while the output of the power supply voltage detection circuit 33 is C
It is fetched from the I / O port of PU1 as an ON / OFF signal compared with the discharge end voltage Vs. Then, when the voltage drop due to the discharge reaches the final voltage Vs, the discharge is terminated, the Ni-Cd battery is in a substantially completely discharged state, and is in a state in which it can be fully charged without a memory effect.

Next, details of the power supply line power supply state of the present camera will be described with reference to the power supply system of the power supply unit of FIG. 2 and the change diagram of the required current in each operation of FIG. As shown in FIG. 2, the output of the Ni-Cd battery 30 is output via the stabilizing circuit 31, one of which is the power supply line V.
0 is directly supplied to the strobe circuit 20, the CPU 1, the power supply voltage detection circuit 33, the switches 22 to 25, and the display circuit 26. Further, the other outputs of the stabilizing circuit 31 are built in the power saving circuit 32, and SW1 to SW which are switches whose ON / OFF is controlled by the CPU 1.
Power supply lines V1 to V4 of each control circuit. One of the outputs, the power supply line V1, is the CPU
It is supplied to the zoom drive circuit 9 through the switch SW1 which operates with the control signal S1 of 1. Furthermore, the power supply line V2 is supplied to the distance measuring circuit 13, the photometric circuit 11, the AF drive circuit 7, the SSG circuit 19, and the FDD 17 via the SW2 operated by the control signal S2 of the CPU 1, respectively. Further, the power supply line V3 is supplied to the image pickup process circuit 14, the recording circuit 15, and the diaphragm drive circuit 8 via SW3 that operates by the control signal S3 of the CPU 1. In addition, the power supply line V4 is connected to the reproduction circuit 18 via SW4 which operates by the control signal S4 of the CPU1.
Is supplied to. The supply relationship between these power supply lines V0 to V4 and each circuit is such that the most power saving can be achieved in each power consumption state in the recording or reproducing operation, and further in the discharging operation, and the desired operation can be performed. It has a supply relationship that can be obtained.

The change in current consumption during the series of recording or reproducing operations will be described with reference to FIG. 3. In this figure, the period Ta is in the power-off state, and the CPU
In the state of 1, only a small current I0 in the power-on waiting state is consumed. Next, the period Tb is an operation state when the mode switch 25 turns on the R side and selects the recording mode. In this case, when the power switch 22 is turned on, the display circuit 26 first enters a display state, and the strobe circuit 20 charges the strobe main capacitor. (Period t1 to t2). The current value I1 at this time is mainly for charging the battery, and varies depending on the camera.
It will be about 4A. After the charging is completed, SW1 of the power saving circuit 32 is turned on, and the zoom drive circuit 9 is activated. At this time, if either the T / W side of the zoom switch 22 is turned on, the zoom drive motor is operated and zooming is performed. The current consumption is indicated by I2 (period t3 to t
Four). As described above, the zoom drive circuit 9 is in the operating state, but the motor is not driven, the current consumption is small, and the power saving circuit 32 is set to the SW1 ON state during the discharging operation as described above.

Then, the trigger switch 24 is operated,
When the first stage is turned on, SW2 of the power saving circuit 32 is turned on. Then, the distance measuring circuit 13, the AF drive circuit 7, the photometric circuit 11, the SSG circuit 19, and the spindle motor of the FDD 17 are activated, and the current consumption at that time is indicated by I3 (period t4 to t5). Further, when the second stage of the trigger switch 24 is turned on, SW3 of the power saving circuit 32 is turned on.
Turns on. Then, the diaphragm drive circuit 8, the imaging process circuit 14, the recording circuit 15 and the like are also activated, and the current consumption at that time is indicated by I4 (time period t5 to t6), which is a current value of about 1 A or less. After recording, SW of power saving circuit 32
2, SW3 is turned off, and the consumption current drops to I5 (period t6 to t7).

Therefore, when the P side of the mode switch 25 is turned on and the reproduction mode is set, SW2 is turned on and F
Start the DD17 spindle motor. Then, when a reproducing instruction is given, SW4 of the power saving circuit 32 is turned on, and the reproducing circuit 18 is brought into an operating state. The current consumption at this time is I
7 (period t8-), the current value is about 1A. Further, when the D side of the mode switch 25 is turned on and the discharge mode is set, only the SW1 of the power saving circuit 32 is turned on and the discharge of the Ni-Cd battery 30 is started. The loads at that time are the strobe circuit 20, the CPU 1, the power supply voltage detection circuit 33, the switches 22 to 25, the display circuit 26, and the zoom drive circuit 9, and the discharge current, that is, the consumption current, has a relatively small value. I2. Therefore, as described above, discharge of a relatively deep depth can be performed.

The operation in the recording / reproducing / discharging mode of the camera of the present embodiment configured as described above will be described in more detail with reference to the flowcharts of FIGS. This camera is usually equipped with the power-on processing rule shown in FIG.
In the chin, it is held in a state of waiting for the ON operation of the power switch 22. Then, the mode switch 25 is switched to one of the R, P, and D sides to perform recording or reproduction.
With the discharge mode selected, the power switch 22
Waiting for the ON operation (step S10), the ON state of the mode switch 25 is discriminated in accordance with the ON operation. Then, when the R side is on, the recording processing routine is performed, when the P side is on, the reproducing processing routine is performed, and when the D side is on, the discharging processing routine is performed.

The power-off process shown in FIG. 5 is a process for ending each operation and turning off each SW of the power-saving circuit 32. As shown in FIG. 5, the display is stopped in step S15. , SW of the power saving circuit 32 in steps S16 to 19
4, SW3, SW2 and SW1 are turned off. After that, the process proceeds to the power-on process (step S20).

FIG. 6 shows a flowchart of the above recording process. In this process, first, the display circuit 26 displays the "recording mode" (step S21). In step S22, the strobe capacitor is charged through the strobe circuit 20. Then, SW1 of the power saving circuit 32 is turned on (step S23), and the power supply line V
Turn 1 on. Then, the 1-minute timer starts counting (step S24). This timer counts to perform the power-off processing from this routine if there is no input from each operation switch during the one-minute counting.

Subsequently, in step S25, the on / off state of the zoom switch 23 is determined. If the zoom switch 23 is turned on, the process jumps to step S26 to call the zoom process of the subroutine of FIG. If there is no ON operation, the process directly proceeds to step S27, and the trigger switch 2
If No. 4 is operated and the first stage is turned on, the process proceeds to step S28, and the trigger 1 process of FIG. 8 is executed. If the first stage is not on, the process proceeds to step S29. And
The state of the mode switch 25 is discriminated. If the P side is turned on, the reproducing process of FIG. 10 is performed (step S3).
0). If the D side is turned on, the discharge process of FIG. 11 is executed (step S31). If the R side remains on, the process proceeds to step S32. Then, the state of the power switch 22 is checked, and if it is off, the power off process of FIG. 5 is executed (step S33). If it is ON, the process proceeds to step S34, it is determined whether or not the 1-minute timer has overflowed, and if it is overflowing, the power-off process is executed. If the overflow has not occurred, the process directly returns to step S25 and waits for the operation of the zoom switch 23 and the trigger switch 24.

In the zoom processing operation of the subroutine called in step S26, as shown in FIG. 7, the state of the zoom switch 23 is determined, and if the W side is on, the zoom lens 4 is driven to the wide side ( Steps S41, 4
3) When the switch 23 is turned off, step S44
Then, the drive of the zoom lens 4 is stopped. Then, in step S47, the 1-minute timer is turned on. On the other hand, T
If the side is on, the zoom lens 4 is driven to the tele side (steps S42 and 45), and if the switch 23 is turned off, the process proceeds to step S46 and the drive of the zoom lens 4 is stopped. Then, similarly, the process proceeds to step S47, and the one-minute timer is turned on. Then, the process returns from the present subroutine to step S27 of the recording process.

Further, in the operation of the trigger 1 process, as shown in FIG. 8, SW2 of the power saving circuit 32 is turned on (step S50), and the power source line V2 is turned on. Then, in steps S51 to S54, distance measurement, AF drive, photometry,
The spindle motor of the FDD 17 is started up. Then, in step S55, the trigger switch 24 is set to 1
After checking if the step is still on,
Similarly, in step S60, it is determined whether or not the second stage of the trigger switch 24 is turned on, and if it is turned on, the trigger 2 processing routine of FIG. 9 is executed. If it is off, the process returns to step S55. If it is confirmed in step S55 that the first stage of the trigger switch 24 is turned off, the process jumps to step S56, the spindle motor is turned off, and SW2 and SW1 are turned off (step S56).
57, 58) and the recording process proceeds in step S59.

In the operation of the trigger 2 process, as shown in FIG. 9, SW3 of the power saving circuit 32 is turned on (step S62), and the power supply line V3 is turned on. Then, the image pickup process circuit 14, the recording circuit 15 and the like are waited for 100 ms, which is a time in which they are in a fully operating state (step S63), and the diaphragm is driven in step S64. Then, the video signal is output to the FDD 17 via the recording circuit 15 to record the video signal on the floppy disk (step S65). Subsequently, the recording head is accessed to the subsequent unrecorded track position (step S66), the spindle motor is turned off in step S56, and the SW
3, SW2, SW1 are turned off (steps S68, 69,
70), and proceeds to the recording process in step S71.

In addition, the above-mentioned reproduction processing is performed by the mode switch 2
5 is selected when the P side is on, and FIG.
As shown in 0, the display circuit 26 first displays the "reproduction mode" (step S72). In steps S73 and S74, SW2 and SW4 of the power saving circuit 32
Is turned on, and the power supply lines V2 and V4 are turned on. Then, in step S75, the spindle motor is turned on to reproduce the video signal. Then, step S76.
At step S77, the on state of the power switch 22 is confirmed, and at step S77, the mode switch 25 confirms that the P side is on, and the process returns to step S76 to continue the reproduction process.

In step S76, the power switch 22
If it is detected that the power is off, the spindle motor is turned off (step S78), and the power off process is executed in step S79. If it is detected in step S77 that the R side of the mode switch 25 is turned on, the process jumps to step S80, the spindle motor is turned off, and SW4, SW2, and SW1 are turned off (step S8).
2, 83, 84) and then the recording process (step S85). When the D-side ON of the mode switch 25 is detected, the process jumps to step S81 to turn off the spindle motor, and further SW4, SW2, SW1.
Is turned off (steps S86, 87, 88), and then the discharge process is started (step S89).

The above-mentioned discharge treatment is performed by Ni--Cd before charging.
This is a process of performing forced discharge of the battery, and as shown in FIG. 11, in step S91, interruption at the time of power supply voltage drop is prohibited. At this time, the power supply voltage detection circuit 33
The power supply voltage output of 1 is fetched from the I / O port of the CPU 1 as an on / off signal compared with the discharge end voltage Vs. In step S92, the "discharge mode" is displayed and only the zoom drive circuit 9 is selected as the discharge load. Therefore, in step S93, SW1 is turned on to start discharging with the power supply line V1 in the power supply state. continue,
In step S94, it is confirmed that the power switch 22 is on, in step S95 it is confirmed whether the power supply voltage has dropped to the final voltage Vs, and the process proceeds to step S97. When the power switch 22 is turned off or the power supply voltage has reached the final voltage Vs, in order to end the discharge operation, the process jumps to step S96 to execute the power off process.

In step S97, the mode switch 25 is set to D.
If it is confirmed that the side is on, the process returns to step S94 to continue the discharge process. However, when the R-side ON is detected, the process jumps to step S98, SW1 is turned off (step S98), and then the process proceeds to the recording process (step S100). If the P-side ON is detected, the process jumps to step S98 ', SW1 is turned off, and the reproduction process is started (step S99).

As described above, in the present embodiment, it is not necessary to newly install a dedicated discharge circuit, and it is usually a relatively light load among the circuits used for camera control and the like. A certain circuit, that is, the zoom drive circuit 9 is used as a discharge load, and discharge at a deeper depth can be performed with a cost or space-effective configuration. Although the zoom drive circuit is used as the discharge load in the present embodiment, the load circuit is not limited to this circuit and a load circuit suitable for deep discharge may be selected from the control circuit.

Next, an electronic still camera which is a battery-operated device showing a second embodiment of the present invention will be described with reference to FIG. The electronic still camera of this embodiment uses a Ni-Cd battery as a power source as in the case of the first embodiment. The discharge characteristics of the Ni-Cd battery are shown in FIG.
As described in 2, when the discharge current of the Ni-Cd battery is large, the discharge rate is high but the dischargeable capacity is small. Further, when the discharge current is small, the discharge speed is slow, but the discharge is more complete. Therefore, the present camera utilizes this characteristic and does not cause the memory effect in the Ni-Cd battery. Therefore, in the discharging process, the load circuit is changed from a heavy load circuit to a light load circuit, that is, a circuit with a large current consumption. It is possible to perform a deeper depth of discharge earlier by sequentially switching from a small circuit to a small number of circuits. The circuit configuration and the processes other than the discharge process are the same as those in the first embodiment. Therefore, FIGS. 1 and 2 showing the circuit configuration are
It can be applied to this embodiment as it is.

FIG. 12 is a flow chart of the discharging process of the camera of this embodiment. When the discharging mode is selected by the mode switch 25, the discharging process is executed.
First, in step S110, interrupts when the power supply voltage drops are disabled. At this time, the power supply voltage detection circuit 33
Output from the I / O port of CPU1 to discharge end voltage Vs
It is taken as an on / off signal compared with.
In step S111, the "discharge mode" is displayed, and only the zoom drive circuit 9 by the power supply line V1, which is the lightest load, is selected as the discharge load.
At 2, SW1 is turned on. Then, it is determined whether or not the power supply voltage at that time has dropped to the final voltage Vs.
If the final voltage Vs has been reached, the discharge is naturally ended, so that the process jumps to step S114 to execute the power-off process. If the final voltage Vs has not been reached, the process further proceeds to step S115, where a slightly heavy load is applied to the power supply line V2.
In order to select the distance measuring circuits 13 to FDD17 (see FIG. 2) according to, the SW2 of the power saving circuit 32 is turned on. Therefore, it is determined whether the power supply voltage has dropped to the final voltage Vs. If the final voltage Vs has been reached, step S117
Jump to step S2, and switch SW2 off and switch SW1 on so that the battery is discharged with a lighter load, and then step S12
Go to 3. If the final voltage Vs has not been reached, the process proceeds to step S118.

In the discharged state of the battery, when the cutoff voltage is reached on a heavy load, switching to a lighter load increases the discharge voltage at the time of switching, but this causes discharge at a deeper depth. Is possible. For example, as shown in FIG. 22, when the discharge current is 5 CmA, when the discharge voltage drops to the final voltage Vs (point H), the load is lightened and the discharge current is switched to 3 CmA. Goes up to point G ', and discharge becomes possible. After discharging to point G, if the load is further reduced and the discharge current is switched to 0.5 CmA,
The discharge voltage rises to the point F ', and further discharge becomes possible, and discharge can be made to the deeper point F. In the camera of the present embodiment, the load is sequentially switched to the lighter one to enable deeper discharge as in step S116 or the processing of step S119 and step S127 described later.

Now, in the step S118,
Further, SW3 is turned on to make the load heavy. Then, it is again determined whether the power supply voltage has dropped to the final voltage Vs (step S119). If the final voltage Vs has been reached, the process jumps to step S120, SW3 is turned off so as to discharge with a medium load, the discharge state is turned on with SW1 and SW2 turned on, and the process proceeds to step S127. Also,
If it is determined in step S119 that the final voltage Vs has not been reached, discharging is performed under a heavy load in the ON state of SW1, SW2, and SW3, and the process proceeds to steps S121 and 122.

In steps S121 and S122, it is confirmed that the power switch 22 is on and the mode switch 25 is on the D side, and the process returns to step S119 to continue the discharge. When the power switch 22 is detected to be off, the process jumps to step S114 to execute power off processing. If the R side of the mode switch 25 is on, the discharge is stopped, the process proceeds to steps S132 to 135 of the connection point M of FIG.
2, SW1 is turned off, and the recording process is started. Furthermore, if the mode switch 25 is on the P side, the discharge is stopped, and steps S136 to S13 of the connection point Q in FIG.
8, the SW3, SW2, and SW1 are turned off, and the reproduction process is started.

In step S127, it is again determined whether the power supply voltage has dropped to the final voltage Vs. If the final voltage Vs has been reached, the process jumps to step S117, and discharge is performed with a lighter load. If the final voltage Vs has not been reached, discharging is performed with a medium load in the ON state of SW1 and SW2, and steps S128, 1
Proceed to 29.

In steps S128 and 129, it is confirmed that the power switch 22 is on and the mode switch 25 is on the D side, and the process returns to step S127 to continue the discharge. When the power switch 22 is detected to be off, the process jumps to step S114 to execute power off processing. If the mode switch 25 is on the R side, discharging is stopped, the process proceeds to steps S139 to 141 of the connection point W in FIG. 13D, SW2 and SW1 are turned off, and the recording process is started. Furthermore, the mode switch 25
Is on the P side, the discharge is stopped, and FIG.
Of the connection point U of step S142, 143, SW
2, SW1 is turned off, and the process proceeds to the reproduction process.

In step S117, SW2 is turned off, and it is determined whether the power supply voltage has dropped to the final voltage Vs (step S123). If the final voltage Vs has been reached, it is determined that the discharge has already ended, and the process jumps to step S114 to execute the power-off process.
If the final voltage Vs has not been reached, discharging is performed with a light load in which only SW1 is on, and steps S124 and S12.
Go to 5.

In steps S124 and S125, it is confirmed that the power switch 22 is on and the mode switch 25 is on the D side, and the process returns to step S123 to continue the discharge. When the power switch 22 is detected to be off, the process jumps to step S114 to execute power off processing. If the mode switch 25 is on the R side, discharging is stopped, the process proceeds to steps S130 and 131 of the connection point L in FIG. 13A, SW1 is turned off,
Move to recording processing. Further, when the mode switch 25 is on the P side, SW1 is turned off and the process proceeds to the reproducing process (step S126).

As described above, in the camera of this embodiment,
In the discharge processing, it is not necessary to add a dedicated discharge circuit, and moreover, it is possible to perform discharge at a deep depth more quickly by switching the circuit which becomes a load.

Next, an electronic still camera which is a battery-operated device showing a third embodiment of the present invention will be described with reference to FIGS. The electronic still camera of this embodiment uses a Ni-Cd battery as a power source as in the first embodiment. However, in this camera, the Ni-Cd battery already has the above memory effect. Even if it happens, the discharge capacity of the battery can be recovered. The Ni-Cd battery has a discharge characteristic line of 2 when it is repeatedly recharged in a state where it is not completely discharged as described in FIG.
It becomes step-shaped, and the initial discharge capacity Vs cannot use the initial discharge capacity. Therefore, in the discharge processing of the present embodiment, as shown in FIG. 15, the discharge that is performed while monitoring the power supply voltage at the point C where the final voltage Vs is once detected for the battery that has caused the memory effect. The process is interrupted, and subsequently, the time up to point B, which is estimated to be the final voltage dropped by one step, is set in advance, and the discharge is executed only during the set time until the time elapses regardless of the voltage. To do. The circuit configuration and
The processes other than the discharge process are the same as those in the first embodiment.
Therefore, FIGS. 1 and 2 showing the circuit configuration can be applied to this embodiment as they are.

The flow chart of the electric discharge process is shown in FIG. First, in step S150, interrupts when the power supply voltage drops are disabled as in the second embodiment. In step S151, "discharge mode" is displayed,
In order to set the lightest load as the discharge load, step S
At 152, SW1 is turned on, and the power supply line V1 is supplied with power. Then, after confirming that the power switch 22 is turned on, the process proceeds to step S155. Power switch 2
If 2 is detected to be off, step S15
Jump to 4 and execute the power-off process.

In step S155, it is determined whether the power supply voltage has dropped to the final voltage Vs. If the final voltage Vs has not been reached, discharging is performed with a light load in which only SW1 is on, and the flow proceeds to step S157. Then, after confirming that the mode switch 25 is on the D side, the process returns to step S153. R of mode switch 25
If the side is on, the discharge is stopped, so SW1 is turned off in step S158, and the process proceeds to the recording process (step S159). Further, when the P side of the mode switch 25 is ON, the SW1 is turned OFF and the reproduction processing is started (step S160).

When it is detected that the power supply voltage has dropped to the final voltage Vs in the determination processing in step S155,
Since it can be determined that point C in FIG. 15 has been reached, step S
Jumping to 156, the T timer, which is a timer for the time T considered to end the deep discharge, that is, the time T between C and B in FIG. 15 with a certain margin, is turned on to start time counting. Then, in step S161, it is confirmed that the power switch 22 is on, and then in step S162.
And continue discharging until the T timer overflows. If the overflow has occurred, proceed to step S163,
The discharge is terminated and the power off process is executed.

As described above, in the camera of this embodiment,
It is not necessary to add a dedicated discharge circuit for the discharge treatment, and it is possible to recover the Ni-Cd battery whose discharge capacity has become insufficient due to the memory effect.

Next, an electronic still camera which is a battery operated device showing a fourth embodiment of the present invention will be described with reference to FIGS. Similar to the third embodiment, the electronic still camera of the present embodiment enables recovery of the discharge capacity of the Ni-Cd battery even when the memory effect has already occurred. Is. In the third embodiment, the discharge process is performed by determining the time required for discharge after detecting the voltage of the first stage discharge end voltage Vs as the power supply voltage by the timer timing process. However, naturally, the time required for the discharge after detecting the discharge end voltage Vs of the first stage varies. If the battery is discharged earlier than the set time, the CPU 1 is reset due to the voltage drop and the discharging is completed, so that the deadlock state of the system can be barely avoided. However, if the complete discharge is not performed within the set time, the discharge capacity is not completely restored.

Therefore, in the camera of the present embodiment, the discharge state is monitored after the discharge stop voltage Vs of the first stage, which is the first voltage and the voltage at which recording and reproduction are operated, is detected. , Which is lower than the voltage and which is the lowest level voltage at which the CPU 1'can operate, and is performed by the second-stage termination voltage Vs' of the second voltage shown in FIG. Therefore, in the case of the present embodiment, even if the discharge characteristic due to the memory effect varies, the final voltage V of the second stage is always maintained.
Discharge until the power supply voltage drops to s'is certainly possible, and a sufficiently deep discharge can be executed.

In the present embodiment, it is necessary to detect the above two final voltages Vs and Vs'. Therefore, the CPU 1'uses A / D conversion to take in the output voltage of the Ni-Cd battery 30. The part 1a 'is built in. The first A / D value is output from the A / D converter 1a 'when the power source voltage reaches the final voltage Vs, and the A / D conversion is performed when the power source voltage reaches the final voltage Vs'. Part 1
The second A / D value is output from a '. The voltage of the battery 30 other than the time of discharging is taken in from the interrupt terminal portion via the power supply voltage detection circuit 33 as in the first embodiment. Further, other circuit configurations and processes other than the discharge process are the same as those in the first embodiment.

FIG. 17 shows a flowchart of the discharge processing of the camera of this embodiment. First, in step S170,
As in the case of the third embodiment, interrupts when the power supply voltage drops are disabled. In step S171, the "discharge mode" is displayed, and the lightest load is set as the discharge load, so that SW1 is turned on in step S172. And
After confirming that the power switch 22 is on, the process proceeds to step S175. If it is detected that the power switch 22 is off, the process jumps to step S174 to execute power off processing.

In step S175, the power supply voltage is set to 1 above.
Whether or not the final voltage Vs of the stage is reached, that is, the first A /
Determine whether a D value was detected. If the first A / D value is not detected, the process proceeds to step S176, it is confirmed that the mode switch 25 is on the D side, the process returns to step S123, and the discharge is continued. Then, when the mode switch 25 is on the R side, the discharge is stopped, so that SW1 is turned off in step S177, and the process proceeds to the recording process (step S179). Further, if the mode switch 25 is on the P side, SW1 is turned off, and the process proceeds to the reproduction process (step S178).

Further, the power supply voltage reaches the final voltage Vs of the first stage by the above discharge, and the first A / A voltage is reached in step S175.
If the D value is detected, the process jumps to step S180 to determine whether the power supply voltage has reached the second-stage final voltage Vs', that is, whether the second A / D value is detected. Then, the discharge is continued until the value is detected. When the power switch 22 is turned off, the process jumps to step S174 to execute power off processing (step S181). Further, the power supply voltage drops to the final voltage Vs' of the second stage, and the second A / D is determined in step S180.
If a value is detected, the process jumps to step S174 to end the discharge.

As described above, in the camera of this embodiment,
The final voltage Vs of the first stage and the limit of 2 at which the CPU 1 ′ operates
Since the discharge voltage is controlled by detecting the end voltage Vs' of the stage, it is possible to more reliably recover the Ni-Cd battery whose discharge capacity has become insufficient due to the memory effect. is there.

Next, an electronic still camera which is a battery operated device showing a fifth embodiment of the present invention will be described with reference to FIG. Like the first embodiment, the electronic still camera of this embodiment uses a Ni-Cd battery as a power source, and normally controls the generation of the memory effect without using a dedicated discharge circuit. A circuit is used to perform discharge processing. Further, in the case of the present embodiment, even if it is suddenly necessary to release the shutter of the camera during the discharge processing period, the photographing and recording can be performed without switching the mode switch 25. Is a camera that can perform. The circuit configuration and the processes other than the discharge process are the same as those in the first embodiment. Therefore, FIGS. 1 and 2 showing the circuit configuration can be applied to this embodiment as they are.

FIG. 18 is a flowchart of the discharge process of the camera of this embodiment. First, in step S190,
As in the case of the first embodiment, interrupts when the power supply voltage drops are disabled. In step S191, "discharge mode" is displayed, and the lightest load is set as the discharge load, so that SW1 is turned on in step S192. And
After confirming that the power switch 22 is on in step S193, the process proceeds to step S194. If it is detected that the power switch 22 is off, the process jumps to step S195 to execute power off processing.

In step S194, it is determined whether or not the power supply voltage has dropped to the final voltage Vs. If the final voltage Vs is reached, the discharge is terminated, so that the process jumps to step S195 to execute the power-off process. If the final voltage Vs has not been reached, step S1
In step 96, it is determined whether the first stage of the trigger switch 24 is on. If it is on, the process jumps to step S199 to turn off SW1 and execute the recording process (step S200). If the first stage is not on, the process proceeds to step S197 to determine the state of the mode switch 25. If it is confirmed that the mode switch 25 is on the D side, step S193
Return to and continue the discharge. Then, the mode switch 25
When the R side is on, the discharge is stopped, so that SW1 is turned off in step S199, and the process proceeds to the recording process (step S200). Furthermore, the mode switch 25 is set to P
If the switch is on, the switch SW1 is turned off and the process proceeds to the reproduction process (step S198).

As described above, in the camera of this embodiment,
The Ni-Cd battery is discharged using a circuit for a camera without using a circuit dedicated to discharging, and at the same time, the mode switch 25 is not switched even during the discharging period, and the camera is immediately discharged. The shutter can be released.

[0061]

As described above, the battery-operated device of the present invention has the discharging means for forcibly discharging the secondary battery to a deep discharge depth, and by the discharging means,
Since the specified part of the circuit applied for other purposes is used as the load during the forced discharge operation in the normal operation state, the discharge process for preventing the decrease of the discharge capacity due to the memory effect is effective. In addition, since there is no need to provide a dedicated discharge means, there is no need to upsize the device for the discharge means, and there are many remarkable effects such as cost advantages. There is.

[Brief description of drawings]

FIG. 1 is a block configuration diagram of an electronic still camera that is a battery-operated device according to a first embodiment of the present invention.

FIG. 2 is a diagram showing a power supply system of a power supply unit of the camera shown in FIG.

FIG. 3 is a diagram showing current consumption in each operation state of the power supply unit of the camera of FIG.

4 is a flowchart of power-on processing of the camera shown in FIG.

5 is a flowchart of a power-off process of the camera shown in FIG.

FIG. 6 is a flowchart of recording processing of the camera of FIG.
To.

7 is a flowchart of zoom processing of the camera shown in FIG.
To.

FIG. 8 is a flowchart of trigger 1 processing of the camera of FIG.

9 is a flowchart of trigger 2 processing of the camera shown in FIG.

10 is a flowchart of a reproduction process of the camera of FIG.
To.

FIG. 11 is a flowchart of discharge processing of the camera shown in FIG.
To.

FIG. 12 is a flowchart of a discharge process of an electronic still camera which is a battery operated device according to a second embodiment of the present invention.

13 is a diagram showing a part of a flow chart of a discharge process of the camera of FIG.

FIG. 14 is a flowchart of a discharge process of an electronic still camera which is a battery operated device according to a third embodiment of the present invention.

15 is a diagram showing discharge characteristics of the Ni—Cd battery of the camera of FIG.

FIG. 16 is a main block configuration diagram of a power supply unit of an electronic still camera that is a battery-operated device according to a fourth embodiment of the present invention.

FIG. 17 is a flowchart of discharge processing of the camera of FIG.

FIG. 18 is a flowchart of a discharge process of an electronic still camera which is a battery operated device according to a fifth embodiment of the present invention.

FIG. 19 is a diagram showing a discharge waveform of a conventional Ni-Cd battery.

FIG. 20 is a diagram showing a discharge waveform in a state where the memory effect of the conventional Ni-Cd battery occurs and the discharge capacity is reduced.

FIG. 21 is a diagram showing a discharge waveform in a state where the discharge capacity is recovered after the memory effect of the conventional Ni-Cd battery occurs.

FIG. 22 is a diagram showing discharge characteristics of a conventional Ni-Cd battery with the discharge current as a parameter.

[Explanation of symbols]

1, 1 '... ............ CPU (power system control means, discharge means) 1a' …………………… A / D converter (power system control means, discharge means) 7 …………………………………… AF drive circuit (load for discharging) 8 ……………………………… Aperture drive circuit (load for discharging) 9 ………… …………………… Zoom drive circuit (load for discharging) 11 ……………………………… Photometry circuit (load for discharging) 13 ………………………… ………… Distance measuring circuit (load for discharging) 14 …………………………………… Imaging process circuit (load for discharging) 15 …………………………………… Record Circuit (load for discharging) 17 …………………………………… FDD (load for discharging) 18 ……………………………… Regeneration circuit (load for discharging) ) 19 ……………… …………………… SSG circuit (load for discharging) 32 ……………………………… Power saving circuit (power system control means, discharge means) 33 ………………………… ……… Power supply voltage detection circuit (power supply system control means)

Claims (5)

[Claims] 1. A battery-operated device comprising discharge means for forcibly discharging a self-power source secondary battery to a relatively deep discharge depth before recharging. 2. The discharging means applies a predetermined part of a circuit of the battery-operated device for other purposes when the battery-operated device is in a normal operation state, as a load for this discharging during a forced discharge operation. The battery-operated device according to claim 1, further comprising a power supply system control means for application. 3. The battery-operated device according to claim 2, wherein the power supply system control means is configured to switch and connect a load during the duration of the forced discharge operation. 4. The power supply system control means counts the duration of the period during the period of forced discharge operation and after the electromotive force of the secondary battery drops below a predetermined value. The battery operated device of claim 2, wherein the battery operated device is configured to be managed by. 5. The power supply system control means is configured such that, during the duration of the forced discharge operation, the electromotive force of the secondary battery is a predetermined first value.
The period after the voltage value falls below the first voltage value is managed as a period until the electromotive force reaches a predetermined second voltage value lower than the first voltage value. The battery operated device of claim 2.