Patent ID: 6233396
Filing Date: 2001-05-15
Classification: H02H

Abstract:
A load control system for a driving unit, comprising:a driving circuit for electrically controlling said driving unit, said driving circuit being directly connected to an electrical power source;a control circuit for generating a control signal for said driving unit;a signal input line through which the control signal from said control circuit is input to said driving circuit; anda determining unit for determining a short-circuited state of said signal input line, wherein:said driving circuit stops operation of said driving unit based on an output signal from said determining unit when the determining unit determines that a short-circuited state of the signal input line exists;the control signal from said control circuit is a duty signal in which a duty ratio becomes 100% when said signal input line is short-circuited;said determining unit determines the short-circuited state of the signal input line when the duty ratio is increased to a value proximate to 100%;said driving circuit controls said driving unit in such a manner that load applied to said driving unit is increased as the duty ratio of the duty signal of said control circuit increase, until the duty ratio is increased to a predetermined value lower than 100%;said driving circuit stops operation of said driving unit when the duty ratio becomes more than the predetermined value; andsaid determining unit determines the short-circuited state of the signal input line when the duty ratio becomes more than the predetermined value.