U.S. patent application number 09/822227 was filed with the patent office on 2001-10-04 for mutual connection judging circuit.
This patent application is currently assigned to NEC Mobile Energy Corporation. Invention is credited to Ohya, Kazumasa.
Application Number | 20010026145 09/822227 |
Document ID | / |
Family ID | 18614391 |
Filed Date | 2001-10-04 |
United States Patent
Application |
20010026145 |
Kind Code |
A1 |
Ohya, Kazumasa |
October 4, 2001 |
Mutual connection judging circuit
Abstract
The present invention provides a mutual connection judging
circuit for judging mutual connection between a device 3 with an
incorporated battery 4 and a charger 1, wherein there are provided
transistors Q1 and Q2 on the charger 1 side and the device 3 side
respectively, bases of the transistors Q1 and Q2 on the charger 1
side and the device 3 side are connected with each other, and
mutual connection is judged by collector potential of the
transistors Q1 and Q2. The charger 1 controls the charging by
judging mutual connection depending upon whether the collector of
the PNP transistor Q1 is in opened state or not. The device 3
comprises a circuit Q3 for controlling emitter potential of the NPN
transistor Q2, controls emitter potential depending upon whether
the charging is in enable state or not, and turns on or off the NPN
transistor Q2, and the charger 1 starts the charging by judging
collector potential of the PNP transistor Q1. With the features of
construction as described above, the mutual connection can be
confirmed by a single signal line, and it is possible to control
connection signal from the device side.
Inventors: |
Ohya, Kazumasa;
(Utsunomiya-shi, JP) |
Correspondence
Address: |
ARMSTRONG,WESTERMAN, HATTORI,
MCLELAND & NAUGHTON, LLP
1725 K STREET, NW, SUITE 1000
WASHINGTON
DC
20006
US
|
Assignee: |
NEC Mobile Energy
Corporation
Utsunomiya-shi
JP
|
Family ID: |
18614391 |
Appl. No.: |
09/822227 |
Filed: |
April 2, 2001 |
Current U.S.
Class: |
320/127 |
Current CPC
Class: |
H02J 7/0036
20130101 |
Class at
Publication: |
320/127 |
International
Class: |
H02J 007/00 |
Foreign Application Data
Date |
Code |
Application Number |
Apr 3, 2000 |
JP |
2000-100147 |
Claims
What we claim is:
1. A mutual connection judging circuit for judging mutual
connection between a device with an incorporated battery and a
charger, said circuit comprising a transistor on each of the
charger side and the device side, a base of the transistor on the
charger side is connected with a base of the transistor on the
device side, and mutual connection is judged by collector potential
of the transistor on the charger side and by collector potential of
the transistor on the device side.
2. A mutual connection judging circuit according to claim 1,
wherein a PNP transistor is provided as the transistor on the
charger side, and charging is controlled by judging the mutual
connection depending upon whether the collector of the PNP
transistor is in opened state or not.
3. A mutual connection judging circuit according to claim 2,
wherein there is provided an NPN transistor as the transistor on
the device side, and the device comprises a circuit for controlling
emitter potential of the NPN transistor, said device turns on or
off the NPN transistor by controlling the emitter potential
depending upon whether the charging is in enable state or not, and
said charger side starts the charging by judging collector
potential of the PNP transistor.
4. A mutual connection judging circuit for judging mutual
connection of a device with an incorporated battery and a charger,
wherein said circuit comprises a transistor with a base thereof
connected to a terminal for recognizing connection with the device
and with an emitter thereof connected to a power source of the
charger, and mutual connection is judged by detecting whether a
collector of the transistor is in opened state or not.
5. A mutual connection judging circuit for judging mutual
connection of a device with an incorporated battery and a charger,
wherein said circuit comprises a transistor with a base thereof
connected to a terminal for recognizing connection with the charger
side and with an emitter thereof grounded, and mutual connection is
judged depending upon whether the collector of the transistor is in
opened state or not.
6. A mutual connection judging circuit according to claim 5,
wherein there is provided a switching circuit for controlling the
switching of the emitter of the transistor to grounded state or to
opened state.
Description
[0001] The present invention relates to a mutual connection judging
circuit for judging mutual connection of a device with an
incorporated battery and a charger.
[0002] FIG. 2 is a diagram for explaining a conventional example of
a mutual connection judging circuit. In the figure, {circle over
(1)} represents a signal line for confirming the connection on
charger side, and {circle over (2)} denotes a signal line for
confirming the connection on device side. When a charger is
connected with a device with an incorporated battery, for the
purpose of starting the charging and terminating the charging by
confirming the mutual connection or interconnection, it is
necessary to judge full charging by the charging current and the
charging voltage. However, when operating condition of the device
is not confirmed, the charging current may be supplied from the
charger while load current corresponding to various loading
conditions is flowing. In this respect, it is difficult to judge or
recognize the full charging, and it is not possible to control the
starting and the termination of the charging. Therefore, for the
purpose of recognizing the connection to the charger with the
device and the stop operation of the device during charging
operation, it is necessary to have two signal lines of {circle over
(1)} and {circle over (2)} as shown in FIG. 2.
[0003] However, when the device with an incorporated battery is
connected with the charger and the battery is charged if
conventional mutual connection judging method as described above is
used, the charger and the device judge the connection respectively
via the signal lines {circle over (1)} and {circle over (2)}. In
the one-sided detection of full charging by the charger, the
detection itself is ambiguous and indefinite. As a result, charging
may be performed beyond the limit, and this may impair the
performance characteristics of the battery. Also, it is necessary
to have two signal lines for mutual recognition of connection as
shown in FIG. 2, and this means that there are many connection
points and complicated structure is needed.
SUMMARY OF THE INVENTION
[0004] To solve the above problems, it is an object of the present
invention to provide a mutual connection judging circuit for
confirming mutual connection by a single signal line and for
controlling connection signal from the device side.
[0005] To attain the above object, the present invention comprises
a transistor on each of the charger side and the device side, a
base of the transistor on the charger side is connected with a base
of the transistor on the device side, and mutual connection is
judged by collector potential of the transistor on the charger side
and by collector potential of the transistor on the device side. In
said circuit, a PNP transistor is provided as the transistor on the
charger side, and charging is controlled by judging the mutual
connection depending upon whether the collector of the PNP
transistor is in opened state or not. Further, there is provided an
NPN transistor as the transistor on the device side, and the device
comprises a circuit for controlling emitter potential of the NPN
transistor, said device turns on or off the NPN transistor by
controlling the emitter potential depending upon whether the
charging is in enable state or not, and said charger side starts
the charging by judging collector potential of the PNP
transistor.
[0006] Also, the present invention comprises a mutual connection
judging circuit for judging mutual connection of a device with an
incorporated battery and a charger, wherein said circuit comprises
a transistor with a base thereof connected to a terminal for
recognizing connection with the device and with an emitter thereof
connected to a power source of the charger, and mutual connection
is judged by detecting whether a collector of the transistor is in
opened state or not. Said circuit comprises a transistor with a
base thereof connected to a terminal for recognizing connection
with the charger side, and with an emitter thereof grounded, and
mutual connection is judged depending upon whether the collector of
the transistor is in opened state or not. Further, there is
provided a switching circuit for controlling the switching of the
emitter of the transistor to grounded state or to opened state.
[0007] Still other objects and advantages of the invention will in
part be obvious and will in part be apparent from the
specification.
[0008] The invention accordingly comprises the features of
construction, combinations of elements, and arrangement of parts
which will be exemplified in the construction hereinafter set
forth, and the scope of the invention will be indicated in the
claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] FIG. 1 is a diagram of an embodiment of a mutual connection
judging circuit according to the present invention; and
[0010] FIG. 2 is a diagram for explaining a conventional example of
mutual connection judging circuit.
DESCRIPTION OF THE PREFERRED EMBODIMENT
[0011] Description will be given below on an embodiment of the
present invention referring to the drawings. FIG. 1 is a diagram
showing an embodiment of a mutual connection judging circuit
according to the present invention. In the figure, reference
numeral 1 denotes a charger, 2 a charging circuit, 3 a device, 4 a
battery, Q1 to Q3 each represents a transistor, R1 to R3 each
represents a resistance, and T1 and T2 each represents a
terminal.
[0012] In FIG. 1, the charger 1 comprises a charging circuit 2 and
a transistor Q1 for judging or recognizing mutual connection. The
device 3 is, for instance, a notebook-sized personal computer or
other type of portable electronic device with an incorporated
battery. It comprises a transistor Q2 for judging mutual
connection, and a transistor Q3 for control. The transistor Q1 is a
PNP transistor with its emitter connected to a power source of the
charger 1, its base connected to a terminal T1 for recognizing the
connection via a resistance R1 for protection, and its collector
connected to a charging circuit 2, or it is a p-channel FET. The
transistor Q2 is an NPN transistor with its emitter grounded, its
base connected to a terminal T2 for recognizing the connection via
a resistance R2 for protection, and its collector connected to a
control bias terminal, or it is an n-channel FET. The transistor Q3
is a control element for controlling the switching of the emitter
of the transistor Q2 to grounded state or opened state, and it is
an NPN transistor for grounding the emitter of the transistor Q2
via collector and emitter and with its base connected to the
collector side of the transistor Q2 via a resistance R3., or it is
an n-channel FET.
[0013] Next, description will be given on operation. When the
charger 1 is connected to the device 3, the terminals T1 and T2 for
recognizing the connection are connected with each other. The base
of the transistor Q1 connected to the terminal T1 for recognizing
the connection of the charger 1 is connected to the base of the
transistor Q2 connected to the terminal T2 for recognizing the
connection of the device 3 via the resistances R1 and R2 for
protection. Therefore, when a predetermined bias voltage is applied
on the control bias terminal of the device 3, the transistor Q3 is
turned on. Thus, both the transistor Q1 and the transistor Q2 are
turned on. At the charger 1, the collector of the transistor Q1 is
on the level of the power source. The changes in collector signal
level of the transistor Q1 is detected, and charging is started by
the charging circuit 2.
[0014] On the other hand, at the device 3, the transistor Q2 is
turned on, and the start of the charging is recognized by detecting
the change in collector signal level of the transistor Q2. Then,
the operation of the device 3 is stopped or restricted. As
described above, when the operation of the device 3 is stopped or
restricted, it can be regarded at the charger 1 as the same
condition as in the case where charging is performed only to the
battery 4. Thus, it is possible to increase the detection accuracy
of full charging. When the battery 4 is not connected, or when it
is not desired to start the charging such as the case where the
device 3 is executing the processing, which should not be
interrupted, the transistor Q3 is turned off by decreasing the bias
voltage applied on the control bias terminal, and the emitter of
the transistor Q2 is opened. As a result, it is possible to avoid
the recognition of the connection by the transistor Q1 and to
prohibit or terminate the charging.
[0015] It is needless to say that the present invention is not
limited to the above embodiment, and various changes and
modifications can be made. For instance, in the above embodiment,
the transistor Q3 for control is inserted and connected between the
emitter of the transistor Q2 on the device side and the earth,
while the emitter of the transistor Q2 may be directly grounded. In
such case, the connection of the charger 1 with the device 3 serves
as a judging signal by itself when the transistor Q1 is turned on
the charger side and the transistor Q2 is turned on the device
side.
[0016] As it is evident from the above description, the present
invention provides a mutual connection judging circuit for judging
mutual connection between the device with an incorporated battery
and a charger, and the circuit comprises a PNP transistor on the
charger side and an NPN transistor on the device side. The base of
the PNP transistor is connected to the base of the NPN transistor,
and mutual connection is judged by collector potential of the
transistors. The charger controls the charging by judging the
mutual connection depending upon whether the collector of the PNP
transistor is in open state or not. The device comprises a circuit
for controlling emitter potential of the NPN transistor and turns
on or off the NPN transistor by controlling the emitter potential
depending on whether the charging is in enable state or not. The
charger starts the charging by judging collector potential of the
PNP transistor. In this connection, the mutual connection can be
confirmed by a single signal line, and connection signal can be
controlled from the device. Therefore, operation is stopped or
operation is restricted by recognizing the mutual connection on the
device side, and it is possible to avoid unpredictable influence on
the operation of the charger.
* * * * *