Daniel D Koch

US Patent:

51091623, Apr 28, 1992

Filed:

May 9, 1990

Appl. No.:

7/521214

Inventors:

Daniel S. Koch - Tremont IL
William H. Lueckenbach - Peoria IL
Daniel C. Wood - East Peoria IL

Assignee:

Caterpillar Inc. - Peoria IL

International Classification:

H02H 318

US Classification:

307127

Abstract:

The subject invention provides a coil driver circuit having protection against a reverse-polarity battery connection and is suitable for use in such control modules. The driver circuit controllably actuates N coils in response to control signals supplied by the control module. The driver circuit includes N control switches, each coupled in series between a first terminal of an associated one of the coils and a first common junction. The first common junction is normally connected to a positive reference terminal of the electrical power source. The control switches are adapted to controllably connect the coil first terminals to the power source positive reference terminal in response to externally supplied control signal. The coils have second terminals connected at a second common junction, and the second common junction is normally connected to a negative reference terminal of said power source. N flyback diodes, each having a cathode connected to a respective coil first terminal and an anode connected to a third common junction.