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Mobile Phone Patent Abstract
An apparatus for supplying power to a mobile phone by utilizing
an external power source when a battery of the mobile phone has
been exhausted. In a mobile phone having an earphone-microphone
connector which can be connected with an earphone-microphone set,
the earphone-microphone connector has additional contacts through
which external power can be supplied to the mobile phone from an
external power source, especially from another mobile phone. Therefore,
even when the battery of the mobile phone has been exhausted, a
user can make communication through the mobile phone by utilizing
external electric power in a simple and easy manner, without largely
changing the existing construction of the mobile phone.
Mobile Phone Patent Claims
What is claimed is:
1. An apparatus for supplying power to a mobile phone having an
earphone-microphone connector which can be connected with an earphone-microphone
set, the apparatus comprising: a first plug which can be connected
in parallel with a power supply section of a first mobile phone
through an earphone-microphone connector of the first mobile phone;
and a second plug which can be connected in parallel with a power
supply section of a second mobile phone through an earphone-microphone
connector of the second mobile phone, so as to supply electric power
from the power supply section of the first mobile phone to the power
supply section of the second mobile phone.
2. An apparatus as claimed in claim 1, wherein the first plug comprises
a first power node and a first ground node, which can be connected
in parallel with the power supply section of the first mobile phone.
3. An apparatus as claimed in claim 2, wherein the second plug
comprises a second power node and a second ground node, which can
be connected in parallel with the power supply section of the second
mobile phone, the second power node being connected with the first
power node, the second ground node being connected with the first
ground node.
4. An earphone-microphone connector of a mobile phone that can
be connected with an earphone-microphone set or a power supply cable,
the earphone-microphone connector comprising a first contact to
be connected with a power node of a power supply section of the
mobile phone and a second contact to be connected with a ground
node of the power supply section, which can be connected with a
plug of the power supply cable for supplying electric power, wherein,
when the plug is connected with the earphone-microphone connector,
the first and second contacts are connected through the plug with
an external power source, thereby supplying electric power from
the external power source to the power supply section.
5. An earphone-microphone connector as claimed in claim 4, wherein
the external power source is a power supply section of another mobile
phone.
6. An earphone-microphone connector as claimed in claim 4, wherein
the earphone-microphone connector generates a signal for maintaining
the mobile phone in a communication mode through the earphone-microphone
set when the earphone-microphone set is connected with the earphone-microphone
connector, and generates a signal for maintaining the mobile phone
in a general communication mode when the plug is connected with
the earphone-microphone connector.
7. An earphone-microphone connector as claimed in claim 4, wherein
the earphone-microphone connector further comprises a third contact
for maintaining the mobile phone in a general communication mode
when the plug is connected with the earphone-microphone connector.
8. An earphone-microphone connector as claimed in claim 7, wherein
the third contact comes into contact with the first contact and
generates a signal for maintaining the mobile phone in a general
communication mode when the plug is connected with the earphone-microphone
connector.
Mobile Phone Patent Description
PRIORITY
This application claims priority to an application entitled "Apparatus
For Supplying Power To Mobile Phone Using Earphone-Microphone Connector"
filed in the Korean Industrial Property Office on May 8, 2002 and
assigned Serial No. 2002-25226, the contents of which are hereby
incorporated by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a mobile phone, and more particularly
to an apparatus for supplying power to a mobile phone by utilizing
an external power source.
2. Description of the Related Art
According to continuous development and progress in wireless communication
technology and semiconductor manufacturing technology, mobile phones
are growing lighter and more compact and coming to have more functions.
Actually, a mobile phone is nowadays an indispensable communication
appliance in daily life. However, it is very inconvenient and even
dangerous for a user to perform communication with a mobile phone
in his or her hand in some situations. For example, it is potentially
very dangerous for a person to communicate while driving with a
mobile phone in his or her hand. Therefore, most mobile phones are
provided with an earphone-microphone connector which can be connected
with an external earphone-microphone set. The earphone-microphone
connector is usually a connector socket which has standardized dimension
and shape.
FIG. 1 is a diagram illustrating an electric construction of a
conventional earphone-microphone set.
Referring to FIG. 1, the conventional earphone-microphone set includes
an earphone 7, a microphone 6, and a plug 5, and the plug 5 includes
four electrical nodes 1, 2, 3, and 4. One end of the earphone 7
is connected with the node 1, and the other end of the earphone
7 is connected with the node 4. Further, one end of the microphone
6 is connected with the node 2, and the other end of the microphone
6 is connected with the node 3. The plug 5 has a construction suitable
for insertion into a socket-type earphone-microphone connector provided
at a mobile phone.
FIG. 2 is a diagram illustrating an internal construction of a
conventional earphone-microphone connector socket in a usual mobile
phone, and FIG. 3 is a diagram schematically illustrating an internal
circuit of the earphone-microphone connector socket shown in FIG.
2.
As shown, the earphone-microphone connector socket 10 includes
four internal contacts 11, 12, 15, and 16, which can be connected
with the corresponding nodes 2, 1, 3, and 4 of the earphone-microphone
set shown in FIG. 1, respectively, and additional internal contacts
13 and 14 which are used in detecting the insertion of the earphone-microphone
set into the earphone-microphone connector socket.
Referring to FIG. 3, when the earphone-microphone set is not inserted
in the earphone-microphone connector socket, the internal contact
13 is physically short-circuited to the internal contact 12 while
the internal contact 14 is physically short-circuited to the internal
contact 15. In FIG. 3, this short-circuited state is represented
by arrows of the internal contacts 13 and 14 in contact with the
internal contacts 12 and 15, respectively. In this case, the internal
contacts 13 and 16 are connected with a speaker on the mobile phone
body, and the internal contacts 11 and 14 are connected with a microphone
on the mobile phone body.
In this case, most of the voltage AVcc is applied to the microphone
of the mobile phone body, which has a relatively large resistance
of about 2.2 k.OMEGA., so that the internal contact 14 is maintained
in the LOW state. As a result, an NPN Field Effect Transistor (FET)
Q, which has a gate input G1, a source S1, and a drain D1, is utilized
as follows. When the gate input G1, which is a status signal of
the internal contact 14, is off, and the signal JACK_IN supplied
to a control section or coder/decoder (CODEC) of the mobile phone,
is shifted to the HIGH state by the voltage Vdd, the signal JACK_IN
maintains the mobile phone in a general communication mode, and
not in a communication mode, where the user communicates through
the earphone-microphone set.
When the plug 5 of the earphone-microphone set, which has the nodes
1, 2, 3, and 4 as shown in FIG. 1, is inserted in the earphone-microphone
connector socket 10, the force of the inserted plug separates the
internal contact 13 from the internal contact 12 and the internal
contact 14 from the internal contact 15, thereby disconnecting the
internal contact 12 and the internal contact 15 from the speaker
and the microphone of the mobile phone body, respectively. Simultaneously,
the internal contacts 12 and 16 are connected with the earphone
7 through the nodes 1 and 4, and the internal contacts 11 and 15
are connected with the microphone 6 through the nodes 2 and 3. In
this case, the internal contact 14 is shifted to the HIGH state
by a pull-up resistor R1 between the internal contact 14 and AVcc.
Therefore, the signal JACK_IN is connected with the ground through
the drain D1 and source S1 of the NPN Field Effect Transistor Q,
the gate input G1 of which is connected to the a status signal of
the internal contact 14, so that the signal JACK_IN shifts to the
LOW state. The signal JACK_IN shifts the mobile phone into the communication
mode through the earphone-microphone set.
As explained above, the function of the conventional earphone-microphone
connector is to connect the earphone-microphone set and the mobile
phone. Typically, the earphone-microphone connector does not perform
any other function. As explained above, once this connection is
made the mobile phone can be operated in the communication mode,
which leaves the user's hands free to perform other tasks.
In the meantime, most mobile phones employ a rechargeable battery
as an electric power source to provide portability. However, the
rechargeable battery has limited capacity, depending on the kind
and lifespan of the battery. Accordingly, the mobile phone cannot
be used once the battery is discharged. Moreover, since the batteries
of mobile phones usually have different shapes and power capacities,
according to manufacturer and model of the battery, it is almost
impossible for a mobile phone to utilize a different battery from
another mobile phone in place of its own battery. In order to solve
this problem, there have been various efforts and research into
developing a technology which can enable a mobile phone to be recharged
regardless of the kind of the battery used. However, it is still
a common case that a user of a mobile phone cannot recharge the
battery of the mobile phone, due to his or her situation or location.
In this case, the user cannot help using a public phone or borrowing
another person's mobile phone.
SUMMARY OF THE INVENTION
Accordingly, the present invention has been made to solve the above-mentioned
problems occurring in the prior art, and an object of the present
invention is to provide an apparatus which enables a mobile phone
to receive electric power when a battery of the mobile phone has
been discharged.
It is another object of the present invention to provide an apparatus
which enables a mobile phone to receive electric power through an
earphone-microphone connector of the mobile phone.
It is another object of the present invention to provide an apparatus
which enables a mobile phone to receive electric power through an
earphone-microphone connector of the mobile phone while communication
is being performed through the mobile phone.
It is another object of the present invention to provide an apparatus
which enables a mobile phone to receive electric power from another
mobile phone.
In order to accomplish these objects, there is provided an apparatus
for supplying power to a mobile phone having an earphone-microphone
connector which can be connected with an earphone-microphone set,
the apparatus comprising: a first plug which can be connected in
parallel with a power supply section of a first mobile phone through
an earphone-microphone connector of the first mobile phone; and
a second plug which can be connected in parallel with a power supply
section of a second mobile phone through an earphone-microphone
connector of the second mobile phone, so as to supply electric power
from the power supply section of the first mobile phone to the power
supply section of the second mobile phone.
In accordance with another aspect of the present invention, there
is provided an apparatus for supplying power to a mobile phone having
an earphone-microphone connector which can be connected with an
earphone-microphone set, the earphone-microphone connector comprising
a first contact connected with a power node of a power supply section
of the mobile phone and a second contact connected with a ground
node of the power supply section, which can be connected with a
plug for supplying electric power, wherein, when the plug is connected
with the earphone-microphone connector, the first and second contacts
are connected through the plug with an external power source, thereby
supplying electric power from the external power source to the power
supply section.
BRIEF DESCRIPTION OF THE DRAWINGS
The above and other objects, features and advantages of the present
invention will be more apparent from the following detailed description
taken in conjunction with the accompanying drawings, in which:
FIG. 1 is a diagram illustrating an electric construction of a
conventional earphone-microphone set;
FIG. 2 is a diagram illustrating an internal construction of a
conventional earphone-microphone connector socket in a usual mobile
phone;
FIG. 3 is a diagram schematically illustrating an internal circuit
of the earphone-microphone connector socket shown in FIG. 2;
FIG. 4 is a block diagram of a mobile phone to which a power supply
apparatus according to the present invention can be applied;
FIG. 5 is a diagram illustrating an electric construction of one
plug of an electric power cable according to the present invention;
FIG. 6 is a diagram illustrating an internal construction of an
earphone-microphone connector socket of a mobile phone according
to the present invention;
FIG. 7 is a diagram schematically illustrating an internal circuit
of the earphone-microphone connector socket shown in FIG. 6; and
FIG. 8 is a view showing the connection of the power supply cable
according to the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Hereinafter, preferred embodiments of the present invention will
be described in detail with reference to the accompanying drawings.
In the following description of the present invention, details of
well known functions and configurations are omitted to avoid making
the subject matter of the present invention unclear.
The present invention, which will be described herein, provides
a power supply cable which enables electric power to be supplied
through a standard earphone-microphone connector socket of a mobile
phone. Also, although a detailed description gives examples that
relate to a wireless phone, such as a mobile phone, cellular phone,
personal communication service (PCS) phone, or personal digital
assistant (PDA) phone, the present invention is not limited to those
phones but can be also employed in all kinds of portable appliances
having a standard earphone-microphone connector, such as portable
cassette players, MP3 players, CD players, etc.
FIG. 4 is a block diagram of a mobile phone to which a power supply
apparatus according to the present invention can be applied.
In the mobile phone shown in FIG. 4, a control section 110 which
is connected with a memory 111, a keypad 112, a display section
113, an RF module 114, a baseband processing section 115, and a
CODEC 116, controls each element of the mobile phone and processes
voice signals and data for usual phone communication or data communication.
The control section 110 described above, for example, a mobile system
modem (MSM) chip such as that manufactured by QUALCOMM Inc., may
be utilized.
The memory 111, which is connected with the control section 110
and can include an Electrically Erasable and Programmable ROM (EEPROM),
a flash memory, and a random access memory (RAM), etc., stores various
reference data and programs necessary in the processing and controlling
operation of the control section 110, and provides a working memory
of the control section 110.
The keypad 112 includes various keys including number keys, thereby
supplying key input signals inputted by a user to the control section
110. The display section 113 is usually an LCD that displays images
containing various information.
The RF module 114 transmits and receives RF (radio frequency) signals
to and from a base station through an antenna. The RF module 114
converts a received RF signal to an IF (intermediate frequency)
signal and outputs it to the baseband processing section 115, and
converts an IF signal received from the baseband processing section
115 to an RF signal and transmits it through the antenna. The baseband
processing section 115 is a BBA (baseband Analog ASIC) which provides
an interface between the control section 110 and the RF module 114.
The baseband processing section 115 converts a digital baseband
signal received from the control section 110 to an analog IF signal
and applies the analog IF signal to the RF module 114, and converts
an analog IF signal received from the RF module 114 to a digital
baseband signal and applies the baseband digital signal to the control
section 110.
The CODEC 116 connected with the control section 110 is connected
with a microphone and speaker of the mobile phone body or a microphone
and speaker of the earphone-microphone set. The CODEC 116 outputs
voice data, which is obtained by Pulse Code Modulation (PCM) encoding
a voice signal inputted from the microphone, to the control section
110, and outputs a voice signal, which is obtained by PCM decoding
voice data inputted from the control section 110, to the speaker.
When the external earphone-microphone set is inserted in the earphone-microphone
connector, the CODEC 116 detects it and passes the inputted or outputted
voice signal to the external earphone-microphone set instead of
the inner microphone or speaker. This means that the mobile phone
has entered the communication mode through the earphone-microphone
set. Meanwhile, although FIG. 4 shows the CODEC 116 constructed
separately from the control section 110, the CODEC 116 may be constructed
in the same chip in which the control section 110 is constructed.
All elements of the mobile phone operate by means of electric power
supplied from the battery. As described already, batteries of mobile
phones have different shapes and power capacities according to manufacturers
and models of the batteries. However, since most mobile phones can
operate without much trouble when an electric power with a voltage
of 3.4 to 4.2 volts and an electric current of 600 to 900 mA is
supplied to them, a mobile phone can be used in communication as
long as an electric power with the above-mentioned voltage and current
is supplied to it, even though the electric power is supplied from
a battery of a different kind of mobile phone with a different shape
and different connection nodes. In consideration of this point,
the present invention enables a mobile phone to receive an external
electric power through an earphone-microphone set having standard
shape and dimension.
However, as described above, when any type of plug is connected
with the earphone-microphone connector, the mobile phone recognizes
this as the earphone-microphone set and automatically shifts to
the communication mode through the earphone-microphone set. Therefore,
an apparatus which can enable communication through the mobile phone,
i.e. in the general communication mode, simultaneous to supplying
electric power to the mobile phone through the earphone-microphone
connector is necessary.
The present invention discloses an electric power cable having
two plugs, each having similar construction, connected with each
other through electric wires. Each of the two plugs can be connected
with an earphone-microphone connector of a mobile phone. In this
case, each of the two plugs is preferably longer than a plug of
a usual earphone-microphone set, so as to prevent the mobile phone
from shifting to the communication mode through the earphone-microphone
set when the plug is inserted into the earphone-microphone connector
socket. Further, the mobile phone is in the communication mode through
the earphone-microphone set when the plug of the conventional earphone-microphone
set is inserted at its relatively shallow depth in the earphone-microphone
connector socket, while the mobile phone will remain in or return
to the general communication mode when the longer plug of the invention
is inserted relatively deeply in the earphone-microphone connector.
FIG. 5 is a diagram illustrating an electric construction of one
plug of the electric power cable according to the present invention,
which is identical to an electric construction of the other plug
of the electric power cable.
The plug 20 shown in FIG. 5 includes two more nodes 24 and 26 in
addition to the four nodes 21, 22, 23, and 25 which are common elements
of the plug of the conventional earphone-microphone set. Making
a comparison between the plug 20 and the conventional plug 5 shown
in FIG. 1, the nodes 21 and 25 correspond to the nodes 1 and 4 for
the earphone while the nodes 22 and 23 correspond to the nodes 2
and 3 for the microphone.
The plug 20 has a shape that extends further than the plug 5 of
the usual earphone-microphone set. Therefore, when the plug 20 has
been inserted only to the node 25 (hereinafter, referred to as "first-type
insertion"), only the four nodes 21, 22, 23, and 25 are in
contact with corresponding internal contacts. Further, when the
plug 20 has been inserted to the node 26 (hereinafter, referred
to as "second-type insertion"), the nodes 24 and 26 are
in contact with corresponding internal contacts and utilized in
supplying electric power.
The additional node 24 is used as a power node, and the additional
node 26 is used as a ground node. The two nodes 24 and 26 are connected
with corresponding nodes of the plug at the other side, respectively.
The plug 20 described above has a construction suitable to be connected
with the conventional earphone-microphone connector socket.
FIG. 6 is a diagram illustrating an internal construction of an
earphone-microphone connector socket of a mobile phone according
to the present invention, and FIG. 7 is a diagram schematically
illustrating an internal circuit of the earphone-microphone connector
socket shown in FIG. 6.
As shown, an earphone-microphone connector socket 30 includes six
internal contacts 31, 32, 35, 36, 37, and 38, which can be connected
with the corresponding nodes 22, 21, 23, 25, 24, and 26 of the earphone-microphone
set shown in FIG. 5, respectively, and three additional internal
contacts 33, 34, and 39 which are used in detecting the insertion
of the earphone-microphone set or power supply cable. In this case,
the internal contact 37 is connected with the power node Vcc of
the battery and the internal contact 38 is connected with the ground
node of the battery in the mobile phone.
Referring to FIG. 7, when any plug of the earphone-microphone set
is not inserted in the earphone-microphone connector socket, the
internal contact 33 is physically short-circuited to the internal
contact 32 while the internal contact 34 is physically short-circuited
to the internal contact 35. In this case, the internal contacts
33 and 36 are connected with a speaker of the mobile phone body,
and the internal contacts 31 and 34 are connected with a microphone
of the mobile phone body. Further, the internal contact 39 is physically
spaced apart from the internal contact 37. In FIG. 7, this state
is represented by arrows of the internal contacts 33 and 34 in contact
with the internal contacts 32 and 35, respectively, and an arrow
for the internal contact 39, which is separated from the internal
contact 37.
In this case, most of the voltage AVcc is applied to the microphone
of the mobile phone body, which has a relatively large resistance
of about 2.2 k.OMEGA., so that the internal contact 34 is maintained
at the LOW state. Therefore, an NPN Field Effect Transistor Q1,
which has G1, S1, and D1, and a gate input G1 of which is a status
signal of the internal contact 34, is off, and the first input 1
of an exclusive OR gate 42 is in the HIGH state due to the voltage
Vdd1. Meanwhile, the internal contact 39 is in the LOW state, since
the internal contact 39 is not electrically connected to anything.
Therefore, an NPN Field Effect Transistor Q2 (which has G2, S2,
and D2), a gate input G2 of which is a status signal of the internal
contact 39, is in the off state, and the second input 2 of the exclusive
OR gate 42 is also in the HIGH state due to the voltage Vdd2. As
a result, the signal JACK_IN outputted from an inverter 44 and supplied
to a control section or CODEC of the mobile phone is in the HIGH
state. The signal JACK_IN maintains the mobile phone in the general
communication mode, not in the communication mode through the earphone-microphone
set.
When the plug 5 of the conventional earphone-microphone set, which
has the nodes 1, 2, 3, and 4 as shown in FIG. 1, is inserted in
the earphone-microphone connector socket 30, or when one plug 20
of the power supply cable, which has the nodes 21, 22, 23, 24, 25,
and 26, is first-type inserted, that is, inserted only to the depth
of node 25, the force of the inserted plug separates the internal
contact 33 from the internal contact 32 and the internal contact
34 from the internal contact 35, thereby disconnecting the internal
contact 32 and the internal contact 35 from the speaker and the
microphone of the mobile phone body, respectively.
In this case, the internal contact 34 is shifted to the HIGH state
by a pull-up resistor R1 between the internal contact 34 and AVcc.
Therefore, the NPN Field Effect Transistor Q1, the gate input G1
of which is a status signal of the internal contact 34, is turned
on. Since the source S1 of the transistor Q1 is now connected to
the ground, the first input 1 of an exclusive OR gate 42 which is
connected with the drain D1 of the transistor Q1 goes to the LOW
state. Meanwhile, the second input 2 of the exclusive OR gate 42
is still in the HIGH state. As a result, the signal JACK_IN outputted
from the inverter 44 and supplied to a control section or CODEC
of the mobile phone goes to the LOW state. The signal JACK_IN shifts
the mobile phone into the communication mode through the earphone-microphone
set.
Finally, when plug 20 of the power supply cable, which has the
nodes 21, 22, 23, 24, 25, and 26 as shown in FIG. 5, is second-type
inserted, that is, inserted up to the node 26, the force of the
inserted plug causes the internal contacts 39 and 37 to be short-circuited
to each other. However, the internal contact 33 and the internal
contact 34 are still separated from the internal contact 32 and
the internal contact 35, respectively.
In this case, the first input 1 of an exclusive OR gate 42 is still
in the LOW state, while the internal contact 39 is shifted to the
HIGH state by the internal contact 37, since the internal contact
37 is connected with the power node Vcc in the mobile phone. Even
when the battery of the mobile phone has been discharged and it
is impossible to further communicate through the mobile phone, the
power node will typically possess sufficient voltage to determine
that it is in the logical HIGH state. Also, even when the battery
has been completely exhausted, the internal contact 37 can receive
electric power through the power supply cable from another mobile
phone connected with the other side plug of the power supply cable.
Therefore, the NPN Field Effect Transistor Q2, a gate input G2
of which is the status signal of the internal contact 39, is turned
on. Since the source S2 of the transistor Q2 is connected to the
ground, the second input 2 of the exclusive OR gate 42, which is
connected with the drain D2 of the transistor Q2, is in the LOW
state. As a result, the signal JACK_IN outputted from the inverter
44 and supplied to the control section or CODEC of the mobile phone
is in the HIGH state. The signal JACK_IN shifts the mobile phone
into the general communication mode and enables the mobile phone
to receive electric power through the power supply cable from another
mobile phone connected with the power supply cable.
Mode shift states of the mobile phone according to the insertion
of the plug are shown in Table 1 below.
TABLE 1 Not inserted First-type insertion Second-type insertion
G1 LOW HIGH HIGH D1 HIGH LOW LOW G2 LOW LOW HIGH D2 HIGH HIGH LOW
JACK_IN HIGH LOW HIGH Mode General mode Through-earphone General
mode mode (power supplied)
FIG. 8 is a view showing the connection of the power supply cable
according to the present invention.
As shown, one plug of the power supply cable 52 is inserted in
an earphone-microphone connector socket of a mobile phone 50, while
the other plug of the power supply cable 52 is inserted in an earphone-microphone
connector socket of another mobile phone 54. Then, a battery of
the mobile phone 50 is connected in parallel with a battery of the
mobile phone 54. Therefore, even when the battery of the mobile
phone 50 has been completely discharged, communication can be made
by the mobile phone 50 by borrowing power from the battery of the
mobile phone 54. In this case, the parallel connection allows only
the capacity of the battery to be increased but the voltage is not
largely elevated, thereby causing no significant damage due to over-voltage
on the circuit of the mobile phone. Further, since the connection
is made in parallel, the voltage is not largely dropped even in
the other mobile phone which provides electric power.
Hereinafter, representative effects of the present invention having
the construction and operation as described above in detail will
be described briefly.
The present invention provides a power supply cable which enables
a mobile phone to utilize external electric power, thereby enabling
a user to make a communication through a mobile phone even when
a battery of the mobile phone has been exhausted, without borrowing
either the battery from another mobile phone or the other phone
itself.
Moreover, the present invention provides a power supply cable which
can be manufactured at low cost and can be used regardless of communication
type of the mobile phones, such as CDMA (Code Division Multiple
Access), GSM (Global Standard Mobile), etc. In other words, the
present invention enables a user to use his or her own mobile phone
in communication by means of external electric power. Therefore,
a user can conveniently use his or her own mobile phone without
uneasiness due to insufficient lifespan of the battery.
While the invention has been shown and described with reference
to certain preferred embodiments thereof, it will be understood
by those skilled in the art that various changes in form and details
may be made therein without departing from the spirit and scope
of the invention as defined by the appended claims.
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