JPH11154041A - Power source system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent an excessive voltage from being applied to a load system due to an excessive voltage of a power source system when power source systems are selectively used. SOLUTION: A source voltage detection part 4 detects and measures the source voltages of a built-in DC power source system 1 and an external DC power source system 2. After the power source is turned ON, a sequence control part 5 selects the external DC power source system 2 by a power source switching part 3, checks the source voltage of this external DC power source system 2, and executes a sequence for normal subsequent operation when the source voltage is lower than a specific voltage. When the source voltage of the external DC power source system 2 exceeds the specific voltage, the sequence control part 5 selects the built-in DC power source system 1 by the power source switching part 3, checks the source voltage of this built-in DC power source system 1, and performs a sequence for normal subsequent operation when the source voltage is lower than the specific voltage. When the source voltage of the built-in power source system 1 exceeds the specific voltage, the process is repeated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power supply system comprising, as a DC power supply system, an internal DC power supply system using an internal battery as a power supply and an external DC power supply system using an external power supply.
In particular, the present invention relates to a power supply system suitable for being mounted on a digital camera.

[0002]

2. Description of the Related Art For example, a digital camera or the like can generally use a plurality of power supply systems such as an external power supply and a built-in battery, and receives power from one of the plurality of power supply systems depending on the situation. It is configured to operate. For example, in the case of a digital camera, it is operated by a built-in battery so that portability is not impaired when the camera is carried, and AC for converting AC to DC when not carried.
It can be operated by a commercial AC power supply via an (AC) adapter. This is because the battery power supply that may lead to environmental pollution is prevented from being unnecessarily consumed, and the commercial AC power supply is more economical than the battery power supply.

For example, a digital camera is connected to a so-called personal computer when not carried,
The photographed image data is transferred to a storage device of a personal computer to be displayed, edited, printed out by a printer, or the like, or the photographed image data is observed and organized. In such a case, a large amount of power is often consumed, such as operating the digital camera for a long time. As described above, when power is supplied using a plurality of power systems such as an external power supply and a built-in battery power supply, a power supply voltage of a battery power supply or the like is conventionally set to a predetermined voltage as disclosed in Japanese Patent No. 2618514. Various systems have been proposed for protection against lower conditions.

Japanese Patent No. 2618514 discloses that in a system having two power supply systems, a built-in storage battery and an external AC power supply, a voltage drop of the built-in storage battery is detected to cut off the power supply, and the built-in storage battery is temporarily stopped. A technique is disclosed in which, when the power supply is cut off due to a voltage drop, the operation of turning on a power switch is not activated until an external AC power supply is used. This patent 2618
In the technique disclosed in Japanese Patent No. 514, the system is started in a state where the power of the built-in storage battery is insufficient, thereby preventing improper operation.

[0005]

As described above, as a technique for a protection operation in a power supply system that supplies power using a plurality of power supply systems such as an external power supply and a built-in battery power supply, conventionally, a power supply voltage is used. Many techniques have been proposed for countermeasures when the value is lower than a predetermined value. However, in a power supply system using a plurality of power supply systems such as an external power supply and a built-in battery power supply, only a voltage lower than a predetermined voltage is not always a problem. There is also a case where troubles such as destruction of the device occur. Therefore, there is a need for a protection system not only for protection against low voltages, but also for protection against excessive voltages.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned circumstances, and when selectively supplying power of a plurality of power supply systems to a load system, when at least one of the power supply systems has an excessive voltage input, the power supply system is not required to supply the power. It is an object of the present invention to provide a power supply system capable of effectively preventing an excessive voltage from being supplied from a power supply system to a load system. An object of claim 1 of the present invention is, in particular, a part for controlling power supply to a load system among a plurality of power supply systems,
That is, at least the portion that supplies drive power to the voltage detection unit that detects the voltage of the DC power supply system only corresponds to the high voltage input, and the power supply to the load system is suppressed when the voltage input is higher than a predetermined value. It is an object of the present invention to provide a power supply system that enables the above.

A second object of the present invention is to limit the voltage detection and protection operation only to an external DC power supply system to which a high voltage is highly likely to be input, and to provide a control time and a manufacturing time for protection. An object of the present invention is to provide a power supply system capable of reducing costs. An object of claim 3 of the present invention is to provide a power supply system in which the operation after the protection operation is stopped, and the power supply is not carelessly supplied to the load system due to erroneous detection of the power supply voltage after the operation. It is in.

A fourth object of the present invention is to limit the voltage detection and protection operation only to an external DC power supply system to which a high voltage is highly likely to be input, and to provide a control time and a manufacturing time for protection. An object of the present invention is to provide a power supply system that reduces costs, stops operations after a protection operation, and does not inadvertently supply power to a load system due to erroneous detection of a power supply voltage after the fact. An object of claim 5 of the present invention is to provide a reasonable power supply system which starts normal power supply to a load system when a normal power supply voltage is supplied in a standby state after the protection operation. It is in.

A further object of the present invention is to provide a power supply system in which the general versatility of the system is improved by using a general AC adapter as an external DC power supply. A further object of the present invention is to provide a power supply system for a digital camera which protects against an excessive voltage.

[0010]

According to a first aspect of the present invention, there is provided a power supply system comprising: an external DC power supply system for supplying power from an external power supply;
A built-in DC power supply system for supplying power of a built-in battery, power supply switching means for selectively switching the external DC power supply system and the built-in DC power supply system, and a power supply system and a load based on the power selected by the power supply switching means. A system drive voltage supply circuit for supplying a drive voltage to a system; a power supply voltage detection means for detecting a power supply voltage selected by at least the power supply switching means of the external DC power supply system and the built-in DC power supply system; Sequence control means for suppressing supply of a drive voltage to the load system by the system drive voltage supply circuit when the power supply voltage detected by the voltage detection means exceeds a preset voltage. It is characterized by.

According to a second aspect of the present invention, in order to achieve the above object, the power supply voltage detecting means and the sequence control means are provided when the external DC power supply system is selected. It is characterized by a means that responds only to the power supply voltage.

According to a third aspect of the present invention, there is provided a power supply system for supplying power from an external power supply and an internal DC power supply for supplying power from a built-in battery. Power supply switching means for selectively switching between the external DC power supply system and the built-in DC power supply system, and a system drive voltage for supplying a drive voltage to the power supply system and the load system based on the power selected by the power supply switch means A supply circuit, a power supply voltage detection means for detecting at least a power supply voltage selected by the power supply switching means of the external DC power supply system and the built-in DC power supply system, and a power supply voltage detected by the power supply voltage detection means. When the voltage exceeds a preset voltage, supply of a drive voltage to the load system by the system drive voltage supply circuit is suppressed. Switching said power switching means,
When the power supply voltages of the external DC power supply system and the built-in DC power supply system both exceed a preset voltage, supply of a drive voltage to the load system by the system drive voltage supply circuit is suppressed and a control sequence is performed. And a sequence control means for stopping the subsequent control.

According to a fourth aspect of the present invention, there is provided a power supply system comprising: an external DC power supply system for supplying power from an external power supply; and a built-in DC power supply for supplying power to a built-in battery. Power supply switching means for selectively switching between the external DC power supply system and the built-in DC power supply system, and a system drive voltage for supplying a drive voltage to the power supply system and the load system based on the power selected by the power supply switch means A power supply circuit, a power supply voltage detection means for detecting a power supply voltage of the external DC power supply system, and a power supply voltage detected by the power supply voltage detection means, when the power supply voltage exceeds a preset voltage, the system drive voltage supply circuit Sequence control means for suppressing the supply of the drive voltage to the load system and terminating the control sequence and stopping the subsequent control. It is characterized in that.

According to a fifth aspect of the present invention, there is provided a power supply system comprising: an external DC power supply system for supplying power from an external power supply; and an internal DC power supply for supplying power to a built-in battery. Power supply switching means for selectively switching between the external DC power supply system and the built-in DC power supply system, and a system drive voltage for supplying a drive voltage to the power supply system and the load system based on the power selected by the power supply switch means A supply circuit, a power supply voltage detection means for detecting at least a power supply voltage selected by the power supply switching means of the external DC power supply system and the built-in DC power supply system, and a power supply voltage detected by the power supply voltage detection means. When the voltage exceeds a preset voltage, supply of a drive voltage to the load system by the system drive voltage supply circuit is suppressed. Switching said power switching means,
When the power supply voltages of the external DC power supply system and the built-in DC power supply system both exceed a preset voltage, supply of a drive voltage to the load system by the system drive voltage supply circuit is suppressed and the external Sequence control means for monitoring a power supply voltage of the DC power supply system and the built-in DC power supply system and setting a standby state to wait for at least one of the power supply voltages to recover to or below the preset voltage. And

According to a sixth aspect of the present invention, there is provided a power supply system according to the first aspect, wherein the external DC power supply system includes means for using a DC taken from a commercial AC power supply by an AC adapter as a power supply. It is characterized by including. The power supply system according to the present invention described in claim 7 is:
In order to achieve the above object, the load system of the system drive voltage supply circuit is a digital camera equipped with the power supply system.

[0016]

The power supply system according to the first aspect of the present invention detects a power supply voltage selected by at least the power supply switching unit of the external DC power supply system and the built-in DC power supply system, and the power supply voltage is set in advance. When the voltage is exceeded, the supply of the drive voltage to the load system is suppressed. With such a configuration, when selectively supplying power of a plurality of power supply systems to the load system, if at least one power supply system has an excessive voltage input, the power supply system supplies an excessive voltage to the load system. In particular, the drive power is supplied to a part of the plurality of power supply systems that controls power supply to the load system, that is, at least a voltage detection unit that detects a voltage of the DC power supply system. Just make the supply part correspond to high voltage input,
When the voltage input is higher than a predetermined value, power supply to the load system can be suppressed.

The power supply system according to the second aspect of the present invention performs detection of the power supply voltage and control for suppressing the drive voltage only in response to the power supply voltage when the external DC power supply system is selected. With such a configuration, in particular, voltage detection and protection operations are limited only to an external DC power supply system to which a high voltage is likely to be input, so that control time for protection and manufacturing cost can be reduced. .

A power supply system according to claim 3 of the present invention comprises:
A power supply voltage selected by at least the power supply switching unit of the external DC power supply system and the built-in DC power supply system is detected, and when the power supply voltage exceeds a preset voltage, the drive voltage of the load system is reduced. While suppressing the supply, the DC power supply system is switched, and when the power supply voltages of the external DC power supply system and the built-in DC power supply system both exceed a preset voltage, the system drive voltage supply circuit supplies the load system with the power supply voltage. The supply of all drive voltages is suppressed, and the control sequence is terminated to stop the subsequent control. With such a configuration, in particular, the operation after the protection operation is stopped, and it is possible to prevent the power supply from being carelessly supplied to the load system due to the erroneous detection of the power supply voltage after the fact.

A power supply system according to claim 4 of the present invention comprises:
A power supply voltage of the external DC power supply system of the external DC power supply system and the built-in DC power supply system is detected, and when the power supply voltage exceeds a preset voltage, a drive voltage is supplied to the load system. The control is suppressed and the control sequence is terminated to stop the subsequent control. With such a configuration, in particular, the voltage detection and the protection operation are limited only to the external DC power supply system in which a high voltage is likely to be input, and the control time for protection and the manufacturing cost are reduced.
The operation after the protection operation is stopped to prevent careless supply of power to the load system due to erroneous detection of the power supply voltage after the fact.

A power supply system according to claim 5 of the present invention comprises:
A power supply voltage selected by at least the power supply switching unit of the external DC power supply system and the built-in DC power supply system is detected, and when the power supply voltage exceeds a preset voltage, the drive voltage of the load system is reduced. While suppressing the supply, the DC power supply system is switched, and when the power supply voltages of the external DC power supply system and the built-in DC power supply system both exceed a preset voltage, the system drive voltage supply circuit supplies the load system with the power supply voltage. A standby state in which the supply of all drive voltages is suppressed and the power supply voltages of the external DC power supply system and the built-in DC power supply system are monitored and at least one of the power supply voltages is restored to the predetermined voltage or less. I do. With such a configuration, in particular, due to the standby state after the protection operation,
When a normal power supply voltage is supplied, normal power supply to the load system can be started.

A power supply system according to claim 6 of the present invention comprises:
The external DC power supply uses a DC taken from a commercial AC power supply by an AC adapter as a power source.

With such a configuration, the versatility of the system can be improved particularly by using a general AC adapter as the external DC power supply. In a power supply system according to claim 7 of the present invention, the load system is a digital camera equipped with the power supply system. With such a configuration, it is possible to configure a power supply system for a digital camera that protects against an excessive voltage.

[0023]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The embodiments of the power supply system of the present invention will be described below in detail with reference to the drawings. FIG. 1 schematically shows a configuration of a power supply system according to a first embodiment of the present invention. The power supply system shown in FIG. 1 is configured as a power supply system for a digital camera built in a digital camera, for example. The power supply system shown in FIG. 1 includes a built-in DC power supply system 1, an external DC power supply system 2, a power supply switching unit 3 as power supply switching means, a power supply voltage detection unit 4 as power supply voltage detection means, and a sequence control unit as sequence control means. 5 and a system drive voltage supply circuit 6.

The built-in DC power supply system 1 is a DC power supply system for supplying DC power using a built-in battery built in the device, for example, a digital camera or the like as a power source. As the built-in battery, a primary battery such as a manganese battery, an alkaline (alkali manganese) battery, or a lithium battery is used. Alternatively, as a built-in battery, Nicad (nickel-cadmium)
A secondary battery such as a battery, a nickel hydride battery, or a lithium ion battery may be used. The external DC power supply system 2 is a DC power supply system that is connected to an external power supply provided outside the device, for example, a digital camera or the like, and supplies DC power using the external power supply as a power source.

As an external power supply, a DC power supply such as an AC (AC) adapter for converting a commercial AC power supply to DC and supplying DC power is used. Alternatively, a DC power supply that supplies DC power from an external battery or the like may be used as the external power supply. Alternatively, a DC power supply such as a generator that generates DC power can be used as the external power supply. The power supply switching unit 3 is one of the DC power supply outputs of the built-in DC power supply system 1 and the external DC power supply system 2, for example,
Is switched to select the power supply switching means for supplying the power to the system drive voltage supply circuit 6. The power supply switching unit 3 is configured by a circuit that selectively outputs a high-voltage side DC power supply output using, for example, a backflow prevention diode.

The power supply switching unit 3 includes a transistor, an F
A switching element such as an ET (field effect transistor) or a relay is used, and the power supply voltage detecting unit 4 or another external circuit controls the switching element to select a high-voltage side DC power supply output. May be. Alternatively, the power supply switching unit 3 is provided with a switch which is mechanically operated by connection of the external DC power supply system 2 which is normally considered to supply a high voltage. It can also be configured by a circuit that selectively outputs the DC power supply output of the DC power supply system 1.

The power supply voltage detecting section 4 constitutes a power supply voltage detecting means for detecting and measuring the power supply voltage of the internal DC power supply system 1 and the external DC power supply system 2. The power supply voltage detection unit 4 is built in the sequence control unit 5 or provided separately from an A / D
It is configured using an (analog-digital) converter, detects and measures the DC voltage of the built-in DC power supply system 1 and the external DC power supply system 2, and supplies it to the sequence control unit 5. In FIG. 1, the power supply voltage detection unit 4 connects the respective outputs of the internal DC power supply system 1 and the external DC power supply system 2 to detect the power supply voltages of these two systems at the same time. If the power supply voltage detecting section 4 is provided at the subsequent stage of the power supply switching section 3 and the voltage of the power supply system selected by the power supply switching section 3 is detected, the power supply voltages of the two systems can be commonly detected by a single circuit. can do.

The sequence control section 5 constitutes a sequence control means for controlling a series of operation sequences after the power supply of the power supply system is turned on. This sequence control unit 5
According to a predetermined sequence, the DC power supply voltages of the built-in DC power supply system 1 and the external DC power supply system 2 are sequentially measured, and when these exceed a preset voltage, control is performed as predetermined to protect the system. . For example, after the power is turned on, the sequence control unit 5 first selects the external DC power supply system 2 by the power supply switching unit 3 and checks the power supply voltage of the external DC power supply system 2 and checks the power supply voltage at a predetermined voltage or less. In some cases, the sequence for the subsequent normal operation is executed and the sequence ends.

If the power supply voltage of the external DC power supply system 2 is higher than the predetermined voltage, the sequence controller 5
Selects the internal DC power supply system 1 by the power supply switching unit 3 and checks the power supply voltage of the internal DC power supply system 1;
If the voltage is equal to or lower than the predetermined voltage, a sequence for a subsequent normal operation is executed, and the sequence ends.
When the power supply voltage of the built-in DC power supply system 1 exceeds the predetermined voltage, the above-described selection of the external DC power supply system 2 and the built-in DC power supply system 1 and the voltage check are repeated.

The system drive voltage supply circuit 6 is a circuit for supplying a drive voltage to a load system of the power supply system, for example, each section of the digital camera. The system drive voltage supply circuit 6 also supplies the power supply voltage to the power supply voltage detection section 4 and the sequence control section 5 described above. A drive voltage is supplied from the system drive voltage supply circuit 6. The system drive voltage supply circuit 6 is configured to be able to drive the system even at the highest expected power supply voltage, for example, a voltage higher than the supply voltage when a dedicated AC adapter is used for the external DC power supply system 2.

Next, an outline of the operation of the power supply system having the configuration shown in FIG. 1 will be described with reference to FIG. 2 showing a flowchart of a control sequence. The flowchart shown in FIG. 2 corresponds to claim 1. The device,
For example, when a power switch (not shown) of the digital camera is turned on, the power is turned on, and the power supply system starts operating (starts), the sequence control unit 5 is initially provided.
The power supply switching unit 3 selects the external DC power supply system 2 based on the control (step S11). In this state, the power supply voltage detector 4 is driven by the power supplied from the system drive voltage supply circuit 6 to operate, and checks whether or not the voltage of the external DC power supply system 2 is equal to or lower than a predetermined voltage (step S12).

If the power supply voltage of the external DC power supply system 2 is equal to or lower than the predetermined voltage, the power supply system proceeds to a subsequent sequence for normal operation under the control of the sequence control unit 5 (step S13), and ends the processing. I do. If the power supply voltage of the external DC power supply system 2 exceeds the predetermined voltage, the power supply switching unit 3 selects the built-in DC power supply system 1 under the control of the sequence control unit 5 (step S14), and the sequence substantially the same as described above. Then, it is determined whether or not the voltage of the internal DC power supply system 1 is equal to or lower than a predetermined voltage (step S15). If the power supply voltage of the built-in DC power supply system 1 is equal to or lower than a predetermined voltage, the sequence controller 5
With this control, the power supply system proceeds to the sequence for the subsequent normal operation (step S16), and ends the processing. If the power supply voltage of the built-in DC power supply system 1 exceeds the predetermined voltage, that is, if any power supply system exceeds the predetermined voltage, the external DC power supply system 2 is selected again and the same sequence as described above is repeated.

In this manner, only the basic system part for controlling the sequence of the power supply system, that is, only the part of the system drive voltage supply circuit 6 which supplies the power supply voltage to the power supply voltage detector 4 is made to correspond to an excessive voltage input. When there is an excessive voltage input, it is possible not to proceed to the subsequent sequence for normal operation. Therefore, it is possible to prevent a system trouble due to excessive voltage input of the power supply.

When the power supply voltage exceeds a predetermined value, the sequence does not proceed to the subsequent sequence for normal operation. Even if the user uses an abnormal power supply, the power supply system corresponding to the subsequent normal operation sequence Since there is no need to use a high-voltage design, the design of the power supply system can be simplified. When the power supply system to which an excessive voltage can be applied is limited to one of the built-in DC power supply system 1 and the external DC power supply system 2, the power supply voltage should be checked only for the power supply system. Often, when an excessive input is made, the other power supply systems are not actually operated, so that only a portion relating to the corresponding single power supply system needs to correspond to a high voltage input.

The second embodiment of the present invention is suitable for such a situation.
The power supply system according to the embodiment can be implemented with the same configuration as that of FIG. 1, and FIG. 3 shows a flowchart of the operation. However, the power supply voltage detector 4 shown in FIG.
It is not necessary to detect both power supply voltages of the built-in DC power supply system 1 and the external DC power supply system 2, and it is sufficient to detect the power supply voltage only on the side where an excessive voltage is expected to be input. In this case, there are a case where an excessive voltage is expected in the built-in DC power supply system 1 and a case where an excessive voltage is expected in the external DC power supply system 2. In the latter case, this embodiment is described in claim 2 of the present invention. Corresponding to

When a power switch (not shown) of the device, for example, a digital camera, is turned on to turn on the power and the power system starts (starts), the power switching unit 3 is controlled based on the control of the sequence control unit 5. Selects one of the built-in DC power supply system 1 and the external DC power supply system 2 on the side where excessive voltage is expected (step S
21). In this state, the power supply voltage detector 4 is driven by the power supplied from the system drive voltage supply circuit 6 to operate, and checks whether or not the voltage of the selected DC power supply system is equal to or lower than a predetermined voltage (step S22). . If the power supply voltage of the selected DC power supply system is equal to or lower than the predetermined voltage, under the control of the sequence control unit 5, the power supply system proceeds to a subsequent sequence for normal operation (step S23), and ends the processing.

If the power supply voltage of the selected DC power supply system exceeds a predetermined voltage, under the control of the sequence control unit 5,
The same sequence as described above is repeated. In this case, switching between the built-in DC power supply system 1 and the external DC power supply system 2 can be performed in a subsequent sequence by, for example, selecting one having a higher voltage or higher input voltage.
In general, the voltage of the built-in battery does not become excessively large. Therefore, an excessive voltage is often predicted in the external DC power supply system 2 rather than the built-in DC power supply system 1. Therefore, in a normal system, it is desirable to select the external DC power supply system 2 in step S21.

In this way, with a simple configuration and control, when there is an excessive voltage input, it is possible to prevent the sequence from proceeding to the subsequent sequence for normal operation.
Therefore, it is possible to prevent a system trouble due to excessive voltage input of the power supply. Also in this case, if the power supply voltage exceeds a predetermined value, the sequence does not proceed to the subsequent sequence for normal operation, and even if the user uses an abnormal power supply, the power supply system corresponding to the subsequent normal operation sequence Since there is no need to use a high-voltage design, the design of the power supply system can be simplified.

FIG. 4 shows a configuration of a main part of a third embodiment of the present invention. The power supply switching unit 3 shown in FIG. 1 is configured so that a high voltage side is automatically selected by a diode. This is a specific example. In each of the embodiments after the third embodiment, the basic configuration of the system is as shown in FIG. In this case, the built-in DC power supply system 1 is substantially composed of only the built-in battery 11 and the external DC power supply system 2
Is configured using an external power supply connector 21. The external power supply connector 21 has, for example, AC of a predetermined voltage.
Adapter is connected.

The power supply switching section 3 is composed of a pair of diodes 31 and 32 having the illustrated polarities. Diode 31
The anode side is connected to the positive electrode of the internal battery 11, and the cathode side is commonly connected to the cathode side of the diode 32 and connected to the system drive voltage supply circuit 6. The anode side of the diode 32 is connected to the external power supply connector 21.
To the hot side (positive electrode side). Diode 31
And 32 are also connected to the power supply voltage detector 4. In such a configuration, the higher voltage of the internal battery 11 and the external power supply connector 21 is automatically selected by the diodes 31 and 32,
It is supplied to the system drive voltage supply circuit 6. At this time, the diode 31 or 32 connected to the lower voltage side
Functions as a so-called backflow prevention diode for blocking the backflow of the power supply voltage in a cutoff state.

FIG. 5 shows the structure of a main part of a fourth embodiment of the present invention. The power supply switching unit 3 shown in FIG.
This is another specific example in which a high voltage side is automatically selected by a diode. In this case, the diodes 31 and 32 are connected to the power supply voltage detector 4.
4 is different from FIG. 4 in that it is not the anode side but the cathode side connected in common. Therefore, the higher voltage of the internal battery 11 and the external power supply connector 21 automatically selected by the diodes 31 and 32 is supplied to the system drive voltage supply circuit 6.

FIG. 6 shows a configuration of a main part of a fifth embodiment of the present invention. The power supply switching section 3 shown in FIG. This is a specific example in which a power supply system is automatically selected depending on the presence or absence of a power supply. In this case, as in FIG.
Is constituted substantially only by the built-in battery 11, and the external DC power supply system 2 is constituted by using an external power supply connection connector 22. For example, an AC adapter having a predetermined voltage is connected to the external power supply connector 22. When the AC adapter is not connected, the external power supply connector 22
Connect the negative electrode of the built-in battery 11 to ground (common potential),
When the C adapter is connected, a switch for shutting off a connection path from the negative electrode of the built-in battery 11 to the ground is provided. The diode 33 of the illustrated polarity has an anode connected to the hot side of the external power supply connector 22 and a cathode connected to the system drive voltage supply circuit 6 together with the positive electrode of the internal battery 11.
Connected to The positive electrode side of the built-in battery 11 and the anode side of the diode 33 are also connected to the power supply voltage detector 4. In such a configuration, when the AC adapter is not connected to the external power supply connector 22, the built-in battery 11 is selected. When the AC adapter is connected, the external power supply connector 22 is selected, and the external power supply connector 22 is selected. The voltage is supplied to the system drive voltage supply circuit 6. In addition,
The diode 33 is a backflow prevention diode when the built-in battery 11 is used.

FIG. 7 shows a configuration of a main part of a sixth embodiment of the present invention. In a manner similar to FIG. 6, the power supply switching section 3 shown in FIG. This is another specific example configured so as to be selectively selected. In this case, the diode 3 is connected to the power supply voltage detector 4.
3 is different from that in FIG. 6 in that it is on the cathode side commonly connected to the positive electrode of the built-in battery 11. Therefore, the internal battery 1 automatically selected by the external power connection connector 22 is used.
1 and one of the external power supply connector 21 are supplied to the system drive voltage supply circuit 6.

Next, a power supply system according to a seventh embodiment of the present invention will be described with reference to FIG. FIG.
The flowchart shown in FIG. When a power switch (not shown) of the device, for example, a digital camera, is turned on, the power is turned on, and the power system starts (starts), the power switching unit 3 is initially controlled by the sequence control unit 5. The external DC power supply system 2 has been selected (step S31). In this state, driven by the power supplied from the system drive voltage supply circuit 6, the power supply voltage detector 4 operates to check whether or not the voltage of the external DC power supply system 2 is equal to or lower than a predetermined voltage (step S32).

If the power supply voltage of the external DC power supply system 2 is equal to or lower than the predetermined voltage, the power supply system proceeds to a subsequent sequence for normal operation under the control of the sequence control unit 5 (step S33), and ends the processing. I do. If the power supply voltage of the external DC power supply system 2 exceeds the predetermined voltage, the power supply switching unit 3 selects the built-in DC power supply system 1 under the control of the sequence control unit 5 (step S34), and the sequence is substantially the same as described above. Then, it is determined whether or not the voltage of the internal DC power supply system 1 is equal to or lower than a predetermined voltage (step S35). If the power supply voltage of the built-in DC power supply system 1 is equal to or lower than a predetermined voltage, the sequence controller 5
With this control, the power supply system proceeds to the sequence for the subsequent normal operation (step S36), and ends the processing. If the power supply voltage of the built-in DC power supply system 1 exceeds the predetermined voltage, that is, if any of the power supply systems exceeds the predetermined voltage, the process is immediately terminated without executing the subsequent sequence.

In this manner, the power supply voltages of the internal DC power supply system 1 and the external DC power supply system 2 are checked, and if both exceed a predetermined voltage, the processing is immediately terminated, and the subsequent operation sequence is continued. In addition, it is possible to prevent the occurrence of a malfunction based on an erroneous detection of the power supply voltage or the like.

Next, a power supply system according to an eighth embodiment of the present invention will be described with reference to FIG. FIG.
The flowchart shown in FIG. When a power switch (not shown) of the device, for example, a digital camera, is turned on, the power is turned on, and the power system starts (starts), the power switching unit 3 is initially controlled by the sequence control unit 5. The external DC power supply system 2 has been selected (step S41). In this state, the power supply voltage detector 4 is driven by the power supplied from the system drive voltage supply circuit 6 to operate, and checks whether or not the voltage of the external DC power supply system 2 is equal to or lower than a predetermined voltage (step S42). If the power supply voltage of the external DC power supply system 2 is equal to or lower than the predetermined voltage, the power supply system proceeds to a subsequent sequence for normal operation under the control of the sequence control unit 5 (step S43), and ends the processing.

If the power supply voltage of the external DC power supply system 2 exceeds the predetermined voltage, the power supply switching section 3 selects the built-in DC power supply system 1 under the control of the sequence control section 5 (step S4).
4), the power supply system proceeds to the sequence for the subsequent normal operation (step S45), and ends the processing.
In this way, the excess voltage is checked only for the power supply voltage of the external DC power supply system 2. If the power supply voltage of the external DC power supply system 2 exceeds the predetermined voltage, the process is immediately terminated, and the subsequent operation is performed. By continuing the sequence, it is possible to prevent the occurrence of a malfunction based on an erroneous detection of the power supply voltage or the like.

Next, a power supply system according to a ninth embodiment of the present invention will be described with reference to FIG. The flowchart shown in FIG. 10 corresponds to claim 5. A power switch (not shown) of the device, for example, a digital camera is turned on, and the power is turned on.
When the power supply system starts (starts), the power supply switching unit 3 initially selects the external DC power supply system 2 based on the control of the sequence control unit 5 (step S51). In this state, the power supply voltage detector 4 is driven by the power supplied from the system drive voltage supply circuit 6 to operate, and checks whether or not the voltage of the external DC power supply system 2 is equal to or lower than a predetermined voltage (step S52). If the power supply voltage of the external DC power supply system 2 is equal to or lower than the predetermined voltage, under the control of the sequence control unit 5, the power supply system proceeds to the subsequent sequence for normal operation (step S53), and ends the processing.

If the power supply voltage of the external DC power supply system 2 exceeds the predetermined voltage, the power supply switching section 3 selects the built-in DC power supply system 1 under the control of the sequence control section 5 (step S5).
4) In substantially the same sequence as described above, it is checked whether or not the voltage of the internal DC power supply system 1 is equal to or lower than a predetermined voltage (step S5).
5). If the power supply voltage of the built-in DC power supply system 1 is equal to or lower than the predetermined voltage, the power supply system proceeds to a subsequent sequence for normal operation under the control of the sequence control unit 5 (step S56), and ends the processing. If the power supply voltage of the built-in DC power supply system 1 exceeds the predetermined voltage, that is, if any of the power supply systems exceeds the predetermined voltage, the sequence is stopped and a standby state is set (step S57). In the standby state, the process returns to step S51 immediately after returning to the normal state, and the system can be restored to the normal operation immediately by repeating the above sequence.

In this way, the power supply voltages of the internal DC power supply system 1 and the external DC power supply system 2 are checked, and if both exceed a predetermined voltage, the sequence is stopped, and the standby state is set. Can be quickly returned to normal operation. In the above description, since the external DC power supply system 2 is configured using the AC adapter, it can be configured as a general-purpose system. Further, as described above, if such a configuration is used for a digital camera, protection against input of an excessive power supply voltage in the digital camera can be easily realized at low cost. Others
It is needless to say that the present invention is not limited to the embodiments described above and shown in the drawings, but can be variously modified and implemented without changing the gist thereof.

[0052]

As described above, according to the present invention, the power supply voltage selected by at least the power supply switching means of the external DC power supply system and the built-in DC power supply system is detected, and the power supply voltage is set in advance. The supply of the drive voltage to the load system when the voltage exceeds the predetermined voltage, the overvoltage input to at least one power supply system in selectively supplying the power of the plurality of power supply systems to the load system. In this case, it is possible to provide a power supply system capable of effectively preventing an excessive voltage from being supplied from the power supply system to the load system.

In particular, according to the first aspect of the present invention, a part for controlling power supply to a load system among a plurality of power supply systems, that is, at least a voltage detection unit for detecting a voltage of a DC power supply system is provided with a drive power. It is possible to suppress the power supply to the load system when the voltage input is higher than the predetermined value only by making only the portion supplying the power supply correspond to the high voltage input.

According to the power supply system of the present invention, the detection of the power supply voltage and the control for suppressing the drive voltage are performed only in response to the power supply voltage when the external DC power supply system is selected. Thus, the voltage detection and protection operations are limited only to the external DC power supply system to which a high voltage is likely to be input, and the control time for protection and the manufacturing cost can be reduced.

According to the power supply system of claim 3 of the present invention, the power supply voltage selected by at least the power supply switching means of the external DC power supply system and the built-in DC power supply system is detected, and the power supply voltage is set in advance. When the voltage is exceeded, the supply of the drive voltage to the load system is suppressed,
The DC power supply system is switched, and when the power supply voltages of the external DC power supply system and the built-in DC power supply system both exceed a preset voltage, supply of a drive voltage to the load system by the system drive voltage supply circuit. In particular, by stopping the control sequence and stopping the subsequent control, the operation after the protection operation is stopped, and the power supply to the load system is carelessly performed due to the erroneous detection of the power supply voltage after the fact. Can be prevented.

According to the power supply system of the present invention, the power supply voltage of the external DC power supply system of the external DC power supply system and the built-in DC power supply system is detected, and the power supply voltage is set to a predetermined voltage. When the voltage exceeds the limit, the supply of the drive voltage to the load system is suppressed, the control sequence is terminated, and the subsequent control is stopped. The voltage detection and protection operation are limited only to the control, the control time for protection and the manufacturing cost are reduced, and the operation after the protection operation is stopped. Prevents the system from being powered.

According to the power supply system of the present invention, the power supply voltage selected by at least the power supply switching means of the external DC power supply system and the built-in DC power supply system is detected, and the power supply voltage is set in advance. When the voltage is exceeded, the supply of the drive voltage to the load system is suppressed,
The DC power supply system is switched, and when the power supply voltages of the external DC power supply system and the built-in DC power supply system both exceed a preset voltage, supply of a drive voltage to the load system by the system drive voltage supply circuit. And by monitoring the power supply voltage of the external DC power supply system and the built-in DC power supply system and waiting for at least one of the power supply voltages to recover to the preset voltage or less, particularly, When a normal power supply voltage is supplied in a standby state after the protection operation, normal power supply to the load system can be started.

According to the power supply system of claim 6 of the present invention, the external DC power supply system uses DC taken from a commercial AC power supply by an AC adapter as a power source.
In particular, by using a general AC adapter as an external DC power supply, the versatility of the system can be improved. According to the power supply system of claim 7 of the present invention, by configuring the load system as a digital camera equipped with the power supply system, a power supply system for a digital camera particularly protected against excessive voltage is configured. Can be.

[Brief description of the drawings]

FIG. 1 is a system block diagram schematically showing a configuration of a main part of a power supply system according to a first embodiment of the present invention.

FIG. 2 is a flowchart illustrating an operation of the power supply system of FIG. 1;

FIG. 3 is a flowchart for explaining an operation of the power supply system according to the second embodiment of the present invention.

FIG. 4 is a circuit diagram schematically showing a configuration of a main part of a power supply system according to a third embodiment of the present invention.

FIG. 5 is a circuit diagram schematically showing a configuration of a main part of a power supply system according to a fourth embodiment of the present invention.

FIG. 6 is a circuit diagram schematically showing a configuration of a main part of a power supply system according to a fifth embodiment of the present invention.

FIG. 7 is a circuit configuration diagram schematically showing a configuration of a main part of a power supply system according to a sixth embodiment of the present invention.

FIG. 8 is a flowchart illustrating an operation of a power supply system according to a seventh embodiment of the present invention.

FIG. 9 is a flowchart illustrating an operation of a power supply system according to an eighth embodiment of the present invention.

FIG. 10 is a flowchart illustrating an operation of a power supply system according to a ninth embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Internal DC power supply system 2 External DC power supply system 3 Power supply switching part (power supply switching means) 4 Power supply voltage detection part (power supply voltage detection means) 5 Sequence control part 6 System drive voltage supply circuit 11 Built-in battery 21, 22 For external power supply connection Connector 31, 32, 33 Diode

Claims (7)

[Claims] 1. An external DC power supply system for supplying electric power from an external power supply, an internal DC power supply system for supplying electric power of an internal battery, and a power supply switch for selectively switching between the external DC power supply system and the internal DC power supply system Means, a system drive voltage supply circuit for supplying a drive voltage to the power supply system and the load system based on the power selected by the power supply switching means, and at least the power supply of the external DC power supply system and the built-in DC power supply system Power supply voltage detection means for detecting a power supply voltage selected by the switching means; and when the power supply voltage detected by the power supply voltage detection means exceeds a preset voltage, the load system by the system drive voltage supply circuit And a sequence control means for suppressing supply of a drive voltage to the power supply system. 2. The power supply according to claim 1, wherein said power supply voltage detection means and said sequence control means are means for responding only to a power supply voltage when said external DC power supply system is selected. system. 3. An external DC power supply system for supplying power from an external power supply, an internal DC power supply system for supplying power of an internal battery, and a power supply switch for selectively switching between the external DC power supply system and the internal DC power supply system. Means, a system drive voltage supply circuit for supplying a drive voltage to the power supply system and the load system based on the power selected by the power supply switching means, and at least the power supply of the external DC power supply system and the built-in DC power supply system Power supply voltage detection means for detecting a power supply voltage selected by the switching means; and when the power supply voltage detected by the power supply voltage detection means exceeds a preset voltage, the load system by the system drive voltage supply circuit Supply of a driving voltage to the external DC power supply system and the built-in DC power supply system. Sequence control for suppressing supply of a drive voltage to the load system by the system drive voltage supply circuit and terminating a control sequence and stopping subsequent control when both power supply voltages exceed a preset voltage. And a power supply system. 4. An external DC power supply system for supplying electric power from an external power supply, an internal DC power supply system for supplying electric power of an internal battery, and a power supply switch for selectively switching between the external DC power supply system and the internal DC power supply system. Means, a system drive voltage supply circuit for supplying a drive voltage to the power supply system and the load system based on the power selected by the power supply switching means, and a power supply voltage detection means for detecting a power supply voltage of the external DC power supply system, When the power supply voltage detected by the power supply voltage detection means exceeds a preset voltage, the supply of the drive voltage to the load system by the system drive voltage supply circuit is suppressed and the control sequence is terminated. And a sequence control means for stopping subsequent control. 5. An external DC power supply system for supplying electric power from an external power supply, an internal DC power supply system for supplying electric power of an internal battery, and a power supply switch for selectively switching between the external DC power supply system and the internal DC power supply system. Means, a system drive voltage supply circuit for supplying a drive voltage to the power supply system and the load system based on the power selected by the power supply switching means, and at least the power supply of the external DC power supply system and the built-in DC power supply system Power supply voltage detection means for detecting a power supply voltage selected by the switching means; and when the power supply voltage detected by the power supply voltage detection means exceeds a preset voltage, the load system by the system drive voltage supply circuit Supply of a driving voltage to the external DC power supply system and the built-in DC power supply system. When both the power supply voltages exceed a preset voltage, the supply of the drive voltage to the load system by the system drive voltage supply circuit is suppressed, and the power supply voltages of the external DC power supply system and the built-in DC power supply system And a sequence control means for monitoring the power supply voltage and setting a standby state to wait for at least one of the power supply voltages to recover to or below the preset voltage. 6. The external DC power supply system according to claim 1, wherein said external DC power supply system includes means for using a DC power taken from a commercial AC power supply by an AC adapter as a power source. Power system. 7. The power supply system according to claim 1, wherein the load system of the system drive voltage supply circuit is a digital camera equipped with the power supply system.