US 6,555,980 B2Granted

Wiper control apparatus

AssigneeYazaki Corporation

InventorHiroo Yabe

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Abstract

A wiper control apparatus includes a combination switch 2, a wiper motor 7, an autostop (AS) switch 8, a first semiconductor switch element 4 for on/off controlling energization of the wiper motor, a second semiconductor switch element 5 for turning on a closed circuit which passes a reverse current through the wiper motor 7 while the energization for the wiper motor 7 is off, a controller for ON/OFF controlling the first and the second semiconductor switch element, a current detecting resistor RS1 for current flowing through the second semiconductor switch 5, and a current limiting circuit A for limiting the current flowing the second semiconductor switch element 5 when the current detected by the current detecting means RS1 exceeds a prescribed threshold value. In this configuration, a wiper control apparatus can be provided which can solve the problem when the abnormality of short-circuiting downstream of the wiper motor occurs, is compact, reliable and surely operable using semiconductor switches and a digital-controlled controller.

Claims5

Dependent claims

A wiper control apparatus comprising:

a combination switch for setting an operation mode of a wiper;
a wiper motor which is driven according to the operation mode set by said combination switch;
an autostop (AS) switch for producing a signal having a level varying according to a park position and other positions as the wiper motor rotates;
a first semiconductor switch element for controlling the on/off energization of the wiper motor;
a second semiconductor switch element for turning on a closed circuit for braking said wiper motor which passes a reverse current through said wiper motor while energization for said wiper motor is off;
a controller for supplying a first ON/OFF control signal to the first semiconductor switch element and a second ON/OFF control signal to said second semiconductor switch element;
an overheating interruption/protection circuit for interrupting/protecting said second semiconductor element when it is overheated;
an overheating-interruption detecting means for detecting an overheating interruption/protection operation of said overheating interruption/protection circuit;
and
an overheating-interruption detecting/latching circuit for interrupting said second control signal when the number of times of overheating interruption in said overheating interruption/protection circuit reaches a prescribed number of times according to a detected signal from the said overheating interruption detecting means.

7 more elements

Dependencies are inferred from the claim text.