JP2003167650A - Precision equipment, computer device, circuit board, and voltage control method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a computer device capable of suppressing power consumption. <P>SOLUTION: In a notebook-sized PC, prescribed voltage is outputted from the OUT of a DC/DC 64 so that power can be supplied to an internal device 101 and a card bus slot 23 to which a PC card is connected, and a part of the outputted voltage is fed back from an FB to the DC/DC 64 so that whether or not the voltage is correctly outputted can be checked. Then, when the connection of the PC card to the card bus slot 23 is detected by a detecting circuit 100, the voltage to be fed back to the FB of the DC/DC 64 is decreased by a resistance R<SB>3</SB>, and the voltage higher than that in the other case is outputted from the DC/DC 64. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to precision equipment such as computer devices, and more particularly to precision equipment capable of suppressing power consumption.

Conventionally, precision devices such as computer devices have been widely used in various places such as workplaces and homes. As a type of this general-purpose computer device, a desktop PC (Personal Computer) which is almost fixed and used at a predetermined place such as a desk or a notebook which is designed to be relatively small in consideration of portability. Type PC, PDA (Perso
nal Digital Assistant) and the like. In particular, in recent years, small computer devices such as notebook PCs have not taken up a lot of space for installation, and thus their development has been remarkable. These small computer devices that take portability into consideration can be used even when fixed at a predetermined position such as at a company or home, and can be used while moving or moving in a train, a car, a place to go out, or the like. it can.

On the other hand, in such a small computer device considering portability, the power is supplied through an AC adapter when the computer device is fixed.
Alternatively, it is performed from the battery of the power supply unit built in the computer device during or while moving. In supplying such power, for example, AC 100V or 200V power is converted into a predetermined current voltage, for example, DC 12V, 5V, 3.3V, and designed so that power can be supplied to internal devices of the computer device. Has been done. When the electric power is supplied from the battery, the electric power supplied is only the electric power stored in the battery, and the usable electric power is limited.
Therefore, in order to enable the computer device that is not supplied with the power from the AC adapter to be used for a long time, it is necessary to take measures such as suppressing the power consumption of the computer device.

[0004]

By the way, in these computer devices, various functions can be realized by an internal device installed in advance, but by connecting a function expansion device to the other devices, the computer device It is also possible to extend the function. Specifically, a function expansion device desired by the user, such as a PC card, is connected to a slot or connector of the computer device to add various functions to the computer device. Therefore, the problem is the power supplied corresponding to such a function expansion device.

Normally, the voltage of the power supplied to the function expansion device is set to be substantially constant according to a predetermined standard. This is because various types of function expansion devices have been developed in recent years, and the industry has established standards so that the function expansion device selected by the user can be connected to any computer device. . Therefore, in a normal computer device equipped with a function expansion device receiving section, assuming that the function expansion device is connected, a relatively high voltage consistent with the voltage specified in the function expansion device standard is always supplied. . That is, even though the internal device of the computer device can be operated at a voltage lower than the standard in the computer device, in order to connect the function expansion device, the predetermined voltage specified for the function expansion device is set. Continue to supply.

Generally, a computer device consumes a predetermined electric power as long as a predetermined voltage is supplied, but the power consumption increases as the voltage increases. Therefore, in the computer device to which the function expansion device as described above can be connected, the high voltage is maintained even if the function expansion device is not connected, and thus the power consumption continues to be relatively high.

The present invention has been made based on the above technical problems, and a main object of the present invention is to provide a precision instrument or the like capable of suppressing power consumption.

[0008]

Based on the above object, the precision equipment of the present invention is a precision equipment to which a function expansion device can be connected, and includes an internal device provided inside the precision equipment and a function expansion device. The converter includes an accepting unit that is receivable, and a converter that can supply electric power of a predetermined voltage to the internal device and the function expanding device. The converter includes the function expanding device when the function expanding device is connected to the receiver. It is characterized in that it outputs a higher voltage than that in the state where is not connected.

The precision instrument may further include a detection circuit for detecting that the function expansion device is connected to the receiving portion. Also, in this precision instrument, the converter, if the function expansion device is not connected to the receiving part,
It is preferable to output a voltage at a level at which the internal device can operate, and to output a voltage at a level according to the standard of the function expansion device when the function expansion device is connected to the receiving unit.

The precision equipment of the present invention is a precision equipment to which a function expansion device can be connected, and a detection circuit for detecting that the function expansion device is connected, an internal device provided inside the precision equipment, And a converter that supplies electric power to the connected function expansion device, and the converter changes the output voltage based on the detection by the detection circuit.

In this precision device, the converter can increase the voltage output when the connection of the function expansion device is detected. Further, the precision device further includes a feedback circuit that feeds back the output voltage, and the detection circuit can be connected to the feedback circuit.

In addition, the precision instrument of the present invention is a precision instrument having an internal device that consumes electric power, and includes a voltage output means for adjusting the electric power to a predetermined voltage and outputting the voltage to the internal device, and a voltage output means. Feedback means for feeding back a part of the output voltage to the voltage output means, and the feedback means feeds back the voltage output by the voltage output means under a predetermined condition by lowering it from a reference value corresponding to the predetermined voltage. However, the voltage output means
It is characterized in that the voltage lowered by the feedback means is compared with a reference value, and a voltage higher than a predetermined voltage is newly output.

The precision equipment further comprises a detection means for detecting that the function expansion device is connected to the precision equipment, and the feedback means detects the function expansion device when the detection means detects the connection of the function expansion device. It is possible to feed back by lowering the voltage than when not detecting.

The present invention can also be understood as a computer device. This computer device is connectable to a PC card, and has a slot capable of receiving the PC card, a detection circuit for transmitting a predetermined signal when the PC card is connected to the slot, and a detection circuit for transmitting the predetermined signal. DC / switching the output voltage based on the signal
It is characterized by comprising a DC converter and a power supply circuit for supplying the power output from the DC / DC converter to the slot. Here, at least some of the connector pins of the slot can be assigned for detection.

The computer device of the present invention is a computer device to which a function expansion device can be connected,
An internal device provided inside the computer device;
A slot for accepting and connecting a function expansion device, wherein the internal device operates at a lower voltage when the function expansion device is not connected to the slot than when the function expansion device is connected to the slot. It is what

In this computer apparatus, a DC / DC converter for supplying electric power to the function expansion device and the internal device is provided, and the DC / DC converter expands the internal device and the function when the function expansion device is connected to the slot. It is possible to supply power at a voltage at which the device can operate.

On the other hand, the present invention can be regarded as a circuit board. This circuit board is a circuit board built in a computer device and is connected to the computer device.
A power supply circuit that supplies power to the internal device; a feedback circuit that branches from the power supply circuit and is connected to the converter; and a detection circuit that detects the connection of the function expansion device connected to the computer device. To do. In this case, it is preferable that the feedback circuit feed back a voltage lower than usual when the connection of the function expansion device is detected.

In addition, the present invention can be understood as a voltage control method. This voltage control method is a voltage control method for controlling a voltage supplied to an internal device of a computer apparatus, and includes a first output step of converting electric power from a power supply source into a predetermined voltage and outputting the converted voltage. A method comprising: a receiving step of receiving a signal generated when an expansion device is connected; and a second outputting step of outputting a voltage higher than a predetermined voltage based on the reception of the signal.

This voltage control method compares the feedback voltage with the reference value and the receiving step of receiving the feedback voltage obtained by feeding back a part of the output voltage, and outputs the result in the second output step based on the result. The method may further include an adjusting step of adjusting the voltage. In this case, it is preferable that in the adjusting step, the output voltage in the second output step is adjusted so that the feedback voltage becomes a value closer to the reference value.

The voltage control method of the present invention is a voltage control method for controlling the voltage output for supplying to an internal device of a computer device and a function expansion device, and is provided when the function expansion device is not connected. The method is characterized in that a voltage of 1 is supplied to the internal device and a second voltage is supplied to the internal device and the function expanding device when the function expanding device is connected. In this voltage control method, it is preferable that the first voltage is determined according to the level at which the internal device can operate, and the second voltage is determined based on the standard of the function expansion device.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described below in detail based on the embodiments shown in the accompanying drawings. FIG. 1 is a diagram showing a hardware configuration of a notebook PC (precision device, computer device) 10 according to the present embodiment.
The notebook PC 10 is, for example, an OADG (Ope
n Architecture Developer's Group) specifications,
A predetermined OS (operating system) is installed.

In the notebook PC 10 shown in FIG. 1, the CPU 11 functions as the brain of the entire notebook PC 10 and executes various programs under the control of the OS. The CPU 11 is an FSB (Fro
nt Side Bus) 12, P as a bus for high-speed I / O devices
CI (Peripheral Component Interconnect) bus 20,
ISA (Industry Stan) as a bus for low-speed I / O devices
dard Architecture) bus 40, which is interconnected with each component through a three-stage bus. This CPU11
Stores the program code and data in the cache memory to speed up the process. in recent years,
Although an SRAM of about 128 Kbytes is integrated as a primary cache inside the CPU 11, a BSB (Back Side Bus) 13 which is a dedicated bus is provided to compensate for the lack of capacity.
A secondary cache 14 of about 512 K to 2 Mbytes is placed via.

The CPU bridge (host-PCI bridge, memory / PCI chip) 15 includes an FSB 12 and a PC.
I'm in contact with I-bus 20. This CPU bridge 15
Has a memory controller function for controlling an access operation to the main memory 16, a data buffer for absorbing a difference in data transfer speed between the FSB 12 and the PCI bus 20, and the like. The main memory 16 is a writable memory used as a read area for the execution program of the CPU 11 or as a work area for writing processing data of the execution program.
For example, a plurality of DRAM chips constitutes 128 MB. The execution program includes various drivers for operating the OS and peripheral devices in hardware, application programs for specific jobs, and BIOS (Basic Input / Outpp) stored in a flash ROM 44 described later.
ut System: Basic I / O system) firmware is included.

The video subsystem 17 is a subsystem for realizing functions related to video and includes a video controller. This video controller processes a drawing command from the CPU 11, writes the processed drawing information in the video memory, reads the drawing information from the video memory, and then displays the drawing information.
D) 18 is output as drawing data.

The PCI bus 20 is a bus capable of relatively high-speed data transfer, and has a data bus width of 32 bits or 64 bits, a maximum operating frequency of 33 MHz, and 66 MH.
z, maximum data transfer rate is 132MB / sec, 528MB
/ Sec is standardized by the specification. This PCI
A card bus controller 22, an audio subsystem 25, and an I / O bridge 50 are connected to the bus 20, respectively.

The card bus controller 22 sends a bus signal of the PCI bus 20 to a card bus slot (reception part).
It is a dedicated controller for connecting directly to 23 interface connectors (card bus). In this card bus slot 23, the PC card 2 is provided as a function expansion device.
4 is loaded. As the PC card 24, for example, a wireless LAN card, a LAN card, a mass storage card,
A memory card etc. can be mentioned. These PC cards 24 are selected according to the wishes of the user, and are properly attached to and detached from the card bus slot 23.

The ISA bus 40 has a lower data transfer rate than the PCI bus 20 (for example, a bus width of 16).
Bit, maximum data transfer rate 4MB / sec). This ISA
The bus 40 includes an embedded controller 41 connected to a gate array logic 42, a CMOS 43, a flash ROM 44, and a Super I / O controller 45.
Are connected. It is also used to connect peripherals that operate at relatively low speeds such as keyboard / mouse controllers. An I / O port 46 is connected to the Super I / O controller 45, and
It controls the driving of the DD, the parallel data input / output (PIO) via the parallel port, and the serial data input / output (SIO) via the serial port.

The embedded controller 41 controls a keyboard (not shown) and is connected to the power supply circuit 60 to have a built-in power management controller (PMC).
r) plays a part of the power management function together with the gate array logic 42.

The I / O bridge 50 has a function of bridging the PCI bus 20 and the ISA bus 40. Also,
DMA controller function, programmable interrupt controller (PIC) function, programmable interval timer (PIT) function, IDE (Integrated Device Ele)
ctronics) interface function, USB (Universal Ser
real-time clock with the SMB (System Management Bus) interface function
(RTC) is built in.

Here, the DMA controller function is the FD
This is a function for executing data transfer between a peripheral device such as D and the main memory 16 without intervention of the CPU 11.
The PIC function is a function for executing a predetermined program (interrupt handler) in response to an interrupt request (IRQ) from a peripheral device. The PIT function is a function of generating a timer signal at a predetermined cycle. The interface realized by the IDE interface function is the ID
E A hard disk drive (HDD) 31 is connected, and a CD-ROM drive 32 is connected to ATAPI (AT Attach
ment Packet Interface) is connected. This CD-ROM
Instead of the drive 32, a DVD (Digital Versatile Di
Other types of IDE devices, such as sc) drives, may be connected. The external storage device such as the HDD 31 and the CD-ROM drive 32 is, for example, a notebook PC.
It is stored in a storage place called a device bay in 10.

Further, the I / O bridge 50 is provided with a USB port, and this USB port is connected to the USB connector 30 provided on the wall surface of the notebook PC 10 main body, for example. Furthermore, I / O bridge 5
An EEPROM 33 is connected to 0 via the SM bus. This EEPROM 33 is a memory for holding information such as a password registered by a user, a supervisor password, a product serial number,
It is non-volatile and is capable of electrically rewriting the stored contents.

Further, the I / O bridge 50 includes a power supply circuit 6
It is connected to 0. In addition, inside the core chip that constitutes the I / O bridge 50, an internal register for managing the power supply state of the notebook PC 10 and a logic for managing the power supply state of the notebook PC 10 including the operation of the internal register. (State machine) is provided. This logic sends and receives various signals to and from the power supply circuit 60, and by sending and receiving these signals, the actual power supply state from the power supply circuit 60 to the notebook PC 10, such as the amount of charge, is recognized. The power supply circuit 60 is the I / O bridge 50.
Notebook type PC1 according to the instruction from the logic
The power supply to 0 is controlled.

A power supply circuit 60 as a power supply source charges an AC adapter 61 connected to a commercial power source and a battery 62 as a battery, and at the same time, the AC adapter 61 and the battery 62.
Battery switching circuit 6 for switching the power supply path from the
3 and a DC / DC converter (DC / D converter) that generates a current of a predetermined voltage used in the notebook PC 10.
C) A circuit such as 64 is provided. The current of a given voltage is
For a given internal device of the notebook PC 10,
Each is supplied. For example, for the card bus slot 23 to which the PC card 24 is connected, the PC card 2
The electric power of 5V defined by the standard of No. 4 is supplied. Here, in the present embodiment, the voltage supplied to the internal device of the notebook PC 10 is higher when the PC card 24 is connected to the card bus slot 23 than when it is not connected. Controlled. Less than,
The control of the supplied voltage will be specifically described.

FIG. 2 is a diagram for explaining the structure of a circuit for controlling the supply of electric power. In FIG. 2, power is supplied to the battery 6
2 through DC / DC 64, internal device 10 of notebook PC 10 such as CPU 11 and main memory 16
1 and the card bus slot 23. In this embodiment, a circuit for adjusting the voltage output from the DC / DC 64 is provided. In this circuit, as shown in FIG. 2, the resistor R _{1 is} branched from OUT of DC / DC 64.
Is further connected to a resistor R ₂ which is continuously provided, and is then grounded. The circuit branched between the resistors R ₁ and R ₂ is connected to the FB (Feed Back In) of the DC / DC 64. In addition, the circuit further branched from the circuit branched between the resistors R ₁ and R ₂ to the resistor FB is the resistor R
Connected to ₃ , transistor (npn transistor) 1
02 is connected. On the other hand, the card bus slot 23 is connected to the detection circuit 100. The signal line 103 extending from the detection circuit 100 is connected to the resistor R ₄ and further connected to the transistor 102.

In the circuit shown in FIG. 2, normally, the electric power supplied from the battery 62 enters from the IN of the DC / DC 64, and the OU
The voltage is adjusted to a predetermined voltage from T and output. When the PC card 24 is not connected to the card bus slot 23, a predetermined voltage, for example, 4.8V is set to be output. This circuit is provided with a feedback mechanism to output a predetermined voltage. Specifically, the output voltage is O of DC / DC64.
DC / DC6 lowered in the circuit branching from UT
No. 4 FB, and it is determined whether or not a predetermined voltage is output. For example, resistance R ₁ : resistance R ₂ is 1: 1
In case of 4.8V, the voltage of 4.8V becomes 2.4V and is sent to the FB of DC / DC64. Then DC /
The DC64 determines whether the received voltage is half of the originally output voltage of 4.8V, that is, 2.4V. If it is lower than 2.4V, the output voltage from OUT is increased. If it is higher than 2.4 V, the output voltage from OUT is lowered.

By the way, as shown in FIG. 2, in the circuit for the feedback mechanism, the DC / DC 64 O
The middle of the circuit from UT to FB is branched and connected to the resistor R ₃ and the transistor 102. In this embodiment,
By this circuit, when the PC card 24 is connected to the card bus slot 23, the connection is detected and DC / DC is detected.
It is possible to increase the output voltage from 64 OUT. Next, the detection of the PC card 24 and the control of the output voltage will be described.

FIG. 3 is a diagram illustrating a circuit for detecting the connection between the card bus slot 23 and the PC card 24. First, the user inserts a PC into the card bus slot 23.
When the card 24 is connected, some pins 23g in the card bus slot 23 are used for detecting the connection of the PC card 24 as shown in FIG. That is, when the pin 23g of the card bus slot 23 is connected to the pin of the PC card 24, a signal notifying that the connection has been made is sent out via the signal line 103 as shown in FIG. As shown in FIG. 2, the signal has a predetermined voltage at the resistor R ₄ , and a current flows to the base of the transistor 102.
Then, a current starts to flow from the collector of the transistor 102 to the emitter, and a current also flows in a circuit branched in the middle of the circuit from OUT to FB of DC / DC 64 of the circuit for the feedback mechanism. As a result, the resistance R
_The voltage drops by ₃ and enters the FB of DC / DC64. At this time, DC / DC is lowered by the resistance R ₃ .
For example, 2.4V is 2.3 as the voltage that enters the FB of 64.
The resistance R ₃ is set so as to decrease to about V.

Next, the DC / DC 64 receives the voltage (2.3 V) received as feedback from the FB and originally O
Compare with half the value of the voltage to be output from the UT (2.4 V). Then, it detects that the received voltage is lower than the voltage normally output,
The voltage output from the UT is increased and then output. That is,
Although the DC / DC 64 outputs a voltage that normally outputs the output voltage from OUT as 4.8 V, the voltage received at the FB by the feedback mechanism is reduced. As a result, a voltage higher than the voltage normally output is output from OUT. In this way, the output voltage corrected to be higher is, for example, 5 V, and the voltage required for the PC card 24 specified by the standard to operate normally is the card bus slot 23.
Will be supplied to.

As described above, in the present embodiment, it can be detected that the PC card 24 is connected to the card bus slot 23 by monitoring the voltage of the pin of the connector of the card bus slot 23. When the connection of the PC card 24 is detected, the processed false voltage is fed back to increase the voltage output from the OUT of the DC / DC 64, and the voltage for operating the PC card 24 normally is provided. It is possible to output. Normally, in a computer device such as the notebook PC 10, the voltage required to operate the internal device 101 is not regulated by a general standard or the like, and the notebook P
Adjustments can be made in the design of the C10 system to allow internal device 101 to operate at lower voltages. That is, the normal output voltage is set to a minimum level at which the internal device 101 can operate, and an optional PC
When the card 24 is connected, the voltage is raised to a voltage conforming to the standard of the PC card 24. Therefore, since the output voltage of the notebook PC 10 can be increased only when necessary, the power consumption of the notebook PC 10 can be suppressed.

Further, in this embodiment, the PC card 24
The mechanism for detecting the connection of the above and controlling the output voltage of the DC / DC 64 can be implemented inexpensively by a simple circuit such as the circuits shown in FIGS. Therefore, no space is taken in the notebook PC 10. Further, in the present embodiment, the detection of whether or not the PC card 24 is connected is not based on the change in the load current detected by the DC / DC 64. Therefore, even when the PC card 24 with low power consumption such as almost zero power consumption is connected, the specified voltage (for example, 5V) required by the PC card 24 can be supplied.

Note that the notebook PC 10 has a plurality of Ds.
A C / DC converter is provided, power supply to the internal device 101 and power supply to the function expansion device are separately performed, and the internal device 101 is supplied with a predetermined voltage supplied to the function expansion device. Low voltage can be supplied. However, it is difficult and costly to secure a space for providing a plurality of DC / DC converters in a small notebook PC 10 considering portability. On the other hand, the notebook PC 10 of the present embodiment does not need to be provided with a plurality of DC / DC converters and can easily suppress power consumption at low cost.

In the present embodiment, the normal voltage output from the DC / DC 64 when the PC card 24 is not connected to the card bus slot 23 is higher than the voltage required for operating the PC card 24. It is preferable to set the voltage at 5% lower, that is, about 5V to 4.75V. At such a voltage, the internal device 10
1 can be operated normally. However, a voltage lower than this may be output as long as the internal device 101 can be operated. When the PC card 24 is connected to the card bus slot 23, DC / D
The upper limit of the voltage output from C64 is preferably about 5.25%. Further, in the above-described embodiment, the voltage of 5 V, which is specified by the standard, is supplied to the PC card 24, but the present invention is not limited to this. For example, 3.
It is also possible to apply to DC / DC64 which supplies the voltage of 3V.

The circuits shown in FIGS. 2 and 3 are examples, and the output voltage of the DC / DC 64 can be increased by receiving the signal for detecting the connection of the PC card 24. However, it is not particularly limited. In addition, in the present embodiment, when the notebook PC 10 includes a plurality of card bus slots 23, for example, when the PC card 24 is connected to any one of the card bus slots 23, the output voltage from the DC / DC 64 is changed. It can be set to be higher.

In this embodiment, DC / DC
The output voltage may be controlled in the 64 notebook PC 10 system. For example, it is possible to control the output voltage by detecting the connection of the PC card 24 by the OS of the system and then sending a signal for lowering the output voltage to the DC / DC 64. In addition, the notebook PC 10 is used to reduce the power consumption in the present embodiment.
However, the present invention is not limited to the above, and can be applied to, for example, PDAs, desktop PCs, and other precision equipment. Other than this, the configurations described in the above embodiments can be selected or changed to other configurations without departing from the gist of the present invention.

[0045]

As described above, according to the present invention, power consumption can be suppressed in precision equipment such as a notebook PC.

[Brief description of drawings]

FIG. 1 is a diagram showing a hardware configuration of a notebook PC according to the present embodiment.

FIG. 2 is a diagram illustrating a configuration of a circuit for controlling power supply.

FIG. 3 is a diagram illustrating a detection circuit for connection between a card bus slot and a PC card.

[Explanation of symbols]

10 ... Notebook type PC (precision equipment, computer device), 23 ... Card bus slot (reception part), 24 ... P
C card, 50 ... I / O bridge, 60 ... Power supply circuit, 6
DESCRIPTION OF SYMBOLS 1 ... AC adapter, 62 ... Battery, 63 ... Battery switching circuit, 64 ... DC / DC, 100 ... Detection circuit, 101 ... Internal device, 102 ... Transistor, 103 ... Signal line

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Masago Nakano             1623 1423 Shimotsuruma, Yamato-shi, Kanagawa Japan             BM Co., Ltd. Daiwa Office (72) Inventor Noriyuki Kato             1623 1423 Shimotsuruma, Yamato-shi, Kanagawa Japan             BM Co., Ltd. Daiwa Office F term (reference) 5B011 DB04 DB19 DC07 EA06 LL06                       LL08

Claims (19)

[Claims] 1. A precision device to which a function expansion device can be connected, an internal device provided inside the precision device, a receiving unit capable of receiving the function expansion device, the internal device and the function expansion device. And a converter capable of supplying electric power of a predetermined voltage with respect to the converter, the converter, when the function expansion device is connected to the receiving unit, compared to a state in which the function expansion device is not connected. Precision equipment that outputs high voltage. 2. The precision instrument according to claim 1, further comprising a detection circuit for detecting that the function expansion device is connected to the receiving unit. 3. The converter outputs a voltage at a level at which the internal device can operate when the function expansion device is not connected to the receiving unit, and the function expansion device is connected to the receiving unit. If it is, the precision device according to claim 1, wherein a voltage of a level according to the standard of the function expansion device is output. 4. A precision device to which a function expansion device can be connected, a detection circuit for detecting that the function expansion device is connected, an internal device provided inside the precision device, and the connected device. A precision instrument comprising: a function expansion device; and a converter for supplying electric power, wherein the converter changes a voltage to be output based on detection by the detection circuit. 5. The precision instrument according to claim 4, wherein the converter increases a voltage output when the connection of the function expansion device is detected. 6. The precision instrument according to claim 4, further comprising a feedback circuit that feeds back the output voltage, and the detection circuit is connected to the feedback circuit. 7. A precision instrument including an internal device that consumes power, comprising: voltage output means for adjusting power to a predetermined voltage and outputting the voltage to the internal device; and the voltage output by the voltage output means. And a feedback means for feeding back a part of the voltage to the voltage output means, wherein the feedback means reduces the voltage output by the voltage output means under a predetermined condition below a reference value corresponding to the predetermined voltage. The precision device is characterized in that the voltage output means compares the voltage lowered by the feedback means with the reference value and newly outputs a voltage higher than the predetermined voltage. 8. The function expansion device further comprises detection means for detecting that the function expansion device is connected to the precision instrument, wherein the feedback means is operable to expand the function when the detection means detects connection of the function expansion device. 8. The precision instrument according to claim 7, wherein the voltage is fed back by lowering the voltage than when no device is detected. 9. A computer device to which a PC card can be connected, a slot capable of receiving the PC card, a detection circuit which sends a predetermined signal when the PC card is connected to the slot, and the detection circuit. A computer comprising a DC / DC converter that switches an output voltage based on the signal sent from the circuit, and a power supply circuit that supplies the power output from the DC / DC converter to the slot. apparatus. 10. The computer device according to claim 9, wherein at least a part of the connector pins of the slot is assigned for detection. 11. A computer device capable of connecting a function expansion device, comprising: an internal device provided inside the computer device; and a slot capable of receiving and connecting the function expansion device, wherein the internal device is A computer apparatus, wherein when the function expansion device is not connected to the slot, the function expansion device operates at a lower voltage than when the function expansion device is connected to the slot. 12. A DC / DC converter that supplies electric power to the function expansion device and the internal device, wherein the DC / DC converter includes the internal device when the function expansion device is connected to the slot. 12. The computer apparatus according to claim 11, wherein the function expansion device supplies power of a voltage at which the function expansion device can operate. 13. A circuit board built in a computer device, comprising: a supply circuit connected to the computer device for supplying electric power to an internal device; and a feedback circuit branched from the supply circuit and connected to a converter. And a detection circuit for detecting connection of a function expansion device connected to the computer device. 14. The circuit board according to claim 13, wherein the feedback circuit feeds back a voltage lower than usual when the connection of the function expansion device is detected. 15. A voltage control method for controlling a voltage supplied to an internal device of a computer device, comprising: a first output step of converting power from a power supply source into a predetermined voltage and outputting the voltage, and a function expansion. A voltage control method comprising: a reception step of receiving a signal generated when a device is connected; and a second output step of outputting a voltage higher than the predetermined voltage based on the reception of the signal. . 16. A step of receiving a feedback voltage obtained by feeding back a part of the output voltage, a step of comparing the feedback voltage with a reference value, and based on the result, a voltage output in the second output step. The voltage control method according to claim 15, further comprising an adjusting step of adjusting. 17. The voltage control method according to claim 16, wherein in the adjusting step, the output voltage in the second output step is adjusted so that the feedback voltage becomes a value closer to the reference value. . 18. A voltage control method for controlling a voltage output to be supplied to an internal device and a function expansion device of a computer apparatus, wherein the first voltage is applied to the internal device when the function expansion device is not connected. A voltage control method for supplying a voltage to a device, and supplying a second voltage to the internal device and the function expansion device when the function expansion device is connected. 19. The first voltage is determined according to a level at which the internal device can operate, and the second voltage is determined based on a standard of the function expansion device. The voltage control method described.