JP2001202144A - Power supply device, method for controlling power supply and medium recording control program for power supply device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve conventional problems such that the connection of power supply cables is complicated and a cause of deteriorating the operability of equipment is generated because power supply routes for a plurality of systems should be secured. SOLUTION: Only a current >=500 mA is extracted from the output of a USB 20, electric double layer capacitors C1, C2 are charged up to prescribed level while regulating the output to a hard disk device(HDD) 30. When the charging reaches prescribed level, the extracted current >=500 mA and an output current from the capacitors C1, C2 are outputted to the HDD 30, so that the driving power shortage of the HDD 30 can be solved by utilizing only the output from the USB 20 whose current capacity is regulated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power supply, a power supply control method, and a medium recording a control program for the power supply, and more particularly, to a power supply interposed between a power supply having a prescribed current capacity and a predetermined load. The present invention relates to a device, a power supply control method, and a medium recording a control program for a power supply device.

[0002]

2. Description of the Related Art When a computer is connected to a computer peripheral, a bus standard such as Universal Serial Bus (USB) or IEEE 1394 is often used. These buses are characterized by including both a signal path and a power supply path, and the current capacity of the power supply path is 500 mA in USB according to the standard, IEEE1
394 specifies 1.5A. Therefore, even a computer peripheral device whose rated current is lower than the standard cannot be used for a device whose temporary current exceeds the standard, such as a hard disk device. In this case, the computer peripheral uses only the signal path from the bus, and the power supply uses a commercial power supply or an AC adapter separately as a power supply.

[0003]

As described above, in a conventional computer peripheral device, a plurality of connection cables, such as a signal cable and a power cable, must be secured, so that the connection is complicated. Also US
Despite being connected by B or IEEE 1394, a separate power supply must be provided on the side of the computer peripherals, so that the computer main unit can be connected to a commercial power supply even if it can be carried by mounting a battery. A power cable and an AC adapter are required to carry the computer, which limits the portability of the computer and causes the usability of computer peripheral devices to deteriorate. The present invention has been made in view of the above problems, and has a power supply device, a power supply control method, and a power supply capable of solving a shortage of driving power in a load by using only an output from a power supply having a specified current capacity. It is an object of the present invention to provide a medium in which a control program for an apparatus is recorded.

[0004]

According to a first aspect of the present invention, there is provided a power supply device interposed between a power supply having a prescribed current capacity and a predetermined load.
A current regulating means connected to the power supply to take out only a current smaller than the current capacity; a current buffer means connected to an output of the current regulating means and chargeable by the output current; the current regulating means and the current buffer A stabilizing means connected to the load means for supplying a current to the load at a predetermined voltage, and a current monitoring means for regulating an output until the current buffer means is charged to a predetermined capacity or more. . In the invention according to claim 1 configured as described above, when the current regulating means takes out only a current having a current capacity equal to or less than the current capacity from a power supply having a prescribed current capacity, the current connected to the output of the current regulating means is reduced. The buffer means performs charging with a current equal to or less than the current capacity output from the current regulating means.

[0005] At this time, the current monitoring means regulates the output until the current buffer means is charged to a predetermined capacity or more, and permits the output when the charging proceeds to the predetermined capacity or more. When the output from the current monitoring means is permitted, the stabilizing means connected to the current regulating means and the current buffer means combines the output from the current regulating means with the output from the current buffer means. To a load at a predetermined voltage. Therefore, at the time of the predetermined operation in the load, even if the driving current is insufficient due to the output from the current regulating unit alone, the shortage of the driving current can be resolved by adding the output from the current buffer unit. Becomes possible.

[0006] The power supply referred to here may be a power supply having a prescribed current capacity. As an example of the configuration, the invention according to claim 2 is the power supply device according to claim 1, wherein the power supply is a universal power supply. Serial bus or IEEE1
394. In the invention according to claim 2 configured as described above, the current regulating means extracts only a current having a current capacity equal to or less than a prescribed current capacity from a universal serial bus or IEEE1394. Therefore,
For example, when a computer peripheral device is applied as the load, a power supply line to the computer peripheral device is configured by using a power path included in USB or IEEE1394 between the computer peripheral device and the computer main body. Therefore, there is no need to secure a separate power supply line, and the number of connection cables can be reduced.

The load is not limited to the computer peripherals described above, since it can be driven by using a power supply having a specified current capacity. It is possible to configure with equipment. The current regulating means only needs to be connected to the power supply and take out only a current smaller than the current capacity.For example, by monitoring the output current, when the output current exceeds a predetermined value, the power supply It may be configured by a switching circuit that cuts off the connection with the switch.

The current buffer means is only required to be connected to the output of the current regulating means and capable of being charged by the output current. As an example of the configuration, the invention according to claim 3 is the invention according to claim 3. The power supply device according to claim 1 or 2, wherein the current buffer means is a capacitor connected to an output of the current regulating means. In the invention according to claim 3 configured as described above, when the current regulating means takes out only a current having a current capacity equal to or less than a current from a power supply having a prescribed current capacity, the capacitor connected to the output of the current regulating means. Performs charging with a current equal to or less than the current capacity output from the current regulating means.

When a capacitor is used, unlike the case where a battery is charged, a charging circuit is not required, so that it is possible to avoid an increase in the size of a device. In addition, since a chemical reaction is not used, charging and discharging are repeatedly performed. However, the charging capacity does not decrease. Furthermore, the quick charging is possible, so that the charging time is shortened. Therefore, the configuration is useful in these respects. As an example of the capacitor, the invention according to claim 4 is the power supply device according to claim 3, wherein the capacitor is an electric double layer capacitor.

In the invention according to claim 4 configured as described above, when the current regulating means extracts only a current having a current capacity equal to or less than a current from a power supply having a prescribed current capacity, the current is connected to the output of the current regulating means. The electric double-layer capacitor thus charged is charged with a current equal to or less than the current capacity output from the current regulating means. As described above, the application of the electric double layer capacitor is useful in that the output can be performed for a relatively long time because the chargeable current capacity with respect to the element size is large. However, the electric double layer capacitor applied here is only an example of the above-mentioned capacitor, and it is possible to use another kind of capacitor as well.

The stabilizing means may be any means which is connected to the current regulating means and the current buffer means and supplies a current to the load at a predetermined voltage. That is,
Any device may be used as long as the output to the load does not fluctuate according to the state of charge in the capacitor. Therefore, for example, it can be configured by a DC-DC converter or the like. The current monitoring means only needs to regulate the output until the current buffer means is charged to a predetermined capacity or more. The current monitoring means may be constituted by hardware using elements such as transistors, or may be a program. It may be configured by software by applying control.

[0012] As an example of the case where the current monitoring means is constituted by hardware, the invention according to claim 5 is the power supply device according to claim 3 or claim 4, wherein the current monitoring means comprises: The switching circuit keeps the output closed until the charging voltage of the capacitor reaches a predetermined voltage. In the invention according to claim 5 configured as described above, the switching circuit includes:
The output is closed until the charging voltage of the capacitor reaches a predetermined voltage, and when the charging of the capacitor progresses and reaches the predetermined voltage, the output is allowed by switching on and off.
That is, in a simple switching circuit incorporated in the power supply device, the charge voltage of the capacitor is monitored, and output is prohibited until the charge voltage reaches a predetermined voltage. When the switching circuit detects that the monitored charging voltage has reached the predetermined voltage, the switching circuit switches on and off the transistor element and the like, thereby allowing the output from the capacitor.

[0013] The above-described power supply control method is not necessarily limited to a substantial device, and as an example, the invention according to claim 6 is based on a power supply having a specified current capacity. While taking out only the electric current,
While regulating the output to the same load until the battery is charged to a predetermined capacity or more, charging is performed with a current less than the same current capacity taken from the same power supply, and after being charged to the same predetermined capacity or more, a predetermined voltage is applied to the same load. To supply current. That is, the above-described power supply control method is not necessarily limited to a substantial device, and is useful as a method thereof. Note that it goes without saying that the device configuration described in claims 2 to 5 can be similarly applied to the method.

[0014] In addition, when the charge amount in the power supply device is insufficient, if the load is continuously driven,
Since there is a possibility that a shortage of the drive current may occur depending on the operation to be executed, it is possible to eliminate the shortage of the drive current by controlling the operation at the same load. As an example of a case where such control is implemented by software, the invention according to claim 7 extracts only a current of not more than the same current capacity from a power supply having a specified current capacity, and outputs an output to a load until it is charged to a predetermined capacity or more. While regulating
The battery is charged with a current equal to or less than the same current capacity taken out of the same power supply, and after being charged to the same predetermined capacity or more, a charge amount in a power supply device that supplies a current at a predetermined voltage to the load is monitored. Is less than the predetermined capacity, the operation at the same load is regulated.

That is, when the charge amount to be monitored is less than the predetermined capacity, if the load is continuously driven, the driving current may be insufficient depending on the operation to be performed. Regulate. Note that the recording medium may be a magnetic recording medium or an optical recording medium. Also, in the case where a part is realized by software and a part is realized by hardware, there is no difference in the concept of the present invention, and a part is recorded on a recording medium and appropriately The form of reading is also included.

[0016]

As described above, the present invention can provide a power supply device capable of resolving a shortage of driving power in a load by using only an output from a power supply having a specified current capacity. . Further, according to the second aspect of the invention, the number of connection cables between devices can be reduced.
Further, according to the third aspect of the present invention, it is possible to realize the downsizing of the device, the improvement of the durability, and the shortening of the charging time.

Further, according to the invention according to claim 4,
The downsizing of the device and the increase of the charging capacity can be realized. Furthermore, according to the invention according to claim 5, the configuration can be simplified. Further, according to the invention according to claim 6, it is possible to provide a power supply control method capable of resolving a shortage of driving power in a load using only an output from a power supply having a specified current capacity. Further, according to the seventh aspect of the present invention, a control program for a power supply device capable of resolving a shortage of driving power in a load even when the amount of charge in the power supply device is insufficient is recorded. A medium can be provided.

[0018]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing a power supply device according to an embodiment of the present invention. The power supply device 10 shown in FIG. 1 has an output side of a USB 20 connected to a computer main body and having a current capacity of 500 mA,
The drive power supply is provided between the power supply input terminal of the hard disk device 30 and the power supply output from a computer main body (not shown) connected to the input side of the USB 20 to supply drive power to the hard disk device 30. In this sense, the hard disk device 30 constitutes a load according to the present invention.

The power supply 10 is connected to a constant current circuit 10a connected to the output side of the USB 20, a current buffer circuit 10b connected to the output side of the constant current circuit 10a, and connected to an output side of the current buffer circuit 10b. Current monitoring circuit 10c
And a stabilizing circuit 10d interposed between the output side of the constant current circuit 10a and the current buffer circuit 10b and the power input terminal of the hard disk drive 30. With this configuration, when the hard disk device 30 is connected to the power supply device 10, the constant current circuit 10a
The current buffer circuit 10
b performs charging by the output current from the constant current circuit 10a. At this time, the current monitoring circuit 10c monitors the amount of charge in the current buffer circuit 10b, and regulates the output from the current buffer circuit 10b until the amount of charge reaches a predetermined value.

When the amount of charge in the current buffer circuit 10b reaches a predetermined value, output to the stabilizing circuit 10d is permitted. Then, the stabilizing circuit 10d supplies the hard disk drive 30 with the output current from the constant current circuit 10a and the output current from the current buffer circuit 10b at a predetermined voltage. Therefore, a constant current circuit 10a for extracting only a current of 500 mA from the USB 20 and a current buffer circuit 10b for charging with an output current from the constant current circuit 10a
A current monitoring circuit 10c that regulates the output from the current buffer circuit 10b until the charged amount in the current buffer circuit 10b reaches a predetermined value; an output current from the constant current circuit 10a and an output current from the current buffer circuit 10b. Is supplied to the hard disk device 30 at a predetermined voltage in this sense, respectively, and constitutes a current regulating means, a current buffer means, a current monitoring means and a stabilizing means according to the present invention.

FIG. 2 is a circuit diagram showing a main configuration of the power supply device 10. The constant current circuit 10a includes a USB 20
R1 having an input terminal connected to the output side of the resistor R1, a PNP transistor Tr1 interposed between the output terminal of the resistor R1 and the current buffer circuit 10b, and a PNP transistor connected in parallel with the resistor R1. Tr2 is provided. The PNP transistor Tr1 has an emitter terminal e1 connected to the output terminal of the resistor R1, and a collector terminal c1 connected to the current buffer circuit 10b.
The base terminal b1 is grounded via a resistor R2. The PNP transistor Tr2 has an emitter terminal e2 connected between the output side of the USB 20 and the input terminal of the resistor R1, and a collector terminal c1 connected between the base terminal b1 of the PNP transistor Tr1 and the resistor R2. The base terminal b1 is connected to the output terminal of the resistor R1 and the emitter terminal e1 of the PNP transistor Tr1.
Connected between

With this configuration, when the hard disk device 30 connected to the power supply device 10 is started, the base terminal b1 of the PNP transistor Tr1 is connected to the ground side circuit. It is higher than the potential of the terminal b1. Therefore, USB20
Is input from the emitter terminal e1 of the PNP transistor Tr1 to the base terminal b1 via the resistor R1. Therefore, the output current from the USB 20 flows from the emitter terminal e1 to the collector terminal c1, and is supplied to the current buffer circuit 10b. Here, when the output current from the USB 20 fluctuates and exceeds the current capacity of 500 mA, the potential at the base terminal b2 drops due to the voltage drop generated by the resistor R1, so that the output current from the USB 20 becomes a PNP transistor. Input from the emitter terminal e2 of Tr2 to the base terminal b2 starts. Then
The PNP transistor Tr2 is turned on, and the output current from the USB 20 flows from the emitter terminal e2 to the collector terminal c2 arranged in the ground side circuit.

As a result, the potential at the base terminal b1 of the PNP transistor Tr1 rises, making it difficult for the output current from the USB 20 to be input from the emitter terminal e1 to the base terminal b1, and from the emitter terminal e1 to the collector terminal c.
1, the current supplied to the current buffer circuit 10b is prevented from exceeding 500 mA. Thus, the constant current circuit 10a includes the current buffer circuit 10b,
The current output to the current monitoring circuit 10c and the stabilizing circuit 10d is regulated to 500 mA or less.

On the other hand, during normal operation, the hard disk drive 30 is driven using a rated current of 400 mA, so that a current of 500 mA output from the constant current circuit 10a is supplied via the stabilizing circuit 10d. By doing so, a sufficient drive current can be obtained. However, at the time of startup, data reading, data writing, and the like, a larger drive current is required than during normal operation. For example, as shown in FIG. 3, at the time of startup, a drive current of about 800 mA is required, which exceeds the rated current of 400 mA. Therefore, the hard disk drive 3 connected to the power supply 10
0 is activated, the constant current circuit 10a outputs 500 mA
Output current of more than 500 m
Since A is the upper limit current value, a sufficient drive current cannot be supplied to the hard disk device 30. In such a case, in order to realize the current supply according to the request of the hard disk device 30, the current buffer circuit 10b and the current monitoring circuit 1
0c and a stabilizing circuit 10d.

The current buffer circuit 10b includes electric double layer capacitors C1 and C2, and the electric double layer capacitors C1 and C2 are charged by the current output from the collector terminal c1 of the PNP transistor Tr1. Here, the use of the electric double layer capacitors C1 and C2 is different from the case where the battery is charged, and does not require a charging circuit. This is because the charge capacity is not reduced even if the charge and discharge are repeatedly performed because the battery is not used. Furthermore, since the rapid charging is possible, the charging time can be shortened, which is useful. Further, since the electric double layer capacitors C1 and C2 have a large charging capacity in spite of a small element size as compared with other types of capacitors, a relatively large capacity can be easily charged by the output current from the PNP transistor Tr1. It becomes possible. Therefore, when the output from the electric double layer capacitors C1 and C2 becomes necessary, it is useful in that the output can be performed for a relatively long time.

The current monitoring circuit 10c includes a PNP transistor Tr3 connected to the collector terminal c1 of the PNP transistor Tr1 via the diode D1, and resistors R3 to R3.
An NPN transistor Tr4 connected to the PNP transistor Tr1 and the PNP transistor Tr3 via the R5. The diode D1 is arranged to prevent the current on the electric double layer capacitors C1 and C2 from flowing back to the collector terminal c1 of the PNP transistor Tr1. PNP transistor Tr
3 connects the emitter terminal e3 to the output terminal of the diode D1, connects the base terminal b3 to the collector terminal c4 of the NPN transistor Tr4, and connects the collector terminal c3 to the stabilization circuit 10d. ing. The NPN transistor Tr4 connects the base terminal b4 to P
The collector terminal c4 is connected to the collector terminal c1 of the NP transistor Tr1, the collector terminal c4 is connected to the emitter terminal e3 and the base terminal b3 of the PNP transistor Tr3, and the emitter terminal e4 is grounded. The base terminal b4 of the NPN transistor Tr4
Are grounded via a resistor R6.

With this configuration, the PNP transistor T
The output current from the collector terminal c1 of r1 is a diode D
1, the electric potential difference between the emitter terminal e3 and the base terminal b3 of the PNP transistor Tr3 is equalized by the resistors R4 and R5 while the electric double layer capacitors C1 and C2 are charged to a predetermined capacity. The PNP transistor Tr3
Is turned off and the emitter terminal e3 to the collector terminal c
Cut off the current to 3. Therefore, while the electric double-layer capacitors C1 and C2 are charged to a predetermined capacity, the output to the stabilizing circuit 10d is shut off. During this time, P
Since the output current from the collector terminal c1 of the NP transistor Tr1 is supplied to the electric double layer capacitors C1 and C2, the potential at the base terminal b4 of the NPN transistor Tr4 does not exceed the threshold value and is turned off. The output from the collector terminal c4 to the emitter terminal e4 is cut off.

When the amount of charge in the electric double layer capacitors C1 and C2 reaches a predetermined value A shown in FIG. 4, the PN which has been supplied to the electric double layer capacitors C1 and C2 until now.
Since the output current from the collector terminal c1 of the P transistor Tr1 starts to be input to the base terminal b4 of the NPN transistor Tr4, the potential at the base terminal b4 of the NPN transistor Tr4 exceeds the threshold value and turns on.
Output from the collector terminal c4 to the emitter terminal e4 is permitted. Then, since the potential at the base terminal b3 of the PNP transistor Tr3 drops, a current is input from the emitter terminal e3 to the base terminal b3 in the PNP transistor Tr3. Therefore, the PNP transistor Tr3
Is turned on, and PN supplied via the diode D1 is turned on.
The output current from the collector terminal c1 of the P transistor Tr1 and the charged electric double layer capacitors C1 and C2
From the emitter terminal e3 to the collector terminal c3, and the hard disk drive 30 requests 500
An output current exceeding mA is supplied to the stabilizing circuit 10d.

Then, the electric double layer capacitors C1, C2
As shown in FIG. 4, while the output current continues to flow to the stabilization circuit 10 d while the output from the electric double layer capacitors C1 and C2 decreases, the electric double layer capacitors C1 and C2 , And sequentially charge the reduced charge amount. At this time, since the potential at the base terminal b4 of the NPN transistor Tr4 is maintained in a state exceeding the threshold, the ON state of the PNP transistor Tr3 continues, and the current continues to be supplied to the stabilizing circuit 10d. Therefore, the diode D1, the resistors R3 to R5, and the PNP transistor Tr3 provided in the current monitoring circuit 10c are provided.
The NPN transistor Tr4 forms a switching circuit according to the present invention.

The stabilizing circuit 10d includes a DC-DC converter 10d1 connected to the collector terminal c3 of the PNP transistor Tr3.
The current output from the third collector terminal c3 is output at 5V required by the hard disk device 30. For this reason, as described above, even when the hard disk device 30 requests a current near 800 mA exceeding the rated current of 400 mA at the time of startup, the requested current is reduced to 5V.
Can be supplied reliably.

In the present embodiment, the output from the current buffer circuit 10b is regulated by the current monitoring circuit 10c constituted by hardware until the amount of charge in the electric double layer capacitors C1 and C2 reaches a predetermined value. The drive current in the hard disk device 30 is controlled so as not to be insufficient. However, such a configuration is only an example,
Under the control of a program executed by the computer connected via the control unit 20, it is also possible to prevent a shortage of drive current in the hard disk device 30. For example, a voltage monitoring circuit that monitors the voltage between both ends of the electric double layer capacitors C1 and C2 shown in FIG. Then, as shown in FIG. 5, the computer main body acquires the charge amount in the electric double layer capacitors C1 and C2 from the voltage value acquired by the voltage monitoring circuit via the USB 20 (step S100), and the charge amount becomes a constant voltage. It is determined whether it is not less than (step S110).

When it is determined that the charged amounts in the electric double layer capacitors C1 and C2 are equal to or lower than a predetermined voltage, and the hard disk device 30 is being accessed, the drive current exceeding 500 mA is maintained by continuing the access state. The required operation is performed, and there is a possibility that the driving current becomes insufficient. Therefore, the hard disk drive 3
0 is temporarily interrupted, and after waiting for a certain time, the access is restarted (steps S120 to S150).
Therefore, even when software is applied, it is possible to avoid a situation in which the drive current is insufficient in the hard disk device 30 as in the present embodiment.

Next, an operation when the hard disk device 30 connected to the power supply device 10 according to the present embodiment is started will be described with reference to FIG. Power supply 10
Is activated (step S200), the output current from the USB 20 is input from the emitter terminal e1 of the PNP transistor Tr1 to the base terminal b1 via the resistor R1. Flow to the collector terminal c1 (step S
210). At this time, if a current exceeding 500 mA is going to flow through the resistor R1, the output current is input from the emitter terminal e2 of the PNP transistor Tr2 to the base terminal b2 due to a voltage drop generated in the resistor R1, so that the emitter terminal It flows from e2 to the collector terminal c2 arranged in the ground side circuit. Therefore, the PNP transistor Tr
1, the potential at the base terminal b1 drops, and the emitter terminal e1 of the PNP transistor Tr1 moves from the base terminal b1 to the base terminal b1.
Current from the emitter terminal e1 to the collector c1 is regulated to 500 mA or less.

The current of 500 mA or less output from the collector terminal c1 of the PNP transistor Tr1 is supplied to the electric double layer capacitors C1 and C2 via the diode D1, so that the electric double layer capacitors C1 and C2 can reach a predetermined capacity. Charging is performed (step S220). During this charging, the PNP transistor Tr3 has an emitter terminal e3
And the base terminal b3 is adjusted so that the potential difference between them and the base terminal b3 becomes the same potential.
From the collector terminal c3. On the other hand, NP
In the N-transistor Tr4, since the potential at the base terminal b4 does not exceed the threshold value, the transistor is turned off to cut off the output from the collector terminal c4 to the emitter terminal e4.

Here, the electric double layer capacitors C1, C2
When the charge amount at the time reaches a predetermined value (step S23).
0), since the output current from the collector terminal c1 of the PNP transistor Tr1 starts to be input to the base terminal b4 of the NPN transistor Tr4, the potential at the base terminal b4 exceeds the threshold, and the NPN transistor Tr4 is turned on. Output from the collector terminal c4 to the emitter terminal e4 is permitted. Then, the potential at the base terminal b3 of the PNP transistor Tr3 drops, so that the emitter terminal e3
Is input to the base terminal b3. Therefore, P
The NP transistor Tr3 turns on, and the diode D1
Terminal c1 of PNP transistor Tr1 through
And the output currents from the charged electric double layer capacitors C1 and C2 flow from the emitter terminal e3 to the collector terminal c3 (step S240).

Therefore, the electric double layer capacitors C1 and C1 are supplied with a current of 500 mA or less output from the constant current circuit 10a.
500m because the output from C2 will be added
An output current exceeding A can be supplied to the DC-DC converter 10d1 (step S250). This 500mA
Is supplied to the DC-DC converter 10d1, the DC-DC converter 10d1 outputs a current exceeding 500 mA required by the hard disk device 30 at 5V. Then, the hard disk device 30
The starting operation is performed using the current output from the DC-DC converter 10d1. As described above, only the current of 500 mA or less is taken out of the output of the USB 20, and while the output to the hard disk device 30 is regulated, the electric double-layer capacitors C1 and C2 are charged to a predetermined capacity, and the charging capacity reaches the predetermined capacity. Then, in order to output the extracted current of 500 mA or less and the output currents from the electric double layer capacitors C1 and C2 to the hard disk device 30, the hard disk drive uses only the output from the USB 20 having the specified current capacity. It is possible to eliminate the shortage of driving power in the device 30.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a schematic configuration of a power supply device according to an embodiment.

FIG. 2 is a circuit diagram showing a main configuration of a power supply device.

FIG. 3 is a time chart showing a change in drive current when the hard disk device is started.

FIG. 4 is a time chart showing a change in the amount of charge in the electric double layer capacitor.

FIG. 5 is a flowchart illustrating an access control procedure in a power supply device according to a modification.

FIG. 6 is a flowchart showing an operation procedure in the power supply device.

[Explanation of symbols]

 Reference Signs List 10 power supply device 10a constant current circuit 10b current buffer circuit 10c current monitoring circuit 10d stabilization circuit 10d1 DC-DC converter 20 USB (universal serial bus) 30 hard disk device C1, C2 electric double layer capacitor D1 Diode R1 to R6 Resistor Tr1 to Tr3 PNP transistor Tr4 NPN transistor

Continued on the front page F term (reference) 5B011 DA13 DB02 DB19 DB21 EB07 GG06 5G065 DA04 DA07 HA07 HA17 LA02 NA01 NA02 NA04 5H430 BB01 BB09 BB12 EE03 EE08 EE17 FF08 FF12 HH02 LA04 LA07

Claims (7)

[Claims] 1. A power supply device interposed between a power supply having a specified current capacity and a predetermined load, wherein the current control means is connected to the power supply and takes out only a current smaller than the current capacity. Current buffer means connected to the output of the current regulating means and chargeable by the output current; stabilizing means connected to the current regulating means and the current buffer means for supplying a current at a predetermined voltage to the load And a current monitoring means for regulating the output until the current buffer means is charged to a predetermined capacity or more. 2. The power supply device according to claim 1, wherein the power supply is a universal serial bus or an IEEE.
A power supply device, which is a power supply path included in 1394. 3. The power supply device according to claim 1, wherein said current buffer means is a capacitor connected to an output of said current regulating means. 4. The power supply device according to claim 3, wherein the capacitor is an electric double layer capacitor. 5. The power supply device according to claim 3, wherein said current monitoring means has a switching circuit for closing an output until a charging voltage of said capacitor reaches a predetermined voltage. A power supply device characterized by the above-mentioned. 6. The same current capacity taken out from the power supply while taking out only a current less than or equal to the current capacity from a power supply having a specified current capacity and regulating the output to the same load until the battery is charged to a predetermined capacity or more. A power supply control method comprising: charging the battery with the following current, and supplying a current at a predetermined voltage to the load after the battery is charged to the predetermined capacity or more. 7. A current source having a specified current capacity is taken out only from a power source having a specified current capacity or less, and an output to a load is regulated until the battery is charged to a predetermined capacity or more. After the battery is charged to a predetermined capacity or more, the amount of charge in a power supply device that supplies a current at a predetermined voltage to the same load after the charge is monitored. A medium storing a control program for a power supply device, wherein the control program regulates the operation of the power supply device.