Controller for electrical power steering apparatus

A controller for a power steering apparatus comprising:

• a motor supplying a steering assist force to said power steering apparatus for a vehicle;
• a motor driving member outputting a driving power to said motor;
• a battery supplying power voltage to said motor driving member;
• an ignition switch turning on or off said battery;
• a switching member mounted in a conducting path from said battery to said motor driving member;
• and
• a condenser mounted at an input side of said motor driving member;
• said switching member has two switching elements to turn on or off said conducting path by turning on or off according to a driving signal being input into a gate, and parasitic diodes mounted in parallel between a drain and a source of said switching elements, said switching elements are connected in series at the opposite direction respectively on said conducting path and are connected to said ignition switch;
• a voltage detecting member detecting output voltage from each of said switching elements;
• and
• a fault judging member judging faults of each of said switching elements and said parasitic diodes in accordance with each of said output voltages detected by said voltage detecting member.