JP4576022B2 - Power circuit - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a power supply circuit for an electronic device that can be driven by a battery, and in particular, effectively reduces battery life due to a sudden change in a load such as a strobe in an electronic camera without significantly increasing the cost. The present invention relates to a power supply circuit of an electronic device that can be prevented.
[0002]
[Prior art]
In recent years, a subject image is imaged on a solid-state image sensor such as a CCD two-dimensional image sensor by an imaging optical system and converted into an electrical signal, and the image data of the still image obtained thereby is recorded as in a semiconductor memory or a magnetic disk. So-called electronic cameras that record on a medium are becoming widespread. Further, since this type of electronic camera is a product that is assumed to be carried by a user, it is naturally configured to be battery-driven.
[0003]
By the way, this type of electronic camera is equipped with a large number of various components (loads) that cause abrupt fluctuations depending on the usage conditions, such as actuators such as strobes and various motors. Such load fluctuations cause a loss in the internal resistance of the battery and cause deterioration of the life. For example, when attention is paid to the usage state of the strobe, as shown in FIG. 8, the fluctuation of the load current greatly appears due to charging and light emission, which causes deterioration of the battery life.
[0004]
Therefore, conventionally, for example, it has been studied to suppress the deterioration of the battery life due to a sudden change on the load side by inserting a capacitor between the battery and the load, for example. However, conventional capacitors are unsuitable for application to electronic cameras that are being miniaturized every day due to their shape and size, and they did not have the ability to follow fluctuations on the load side. In the first place, there was a problem that application to an electronic camera was not realistic.
[0005]
In this situation, on the other hand, due to improvements in electrolytic membrane technology, it has become possible to form a physical adsorption layer of ions. Therefore, as with conventional capacitors, the electrolyte is sealed to accumulate charge. In other words, an electric double layer capacitor that can be rapidly charged and discharged by accumulating electric charge by physical adsorption rather than using a chemical reaction has been developed. Since this electric double layer capacitor can be provided in any shape, for example, as in the power supply circuit described in Japanese Patent Application Laid-Open No. 11-27859, the capacitor is inserted between the battery and the load to rapidly It has become possible to suppress the deterioration of battery life due to various fluctuations even in electronic devices that are becoming smaller.
[0006]
[Problems to be solved by the invention]
However, if an electric double layer capacitor is provided for each load that fluctuates as in the power supply circuit described in Japanese Patent Application Laid-Open No. 11-27859, there is a risk that the cost will increase significantly. No consideration is given to the leakage problem caused by the double layer capacitor when the power is turned off.
[0007]
The present invention has been made in consideration of such circumstances, and effectively prevents deterioration of the battery life due to sudden fluctuations in the load, such as a strobe in an electronic camera, without significantly increasing the cost. An object of the present invention is to provide a power supply circuit for an electronic device that can be used.
[0008]
[Means for Solving the Problems]
In order to achieve the above-described object, the power supply circuit according to the present invention distributes the power from the battery to a plurality of systems and supplies the power to a plurality of loads including at least a system controller. A switch that can be switched on / off, and an electric double layer capacitor that suppresses the deterioration of the battery life due to a sudden change in each load. The switch and the electric double layer capacitor are connected in series. The system controller is connected between a normal mode and a standby mode as an operating state of the device main body, and is provided so as to be interposed between the battery and each load at a location before power distribution. controls, by turning off the switch when a transition operation state to the standby mode, the power supply to the load And the battery that is characterized by interrupting the circuit of the electric double layer capacitor.
[0010]
According to another aspect of the present invention, there is provided a power supply circuit that supplies power from any one of a plurality of power supplies including a battery to a plurality of loads including at least a system controller via a power supply line. Switching means for selectively taking in power from the power source, a switch that is switched on / off in conjunction with the operating state of the device main body, and suppressing the deterioration of the battery life due to sudden fluctuations in each load An electric double layer capacitor for connecting the switch and the electric double layer capacitor in series and interposing at least between the battery and each load, wherein the system controller includes the device Controls the transition between normal mode and standby mode as the operating state of the main unit, and shifts the operating state to standby mode. If off the switch, and the battery power supplied to the load, characterized by interrupting the circuit of the electric double layer capacitor.
[0011]
In the power supply circuit of the present invention, while preventing the influence of the leakage generated by the electric double layer capacitor on the battery when the power is off or in the standby mode, the battery life is effectively prevented from being deteriorated due to a sudden change in the load. It is possible to do.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
[0013]
FIG. 1 is an external view of an electronic camera according to an embodiment of the present invention.
[0014]
As shown in FIG. 1, this electronic camera is provided with a lens 2, a strobe 3, a release switch 4, and the like on the peripheral wall of the camera body 1, and the electronic camera operates inside the camera body 1. A battery 5 for supplying electric power to be stored is detachably stored.
[0015]
FIG. 2 is a diagram showing a device configuration inside the electronic camera. Here, the imaging principle of the electronic camera will be described with reference to FIG.
[0016]
The amount of light of the subject light is controlled by the diaphragm 6 after passing through the lens 2. The lens 2 and the diaphragm 6 are driven by a drive circuit 7. The subject light that has passed through the lens 2 and the diaphragm 6 is incident on the CCD 8, and a subject image is formed on the imaging surface. This imaging surface is configured by arranging a plurality of pixels that perform photoelectric conversion in a two-dimensional matrix and further arranging a color filter, and accumulates signal charges corresponding to the formed subject image. The accumulated signal charge is read as an electrical signal called a pixel signal and converted into digital image data, and then temporarily stored in a buffer memory 9 made of, for example, a DRAM.
[0017]
An image recording / reproducing unit 10 is connected to the buffer memory 9, and the image data stored in the buffer memory 9 is recorded on the recording medium 11. The recording medium 11 is generally a memory card composed of a semiconductor memory such as a card-type flash memory, but is not limited to a memory card, and is a magnetic recording medium such as a hard disk or a floppy disk. Etc., various forms can be used.
[0018]
All the operations described above are governed by the system controller 12, and the system controller 12 executes the above-described operation control according to the operation contents of various switches including the depression of the release switch 4 notified from the operation input unit 13.
[0019]
The strobe 3 is a light source for taking a dark subject image, and is controlled by the strobe control circuit 14 to control the light emission amount. The strobe control circuit 14 includes a strobe capacitor capable of storing a predetermined amount of charge, and drives the strobe 3 by charging and discharging the strobe capacitor.
[0020]
Further, the power supply circuit 15 boosts or steps down the power from the battery 5 and controls supply to each unit. The strobe control circuit 14 and the power supply circuit 15 are also driven and controlled by the system controller 12.
[0021]
The power supply circuit according to the present invention can effectively prevent the life of the battery 5 from being deteriorated due to a sudden change caused by the drive circuit 7 or the strobe control circuit 14 without causing a significant increase in cost. This point is described in detail below.
[0022]
FIG. 3 is a schematic configuration diagram of a power supply circuit 15 applied to the electronic camera.
[0023]
As shown in FIG. 3, the power supply circuit 15 supplies the electric power from the battery 5 to the strobe control circuit 14 as it is. For example, the system controller 12 and the drive circuit 7 are each supplied with a DC / DC converter 151. After being converted to the desired voltage, it is distributed and supplied. In the power supply circuit 15, the electric double layer capacitor 152 for preventing the life deterioration of the battery 5 from being caused by the sudden fluctuation of the strobe control circuit 14, the drive circuit 7, etc. Insert it into the power line before sorting. Thereby, since it is not necessary to provide a plurality of electric double layer capacitors, it is possible to effectively prevent the deterioration of the battery life due to a sudden change in load without causing a significant increase in cost.
[0024]
Also, FIG. 4 is connected in series with the electric double layer capacitor 152 and is turned on / off in conjunction with the operating state of the camera body such as on / off of the power switch and transition between the normal mode and the standby mode. It is a schematic block diagram of the power supply circuit 15 further provided with the switch 153 switched.
[0025]
In the power supply circuit 15, the circuit between the battery 5 and the electric double layer capacitor 152 is cut off when the power source of the camera body is turned off or when the power supply circuit 15 is shifted to a standby mode where no load fluctuation can occur. Therefore, in addition to the effect of the configuration shown in FIG. 3, the leakage of the electric double layer capacitor 151 is further prevented from adversely affecting the battery 5.
[0026]
FIG. 5 is a diagram for more specifically showing the relationship between the switch 153 and the electric double layer capacitor 152. As shown in FIG. 5, the switch 153 and the electric double layer capacitor 152 are connected in series. The switch 153 switches on / off in conjunction with the operating state of the camera body, such as turning on / off the power switch and switching between the normal mode and the standby mode, so that the load of the camera body can be In the normal mode where fluctuations can occur, the circuit of the electric double layer capacitor 151 and the battery 5 is established. On the other hand, when the camera body is turned off or in the standby mode where no load fluctuation can occur, the electric double layer capacitor 152 and the battery 5 Shut off the circuit.
[0027]
FIG. 6 is a schematic configuration diagram of a power supply circuit 15 that selectively takes in power from, for example, an external commercial power supply in addition to the battery 5 and controls supply to each unit. The power supply circuit 15 performs switching to take in this power when the power from the external commercial power source is available, and to take in the power from the battery 5 when the power from the external commercial power source is not available. It has. The switching device 154 performs known mechanical or electrical switching.
[0028]
Even in the power supply circuit having such a configuration, by inserting the electric double layer capacitor 152 into the power supply line before being distributed to a plurality of systems, the battery 5 accompanying a rapid change in load is caused without causing a significant cost increase. It is possible to effectively prevent the deterioration of the lifetime.
[0029]
The electric double layer capacitor 152 is provided between the battery 5 and the switching device 154 because the same effect can be obtained if it is interposed at least between the battery 5 and each part before being distributed to a plurality of systems. It doesn't matter. In addition, the selective capture of power from a plurality of power sources by the switching device 154 is not necessarily exclusive.
[0030]
Similarly, FIG. 7 is also a schematic configuration diagram of a power supply circuit 15 that selectively takes in power from, for example, an external commercial power supply in addition to the battery 5 and controls supply to each unit. The power supply circuit 15 also performs switching to take in this power when the power from the external commercial power source is available, and to take in the power from the battery 5 when the power from the external commercial power source is not available. It has. This switching device 154 also performs known mechanical or electrical switching.
[0031]
Even in such a configuration, by connecting the switch 153 and the electric double layer capacitor 152 in series and inserting the switch 153 and the electric double layer capacitor 152 into the power supply line, the battery 5 accompanying a sudden change in the load is caused without causing a significant cost increase. It is possible to effectively prevent the life of the battery 5 from being deteriorated and to prevent the leakage of the electric double layer capacitor 152 from adversely affecting the battery 5.
[0032]
The switch 153 and the electric double layer capacitor 152 can also be provided between the battery 5 and the switching device 154 because the same effect can be obtained if it is interposed at least between the battery 5 and each part. Further, the selective capturing of power from a plurality of power sources by the switching device 154 is not necessarily exclusive.
[0033]
As described above, the power supply circuit according to the present invention effectively prevents battery life deterioration due to sudden fluctuation on the load side without causing a significant increase in cost, and appropriately copes with leakage when the power is turned off. To do.
[0034]
【The invention's effect】
As described above in detail, according to the power supply circuit of the present invention, the electric double layer capacitor for suppressing the deterioration of the life of the battery due to the rapid fluctuation of the load is obtained before the power from the battery is distributed to a plurality of systems. Since it is inserted on the power supply line, it can absorb sudden fluctuations of these loads by providing only one electric double layer capacitor without providing an electric double layer capacitor for each load that fluctuates rapidly. Therefore, it is possible to prevent a significant increase in cost as in the conventional case.
[0035]
In addition, for example, a switch that is switched on / off in conjunction with the operating state of the device body, such as a power switch on / off or a transition between a normal mode and a standby mode, and a battery load change accompanying a sudden load change Leakage generated by the electric double layer capacitor when the power is turned off or in the standby mode because the electric double layer capacitor is connected in series and inserted into the power line for supplying power from the battery to the load. It is possible to effectively prevent the deterioration of the battery life due to the rapid fluctuation of the load while preventing the influence of the above on the battery.
[Brief description of the drawings]
FIG. 1 is an external view of an electronic camera according to an embodiment of the present invention.
FIG. 2 is an exemplary view showing a device configuration inside the electronic camera of the embodiment.
FIG. 3 is a first schematic configuration diagram of a power supply circuit applied to the electronic camera of the embodiment.
FIG. 4 is a second schematic configuration diagram of a power supply circuit applied to the electronic camera of the embodiment.
5 is a diagram for more specifically showing a relationship between a switch and an electric double layer capacitor in FIG. 4; FIG.
FIG. 6 is a third schematic configuration diagram of a power supply circuit applied to the electronic camera of the embodiment.
FIG. 7 is a fourth schematic configuration diagram of a power supply circuit applied to the electronic camera of the embodiment.
FIG. 8 is a diagram for explaining battery life deterioration caused by a sudden change on the load side;
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Camera body 2 ... Lens 3 ... Strobe 4 ... Release switch 5 ... Battery 6 ... Aperture 7 ... Drive circuit 8 ... CCD
DESCRIPTION OF SYMBOLS 9 ... Buffer memory 10 ... Image recording / reproducing part 11 ... Recording medium 12 ... System controller 13 ... Operation input part 14 ... Strobe control circuit 15 ... Power supply circuit 151 ... DC / DC converter 152 ... Electric double layer capacitor 153 ... Switch 154 ... Switching apparatus

Claims (4)

In a power supply circuit that distributes power from a battery to a plurality of systems and supplies a plurality of loads including at least a system controller,
A switch that can be switched on / off in conjunction with the operating state of the device,
An electric double layer capacitor for suppressing deterioration of the battery life due to a sudden change in each load;
The switch and the electric double layer capacitor are connected in series, and are provided so as to be interposed between the battery and each load at a location before the power distribution,
The system controller controls the transition between the normal mode and the standby mode as the operation state of the device main body, and when the operation state shifts to the standby mode, turns off the switch and supplies power to the load. A power supply circuit , wherein a circuit between the battery and the electric double layer capacitor is cut off. In a power supply circuit that supplies power from any one of a plurality of power supplies including a battery to a plurality of loads including at least a system controller via a power supply line,
Switching means for selectively taking in power from the plurality of power sources;
A switch that can be switched on / off in conjunction with the operating state of the device,
An electric double layer capacitor for suppressing deterioration of the battery life due to a sudden change in each load;
The switch and the electric double layer capacitor are connected in series, and are provided so as to be interposed between at least the battery and each load,
The system controller controls the transition between the normal mode and the standby mode as the operation state of the device main body, and when the operation state shifts to the standby mode, turns off the switch and supplies power to the load. A power supply circuit , wherein a circuit between the battery and the electric double layer capacitor is cut off.   3. The power supply circuit according to claim 2, wherein the switch and the electric double layer capacitor connected in series are provided between the battery and the switching means.   3. The power supply circuit according to claim 2, wherein the switch and the electric double layer capacitor connected in series are provided between the switching means and the loads.

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