Electricity: electrical systems and devices – Control circuits for electromagnetic devices – For relays or solenoids
Reexamination Certificate
1999-07-27
2002-02-12
Ballato, Josie (Department: 2836)
Electricity: electrical systems and devices
Control circuits for electromagnetic devices
For relays or solenoids
C361S018000, C361S086000, C361S160000, C361S166000, C361S167000, C361S168100, C361S170000, C307S010600
Reexamination Certificate
active
06347030
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a battery supply control unit that controls a current supply from a battery to a load, and more particularly to a battery supply control unit capable of preventing electric discharge by a dark current from the battery.
BACKGROUND OF THE INVENTION
According to considerations of the inventor of the present invention, a vehicle such as an automobile includes a plurality of loads such as an engine electronic control unit, meter electronic control unit, automatic transmission electronic control unit, memory provided unit and the like. To drive such plural loads during driving of the vehicle, an electric power needs to be supplied and therefore, the vehicle is provided with a battery.
The battery supply control unit provided to the vehicle controls a supply of electric current from the battery to the plural loads.
FIG. 3
shows a structure of a circuit which is an example of a conventional battery supply control unit which has been analyzed by the present inventor.
Referring to
FIG. 3
, the battery supply control unit
114
a
controls a supply of electric power of a battery
111
applied via a fuse
113
to a plurality of loads
121
a
to
121
n
. The battery supply control unit
114
a
comprises a vehicle mounted relay
115
, a transistor
117
and a controller
119
. The vehicle mounted relay
115
has an electromagnetic coil
116
a
and a contact piece
116
b
. When the contact piece
116
b
is closed (ON), loads
121
a
to
121
n
are supplied with electric power from battery
111
.
With the above structure, when a vehicle is driving, ignition (IG) is turned ON or its engine is turned ON, so that ignition signal IGS (H level) is input to a controller
119
through a terminal B.
Next, the controller
119
turns ON the transistor
117
so that a current flows from the battery
111
to the transistor
117
through the electromagnetic coil
116
a
. Thus, causing the contact piece
116
b
to close, i.e., is turned ON. As a result, electric power from the battery
111
is supplied to the plurality of loads
121
a
to
121
n
so that a predetermined current of about several amperes (A) flows through these loads.
On the other hand, during non-driving conditions, ignition is turned OFF or the engine is turned OFF, so that the ignition signal IGS (L level) is input to the controller
119
. Then, the controller
119
outputs L level ignition signal IGS for a predetermined period of time interval. The predetermined period of time interval may, for example, be several days to about one month.
Because the transistor
117
is kept ON for a predetermined period of time interval, a dark current I of several tens mA flows from the battery
111
to the transistor
117
through the electromagnetic coil
116
a
. At the same time, because the contact piece
116
b
is ON for the predetermined period of time interval, electric power of the battery
111
is supplied to the plurality of the loads
121
a
to
121
n.
After the predetermined period of time interval elapses, the controller
119
turns OFF the transistor
117
so that no dark current flows from the battery
111
to the electromagnetic coil
116
a
. Thus, the contact piece
116
b
is opened (OFF) thereby interrupting the supply of the electric power from the battery
111
to the plurality of the loads
121
a
to
121
n.
However, such a structure can not prevent a large discharge of the battery. Further, because the dark current may continue to flow, the discharge period of the battery
111
is also quickened.
FIG. 4
shows a circuit structure diagram of another example of a conventional battery supply control unit.
In
FIG. 4
, a battery supply control unit
114
b
comprises a keep relay
123
, a controller
125
, a reset transistor
126
and a set transistor
127
. The keep relay
123
has a 2-winding coil
124
a
and a contact piece
124
b
. The keep relay
123
allows an electric power to be supplied to the 2-winding coil
124
a
only when the contact piece
124
b
is turned from ON to OFF or from OFF to ON, and after this changeover, the OFF state or ON state is maintained. The reset transistor
126
is connected to an end of one winding coil of the 2-winding coil
124
a
and the set transistor
127
is connected to an end of the other winding coil.
With such a structure, if H level ignition signal is input to the controller
125
through the terminal B, the controller
125
turns ON the set transistor
127
so that a current flows from one end of one winding coil to the other end thereby the contact piece
124
b
being turned ON.
On the other hand, during non-driving, if the L level ignition signal is input to the controller
125
, the controller
125
turns ON the reset transistor
126
so that a current flows from the other end of the other winding coil to one end thereby the contact piece
124
b
being turned OFF.
Therefore, with such a structure, because a current flows to the 2-winding coil
124
a
only when contact piece
124
b
is turned from ON to OFF or from OFF to ON through the keep relay
123
, power consumption is reduced.
However, because keep relay
123
generally has a low holding force for closing the contact point, the contact piece
124
b
may accidentally be turned OFF because of vibration or the like during vehicle driving. Thus, there is a need for improvement in the connection reliability of conventional battery supply control units during vehicle driving. Further, in general, keep relays are often not suitable for large currents. Therefore, to make it match such a large current, a more expensive keep relay is often required.
REFERENCES:
patent: 4305004 (1981-12-01), Tanaka et al.
patent: 4600966 (1986-07-01), Mueller et al.
patent: 4707788 (1987-11-01), Tashiro et al.
patent: 5142162 (1992-08-01), Sunden et al.
patent: 5321309 (1994-06-01), Kolomyski
patent: 5473201 (1995-12-01), Gantenbein et al.
patent: 5633540 (1997-05-01), Moan
patent: 5856711 (1999-01-01), Kato et al.
patent: 5889645 (1999-03-01), Kadah et al.
patent: 5920186 (1999-07-01), Ninh et al.
Ballato Josie
Finnegan Henderson Farabow Garrett & Dunner L.L.P.
Marquis Vaughn J.
Yazaki -Corporation
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