Patent ID: 6069520
Filing Date: 2000-05-30
Classification: G05F

Abstract:
A load actuating circuit comprising:a switching means having a first terminal receiving a power source voltage, a second terminal connected to a ground via a load, and a control terminal connected to a control circuit;a resistor having one end connected to said first terminal of said switching means and the other end connected to a constant current circuit for causing a constant voltage drop;a comparator having one input terminal connected to said other end of said resistor and the other input terminal connected to said second terminal of said switching means for detecting an excessive current flowing across said load by comparing the constant voltage drop at said resistor with a momentary voltage drop between said first and second terminals of said switching means; andsaid constant current circuit comprising:a current mirror circuit including an input transistor and an output transistor;a buffer means for absorbing an electrical potential difference between said other end of said resistor and an output terminal of said output transistor; anda clamp means for fixing an electrical potential of said output terminal of said output transistor.