JP2000029544A - Power supply control device, USB device, and power supply control method - Google Patents

Abstract

(57) [Summary] [Problem] To provide a power control device for a USB device which can ensure convenience and simplicity of the USB device without deteriorating the performance of the USB device. SOLUTION: A rechargeable battery 116 is mounted in the device, and the battery 116 is charged when the normal power consumption is equal to or less than a USB current limit value, and the current consumption of a power block unit 50 transitions to the limited current transiently. When the value exceeds the value, that is, when the supply current is insufficient, the battery 1
16 supplies power to the power block unit 50.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power supply control device and a power supply control method for a drive device such as a speaker device or a floppy disk drive with a built-in power amplifier, and a USB device provided with the power supply control device.

[0002]

2. Description of the Related Art At present, USB (Universal Serial Bus), IEEE 1394 and the like are receiving attention as interface buses for personal computers. These interfaces are designed for ease of connection and convenience,
The power line is included in it.

However, considering the burden of power supply on the host device side, the supply power must be limited, and the USB has a current limit of 5 V and a maximum of 500 mA in the standard. On the USB host device, that is, on the power supply side, when the load current of the connected USB device exceeds the current limit value, the protection circuit operates to cut off the power supply to the USB device. .

[0004]

However, conventional USB devices have the following problems.

[0005] Among devices that can be considered as USB devices, there are devices in which the average power consumption of the device is small, but which requires a transiently large current consumption for a short time. For example, when a large sound is output from a speaker device with a built-in amplifier, or when a motor is started in a disk device such as a floppy disk.

If these transient powers are covered with a capacitor or the like for a short time, the capacity becomes too large, which is not practical. Therefore, conventionally, in such a case, even if the performance of the device is reduced, the device is designed to operate within the power supply capability range, or the performance of the device is prioritized. It is possible. However, if the performance of the device is prioritized, the power supply of the device must be separately supplied from the outside instead of the USB interface bus, and the convenience and simplicity of the USB are deteriorated. Was.

For example, when trying to design a stereo speaker system using a USB interface,
The maximum output achievable with a 5 V 500 mA (250 mA per channel) power supply is only 625 mW per channel, even if there is no loss. Furthermore, OT
L (Output Transformer Less)
In order to obtain the maximum output, unless a DC-DC converter or the like is used, the impedance of the speaker is limited to 20Ω, which is not a general value. The maximum output obtained with a power supply voltage of 5 V, a general speaker impedance of 4Ω, and OTL is 3.13 W.
It is.

The present invention has been made in view of the above-mentioned conventional problems, and has been developed in consideration of the USB.
It is an object of the present invention to provide a power supply control device and a power supply control method for a USB device that can ensure convenience and simplicity of a USB device without deteriorating the performance of the device, and a USB device including the power supply control device. I do.

[0009]

In order to achieve the above object, in a power supply control device according to the present invention, a power supply is supplied from a power supply device which is current-limited at a predetermined current limit value. In the power supply control device, a rechargeable battery and a charge control unit that charges the battery when the current consumption is lower than the limit current value are provided, and when the current consumption exceeds the limit current value, the driving is performed. A current is supplied to the apparatus from the battery.

According to a second aspect of the present invention, in the power supply control apparatus according to the first aspect, the driving device is a device whose current consumption transiently exceeds the limit current value. .

According to a third aspect of the present invention, in the power supply control device according to the first or second aspect,
Power is supplied from the power supply device via a USB connector.

According to a fourth aspect of the present invention, in the USB device, a driving device to which power is supplied from a power supply device which is subjected to a current limit at a predetermined current limit value, and a drive device connected to the power supply device via a USB connector, A USB device comprising a power control device for controlling power supply to the drive device;
The power supply control device includes a chargeable battery and a charge control unit that charges the battery when current consumption is lower than the limit current value. A current is supplied to the apparatus from the battery.

According to a fifth aspect of the present invention, in the USB device according to the fourth aspect, the driving device is a device in which current consumption transiently exceeds the limit current value.

According to a sixth aspect of the present invention, there is provided a USB device according to the fifth aspect, wherein the driving device is constituted by a speaker device having a built-in power amplifier.

According to a seventh aspect of the present invention, in the USB device according to the fifth aspect, the driving device is constituted by a floppy disk device.

In the power supply control method according to the present invention, a rechargeable battery is provided in the power supply control method for a driving device to which power is supplied from a power supply device which is subjected to a current limit at a predetermined current limit value. When the current consumption is lower than the limit current value, the battery is charged, and when the current consumption exceeds the limit current value, a current is supplied from the battery to the driving device.

According to a ninth aspect of the present invention, in the power supply control method according to the eighth aspect, the driving device is a device whose current consumption transiently exceeds the limit current value. .

[0018]

Embodiments of the present invention will be described below with reference to the drawings.

(First Embodiment) FIG. 1 is a block diagram showing the overall configuration of a USB device according to a first embodiment of the present invention.

The USB device of this embodiment is configured as a speaker device with a built-in amplifier. This speaker device with a built-in amplifier receives a digitized sound signal from a host computer such as a PC (personal computer) or WS (workstation) through a USB connector, converts the sound signal into an analog signal, and further amplifies the sound signal. It is more regenerating.

This speaker device with a built-in amplifier includes a power supply control block 10, a power block 20, a left channel speaker 104L and a right channel speaker 104R.

In the figure, 100 is a USB connector,
The USB signal line s101 and the power supply line ps101 are assigned. In the power supply control block 10, 101 is
A USB controller that transmits and receives data to and from a host computer via a USB signal line s101;
The audio data is separated from the data and output to the digital audio signal line s102.

Reference numeral 102 denotes a D / A converter, which receives the digital audio signal s102, and outputs
Channel audio analog signals s104L, s1
04R is output.

Reference numerals 103L and 103R denote audio power amplifiers, and the audio analog signal s10
4L and s104R, and amplifies the power to drive the speakers 104L and 104R to be described later.
05L, output to s105R.

Reference numerals 104L and 104R denote speakers, which are supplied with power from the power supply line ps105, input the electroacoustic signals of the signal lines s105L and s105R, convert them into air vibrations, and emit sound.

Reference numeral 111 denotes a current limiter (1),
Power supply line ps101 input from USB connector 100
The power supply current. This is a value i slightly smaller than the maximum power supply current of 50 mA, which is the USB standard.
L1 is set.

Reference numeral 112 denotes a current detection unit,
The entire current consumption of the device, that is, the current i01 flowing through the power supply line psL02 is monitored, and the
The current i02 is controlled such that the sum of the current i02 flowing through the power supply line ps106 to the power supply line 15 and the device operating current i03 other than the battery charging is less than the set value of the current limiter 111. By doing so, the charging current to the battery 116 is smaller than the value obtained by subtracting the device operating current i03 from the set value iL1 of the current limiter 111.

Reference numeral 113 denotes a current limiter (2),
A value iL such that the current input from the power supply line ps103 becomes smaller than the difference between the set value iL1 of the current limiter 111 and the maximum value of the current i03a to the power supply control block 10.
2, the current supplied to the power control block 10 is secured by the current from the USB connector 100 even when the current i05 of the power block 20 described later transiently increases. .

Reference numeral 114 denotes a power supply switching unit, which is a power supply line p.
s104 and the current from the power supply line ps109
The power is supplied to the power block 20 through 105. At this time, when the current i05 to the power block 20 exceeds the set value iL2 of the current limiter 113, the shortage is controlled so as to be supplied from the power supply line ps117 through the battery 116 and the output voltage adjustment unit 117. .
At this time, if the battery 116 is insufficiently charged and the current supply to the power block 20 is not sufficient, the sound may be distorted.

Reference numeral 115 denotes a charge control unit, which receives a current from the output ps106 of the current detection unit 112 and controls charging of the battery 116 through a charging power supply line ps107. Here, the battery 116 is a rechargeable secondary battery, which is charged from the charging line ps107 and supplies power through the output line ps108.

Reference numeral 117 denotes an output voltage adjusting unit which adjusts the voltage of ps108 output from the battery 116 to a value slightly lower than the voltage of the input power supply line ps102, and supplies the voltage to the power supply switching unit 114 through the power supply line ps109. Is output.

The change in the current consumption i03a in the power supply control block 10 is determined by the power amplifiers 103L and 103L.
Compared to 3R, it is very small, can be absorbed by a small-capacity capacitor, so-called bass condenser, and is almost constant.

On the other hand, the power block 20 is composed of left and right power amplifiers 103L and 103R, and the current consumption i05 here largely fluctuates depending on the audio input, and the power consumption is determined by USB.
May exceed the standard of 500 mA.

Next, the operation of the first embodiment will be described with reference to the flowchart of FIG.

When the device starts operating, first, in step S1
Thus, the battery 116 is charged with a current within (iL1-i03). Note that iL1 is the current limiter 1
11 and i03 is the operating current value of the device. At this time, if i03 becomes equal to iL1, charging is interrupted, and the maximum current supplied from the USB connector 100 is used for device operation.

In step S2, i05 ≧ iL
2 is monitored. Here, i05 is the current consumption of the power block 20, and iL2 is the current limiter 113.
Is the set value. If i05 <iL2, step S
Then, the power supply switching unit 114 supplies the current only from the power supply line ps104 because all the current can be supplied from the USB connector 100.

At this point, there is still a surplus in the supply current from the USB connector 100, and this amount is used in step S1.
And is used for charging the battery 116.

Here, when a situation such that i05 ≧ iL2 occurs, the process proceeds to step S4, where (i05−iL2)
Since the supply current from the USB connector 100 is insufficient for 5), the power supply switching unit 114 supplies the insufficient current from the battery 116 through the power supply line ps109.

As described above, in this embodiment, the rechargeable battery 116 is mounted in the USB device, and when the normal power consumption is equal to or less than the USB current limit value, the battery 11 is charged.
When the supply current is insufficient and the supply current is insufficient, power is supplied from the battery 116. This makes it possible to realize a USB device that operates only by power supply from the USB connector 100 without deteriorating the performance of the device. In other words, it is possible to realize a USB device that can fully enjoy the convenience and simplicity of USB without supplying power to the device from another power source other than the USB interface bus.

(Second Embodiment) FIG. 3 is a block diagram showing the overall configuration of a USB device according to a second embodiment of the present invention.

The USB device of this embodiment is configured as a floppy disk device. This floppy disk device transmits and receives data from a host computer such as a PC (personal computer) or WS (workstation) through a USB connector, and writes and reads the data to and from a floppy disk medium inserted in the device. Device.

This floppy disk drive includes a power supply control block 40 and a power block 50 together with a head 4.
05, head motor 406a and spindle motor 40
6b.

Reference numeral 400 in the figure denotes a USB connector.
A USB signal line s401 and a power supply line ps401 are allocated. In the power control block 40, 401
A USB controller that transmits and receives data to and from a host computer via a USB signal line s401;
Information necessary for a floppy disk controller (hereinafter abbreviated as FDD controller) and read / write data of the floppy are separated and output to a signal line s402.

Reference numeral 402 denotes an FDD controller,
A signal is input from the signal line s402 and the power line ps40
3a, output of control signals of various motors and the like necessary for floppy disk control through ps403b and ps403c,
The output of write data to the floppy media and the input of read data are performed.

The charge control unit 415 sends the information power line p
The information of the battery 416 is input through s408, and it is also determined whether the battery 416 is insufficiently charged and the current supply to the power block 50 is not sufficient.

Reference numeral 403 denotes a write / read (R / W) amplifier for a floppy data head, which is a power supply line ps.
Data is written / read to / from the floppy disk medium through the 403a and the ps 404a.

Reference numerals 404a and 404b denote floppy control motor drivers, and the signal lines s403a and s4
The drive of the head motor 406a and the spindle motor 406b is controlled by the control unit 03b.

Reference numeral 405 denotes a floppy data read / write head for reading / writing data from / to a floppy disk through the R / W amplifier 403. Reference numeral 406a denotes a moving motor of the read / write head 405, which is driven by the motor driver 404a, and moves the head 405 to a place where reading / writing of a floppy medium is required.

Reference numeral 406b denotes a spindle motor for rotating the floppy disk.
b and is used to rotate the floppy disk when reading / writing the floppy medium. Reference numeral 411 denotes a current limiter (1), which is a power supply line p input from the USB connector 400.
The power supply current from s401 is limited. This is USB
Is set to a value iL41 which is slightly smaller than the maximum power supply current 500 mA which is a standard of the above.

Reference numeral 412 denotes a current detection unit, which is the entire current consumption of the device in this embodiment, that is, the power supply line ps4.
02, the current i42 flowing through the power line ps406 to the charge control unit 415 and the battery 41 are monitored.
The current i42 is controlled so that the sum with the device operating current i43 other than the charging of No. 6 is less than the set value of the current limiter 411. By doing so, the charging current to the battery 416 is smaller than the value obtained by subtracting the device operating current i43 from the set value iL41 of the current limiter 411.

413 is a current limiter (2),
The current input from the power supply line ps403 is the same as the set value iL41 of the current limiter 411 and the power control block 40.
I that is less than the difference from the maximum value of the current i43a to
L42, the current to the power control block 40 is secured by the current from the USB connector 400 even if the current i45 of the power block 50 described later transiently increases at the time of starting the motor. ing.

Reference numeral 414 denotes a power supply switching unit, which is a power supply line p.
s404 and the current from the power supply line ps410 to the power supply line ps
Through 405, the power is supplied to the power block 20.

At this time, the current i4 to the power block 50
5 exceeds the set value iL42 of the current limiter 413, the shortfall is caused by the battery 416 and the output voltage adjuster 4.
17 is controlled to be supplied from a power supply line ps417.

Reference numeral 415 denotes a charging control unit which receives a current from the output ps406 of the current detecting unit, controls charging of the battery 416 through a charging power supply line ps407, and monitors the remaining amount of the battery 416. Then, the information is output from the information power supply line ps408. Here, the battery 416 is a rechargeable secondary battery that is charged from the charging line ps407 and supplies power through the output line ps408.

An output voltage adjustment unit 417 adjusts the voltage of the output ps409 from the battery 416 to a value slightly lower than the voltage of the input power supply line ps402, and outputs the voltage to the power supply switching unit 414 through the power supply line ps410. Is done.

The change of the current consumption i43a in the power supply control block 40 is very small as compared with the R / W amplifier 403 and the various motors 404a and 404b. It is.

On the other hand, the power block 50 is composed of an R / W amplifier 403 and various motors 404a and 404b.
It greatly varies depending on the seek of the head and the like, and may exceed 500 mA which is a USB standard.

Next, the operation of the second embodiment will be described with reference to FIG.

When the device starts operating, first, in step S1
1, the battery 41 with a current within (iL41-i43).
6 is being charged. Note that iL41 is a set value of the current limiter 411, and i43 is an operation current value of the device. At this time, if i43 becomes equal to iL41, charging is interrupted, and the USB connector 400
The maximum current supplied is used.

Then, in step S12, i45 ≧ i
It is monitored whether it is L43. Note that i45 is the current consumption of the power block 50, and iL43 is the set value of the current limiter 413.

If i45 <iL43, the process proceeds to step S14, where the entire current can be supplied from the USB connector 400, so that the power supply switching unit 414 supplies current only from the power supply line ps404. At this point, the USB connector 4
There is still a surplus in the supply current from 00, which is monitored in step S11 and used for charging the battery 416.

Here, if a situation where i45 ≧ iL42 occurs, the supply current from the USB connector 400 becomes insufficient by (i45−iL42). In this case, the process proceeds to step S13, and the FDD controller 402 determines whether the battery 416 has power for the various floppy drive motors 406a and 406b and power for driving the R / W amplifier 403 of the head 405.

If it is determined that the battery 416 has power, the process proceeds to step S15, where the FDD controller 402
a, 406b, and the R / W amplifier 403 of the head 405
Is driven. Then, the power supply switching unit 414 supplies the insufficient current to the battery 4 through the power supply line ps410.
Supplied from 16.

If it is determined that the battery 416 has no power, the process proceeds to step S16, where the FDD controller 4
No. 02 judges that an abnormality has occurred in the device, temporarily suspends the operation of the floppy, transfers the information to the host computer, and waits for an instruction.

In this embodiment, the same effects as those of the first embodiment can be obtained. That is, by providing a rechargeable battery in the main body, charging while the power consumption of the device is in excess of the supply power, and by replenishing the transiently insufficient power of the device from the charged battery, It is possible to provide a USB device that operates only by power supply from a USB connector without deteriorating the performance of the device.

[0066]

As described in detail above, the power supply control device according to the first to third aspects of the present invention, the USB device according to the fourth to seventh aspects of the invention, the eighth aspect or the ninth aspect of the present invention. According to the power supply control method according to the described invention, it is possible to ensure the convenience and simplicity of USB without lowering the performance of the device. That is, the power supply to the device is
It is possible to realize a USB device that operates with good performance only by supplying power from the USB connector without using a separate power supply other than the B interface bus.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating an overall configuration of a USB device according to a first embodiment of the present invention.

FIG. 2 is a flowchart illustrating an operation of the first embodiment.

FIG. 3 is a block diagram illustrating an overall configuration of a USB device according to a second embodiment of the present invention.

FIG. 4 is a flowchart showing an operation of the second embodiment.

[Explanation of symbols]

 10, 40 power control block 20, 50 power block 100, 400 USB connector 101, 401 USB controller 102, 402 D / A converter 103L, 103R audio power amplifier 104L, 104R, speaker 111, 411 current limiter (1) 112, 412 Current detection unit 113, 413 Current limiter (2) 114, 414 Power supply switching unit 115, 415 Charge control unit 116, 416 Battery 117, 417 Output voltage adjustment unit

Claims (9)

[Claims] 1. A power supply control device for a drive device, to which power is supplied from a power supply device which is subjected to a current limit at a predetermined current limit value, wherein a chargeable battery and the battery when a current consumption is lower than the limit current value. And a charge control unit for charging the battery when the current consumption exceeds the limit current value. 2. The power supply control device according to claim 1, wherein the drive device is a device whose current consumption transiently exceeds the limit current value. 3. The power supply control device according to claim 1, wherein the power supply from the power supply device is supplied via a USB connector. 4. A drive device to which power is supplied from a power supply device that is subjected to current limitation at a predetermined current limit value, and a power supply connected to the power supply device via a USB connector and controlling power supply to the drive device. A USB device including a control device, wherein the power supply control device includes a chargeable battery, and a charge control unit that charges the battery when current consumption is lower than the current limit value. A USB device, wherein a current is supplied from the battery to the driving device when the current value exceeds a limit current value. 5. The USB device according to claim 4, wherein the driving device is a device whose current consumption transiently exceeds the limit current value. 6. The USB device according to claim 5, wherein the drive device is a speaker device with a built-in power amplifier. 7. The USB device according to claim 5, wherein said drive device is constituted by a floppy disk device. 8. A power supply control method for a drive device in which power is supplied from a power supply device which is subject to a current limit at a predetermined current limit value, wherein a rechargeable battery is provided, and a current consumption is lower than the limit current value. A power supply control method, comprising: charging the battery when the current consumption exceeds the current limit value; 9. The power supply control method according to claim 8, wherein the driving device is a device whose current consumption transiently exceeds the limit current value.