JP2001331241A - Power source device of data source device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent power supply from being shut down while data are being read from a data source device to a computer. SOLUTION: When a data source device having a USB interface is connected through a USB cable to a computer PC, the power source of the data source device is automatically switched from a built-in battery power source to a USB bus power source, and the transitive mode of the data source device is limited according to the preliminarily set power supply capabilities of the PC side.

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 data source device, and more particularly to a power supply for a camera-integrated image recording / reproducing apparatus such as an electronic still camera.

[0002]

2. Description of the Related Art A conventional data source device, for example, an image recording / reproducing device such as a digital still camera operates by receiving power from a battery. When reading a large amount of image data or large-sized image data from such an image recording / reproducing apparatus into a computer PC, a battery failure occurs while the image is being read,
There was a problem that all the work performed before that was wasted. In order to avoid this, a troublesome operation such as connecting an AC adapter is required.

[0003]

SUMMARY OF THE INVENTION It is an object of the present invention to overcome the disadvantages of the power source of the above-mentioned conventional small image recording / reproducing apparatus such as a digital still camera.

[0004]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides a power supply for a data source device having the following means. That is, U
An SB interface is provided, and the interface
When a computer PC is connected via the SB cable, the power source of the data source device is switched from the built-in battery power source to the USB bus power source, and the data source device is switched according to a preset power supply capability of the PC side. (For example, 5V, 100V)
Operation mode with power consumption within mA or 5V, 50V
(Selecting a mode operable with a power consumption of 0 mA or less).

[0005] The present invention also provides the above power supply device,
When the data source device is connected to an external power source such as an AC adapter, the power source device of the data source device is forcibly shifted to the external power mode and releases the limitation of the transition mode. provide. According to the present invention, in the power supply device, when power is supplied from a USB bus power supply, the power supply voltage from the USB bus is converted to a voltage level within a supply voltage range of a built-in battery, and then the voltage is stabilized. The invention also provides a power supply for a data source device adapted to supply to an input of a power supply circuit.

In any one of the power supply devices, when the data source device shifts to the operation mode using the USB bus power supply, the user can recognize the contents of the limited operation (operable mode, notes, etc.). There is also provided a power source device of a data source device to be displayed on a liquid crystal display device or the like.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram of a power supply system according to an embodiment of the present invention.
This power supply system includes three parts separated by two dotted lines in FIG. The left of the left dotted line indicates the computer PC, and the right of the right dotted line indicates the data source device. The left dotted line and the right dotted line are connected by a USB bus.

This data source device is connected to a battery (for example,
It operates by the electric power supplied from the dry battery 6. The voltage of 1.8 V to 3.2 V supplied from the battery 6 is converted into a voltage of 3.2 V by the up converter 13, and is passed through the changeover switch 16 to the HI microcomputer and the main microcomputer 2.
0 is supplied.

When an external power supply is used, an external power supply is connected to an external input terminal 9 via an AC adapter, and a control input is applied to a control terminal of a changeover switch 8 to switch the switch 8.
Is switched to the external input side, and the power supply from the terminal 9 is sent to the up-converter 13.

Now, when this data source device is connected to a PC using a USB cable, the 5 V power supplied from the USB bus power supply on the PC side passes through the common mode filter 3 to the down converter 11. , And 3.
It is converted to 2V (microcomputer Vcc voltage level), supplied to the inputs of the power supply changeover switches 16 and 17, and applied to the first input of the AND circuit 15.

On the other hand, since no external power supply is connected to the EXTDC connector 9, a voltage of a logic level "0" is applied to the input of the inverter 14, and the output of the inverter 14 is a logic level "1". It has become. Therefore, a logic level "1" is inputted to the other input of the AND circuit 15, the output of the AND circuit 15 becomes a logic level "1", and the switches 16 and 17 are switched to the positions opposite to those shown in FIG. The output voltage from 11 is supplied to a subsequent circuit.

The output of the switch 16 is supplied to an HI (personal interface) microcomputer 19 and a main microcomputer 20.
And the reset (RES)
ET) circuit 18. As a result, the HI microcomputer 19 is reset, and the HI microcomputer 19 is subsequently activated. After that, the HI microcomputer 19 to the main microcomputer 20
, A reset signal is sent, and the main microcomputer 20 is also activated.

At this time, since the output of the down converter 11 is also supplied to the USB detection signal input terminal of the HI microcomputer 19, the power supply source of the HI microcomputer 19 is a USB bus power supply. Recognize that. The HI microcomputer 19 is further provided with a PC selection input. When the user switches the PC selection switch 22 to set the amount of current, the computer (for example, personal computer) PC1 connected to the present (data source) device is set. The HI microcomputer 19 can recognize the power supply capability. This value is 100 mA and 500 m in the illustrated example.
A is switched. In the above state, the HI microcomputer 1
9 selects the transition possible mode of the present apparatus and restricts the subsequent transition modes.

Next, the operation of the power supply circuit of the data source device will be described with reference to an embodiment. (A) The power consumption of the apparatus is 500 in a mode in which the computer PC can read image data from the apparatus.
Within 25 mW, power consumption when operating in another mode is 25
When the power is set within 00 mW: (A1). The current capacity of the power supply of the computer PC is 100
In the case of mA; the transition mode of the present apparatus is limited to only the mode in which the computer PC can read image data from the present apparatus, and the transition to other modes cannot be performed. (A2). The current capacity of the power supply of the computer PC is 500
In the case of mA; the transition to all modes is permitted as the transition mode of the present apparatus.

(B) The power consumption of the present apparatus is within 1000 mW in the mode in which the computer PC can read image data from the present apparatus, and the power consumption of other modes is 2 mW.
In the case of 500 mW or more: (B1). The current capacity of the power supply of the computer PC is 100
In the case of mA; prohibit the transition of this device to all modes. (B2). The current capacity of the computer PC power supply is 500m
In the case of A: The transition mode of the present apparatus is limited to only reading of image data from the computer PC, and transition to other modes is disabled.

Next, the stabilized power supply (DD converter: DC / DC converter) portion of the data source device will be described. A dry battery (2 AA) is used as a power source for driving this device.
When used: (i) When a dry battery is used as a power supply, a practical supply voltage is about 1.8 V to 3.2 V.
Therefore, in FIG. 1, the voltage of the power supplied from the dry cell 6 to the power switch 8 via the connector 7 is 1.8.
~ 3.2V.

(Ii) In the state shown in the figure, since the EXTDC connector 9 is not connected to an external power supply supplied via an AC_adapter or the like, the control input of the switch 8 is off, and the contact of the switch 8 is turned off. Is connected to the off side (position shown). Also, since the external power input from the EXTDC is off, the input of the inverter 14 is off, the output of the inverter is on, and one input of the AND circuit 15 is on, but the down converter from the PC side The output of the AND circuit 15 is off because the other input supplied via 11 is off, and the movable contacts of the changeover switches 16 and 17 are both connected to the off side.

(Iii) The power supplied from the dry cell 6 to the changeover switch 8 in the above (i) is supplied to the up (UP) converter 13 where it is converted to the power supply voltage level of each microcomputer and passed through the changeover switch 16. Is supplied to the microcomputers 19 and 20. Further, the output voltage of the switch 8 is supplied to the DD converter 21 via the changeover switch 17, and is converted into a plurality of voltages necessary for each circuit constituting the present apparatus and output. In this case, the DD converter 21
Is designed such that the efficiency and the like are optimal for the output voltage fluctuation range of 1.8 to 3.2 V of the dry battery.

(Iv) In the above state (iii), the US
When the computer PC1 is connected to the connector 2 using the B cable, 5V power supplied from the computer PC1 through the USB bus is supplied to the DD converter 21 via the changeover switch 17 as described above. However, at this time, without going through the down converter 11,
If the 5 V power supplied from the computer is supplied to the DD converter 21 as it is, the DD converter 21
Will operate in a wide range of 1.8 to 5.0 V, and depending on the type of load power supply, the efficiency will be degraded and the stability will be degraded.

(V) When the USB bus power supply is used for the above reason, the voltage is converted to a voltage level within the upper limit voltage of the battery by the down converter 11 and then supplied to the DD converter 21 as described above. Can be solved.

[0021]

The power supply device of the present invention has the following effects. 1. When image data is read into the computer PC from the data source device via the USB interface, whether or not the data source device has a built-in battery and whether or not the AC adapter has a connection terminal Regardless of whether the power source of the data source device is US
By using the B bus power supply, data can be read quickly and easily at any time.

2. When the data source device is driven by a battery, when the image data is read from the data source device to the computer, the power source is automatically switched to the power supplied from the computer side. As described above, it is possible to overcome the disadvantage that all the work up to that point is wasted because the battery goes down during the work. 3. When image data is read from the data source device (for example, an image recording / reproducing device of an electronic still camera) to a computer (for example, a personal computer) PC, an external power source such as an AC adapter is again used as a power source for the data source device. It is free from the trouble and trouble of connecting.

4. When a USB bus power is supplied to the data source device, the data is not supplied directly to the DD converter of the data source device but supplied via a down converter, so that the data is supplied to the DD converter. Can always be kept within the voltage fluctuation range of the built-in battery, whereby the efficiency and stability of the DD converter can be kept optimal.

[Brief description of the drawings]

FIG. 1 is a circuit diagram of a power supply device of the present invention.

[Explanation of symbols]

1 ... USB interface connector on the computer side 2 ... USB interface connector on the data source side 3-5, 10 ... Common mode filter
6 ... Dry battery, 7 ... Battery connector, 8, 1
6, 17 ... Changeover switch, 9 ... AC adapter connector, 11 ... Down converter.

Claims (4)

[Claims] When a data source device having a serial bus interface having a power supply terminal is connected to a computer PC via a serial bus cable, the data source device is powered from a built-in battery power source. A power supply device for a data source device, which automatically switches to a bus power source and restricts a transition enable mode of the data source device according to a preset power supply capability of a PC. 2. The power supply device according to claim 1, wherein when the data source device is connected to an external power supply such as an AC adapter, the data source device is forcibly shifted to an external power supply mode.
Data to remove restrictions on the transition mode
Power supply for the source device. 3. The power supply device according to claim 1, wherein when the power supply of the data source device is supplied from a bus power supply, the power supply voltage from the bus is reduced to a voltage level within a supply voltage range of the built-in battery. A power supply for a data source device that supplies voltage to an input terminal of a stabilized power supply circuit after voltage conversion. 4. The power supply device according to claim 1, wherein when the data source device shifts to an operation mode using a bus power supply, the contents of the limited operation (operable mode and notes). Etc.) on a liquid crystal display device or the like so that the user can recognize them.