JP2001211564A - Power supply for camera - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable the downsizing of a camera and to feed power to a camera body circuit from an external charging device with a simple structure. SOLUTION: The device comprises a secondary battery 4 housed in a camera body 1 and the external charging device 5 having an AC-DC conversion circuit 6. The camera body 1 to which the output power of the secondary battery 4 is fed comprises a DC-DC conversion circuit 2 that loads a predetermined DC voltage to the camera body circuit 8 and a switch 3 that is connected in between the secondary battery 4 and the DC-DC conversion circuit 2. The external charging device 5 comprises the AC-DC conversion circuit 6 and a charging circuit 7 that is connected thereto. The switch 3 loads the output voltage from the charging circuit 6 to the secondary battery 4 corresponding to a control signal from the camera body circuit 8, or loads the output voltage to the DC-DC conversion circuit 2 from the secondary battery.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power supply for a camera, such as a digital camera, for supplying power to the camera.

[0002]

2. Description of the Related Art FIGS. 5 and 6 show a power supply device for a digital camera. FIG.
1 is housed in a DC-DC conversion circuit 102, a switch 103, a lithium ion secondary battery 104, a charging circuit 105, and an external charging device 106 housed in a camera body 101. AC-
And a DC conversion circuit 107. The DC-DC conversion circuit 102 is connected to the camera body circuit 108.
The camera body 101 has a connector 109. The external charging device 106 has a connector 110 detachably connected to the connector 109. External charging device 106
Has an outlet 111 for connecting to a commercial power supply. In the power supply of this camera, AC-DC
The conversion circuit 107 converts AC power from a commercial power supply into DC power, and supplies the DC power to the DC-DC conversion circuit 102 and the charging circuit 105. The DC-DC conversion circuit 102
An output voltage from the C-DC conversion circuit 107 is received, converted into a predetermined DC voltage, and DC power is supplied to the camera body circuit 108. The charging circuit 105 charges the lithium ion secondary battery 104. The lithium ion secondary battery 104
The output power is supplied to the DC-DC conversion circuit 102 via the switch 103. Charge circuit 105 and switch 103
Is controlled by a control signal from the camera body circuit 108. The conventional power supply device for a camera shown in FIG. 6 is a DC-DC conversion circuit 1 housed in a camera body 101.
02, a lithium ion secondary battery 104, and an AC-DC conversion circuit 107 housed in the external charging device 106
And a charging circuit 112. The DC-DC conversion circuit 102 is connected to the camera body circuit 108.
The camera body 101 has a connector 109. The external charging device 106 has a connector 110 detachably connected to the connector 109. External charging device 106
Has an outlet 111 for connecting to a commercial power supply. The charging circuit 112 includes an AC-DC conversion circuit 107
From the output voltage to a predetermined output voltage.
This is given to the conversion circuit 102. DC-DC conversion circuit 102
Receives the output voltage from the charging circuit 112, converts it to a predetermined DC voltage, supplies DC power to the camera body circuit 108, and charges the lithium ion secondary battery 104.

[0003]

However, in the conventional camera power supply device shown in FIG.
01 has a built-in charging circuit 105,
Since a space for accommodating the camera 5 is required, there is a problem that a reduction in camera size is hindered. In the conventional camera power supply device shown in FIG. 6, since the external charging device 106 has the built-in charging circuit 112, the camera main body 101 does not need a charging circuit. When the camera main body 101 is operated by supplying power from the external charging device 106, a voltage is also applied to the lithium ion secondary battery 104. Since it is necessary to control the charging current to the secondary battery, there is a problem that current control is complicated, and when the lithium ion secondary battery is already charged, the lithium ion secondary battery is overcharged. Problem. An object of the present invention is to solve such a problem. That is, the object of the present invention is:
It is an object of the present invention to provide a power supply device for a camera that can reduce the size of the camera and that can supply power from an external charging device to a camera body circuit with a simple configuration.

[0004]

According to a first aspect of the present invention, there is provided a secondary battery which is housed in a camera body and supplies DC power to a camera body circuit of the camera body. An external charging device having an AC-DC conversion circuit for receiving AC power and converting it to DC power, wherein the camera body is supplied with output power of the secondary battery and receives a predetermined DC power. A DC-DC conversion circuit that supplies a voltage to the camera body circuit; and a switch connected between the secondary battery and the DC-DC conversion circuit, wherein the external charging device includes the AC-DC A conversion circuit, and a charging circuit connected between the AC-DC conversion circuit and the switch, wherein the switch responds to a control signal from the camera body circuit to output from the charging circuit. Electric The given to the secondary battery, or, and controlling the output voltage of the secondary battery to provide the DC-DC converter circuit. According to a second aspect of the present invention, there is provided a secondary battery which is housed in a camera body and supplies DC power to a camera body circuit of the camera body, and an AC-DC conversion circuit which receives AC power and converts it into DC power. A power supply device for a camera having an external charging device, wherein the camera body is supplied with output power of the secondary battery and provides a predetermined DC voltage to the camera body circuit.
A DC switch, a first switch connected between the secondary battery and the DC-DC converter,
The external charging device has a second switch connected between the AC-DC conversion circuit and the first switch, and a charging circuit connected in parallel to the second switch. The first and second switches respond to a control signal from the camera body circuit to output voltages from the AC-DC conversion circuit and the charging circuit to the DC-D
The output voltage from the charging circuit is supplied to the secondary battery, or the output voltage of the secondary battery is supplied to the DC-DC conversion circuit. According to a third aspect of the present invention, in the first aspect of the present invention, the camera body is connected between the secondary battery and the first switch, and includes a voltage or A voltage detection circuit or a current detection circuit for detecting a current and supplying the detected voltage value or the detected current value to the camera body circuit.

[0005]

Next, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a block diagram showing a power supply device for a camera according to a first embodiment of the present invention. As shown in FIG. 1, the power supply device of the camera includes a DC-DC conversion circuit 2 housed in a camera body 1, a switch 3, a secondary battery 4, and an AC power supply housed in an external charging device 5. It has a DC conversion circuit 6 and a charging circuit 7.
The DC-DC conversion circuit 2 is connected to the camera body circuit 8 of the camera body 1. The camera body 1 has a connector 9. The external charging device 5 has a connector 10 detachably connected to the connector 9. External charging device 5
Has an outlet 11 for connection to a commercial power supply (not shown). The DC-DC conversion circuit 2 is connected to the connector 9. The switch 3 is connected between a connection point between the DC-DC conversion circuit 2 and the connector 9 and the secondary battery 4. The switch 3 is connected to the camera body circuit 8 and receives a control signal from the camera body circuit 8. The switch 3 connects the secondary battery 4 to the connector 9 and the DC-DC conversion circuit 2 when the switch 3 is turned on (closed) in response to a control signal from the camera body circuit 8. When the battery is in an off (opened) state not receiving the control signal, the secondary battery 4 is connected to the connector 9 and the DC-DC
Not connected to conversion circuit 2. The AC-DC conversion circuit 6 is connected to a commercial power supply (not shown) via an outlet 11. The charging circuit 7 is connected between the output terminal of the AC-DC conversion circuit 6 and the connector 10. The charging circuit 7 is connected to the camera body circuit 8 and receives a control signal from the camera body circuit 8.

The AC-DC conversion circuit 6 receives AC power from a commercial power supply and converts it into DC power. The charging circuit 7
Receiving the output power from the AC-DC conversion circuit 6, the secondary battery 4 is charged via the connectors 10, 9 and the switch 3. In this case, the charging circuit 7 includes the AC-DC conversion circuit 6
Is converted into an optimal current and voltage for charging the secondary battery 3. The secondary battery 4 is connected to the D
DC power is supplied to the C-DC conversion circuit 2. DC-DC
When receiving the output power from either the secondary battery 4 or the charging circuit 7, the conversion circuit 2 converts the voltage of the output power to an optimal voltage for the operation of the camera body circuit 8 and converts this voltage to the camera body circuit 8. To supply. The camera body circuit 8 gives a control signal to the switch 3 when the photographing instruction signal is received by the operation switch in a state where the external charging device 5 is detached from the camera body 1, turns the switch 3 on (closes), and turns the switch 3 on. Only the output power of the battery 4 is supplied to the DC
-Supply to DC conversion circuit 2. In a state where the external charging device 5 is connected to the camera main body 1 by the connectors 10 and 9, the camera main body circuit 8 gives a control signal to the switch 3 and turns on the switch 3 when the photographing instruction signal is received by the operation switch. In the (closed) state, the output power of the secondary battery 4 is supplied to the DC-DC conversion circuit 2 via the switch 3, and the charging circuit 7 of the external charging device 5 is connected to the DC-DC conversion circuit 2. Since it is connected, the charging circuit 7 supplies DC power to the DC-DC conversion circuit 2. Further, the camera body circuit 8 stores the secondary battery 4 discharged after the photographing is completed.
Is charged by the external charging device 5 in a state where the external charging device 5 is connected to the camera body 1 by the connectors 10 and 9. In this case, the camera body circuit 8 gives a control signal to the switch 3 only for a predetermined time from the time when the connectors 10 and 9 are connected, and turns the switch 3 on (closed). When the switch 3 is turned on (closed), the output power of the charging circuit 7 is supplied to the secondary battery 4 via the connectors 10 and 9 and the switch 3. Further, the camera body circuit 8 connects the external charging device 5 to the camera body 1 via the connectors 10 and 9 when the camera body circuit 8 performs an operation of importing a captured image to a computer or displaying the captured image on a television monitor. The camera body circuit 8 is turned off (opened) without supplying a control signal to the switch 3. When the switch 3 is turned off (open), the output power of the charging circuit 7 is not applied to the secondary battery 4 and the output power from the charging circuit 7 is supplied to the DC-D through the connectors 10 and 9.
It is supplied to the C conversion circuit 2. Thus, the first aspect of the present invention
In the power supply device for a camera according to the embodiment, since the charging circuit 7 is built in the external charging device 5 side instead of the camera body 1, the camera size can be reduced, and
The configuration for supplying power from the external charging device 5 to the camera body circuit 8 is simple. The power supply device for a camera according to the present invention, when supplying power from the external power supply device 5 to the camera body circuit 8 via the DC-DC conversion circuit 2, uses the charging circuit 7.
Is not applied to the secondary battery 4 and AC-
The output power from the DC conversion circuit 6 is changed to the DC-DC conversion circuit 2
, It can be safely operated without the need for complicated control and circuits, and requires a current value greater than or equal to the current value that can be passed to the charging circuit 7 for the operation of the camera body circuit 8. Also in this case, the necessary current value can be supplied to the camera body circuit 8, so that the camera body circuit 8 can be operated safely.

Next, a second embodiment of the present invention will be described with reference to FIG. FIG. 2 is a block diagram showing a power supply device of a camera according to a second embodiment of the present invention. In the second embodiment of the present invention shown in FIG. 2, the same components as those in the first embodiment of the present invention shown in FIG. 1 are denoted by the same reference numerals. The power supply device for a camera according to the second embodiment of the present invention is configured by connecting a switch 12 in parallel to the charging circuit 7 in the power supply device for a camera according to the first embodiment of the present invention shown in FIG. Things. The camera body circuit 8 gives a control signal to the switch 3 when the photographing instruction signal is received by the operation switch in a state where the external charging device 5 is detached from the camera body 1, turns the switch 3 on (closed), and sets the switch 3 to the secondary state. The output power of the battery 4 is supplied to the DC-DC conversion circuit 2 via the switch 3. In a state where the external charging device 5 is connected to the camera main body 1 by the connectors 10 and 9, the camera main body circuit 8 gives a control signal to the switch 3 when receiving a shooting instruction signal by the operation switch, and turns on the switch 3 ( In the closed state, the output power of the secondary battery 4 is supplied to the DC-D
The state can be supplied to the C conversion circuit 2. However, in this case, the camera body circuit 8 supplies a control signal to the switch 12 to turn the switch 12 on (closed) and set the DC-D
AC-DC conversion circuit 6 of external charging device 5
Are connected via the switch 12 and the connectors 10 and 9 so that the AC-DC conversion circuit 6 directly
Supply DC power to Further, the camera body circuit 8 charges the secondary battery 4 discharged from the camera body 1 with the external charger 5 while the external battery charger 5 is connected to the camera body 1 by the connectors 10 and 9 when charging the discharged secondary battery 4 after the photographing is completed. Do. In this case, the camera body circuit 8 supplies the control signal to the switch 3 to turn on the switch 3 (closed), and does not supply the control signal to the switch 12 to turn off the switch 12 (opened). I have. Thus, the switch 3 is turned on (closed) and the switch 12 is turned on.
Is turned off (open), the output power of the charging circuit 7 is supplied to the secondary battery 4 via the connectors 10 and 9 and the switch 3.
Given to.

Further, the camera body circuit 8 connects the external charging device 5 to the camera body 1 via the connectors 10 and 9, and captures the captured image into a computer or displays the captured image on a television monitor. In this case, the camera body circuit 8 turns off (opens) without supplying a control signal to the switch 3, and supplies a control signal to the switch 8 to switch 12.
Is turned on (closed). When the switch 3 is turned off (open) and the switch 12 is turned on (closed), the output power of the charging circuit 7 is not applied to the secondary battery 4 and The output power from the DC conversion circuit 6 is the switch 12 and the connector 10,
9 is supplied to the DC-DC conversion circuit 2. In this case, the output power of the charging circuit 7 is also supplied to the DC-DC conversion circuit 2 via the connectors 10 and 9. As described above, the camera power supply device according to the second embodiment of the present invention incorporates the charging circuit 7 not in the camera body 1 but in the external charging device 5 side. And power is supplied from the external charging device 5 to the camera body circuit 8.
Is simple to supply. The power supply device for a camera according to the second embodiment of the present invention, when supplying power from the external power supply device 5 to the camera body circuit 8 via the DC-DC conversion circuit 2, outputs the power of the charging circuit 7. Since the output power from the AC-DC conversion circuit 6 is supplied to the DC-DC conversion circuit 2 without power being applied to the secondary battery 4, the operation can be performed safely without requiring complicated control and circuits. When the operation of the camera body circuit 8 requires a current value equal to or greater than the current value that can be supplied to the charging circuit 7, the necessary current value can be supplied to the camera body circuit 8. The main body circuit 8 can be operated safely.

Next, a third embodiment of the present invention will be described with reference to FIG. FIG. 3 is a block diagram showing a power supply device for a camera according to a third embodiment of the present invention. In the third embodiment of the present invention shown in FIG. 3, the same components as those in the first embodiment of the present invention shown in FIG. 1 are denoted by the same reference numerals. The power supply device for a camera according to the third embodiment of the present invention is similar to the power supply device for a camera according to the first embodiment of the present invention shown in FIG. The circuit 13 is added. The voltage detection circuit 13 detects a voltage between the first switch 3 and the secondary battery 4 and supplies the detected voltage value to the camera body circuit 8. The camera body circuit 8 controls the charging circuit 7 based on the detected voltage value from the voltage detecting circuit 13 and detects an abnormality of the secondary battery 4. Instead of the voltage detection circuit 13, a current detection circuit for detecting a current between the switch 3 and the secondary battery 4 may be used. Other configurations and operations of the third embodiment of the present invention are the same as those of the first embodiment of the present invention. In the camera power supply device according to the third embodiment of the present invention, the voltage or current is detected in the vicinity of the secondary battery 4, so that the charging circuit 7 can be accurately controlled based on the detected voltage or current value. The control can be performed, and the abnormality of the secondary battery 4 can be detected.

Next, a fourth embodiment of the present invention will be described with reference to FIG. FIG. 4 is a block diagram showing a power supply device for a camera according to a fourth embodiment of the present invention. In the fourth embodiment of the present invention shown in FIG. 4, the same components as those of the second embodiment of the present invention shown in FIG. 2 are denoted by the same reference numerals. The power supply device for a camera according to the fourth embodiment of the present invention is similar to the power supply device for a camera according to the second embodiment of the present invention shown in FIG. The circuit 13 is added. The voltage detection circuit 13 detects the voltage between the switch 3 and the secondary battery 4 and supplies the detected voltage value to the camera body circuit 8 as described above. Camera body circuit 8
Controls the charging circuit 7 based on the detected voltage value from the voltage detecting circuit 13 and detects an abnormality of the secondary battery 4.
Instead of the voltage detection circuit 13, a current detection circuit for detecting a current between the switch 3 and the secondary battery 4 may be used. Other configurations and operations of the fourth embodiment of the present invention are the same as those of the second embodiment of the present invention. In the power supply device for a camera according to the fourth embodiment of the present invention, since the voltage or current is detected near the secondary battery 4, the charging circuit 7 can accurately detect the voltage or current based on the detected voltage or current value. The control can be performed, and the abnormality of the secondary battery 4 can be detected. The secondary battery 4 includes a lithium ion secondary battery, a nickel hydride secondary battery, or another secondary battery.

[0011]

According to the first aspect of the present invention, since the charging circuit is built in the external charging device side instead of the camera body, the camera size can be reduced, and the external charging device can be used. The configuration for supplying power to the camera body circuit is simple. Further, according to the first aspect of the present invention, when power is supplied from an external power supply to a camera body circuit via a DC-DC conversion circuit, the output power of the charging circuit is not applied to the secondary battery. Since the output power from the AC-DC conversion circuit is supplied to the DC-DC conversion circuit, the operation can be performed safely without the need for complicated control and circuits, and the operation of the camera body circuit is performed by the charging circuit. Even when a current value greater than the current value that can be passed is required, this necessary current value can be supplied to the camera body circuit,
The camera body circuit can be operated safely. According to the second aspect of the present invention, since the charging circuit is built in the external charging device side instead of the camera main body side, the size of the camera can be reduced, and power is supplied from the external charging device to the camera main body circuit. Is simple to supply. Further, according to the invention described in claim 2, when power is supplied from an external power supply device to a camera body circuit via a DC-DC conversion circuit,
Without the output power of the charging circuit being applied to the secondary battery,
Since the output power from the AC-DC conversion circuit is supplied to the DC-DC conversion circuit, the operation can be performed safely without the need for complicated control and circuits, and the operation of the camera body circuit is performed by the charging circuit. Even when a current value larger than the current value that can be passed is required, the necessary current value can be supplied to the camera body circuit, so that the camera body circuit can be operated safely. The invention according to claim 3 is
In the invention according to any one of claims 1 and 2, the camera body is connected between the secondary battery and the first switch, and the detected voltage value or the detected current value is applied to the camera body circuit. Since a circuit or a current detection circuit is provided, voltage or current is detected in the vicinity of the secondary battery 4, so that in addition to the effects of the invention described in claim 1 and claim 2, the detected voltage or current value It is possible to accurately control the charging circuit based on the above, and to detect abnormality of the secondary battery.

[Brief description of the drawings]

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

FIG. 2 is a block diagram showing a power supply device of a camera according to a second embodiment of the present invention.

FIG. 3 is a block diagram showing a power supply device of a camera according to a third embodiment of the present invention.

FIG. 4 is a block diagram showing a power supply device for a camera according to a fourth embodiment of the present invention.

FIG. 5 is a block diagram showing a conventional power supply device for a camera.

FIG. 6 is a block diagram showing a power supply device of another conventional camera.

[Explanation of symbols]

1 camera body, 2 DC-DC conversion circuit, 3 switch, 4 secondary battery, 5 external charging device, 6 AC-DC
Conversion circuit, 7 charging circuit, 8 camera body circuit, 9, 1
0 connector, 11 outlets, 12 switches, 1
3 Voltage detection circuit

Claims (3)

[Claims] 1. An external charging device which is housed in a camera body and has a secondary battery for supplying DC power to a camera body circuit of the camera body, and an AC-DC conversion circuit which receives AC power and converts it into DC power. And a DC-DC conversion circuit that is supplied with output power of the secondary battery and applies a predetermined DC voltage to the camera main body circuit; and DC-
A switch connected to a DC conversion circuit, wherein the external charging device includes the AC-DC conversion circuit,
A charging circuit connected between the AC-DC conversion circuit and the switch, wherein the switch responds to a control signal from the camera body circuit to output an output voltage from the charging circuit to the second circuit. A power supply device for a camera, wherein the power is supplied to a secondary battery or the output voltage of the secondary battery is supplied to the DC-DC conversion circuit. 2. An external charging device that is housed in a camera body and has a secondary battery for supplying DC power to a camera body circuit of the camera body, and an AC-DC conversion circuit that receives AC power and converts it into DC power. And a DC-DC conversion circuit that is supplied with output power of the secondary battery and applies a predetermined DC voltage to the camera main body circuit; and DC-
A first switch connected between the AC-DC conversion circuit and the first switch; and a second switch connected between the AC-DC conversion circuit and the first switch. , A charging circuit connected in parallel to the second switch, wherein the first and second switches respond to a control signal from the camera body circuit, and the AC-
An output voltage from the DC conversion circuit and the charging circuit is supplied to the DC-DC conversion circuit, an output voltage from the charging circuit is supplied to the secondary battery, or an output voltage of the secondary battery is supplied to the DC-DC A power supply device for a camera, wherein the power supply is provided to a conversion circuit. 3. The power supply device for a camera according to claim 1, wherein the camera body is connected between the secondary battery and the first switch, and is a voltage or a current. A voltage detection circuit or a current detection circuit for detecting the detected voltage value or the detected current value to the camera body circuit.