IE990360A1

IE990360A1 - A computer, a power supply and a method for controlling a supply of an electric current

Info

Publication number: IE990360A1
Application number: IE990360A
Authority: IE
Inventors: Mitsuhiko Aoyagi; Kazuaki Mori; Takeshi Ishimoto
Original assignee: Ibm
Priority date: 1998-05-15
Filing date: 1999-04-30
Publication date: 1999-11-17
Also published as: IL129648A0; JPH11338584A; TW425502B; CN1236923A; CN1203415C

Abstract

PROBLEM TO BE SOLVED: To prevent a host PC(personal computer) or peripheral equipment from being damaged electrically and to prevent data from being destroyed. SOLUTION: The host PC 410 has a slot 412 into which a memory card C420 is inserted. The memory card C420 when inserted into the slot 412 is electrically connected to the host PC 410. The host PC 410 has on its internal nonvolatile memory an electricity feeding capacity ID indicating the maximum value of a current that can be supplied to connected peripheral equipment. Further, the memory card C420 has on its internal nonvolatile memory a maximum current consumption ID showing a maximum current value needed for operation[JP11338584A]

Description

Field of the Invention OPEN TO PUBLIC INSPECTION UNDER SECTION 28 AND RULE 23 noJS22~of. .....

The present invention relates to a computer and a power supply device. More particularly, the present invention relates to a computer and a power supply device which is capable of controlling a supply of electric current to an external device.

INT CL Background of the Invention Fig. 1 shows a memory card and a host PC (personal computer) of a prior technology.

In the Fig. 1, the host PC 110 includes a slot 112 into which the memory card A 120 is inserted. When the memory card A 112 is inserted into the slot 112, the memory card A 120 is electrically connected to the host PC 110. The host PC 110 has a capability of supplying a maximum electric current of 100mA, for example, to a peripheral device, such as the memory card, etc. which is inserted into the slot 112. The memory card A 120 requires a maximum electric current of 75mA, for example.

Fig.2 shows the operation performed when the memory card A 120 is inserted into the host PC 110. The operation starts in a step 210, and in a step 220, the memory card A 120 is inserted into the slot of the host PC. Next, in a step 230, the memory card is electrically connected to the host PC, and the electric power is supplied from the host PC to the memory 0 card. When the electric power for operating the memory card is supplied to the memory card, the operation of the memory card is ready, the memory card can be operated in a step 240, and JA998-062 the operation is terminated in a step 250. In this case, since the maximum electric current (75mA) required for operating the memory card is smaller than the maximum electric current (100mA) which can be supplied from the host PC 110 to the memory card A 120, the memory card stably operates.

However, the maximum electric current required for operating the peripheral device, such as the memory card, is not always smaller than the maximum electric current which can be supplied by the host PC. In the case, for example, that the host PC is a small type PC, such as a Palm PC, a Handheld PC, etc., the host PC is driven by a battery, so that the capability of supplying the electric power is limited. Since a size of a PCMCIA card is large, a Compact io Flash card is mainly used as the memory card for such small type PC. Although only the Compact Flash card using the Flash RAM is marketed in the past, it is considered that the peripheral device, such as a network card, a modem card, a hard disk, etc., which has the same size as that of the memory card in the past, but requires more drive current is expected to be marketed in the near future.

Fig.3 shows the case that the peripheral device requiring such large drive current is inserted into the host PC. The components shown in the Fig.3, which are assigned with the same reference numerals as that shown in the Fig.l are the same components as that shown in the Fig. 1. When the memory card B 320 constituted by the hard disk, for example, is inserted into the slot 112 of host PC 110, the memory card B 320 is electrically connected to the host PC 110. In this case, the maximum electric current of the memory card B 320 for its operation is 300mA, for example, while the maximum electric current which can be supplied by the host PC 110 is 100mA, as in the case of the Fig.l, so that there is a possibility that sufficient electric current required for operating the memory card B 320 cannot supplied, the memory card B 320 cannot stably operate, and the host PC 110 or the memory card B 320 will be electrically JA998-062 2 damaged, or data lost. The prior PCMCIA card has been designed on the premise that the capability of the host PC for supplying the electric current is sufficient, and hence a system or an operating system (OS) for defining the capability of supplying the electric current did not exist.

As one method for solving such problem, it is considered that a recognition of the 5 peripheral device requiring the large drive current due to its mechanical operation is made at the host PC side. But, this approach can not be realized for the following reason. That is, an extemai shape of the card, such as the Compact Flash card, based upon a standard is defined by a specification of the standard, and hence if such recognition scheme is applied to the card, the specification must be modified. Also, such recognition scheme cannot be applied to cards io already available in the marketplace.

It is, therefore, one object of the present invention is to prevent the host PC or the peripheral device from being electrically damaged and to prevent the data from being lost.

Another object of the present invention is to make possible to recognize, at the host PC side, the peripheral device, such as the memory card, with power consumption exceeding the electric current supply capability of the host PC.

Summary of the Invention The present invention defines a registry or a system ID representing the maximum electric current which can be supplied by the system with the limited electric current supply capability. A computer in accordance with the present invention comprises: a power supply for 0 supplying an electric current to an extemai device; and a nonvolatile memory for storing information indicating the maximum value of the electric current which can be supplied to the external device by the power supply. JA998-062 A power supply apparatus in accordance with the present invention comprises: an electrically readable nonvolatile memory for storing information indicating the maximum value of the electric current which can be supplied to the external device by the power supply apparatus.

A method for controlling a supply of an electric current in accordance with the present invention comprises the steps of: reading the maximum value of the electric current which can be supplied to an external device by a first device: reading the maximum value of the electric current consumed by a second device; detecting that the maximum value of the electric current which can be supplied to. the external device by the first device is smaller than the maximum 10 value of the electric current consumed by the second device; and cutting off the supply of the electric current from the first device to the second device.

A method for controlling a supply of an electric current in accordance with the present invention comprises the steps of: supplying an electric current of a first value from a first device to a second device; reading the maximum value of the electric current which can be supplied to an external device by the first device; reading the maximum value of the electric current consumed by the second device; detecting that the maximum value of the electric current which can be supplied to the external device by the first device is equal to or larger than the maximum value of the electric current consumed by the second device; and supplying the current of a second value, which is larger than the current of the first value, from the first device to the second derice.

Brief Description of the Drawings The invention will now' be described in greater detail with specific reference to the appended drawings wherein: JA998-062 Figure 1 shows a memory card and a host PC (personal computer) of a prior technology; Figure 2 shows a flow chart of the operation performed when the memory card A 120 is inserted into the host PC 110; Figure 3 shows the memory card and the host PC; Figure 4 shows a memory card and a host PC in accordance with the present invention; and Figure 5 shows the operation in accordance with the present invention when the memory card is inserted into the host PC. io Detailed Description of the Preferred Embodiment Fig.4 shows a memory card and a host PC in accordance with the present invention. In the Fig.4, the host PC 410 includes a slot 412 into which the memory card C 420 is inserted. When the memory card C 420 is inserted into the slot 412, the memory card C 420 is electrically connected to the host PC 410. The host PC 410 stores a power feed capability ID representing the maximum electric current supplied to the peripheral device by the host PC, in a nonvolatile memory within the host PC. The power feed capability ID can be electrically read. The memory card C 420 stores a maximum consumed electric current ID required for its operation in a nonvolatile memory within the memory card, and the maximum electric current consumption ID can be electrically read. A device driver is loaded into the memory', not shown, 2Q in the host PC 410, and the device driver is executed by a central processing unit (CPU, not shown) when the memory card is electrically connected to the host PC. The device driver may be provided as a sole program or a portion of the operating system (OS).

JA998-062 5 Fig.5 shows the operation in accordance with the present invention when the memory card is inserted into the host PC. The operation starts in a step 510, and the memory card is inserted into the slot of the host PC in a step 512. Next, in a step 514, the memory cars is electrically connected to the host PC, and the electric current of a first electric current value is 5 supplied to the memory card by the host PC. The first electric current value is equal to or larger than a minimum electric current value required for reading the maximum consumed electric current ID from the memory card, and is equal to or smaller than the maximum electric current value supplied by the host PC.

In a step 516, the CPU reads the power feed capability ID of the host PC and the 10 maximum consumed electric current ID of the memory card, and the CPU determines as to whether the power feed capability of the host PC is equal to or larger than the maximum electric current consumed by the memory card, or not, in a step 518. In the case that the power feed capability of the host PC is equal to or larger than the maximum electric current consumed by the memory card, the host PC supplies the electric current of a second electric current value to the memory card, in a step 520. The electric current of the second electric current value is the electric current required for operating the memory card, and it maximum value is equal to the maximum electric current consumed by the memory card. In a step 522, the operation of the memory card becomes ready, and the operation is terminated in a step 524.

In the case that the memory card is the hard disk, for example, the power feed 0 capability of the host PC is smaller than the maximum electric current consumed by the memory card in the step 518. In this case, the supply of the electric current from the host PC to the memory card is cut off or shut off in a step 530. When the electric current is cut off, an error code indicating that the maximum electric current consumed by the memory card exceeds the JA998-062 maximum electric feed capability of the host PC, is sent to the CPU in a step 532, and the operation terminates in a step 534. ' The present invention is not limited to the above embodiment. For example, the power feed capability ID can be stored in the nonvolatile memory of the power supply device, and the power supply device can be externally controlled.

In accordance with the present invention, the memory card consuming the electric current exceeding the power feed capability of the host PC can be recognized in advance, so that the supply of the electric current exceeding the power feed capability of the host PC can be prevented, whereby the damage of the host PC and the peripheral device, such as the memory card, can be prevented, and the loss of the data can be prevented.

In accordance with the present invention, it is possible for the host PC to recognize in advance the peripheral device, such as the memory card, consuming the electric current exceeding the power feed capability of the host PC.

Claims

What is claimed is: 1. O from said first device to said second device when said maximum consumption value does not exceed said maximum supply value. 22. The operating system of claim 20 further comprising program execution means for generating an error code when said maximum consumption value exceeds said maximum supply value.. 15 23. A computer or power supply apparatus for supplying an electric current to an external device substantially as hereinbefore described with reference to and or as illustrated in Figures 4 and 5. 24. A method for controlling the supply of an electric current substantially as 20 hereinbefore described with reference to and or as illustrated in Figure 5. JA998-062 25. A computer readable storage medium or computer program product substantially as hereinbefore described with reference to and or as illustrated in Figure

1. A computer comprising: a power supply for supplying an electric current to an extemai device; and a nonvolatile memory for storing information indicating a maximum supply value of the 5 electric current which can be supplied to said extemai device by said power supply. 2. 0 a program execution means for reading a maximum supply value of the electric current which can be supplied to an external device by said first device; JA998-062 a program execution means for reading a maximum consumption value of the electric current consumed by said second device; and a program execution means for comparing said maximum supply value to said maximum consumption value of the electric current consumed by said second device. 5 20. The operating system of claim 19 further comprising program execution means for cutting off the supply of the electric current from said fust device to said second device when said maximum consumption value exceeds said maximum supply value. 21. The operating system of claim 19 further comprising program execution means for supplying the current of a second value, which is larger than the current of said first value, 2 0 16. A device driver comprising: JA998-062 a program execution means for supplying an electric current of a first value from a first device to a second device; a program execution means for reading a maximum supply value of the electric current which can be supplied to an external device by said first device: 5 a program execution means for reading a maximum consumption value of the electric current consumed by said second device; a program execution means for comparing said maximum supply value to said maximum consumption value. 17. The device driver of claim 16 further comprising program execution means for 10 cutting off the supply of the electric current from said first device to said second device when said maximum consumption value exceeds said maximum supply value. 18. The device driver of claim 16 further comprising program execution means for supplying the current of a second value, which is larger than the current of said first value, from said first device to said second device when said maximum consumption value does not exceed 15 said maximum supply value. 19. An operating system comprising: a program execution means for supplying an electric current of a first value from a first device to a second device; 2 o supplying the current of a second value, which is larger than the current of said first value, from JA998-062 said first device to said second device when said maximum consumption value docs not exceed said maximum supply value. 13. A computer program product comprising: a program execution means for supplying an electric current of a first value from a first 5 device to a second device; a program execution means for reading a maximum supply value of the electric current which can be supplied to an external device by said first device; a program execution means for reading a maximum consumption value of the electric current consumed by said second device; and 10 a program execution means for comparing said maximum supply value to said maximum consumption value. 14. The computer program product of claim 13 wherein said program further comprises program execution means for cutting off the supply of the electric current from said first device to said second device when said maximum consumption value exceeds said is maximum supply value. 15. The computer program product of claim 13 wherein said program further comprises program execution means for supplying the current of a second value, which is larger than the current of said first value, from said first device to said second device when said maximum consumption value does not exceed said maximum supply value.

2. The computer of claim 1 further comprising means for reading the maximum consumption value of electric current required by said extemai device.

3. The computer of claim 1 further comprising a component for comparing the maximum supply value to the maximum consumption value, said power supply being adapted to io terminate supply of electric current when said maximum consumption value exceeds said maximum supply value.

4. A power supply apparatus for supplying an electric current to an extemai device comprising: power supply means; and 15 an electrically readable nonvolatile memory for storing information indicating a maximum value of the electric current which can be supplied to said extemai device by said power supply means.

5. The power supply apparatus of claim 4 further comprising means for reading the maximum consumption value of electric current required by said extemai device. JA998-062

6. A method for controlling a supply of an electric current comprising the steps of: reading a maximum supply value of the electric current which can be supplied to an external device by a first device; 5 reading a maximum comsumption value of the electric current consumed by a second device; and comparing said maximum supply value to said maximum consumption value.

7. The method of claim 6 further comprising cutting off the supply of the electric current from said first device to said second device when said maximum consumption value 10 exceeds said maximum supply value.

8. A method for controlling a supply of an electric current comprising the steps of: supplying an electric current of a first value from a first device to a second device; reading a maximum supply value of the electric current which can be supplied to an 15 external device by said first device; reading a maximum consumption value of the electric current consumed by said second device; comparing said maximum supply value to said maximum consumption value; JA998-062 supplying current of a second value, which is larger than the current of said first value, from said first device to said second device when said maximum consumption value docs not exceed said maximum supply value; and cutting off the supply of electric current from said first device to said second device 5 when said maximum consumption value exceeds said maximum supply value.

9. The method of claim 8 further comprising generating an error code when said maximum consumption value exceeds said maximum supply value.

10. A computer readable storage medium for storing in a tangible form a computer program executed on a computer system, said computer program comprising the steps of: 10 supplying an electric current of a first value from a first device to a second device; reading a maximum supply value of the electric current which can be supplied to an external device by said first device; reading a maximum consumption value of the electric current consumed by said second device; and 15 comparing said maximum supply value to said maximum consumption value.

11. The medium of claim 10 further comprising cutting off the supply of the electric current from said first device to said second device when said maximum consumption value exceeds said maximum supply value.

12. The medium of claim 10 wherein said program further comprises the step of 5.