Electrical transmission or interconnection systems – Plural load circuit systems – Selectively connected or controlled load circuits
Reexamination Certificate
2000-02-10
2003-04-22
Fleming, Fritz M (Department: 2836)
Electrical transmission or interconnection systems
Plural load circuit systems
Selectively connected or controlled load circuits
C307S039000, C307S140000
Reexamination Certificate
active
06552445
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to an electronic apparatus and a circuit board for use in, e.g., a notebook-sized personal computer of a type supplying an electric power to loads in response to a plurality of action modes, and more particularly to an electronic apparatus and a circuit board designed to supply an electric power to the loads consisting of a plurality of groups in response to the action modes including the supply of power and the suspension.
2. Description of the Related Arts
Referring first to
FIG. 1
, a typical circuit is shown which feeds electric powers for action to a diversity of devices, i.e., loads incorporated in notebook-sized personal computers. In response to action modes, a DC/DC converter
100
serving as a DC power source feeds powers to the loads, e.g., a CPU module
102
, a memory module
104
and CD-ROM module
106
. In this event, the CPU module
102
includes a CPU and an HDD, and the memory module
104
includes an SDRAM and a VGA. The CD-ROM module
106
includes a CD-ROM player and an AMP. A power supply line
114
from DC/DC converter
100
diverges at a node into a line
116
and a line
118
which connects via an FET switch circuit
112
to the CD-ROM module
106
. The line
118
further diverges into a line
120
and a line
122
which connect to the CPU module
102
and the memory module
104
, respectively. FET switches
108
,
110
and
112
are disposed on the lines
118
,
120
and
116
, respectively, and are on/off controlled by a control circuit
115
in such a manner as to conform the action modes. The control circuit
115
provides an on/off control of the DC/DC converter
100
as well. Once a power switch of a personal computer is acted upon, the control circuit
115
provides a control of the activation mode to turn on the DC/DC converter
100
as well as to turn on all of the FET switches
108
,
110
and
112
, allowing powers to be supplied to all of the CPU module
102
, the memory module
104
and the CD-ROM module
106
for their respective actions. When a suspend switch is operated in those actions, the control circuit
115
provides a suspend mode to turn off the FET switch
110
to halt the supply of power to the CPU module
102
. In this state, a resume switch is operated so that the FET switch circuit
110
is turned on and restored to its pre-suspension state. The migration to the suspension mode could be designated by software.
By the way, in the conventional electronic circuit supplying electric powers to the loads in response to the action modes, a relatively large amount of current of, e.g., 3 amperes flows through the CPU module
102
whereas a small amount of current of, e.g., 0.3 ampres flows through the memory module
104
. As a result of this, 3.3 ampere current, the sum of the 3 ampere current through the CPU module
102
and the 0.3 ampere current through the memory module
104
, flows through the FET switch circuit
108
. This results in a deficiency that a combined current to two loads flows through the FET switch circuit
108
, causing a greater power loss. Furthermore, the FET switch circuit
108
needs to be an PET having a large current capacity so as to allow a passage of as large a current as 3.3 amperes therethrough, which results in an increased circuit mounting area as well as in increased costs.
SUMMARY OF THE INVENTION
According to the present invention there are provided an electronic apparatus and a circuit board which have contrived paths for supplying an electric power to loads in response to action modes so as to allow a minimal amount of current to flow through switch circuits turning on/off the supply of electric power, thereby reducing the power loss as well as the circuit mounting area.
A first aspect of the present invention provides an electronic apparatus for feeding an electric power to loads in response to a plurality of action modes, the electronic apparatus comprising an on/off controllable power source circuit for providing an electric power as its output to the loads; a first switch circuit disposed on a power supply line extending from the power source circuit to a first load; a second switch circuit disposed on a power supply line to a second load diverging from the input side of the first switch circuit; and a control circuit for providing an on/off control of the power source circuit, the first switch circuit and the second switch circuit in response to the plurality of action modes. In this manner, separate power supply lines are disposed which extend from the power source to the respective loads and which are each provided with a switch circuit, so that each switch circuit allows only a flow of current determined by one load supplied with an electric power, whereby the sum of currents to a plurality of loads is prevented from flowing into a specific switch circuit even though the on/off state of the switch circuit has changed depending on the action modes, thereby reducing the power loss of the switch circuit disposed on the power supply line and diminishing the current capacity to reduce the size of the elements and parts used, for the reduction of the circuit mounting area.
The control circuit in a first action mode turns on the power source circuit, the first switch circuit and the second switch circuit to permit a supply of electric power to the first and second loads. The control circuit in a second action mode turns on the power source circuit and the second switch circuit but off the first switch circuit to permit a supply of electric power to only the second load. Herein, the first action mode is a normal action mode, and the second action mode is a suspend mode permitting a supply of electric power to only a specific, limited load. The first load includes a CPU, and the second load includes a memory.
The electronic apparatus of the present invention further comprises a third switch circuit disposed on a power supply line to a third load diverging from the line on the input side of the first switch circuit, and the control circuit further provides an on/off control of the third switch circuit in response to the action modes. In this event, the control circuit turns on both the power source circuit and the third switch circuit in a third action mode permitting a supply of electric power to the third load in the state of the first action mode, the second action mode or a stop mode. The third load includes a CD drive for replaying a CD-ROM or a CD for example, and the control circuit defines the third action mode independently of the first action mode, the second action mode or the stop mode so as to allow a replaying action of the CD drive.
A second aspect of the present invention provides a circuit board for feeding an electric power to loads in response to a plurality of action modes, the circuit board comprising a first switch circuit disposed on a first power supply line extending from a power source circuit to a first load; a second switch circuit disposed on a second power supply line to a second load diverging from the input side of the first switch circuit; and a control circuit for providing an on/off control of the power source circuit, the first switch circuit and the second switch circuit in response to the plurality of action modes. In this event as well, the circuit board further comprises a third switch circuit disposed on a third power supply line to a third load diverging from the line on the input side of the first switch circuit, and the control circuit provides an on/off control of the third switch circuit in response to the plurality of action modes.
The above and other objects, aspect, features and advantages of the present invention will become more apparent from the following detailed description with reference to the accompanying drawings.
REFERENCES:
patent: 5339445 (1994-08-01), Gasztonyi
patent: 5729061 (1998-03-01), Narita
patent: 5737616 (1998-04-01), Watanabe
patent: 5796982 (1998-08-01), Iwami et al.
patent: 5838983 (1998-11-01), Atkinson
patent: 5959368 (1999-09-
Fleming Fritz M
Fujitsu Limited
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