Electricity: electrical systems and devices – Safety and protection of systems and devices – With specific voltage responsive fault sensor
Reexamination Certificate
2002-05-31
2004-06-22
Toatley, Jr., Gregory J (Department: 2836)
Electricity: electrical systems and devices
Safety and protection of systems and devices
With specific voltage responsive fault sensor
Reexamination Certificate
active
06754058
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a current breaker circuit for cutting off a plurality of storage devices connected in series, and load circuits (voltage detection circuit) for the respective storage devices in accordance with a single external signal so that a leakage current can be prevented; to a voltage detection circuit for such storage devices; and an abnormality detection circuit.
In a circuit in which a plurality of storage devices are connected in series and loads are connected to the storage devices respectively, it has been heretofore necessary to prevent consumption of energy accumulated in the storage devices.
To this end, there have been related-art current breaker circuits as shown in
FIGS. 6 and 7
. Such current breaker circuits can disconnect all the loads in accordance with a single control signal when the storage devices and the loads are disconnected respectively.
The configurations and operations of the related-art circuits will be described below with reference to
FIGS. 6 and 7
.
FIG. 6
shows an example of a related-art current breaker circuit.
In
FIG. 6
, storage devices B
1
to B
4
are connected in series. In addition, loads R
1
to R
4
are connected to the storage devices B
1
to B
4
respectively.
In addition, semiconductor switching devices Q
1
to Q
4
are connected between the storage devices B
1
to B
4
and the loads R
1
to R
4
respectively.
The bases of the semiconductor switching devices Q
1
to Q
4
which are control terminals are connected in common through diodes d
1
to d
4
and resistors r
1
to r
4
so that an external signal switch S provided between the common connection terminal and the negative terminal of the storage device B
1
can be turned ON or OFF in accordance with an ON/OFF signal.
As for the operation of this current breaker circuit, when the external signal switch S provided between the common connection terminal of the resistors r
1
to r
4
and the negative terminal of the storage device B
1
is turned ON in accordance with the ON/OFF signal supplied to the switch S, all the semiconductor switching devices Q
1
to Q
4
are turned ON. Thus, currents are supplied from the storage devices B
1
to B
4
to the loads R
1
to R
4
corresponding and respectively.
On the contrary, when the external signal switch S is turned OFF, the semiconductor switching devices Q
1
to Q
4
are turned OFF so that no current is supplied to the loads R
1
to R
4
.
In this current breaker circuit, all the semiconductor switching devices Q
1
to Q
4
can be turned ON/OFF in accordance with a single ON/OFF signal. However, on the higher potential side (the storage device B
4
side in
FIG. 6
) of the storage devices connected in series, the voltage between the emitter of the semiconductor switching device and the negative terminal of the storage device B
1
increases. Thus, there is a problem that the power loss of the resistor increases and a high voltage switch has to be used as the external signal switch S.
FIG. 7
shows another example of a related-art current breaker circuit.
In
FIG. 7
, storage devices B
1
to B
4
are connected in series in the same manner as those in FIG.
6
.
In addition, loads R
1
to R
4
are connected to the storage devices B
1
to B
4
respectively.
In addition, photo-couplers (photo-relays) PH
1
to PH
4
are connected between the storage devices B
1
to B
4
and the loads R
1
to R
4
respectively.
All of light-emitting diodes of the photo-couplers PH
1
to PH
4
are connected in series, and designed so that a current is supplied between opposite terminals of each light-emitting diode in accordance with an ON/OFF signal given to the switch S.
As for the operation of this current breaker circuit, all the photo-couplers PH
1
to PH
4
are turned ON when a current is supplied to the light-emitting diodes connected in series. Thus, currents are supplied from the storage devices B
1
to B
4
to the loads R
1
to R
4
respectively.
On the contrary, when no current is supplied to the light-emitting diodes connected in series, all the photo-couplers PH
1
to PH
4
are turned OFF. Thus, no current is supplied to the loads R
1
to R
4
.
In this current breaker circuit, all the semiconductor switching devices Q
1
to Q
4
can be turned ON/OFF in accordance with a single ON/OFF signal. Accordingly, the problem of withstanding voltage as in the circuit of
FIG. 6
is solved. On the other hand, there is however a problem that a large number of expensive photo-couplers or the like have to be used.
SUMMARY OF THE INVENTION
In order to solve the defects in the related-art current breaker circuits, an object of the invention is to provide a current breaker circuit which can surely break currents supplied to a plurality of loads from a plurality of storage devices connected in series, in accordance with a single external control signal without using any high-voltage withstanding switch or any expensive photo-coupler; and to provide a voltage detection circuit for such storage devices.
In addition, another object of the invention is to provide an abnormality detection circuit for such a current breaker circuit.
To solve the foregoing problems, according to the invention, there is provided a current breaker circuit for turning off currents flowing in loads in accordance with a single external control signal, while the loads are connected between terminals of a plurality of storage devices connected in series respectively. The current breaker circuit includes semiconductor switching devices inserted between the storage devices and the loads respectively, a unit for supplying the external control signal to at least one of the semiconductor switching devices, and a control signal generating unit for generating an ON/OFF signal in response to an electric change based on turning ON/OFF of the semiconductor switching device supplied with the external control signal, the ON/OFF signal being supplied to other semiconductor switching devices.
Accordingly, currents supplied from the plurality of storage devices connected in series to the plurality of loads can be surely broken in accordance with a single external control signal without using any high-voltage withstanding switch or any expensive photo-coupler.
The loads in this configuration may be formed as pieces of a voltage detection circuit for storage devices. In this case, the current breaker circuit for storage devices has features in that:
(1) a plurality of storage devices are connected in series;
(2) a piece of the voltage detection circuit is connected for every unit cell of the plurality of storage devices;
(3) each piece of the voltage detection circuit is connected between a positive terminal and a negative terminal of a corresponding unit cell of the plurality of storage devices;
(4) a semiconductor switching device is inserted between the storage device and the voltage detection circuit;
(5) a control signal generator circuit for supplying a control signal to a control electrode of the semiconductor switching device inserted in series is connected to the control electrode of the semiconductor switching device; and
(6) the control signal generator circuit detects a voltage change on the voltage detection circuit side of the semiconductor switching devices connected to the storage devices other than the storage device to which the semiconductor switching device for supplying the control signal is connected, and the control signal generator circuit generates the control signal in accordance with the detection of the voltage change.
In addition, when the external control signal is supplied to at least two adjacent ones of the semiconductor switching devices simultaneously, the current breaker circuit for storage devices can be formed out of a smaller number of constituent members.
In addition, when the control signal generating unit supplies the ON/OFF signal to at least two adjacent ones of the semiconductor switching devices simultaneously, the number of the control signal generator circuits can be reduced.
In addition, when the semiconductor switc
Anzawa Seiichi
Inoue Chihiro
Matsui Fujio
Nishizawa Hiroshi
Kitov Zeev
Nagano Japan Radio Co. Ltd.
Osha & May L.L.P.
Toatley Jr. Gregory J
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