Miscellaneous active electrical nonlinear devices – circuits – and – Gating – Utilizing three or more electrode solid-state device
Reexamination Certificate
2002-01-30
2004-08-17
Nguyen, Minh (Department: 2816)
Miscellaneous active electrical nonlinear devices, circuits, and
Gating
Utilizing three or more electrode solid-state device
C327S109000, C327S387000, C323S265000
Reexamination Certificate
active
06778001
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a semiconductor circuit component which can be driven when an externally provided switch unit is turned on so that a power supply voltage is supplied to the semiconductor circuit component.
A mechanical relay has been heretofore mainly used for the ON/OFF control of a power supply voltage supplied to an on-vehicle electrical component. That is, as shown in
FIG. 6
, a mechanical relay
101
has a relay coil
102
, and relay contacts
103
. One terminal T
1
of the relay coil
102
is connected to a +B terminal of a battery power supply through a switch
104
while the other terminal T
2
of the relay coil
102
is grounded. A terminal T
3
of corresponding one of the relay contacts
103
is connected to the one terminal T
1
of the relay coil
102
while a terminal T
4
of the other of the relay contacts
103
is connected to one end of a load L
105
which has its other end grounded. In this relay circuit, when the power supply side switch
104
is turned on, the relay contacts
103
closed to drive the load
105
.
There is another case where, as shown in
FIG. 7
, the one terminal T
1
of the relay coil
102
is connected to the +B terminal of the battery power supply while the other terminal T
2
of the relay coil
102
is grounded through a switch
106
. Incidentally, the connection of the terminals T
3
and T
4
of the relay contacts
103
is the same as shown in FIG.
6
. In this relay circuit, when the ground side switch
106
is turned on, the relay contacts
103
are closed to drive the load
105
.
There is a further case where, as shown in
FIG. 8
, the one terminal T
1
of the relay coil
102
is connected to the +B terminal of the battery power supply through a switch
107
while the other terminal T
2
of the relay coil
102
is grounded through a switch
108
. Also in this case, the connection of the terminals T
3
and T
4
of the relay contacts
103
is the same as shown in FIG.
6
. In this relay circuit, when the power supply side switch
107
and the ground side switch
108
are turned on simultaneously, the relay contacts
103
are closed to drive the load
105
. Incidentally, any one of the relay circuits is formed by mounting the mechanical relay
101
on bus bar terminals of a bus bar circuit board received in an electric connection box.
On the other hand, a semiconductor circuit component
109
having a switching function superior to that of the mechanical relay in terms of reduction in size and cost, and increase in reliability has been developed as schematically shown in
FIG. 9
with the rapid advance of the semiconductor producing technique in recent years and has been used widely. The semiconductor circuit component
109
has an MOS-FET
110
, and a control signal supply circuit
111
including a charging pump circuit for supplying a control signal to a gate G of the MOS-FET
110
. A power input end
112
of the control signal supply circuit
111
and a drain D of the MOS-FET
110
are both connected to a first externally leading-out terminal T
11
, a ground end
113
of the control signal supply circuit
111
is connected to a second externally leading-out terminal T
12
, and a source S of the MOS-FET
110
is connected to a third externally leading-out terminal T
13
.
In the semiconductor circuit component
109
configured thus, a switching operation approximating that of the relay circuit shown in
FIG. 6
can be made when, for example, the first externally leading-out terminal T
11
is connected to the +B terminal of the battery power supply through a switch, the second externally leading-out terminal T
12
is grounded and the third externally leading-out terminal T
13
is connected to one end of a load having its other end grounded. Alternatively, a switching operation approximating that of the relay circuit shown in
FIG. 7
can be made when the first externally leading-out terminal T
11
is connected to the +B terminal of the battery power supply, the second externally leading-out terminal T
12
is grounded through a switch and the third externally leading-out terminal T
13
is connected to a load.
Alternatively, a switching operation approximating that of the relay circuit shown in
FIG. 8
can be made when the first externally leading-out terminal T
11
is connected to the +B terminal of the battery power supply through a switch, the second externally leading-out terminal T
12
is grounded through a switch and the third externally leading-out terminal T
13
is connected to a load. Accordingly, in any relay circuit, it may be considered that the semiconductor circuit component can be designed to take the place of the mechanical relay
101
directly without any substantial change of the circuit configuration of the bus bar circuit board.
In each of the switches
104
,
105
,
106
,
107
and
108
externally provided as shown
FIGS. 6
,
7
or
8
, leakage resistance, for example, of about 10 K&OHgr; may be generated between contacts due to dew drops. In the case where the mechanical relay
101
is used as shown in each of
FIGS. 6
,
7
and
8
, the mechanical relay
101
never operates with such a small value of leakage resistance because the current flowing in the relay coil
102
is too small. In the case of a circuit using the semiconductor circuit component
109
, however, the circuit impedance generated between the first and second externally leading-out terminals T
11
and T
12
is considerably higher than the leakage resistance generated between the contacts of the switch. Accordingly, if leakage resistance is generated between the contacts of the switch connected to the first or second externally leading-out terminal T
11
or T
12
side due to dew drops, electrical conduction may be made substantially between the contacts of the switch as if the switch were turned on. As a result, there is a risk that the semiconductor circuit component
109
operates to allow the load
105
to malfunction. Hence, there was a problem that the semiconductor circuit component was difficult to take the place of the mechanical relay directly in the ON-OFF control circuit of the on-vehicle electrical component.
SUMMARY OF THE INVENTION
The invention is devised upon such circumstances and an object of the invention is to provide a semiconductor circuit component in which the operation of a load can be switched in response to the ON/OFF operation of a switch unit externally provided in the same manner as in the prior-art mechanical relay and in which the malfunction of the load caused by leakage resistance of the switch unit can be avoided.
(1) To achieve the foregoing object, in accordance with the invention, there is provided a semiconductor circuit component capable of being driven when an externally provided switch unit is turned on to thereby supply a power supply voltage to the semiconductor circuit component, the semiconductor circuit component having: a load-control semiconductor switching device with a control terminal; a control signal supply circuit for supplying a control signal to the control terminal of the load-control semiconductor switching device to thereby drive the load-control semiconductor switching device; and a drive control circuit for controlling drive in a manner so that, only when the switch unit is turned on, a power supply voltage is supplied from the drive control circuit to the control signal supply circuit to make the control signal supply circuit output the control signal.
In this configuration, only when the switch unit is turned on, the control signal supply circuit is driven to supply a control signal to the control terminal of the load-control semiconductor switching device to thereby make the load-control semiconductor switching device electrically conductive. For this reason, the control signal supply circuit is not driven even if leakage resistance is generated between contacts of the switch unit due to dew drops when the switch unit is not turned on. As a result, the load can be prevented from malfunctioning due to the exter
Ikeda Keizou
Mayama Syuji
Autonetworks Technologies Ltd.
Nguyen Minh
LandOfFree
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