Electrical transmission or interconnection systems – Vehicle mounted systems – Automobile
Reexamination Certificate
1997-06-04
2001-11-27
Paladini, Albert W. (Department: 2836)
Electrical transmission or interconnection systems
Vehicle mounted systems
Automobile
C307S089000, C307S091000, C180S167000, C315S085000, C361S159000
Reexamination Certificate
active
06323564
ABSTRACT:
BACKGROUND OF THE INVENTION
FIELD OF THE INVENTION
The present invention relates to a circuit configuration in a motor vehicle, having a semiconductor switch with a load section that is connected, on one hand, through a first supply line to a positive battery terminal and, on the other hand, through a second supply line to a load and a freewheeling diode, and a device for pulse-width modulation which controls the semiconductor switch.
Such a circuit configuration is basically used for pulse-width modulation in motors or valves. However, in motor vehicles such a configuration is only reluctantly used, and in the case of switched currents in the region of 20 A, no use is made of such circuits in the motor vehicle sector, because of the high risk of EMC (electromagnetic interference).
SUMMARY OF THE INVENTION
It is accordingly an object of the invention to provide a circuit configuration with reduced EMC, which overcomes the hereinbefore mentioned disadvantages of the heretofore-known devices of this general type and which permits the use of such pulse-width modulation even with currents in the range of 20 A and more.
With the foregoing and other objects in view there is provided, in accordance with the invention, a circuit configuration in a motor vehicle having a battery with a positive battery terminal, comprising a semiconductor switch having a load section; a pulse-width modulation device controlling the semiconductor switch; a first supply line connected between the load section of the semiconductor switch and the positive battery terminal; a second supply line connected to the load section of the semiconductor switch; a load and a freewheeling diode connected to the second supply line and defining a portion of the second supply line between the semiconductor switch and the freewheeling diode and a remainder of the second supply line leading to the load; and the semiconductor switch and the freewheeling diode disposed as close as possible to the positive battery terminal, for shortening the first supply line and the portion of the second supply line relative to the remainder of the second supply.
The invention utilizes the fact that only a current with a relatively low ripple flows in the region of the supply lead between the freewheeling diode and the load. Since the current is important for the EMI, the invention therefore proposes to mount the semiconductor switch and the freewheeling diode as close as possible to the battery.
In accordance with another feature of the invention, the semiconductor switch and the freewheeling diode are part of the battery terminal, thus ensuring the most optimum shortening of the supply lead to the semiconductor switch and the freewheeling diode.
In accordance with a concomitant feature of the invention, a plurality of semiconductor switches and freewheeling diodes are accommodated in a distributor box which is mounted as close as possible to the battery or at or on the battery.
Other features which are considered as characteristic for the invention are set forth in the appended claims.
Although the invention is illustrated and described herein as embodied in a circuit configuration with reduced EMI, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.
The construction and method of operation of the invention, however, together with additional objects and advantages thereof will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.
REFERENCES:
patent: 4730243 (1988-03-01), Glennon
patent: 5148358 (1992-09-01), Estes, Jr.
patent: 5661390 (1997-08-01), Lipo et al.
patent: 5757628 (1998-05-01), Kamata
patent: 5789723 (1998-08-01), Hirst
patent: 34 20 535 C2 (1985-12-01), None
patent: 89/01260 (1989-02-01), None
Greenberg Laurence A.
Lerner Herbert L.
Paladini Albert W.
Siemens Aktiengesellschaft
Stemer Werner H.
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