Note: Descriptions are shown in the official language in which they were submitted.
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CHARGING SYSTEM FOR PORTABLE EQUIPMENT
BACKGROUND OF THE INVENTION
Field of the invention
The present invention relates to a charging system. More specifically, the
present
invention relates to a charging system for portable equipment connected to a
terminal
device such as a personal computer.
Description of related art
Recently, the use of mobile phones has increased rapidly and it is said that
one
in every three Japanese people has a mobile phone. It seems merely a matter of
time
that the day will come when almost all people in the country, except infants,
possess a
mobile phone of some kind.
On the other hand, use of a personal computer (PC) has also rapidly increased
and many businessmen, in general, use a personal computer in their workplace.
Among them, the number of people who possess both a note book-type portable PC
and a mobile phone and who use them in places where there is no external power
supply has significantly increased.
The first thing that must be accounted for when a note book-type portable PC
or a mobile phone is expected to be used outside is how to charge the
batteries.
Especially in a situation where the note book-type portable PC and the mobile
phone
are expected to be used outside for a long time, it has been necessary to
carry charging
devices specially designed for both the PC and the mobile phone, respectively.
FIG. 7 is a diagram showing a conventional manner of connecting a computer
and a mobile phone during operating conditions. A mobile phone 51 is connected
to a
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computer 52 via a cable 55 and an interface card 54, to carry out a
sendingheceiving
operation of data. Electric power for the operation of the computer 52 is
supplied from
an outlet 56 via an DC adapter 53. In order to charge the mobile phone 51, it
is
necessary to connect the mobile phone 51 to the outlet 56 via a charging
device 57
which is specially designed for the mobile phone 51.
Also on many occasions, it is desired to connect the computer 52 to the
Internet using the mobile phone 51 when there is no outlet 56, such as in a
situation
when working outside. In such a circumstance, however, it often happens that a
connection to the Internet cannot be made due to the exhaustion of the
batteries
contained in the mobile phone 51 even though the remaining charge of the
batteries in
the computer 52 is sufficient.
In the case described above, if a charging device specifically designed for
charging the mobile phone 51 is merely mounted in the computer 52 to carry out
a
charging process for the mobile phone 51, the circuit thereof will overlap
with the
l5 charging circuit for the computer 52, and the size of the computer 52, as
well as the
cost necessary for the production thereof, will increase.
Accordingly, a charging system has been awaited, which is capable of
charging the batteries of a computer and a mobile phone in a uniform manner,
and
which is also capable of charging the mobile phone when the computer does not
require electric power from an external power supply, i.e., when the computer
is
powered by internal batteries and the remaining charge of the batteries is
sufficient.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide a charging
system
for portable equipment which does not require an increase in the size and cost
of a
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computer and which is capable of charging portable equipment by using electric
power
supplied from the computer.
Accordingly, the present invention provides a charging system for portable
equipment used in a system including an information terminal and portable
equipment
connected to the information terminal, the portable equipment being operated
by using
electric power supplied from a battery and data is transmitted between the
information
terminal and the portable equipment via a communication unit, comprising a
power
supply output device provided with the information terminal, the power supply
output
device being capable of supplying electric power, which is supplied to the
information
terminal and to the portable equipment; and a first battery control device
provided
inside the portable equipment, the first battery control device receives
electric power
supplied from the power supply output device and performs a charging operation
for
the battery of the portable equipment, wherein the first battery control
device detects a
remaining charge of the battery of the portable equipment; and the power
supply output
device supplies electric power to the portable equipment when the remaining
charge of
the battery of the portable equipment detected by the first battery control
device is
equal to or less than a first allowable value.
The present invention also provides a charging system for portable equipment,
further comprising an identification device provided with the information
terminal, the
identification device identifies whether the information terminal is being
operated in
battery mode, wherein the power supply output device supples electric power to
the
portable equipment when the identification device identifies that the
information
terminal is not being operated in battery mode.
The present invention also provides a charging system for portable equipment,
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further comprising a second battery control device provided with the
information
terminal, the second battery control device detects the remaining charge of a
second
battery which supplies electric power to the information terminal, wherein the
power
supply output device supplies electric power to the portable equipment when
the
identification device identifies that the information terminal is not being
operated in
battery mode or the remaining charge of the second battery detected by the
second
battery control device is greater than a second allowable value, and the power
supply
output device stops supplying electric power to the portable equipment when
the
identification device identifies that the information terminal is being
operated in
battery mode and the remaining charge of the second battery detected by the
second
battery control device is equal to or less than a second allowable value.
The present invention also provides a charging system for portable equipment,
further comprising a display unit which displays a reduction in the remaining
charge of
the second battery when the remaining charge of the second battery detected by
the
second battery control device is equal to or less than the second allowable
value and no
electric power is being supplied from the information terminal.
The present invention also provides a charging system for portable equipment,
further comprising an alarm unit which produces an alarm sound when the
remaining
charge of the second battery detected by the second battery control device is
equal to or
less than the second allowable value and no electric power is being supplied
from the
information terminal.
The present invention also provides a charging system for portable equipment,
further comprising a power transmission coil provided with the information
terminal,
electric power is supplied to the power transmission coil from the information
terminal;
and a power receiving coil provided with the portable equipment, wherein the
power
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receiving coil is electromagnetically coupled with the power transmission coil
and
supplies an induced voltage to the portable equipment, and the communication
unit
carnes out data transmission between the information terminal and the portable
equipment by means of radio communication or optical communication.
According to the present invention, since the electric power to be supplied to
an information terminal may be supplied to portable equipment, a charging
operation
for the portable equipment may be performed without using a separate charging
device
which is specially designed for the portable equipment. Thus, the charging
operation
may be carned out in a significantly more convenient manner.
Also, according to the present invention, the charging operation for the
portable equipment is performed when the information terminal is operated in
battery
mode and the remaining charge of the battery is greater than an allowable
value. That
is, the charging operation for the portable equipment is not carned out when
the
remaining charge of the battery is equal to or less than the allowable value.
In this
manner, a situation where the battery of the information terminal runs out and
becomes
inoperative is prevented.
Moreover, according to the present invention, data is transmitted between the
information terminal and the portable equipment by means of radio
communication or
optical communication, and electric power is transferred by the
electromagnetic
coupling of coils provided in both the information terminal and the portable
equipment.
Accordingly, use of a coupling cable which physically connects the portable
equipment
and the information terminal becomes unnecessary and portability of the
present
invention is further increased
BRIEF DESCRIPTION OF THE DRAWINGS
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Some of the features and advantages of the invention having been described,
others will become apparent from the detailed description which follows, and
from the
accompanying drawings, in which:
FIG. 1 is a schematic block diagram showing a structure of a charging system
for portable equipment according to an embodiment of the present invention;
FIG. 2 is a diagram showing an example of a connection state in which a
computer 2, to which a power is supplied from an external power source, and a
mobile
phone 1 are connected to each other;
FIG. 3 is a diagram showing a state in which the computer 2 shown in FIG. 2 is
powered by internal batteries and connected to the mobile phone 1;
FIG. 4 is a schematic block diagram showing a structure of a non-contact power
supply between the computer 2 and the mobile phone 1;
FIG. 5 is a flowchart for explaining the operation of the computer 2 when
carrying out a charging operation for the mobile phone l;
FIG. 6 is a flowchart for explaining a charging operation carned out by the
mobile phone 1; and
FIG. 7 is a diagram showing a conventional manner of connecting a computer
with a mobile phone.
DETAILED DESCRIPTION OF THE INVENTION
The invention summarized above and defined by the enumerated claims may be
better understood by refernng to the following detailed description, which
should be
read with reference to the accompanying drawings. This detailed description of
a
particular preferred embodiment, set out below to enable one to build and use
one
particular implementation of the invention, is not intended to limit the
enumerated
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claims, but to serve as a particular example thereof.
FIG. 1 is a schematic block diagram showing a structure of the charging system
for portable equipment according to an embodiment of the present invention. In
FIG. 1,
a computer 2 is, for instance, a note book-type PC which may be carried
around. A
voltage sensor 312 measures the voltage supplied via a power supply terminal
320 and
outputs the results to a central processing unit (CPU) 311 via a control
signal bus 314.
A diode 316 prevents the electric current from flowing to the power supply
terminal 320
from a battery 318. When electric power is not supplied to the computer 2 via
the
power supply terminal 320, the input voltage of the voltage sensor 312
decreases to
about 0 volts due to the internal resistance of the voltage sensor 312 and the
action of the
diode 316. On the other hand, when electric power is supplied to the computer
2, the
voltage supplied externally via the power supply terminal 320 is detected by
the voltage
sensor 312.
A battery control circuit 317 charges the battery 318, based on a command from
the CPU 311, by using power supplied externally via the power supply terminal
320.
The battery control circuit 317 also detects the remaining charge of the
battery 318 and
outputs the result of the detection to the CPU 311. The remaining charge of
the battery
318 may be determined based on the result of the detection of the terminal
voltage of the
battery 318. Also, the remaining charge of the battery 318 may be detected by
the
battery control circuit 317 which carries out an operation of multiplying a
charging
current by a discharging current of the battery 318. A voltage stabilizing
circuit 313
stabilizes a power supplied to the CPU 311.
The CPU 311 compares the detection result, which is output from the voltage
sensor 312, with a predetermined voltage value and, if the detection result is
greater than
the predetermined voltage value, sets the mode to external power supply mode
so that
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the device is actuated by a power supplied from an external power supply via a
DC
adapter 3 (refer to FIG. 2) and the power supply terminal 320. If the
detection result is
less than the predetermined voltage value, the CPU 311 sets the mode to
battery mode
(battery actuation mode) so that the device is actuated by power supplied by
the battery
318.
In battery mode, if the CPU 311 detects that the remaining charge of the
battery
318 is less than a predetermined value or an allowable value set by a user,
based on the
detection result of the battery control circuit 317, the CPU 311 switches off
a switch 319
and terminates the power being supplied to a mobile phone 1. On the other
hand, if the
CPU 311 detects, based on the detection result of the battery control circuit
317, that the
remaining charge of the battery 318 is greater than a predetermined value or
an
allowable value set by a user, the CPU 311 switches on the switch 319 and
supplies
power to the mobile phone 1 from the battery 318.
The above-mentioned switching operation of the switch 319 by the CPU 311
can be carned out in accordance with a charging request from the mobile phone
1.
That is, when there is a charging request from the mobile phone 1 and the
remaining
charge of the battery 318 is greater than the predetermined value, the CPU 311
switches
on the switch 319 to supply power to the mobile phone 1 from the battery 318.
On the
other hand, when there is no charging request from the mobile phone 1 or the
remaining
charge of the battery 318 is less than the allowable value, the CPU 311
switches off the
switch 319.
In external power supply mode, the computer 2 is actuated by the power
supplied externally via the diodes 315 and 316 and the voltage stabilizing
circuit 313 and
carries out a charging operation for the battery 318 via the battery control
circuit 317.
Also, in external power supply mode, when there is a charging request from the
mobile
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phone l, the CPU 311 switches on the switch 319 to supply power to the mobile
phone 1
via, in the order of elements closest to the external power supply: the power
supply
terminal 320, the diode 316, and the switch 319.
Next, the structure of the mobile phone shown in FIG. 1 will be explained. In
FIG. 1, a voltage sensor 302 detects a power supply voltage output from the
computer 2
and outputs the detection result to a CPU 301 via a control signal bus 304.
A diode 306 prevents the electric current from flowing to the computer 2 from
a
battery 308. When electric power is not supplied from the computer 2, the
input
voltage of a voltage sensor 302 decreases to about 0 volts due to the internal
resistance
of the voltage sensor 302 and the action of the diode 306. On the other hand,
when
electric power is supplied from the computer 2, the voltage supplied from the
computer
2 is detected by the voltage sensor 302.
A battery control circuit 307 charges the battery 308, based on a command from
the CPU 301, by using power supplied by the computer 2. The battery control
circuit
307 also detects the remaining charge of the battery 308 and outputs the
result of the
detection to the CPU 301. The remaining charge of the battery 308 may be
determined
based on the result of the detection of the terminal voltage of the battery
308. Also, the
remaining charge of the battery 308 may be detected by the battery control
circuit 307
which carries out an operation of multiplying a charging current by a
discharging current
of the battery 308. A voltage stabilizing circuit 303 stabilizes a power
supplied to the
CPU 301.
The CPU 301 detects, based on the detection result output from the voltage
sensor 302, if power is supplied by the computer 2. The CPU also carries out a
charging operation for the battery 308 via the battery control circuit 307
when, based on
the detection result output from the battery control circuit 307, the
remaining charge of
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the battery 308 is less than a predetermined value or an allowable value set
by a user.
Moreover, when the remaining charge of the battery 308 is less than the
predetermined
amount, the CPU 301 displays an alarm on a display and makes an alarm sound
via a
speaker to inform the user that the remaining charge of the battery is low.
5 FIG. 2 is a diagram showing an example of a connection state in which the
mobile
phone 1 and the computer 2 having the structure shown in FIG. 1 are connected
to each
other. In FIG. 2, since the computer 2 provides a charging function for the
mobile
phone as shown in FIG. 1, use of a specially designed charging device, which
is
equivalent to the charging device 57 for charging the mobile phone 51 shown in
FIG. 7,
10 is not necessary. Accordingly, the connection between the charging device
and the
outlet 56 in FIG. 7 is not required.
The electric power for charging and operating the computer 2 is supplied from
an outlet 6 via the DC adapter 3. The charging operation for the mobile phone
1 is
carried out by supplying electric power from the computer 2 via an interface
card 4 (not
shown in FIG. 1 ), such as a PCMCIA card, and a coupling cable 5. Also, data
communication between the mobile phone l and the computer 2 and a
sending/receiving
operation of control signals necessary for the charging operation for the
mobile phone 1
are carned out via the interface card 4 and the coupling cable 5.
As mentioned above, although FIG. 2 shows the computer 2 in a state where the
power is supplied from an external power source, the computer 2 may be used
outside
where there is no outlet 6 present. In such a situation, the DC adapter 3 is
not
connected to the outlet 6 as shown in FIG. 3, and the computer 2 is operated
by electric
power supplied from the internal batteries thereof
Next, an operation of charging the mobile phone 1 using the power supplied
from the computer 2 will be described with reference to the flowcharts shown
in FIGS. 5
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and 6. FIG. 5 shows a flowchart for explaining the operation of the computer 2
when
carrying out a charging operation for the mobile phone 1. FIG. 6 shows a
flowchart for
explaining a charging operation carried out by the mobile phone 1. In FIG. 5,
the
switch 319 is initially in its OFF state. When the computer 2 is switched on,
the
voltage sensor 312 detects the voltage of the power supply terminal 320 and
outputs the
detection result to the CPU 311. Also, the battery control circuit 317 detects
the
remaining charge of the battery 318 and outputs the result to the CPU 311. At
the same
time, the CPU 311 detects if there is a charging request from the mobile phone
1 (step
S 1 ). If there is no charging request from the mobile phone 1, the CPU 311
leaves the
switch 319 in its OFF state (step S7).
Next, when receiving a charging request from the mobile phone 1, the CPU 311
detects if the computer 2 is operated by electric power supplied from an
external power
source based on the detection result output from the voltage sensor 312 (step
S2). If it
is detected that the operation of the computer 2 is being carned out by an
external power
source (i.e., "YES" in step S2), the CPU 311 sends a charging permit signal to
the
mobile phone 1 (step S3) and starts the charging operation by switching the
switch 319
to its ON state (step S8).
On the other hand, if an external power source is not used (i.e., "NO" in step
S2), that is, the computer 2 is operated in battery mode, the CPU 311 detects
the
remaining charge, B2, of the battery 318 based on the detection result of the
battery
control circuit 317 (step S4). Then, if the remaining charge of the battery
318 is greater
than an allowable value (i.e., "YES" in step SS), the CPU 311 sends a charging
permit
signal to the mobile phone 1 (step S3), and starts the charging operation by
switching the
switch 319 to its ON state (step S8).
If the remaining charge of the battery 318 is less than the allowable value
(i.e.,
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""NO in step SS), the CPU 311 sends a charging deny signal to the mobile phone
1 (step
S6), and stops the charging operation by switching the switch 319 to its OFF
state.
Next, the charging operation for the mobile phone 1 will be explained with
reference to FIG. 6. When the computer 2 is switched on, the battery control
circuit
307 constantly detects the remaining charge, B 1, of the battery 308 (step S
10) and
outputs the detection result to the CPU 301. Based on the detection result, if
the
remaining charge of the battery 308 is greater than the predetermined
allowable value,
the CPU 301 stops sending the charging request signal to the computer 2 and
terminates
the charging operation (step S 16).
On the other hand, if the remaining charge of the battery 308 is less than the
predetermined allowable value (i.e., "NO" in step S11), the CPU 301 sends a
charging
request signal to the computer 2 (step S 12). Then, if a charging permit
signal is not
received from the computer 2 (i.e., "NO" in step S 13) and no charging deny
signal is
received (i.e., "NO" in step S14), the CPU 301 sends a charging request again
(step
S12).
If a charging permit signal is received (i.e., "YES" in step S13), the CPU 301
starts the charging operation of the battery 308 using the battery control
circuit 307 (step
S 17). On the other hand, if a charging deny signal is received (i.e., "YES"
in step S 14),
the CPU 301 indicate$ that the remaining charge of the battery is low by means
of an
alarm display or an alarm sound (step S 15) and stops sending a charging
request (step
S 16).
In the above-mentioned embodiment, although the mobile phone 1 and the
computer 2 are connected via the coupling cable 5 to supply data and electric
power, the
coupling cable 5 may be a non-contact type. This will be explained with
reference to
FIG. 4 as follows. FIG. 4 is a schematic block diagram showing a structure of
a non-
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contact power supply between the computer 2 and the mobile phone 1. In FIG. 4,
communication units 403 and 413 include a wireless interface, such as
BLUETOOTH
(refer to URL: http://www. bluetooth.com/default. asp), and an infrared
interface, such
as IrDA (refer to URL:http://www.irda. orgy, and carry out non-contact
transmission of
data.
An inverter 411 of the computer 2 converts the direct current power output
from
the switch 319 into alternating current power and outputs the power to an
electromagnetic junction coil 412. On the other hand, another electromagnetic
junction
coil 402 is provided with the mobile phone 1 at a position opposite the
electromagnetic
junction coil 412. Each of the electromagnetic junction coils 402 and 412 has
a
magnetic body core and forms a transformer when they are opposite each other
in their
proximity and coupled electromagnetically. The ratio of the winding of the
electromagnetic junction coils 402 and 412 is set in accordance with the power
source
voltage of the computer 2 (for instance, 12V) and the power source voltage of
the mobile
phone 1 (for example 3V). Accordingly, a transfer of electric power is
possible even if
the difference in voltage between the two power sources is large.
The electric power supplied to the mobile phone 1 is converted into a direct
current power by a rectification circuit 401 due to the electromagnetic
coupling of the
electromagnetic junction coils 402 and 412. Accordingly, the electric power
may be
supplied to the mobile phone 1 to carry out a charging operation for the
battery 308. In
this manner, a transfer of data and a charging operation may be carned out
without
physically connecting the computer 2 with the mobile phone 1.
In the embodiment described above, the case in which a charging operation is
carried out by using electric power supplied to the mobile phone from the
computer is
explained. However, it is possible to interchange the mobile phone with the
computer
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and the computer with the mobile phone. That is, an information terminal
device may
be represented by a mobile phone and portable equipment may be represented by
a
computer. It is possible that a computer outputs a charging request to a
mobile phone
and, based on the charging request, the mobile phone may carry out a charging
operation
for the computer
Moreover, all of the above may be combined and the charging operation may be
performed reciprocally when the electric power of either one of the terminal
device and
the mobile phone is exhausted.
The present invention is characterized by an information terminal device which
may be actuated by two kinds of power sources, i.e., internal batteries and an
external
power source, having a charging function for portable equipment which is
simultaneously used with the information terminal device. The information
terminal
device may be represented by a note book-type portable PC and the portable
equipment
may be represented by a mobile phone, a digital camera, or a portable
information
terminal. Accordingly, in this specification, the information terminal device
is
represented by a note book-type PC (or, simply, a PC) and the portable
equipment is
represented by a mobile phone. However, it is obvious that the present
invention is
applicable to a charging operation between an information terminal device and
portable
equipment in general.
Having thus described several exemplary embodiments of the invention, it will
be apparent that various alterations and modifications will readily occur to
those skilled
in the art. Such alterations and modifications, though not expressly described
above,
are nonetheless intended and implied to be within the spirit and scope of the
invention.
Accordingly, the foregoing discussion is intended to be illustrative only; the
invention is
limited and defined only by the following claims and equivalents thereto.
