MOTOR DRIVING CONTROL CIRCUIT OF ELECTRIC POWER STEERING SYSTEM FOR ARM SHORT PREVENTION CAPABLE OF AVOIDING DAMAGES OF FET AND ECU

摘要

PURPOSE: A motor driving control circuit is provided to prevent damages of FET and ECU by preventing an arm short phenomenon caused due to erroneous operations of main control unit and motor driver IC. CONSTITUTION: A motor driving control circuit comprises a first arm short prevention unit(11) and a second arm short prevention unit(12). The first arm short prevention unit includes a first Zener diode(ZD1) connected in a reverse direction to the gate terminal of a first FET(Q1) in an H-bridge circuit such that the first Zener diode turns on when the high signal having a voltage higher than a predetermined voltage is input; and a first transistor(TR1) having a base terminal connected to the first Zener diode, and a collector terminal connected to the gate terminal of a third FET(Q3) such that the first transistor turns on by the base current which is input when the first Zener diode is turned on. The second arm short prevention unit includes a second Zener diode(ZD2) connected in a reverse direction to the gate terminal of a second FET(Q2) in the H-bridge circuit such that the second Zener diode turns on when the high signal having a voltage higher than a predetermined voltage is input; and a second transistor(TR2) having a base terminal connected to the second Zener diode, and a collector terminal connected to the gate terminal of a fourth FET(Q4) such that the second transistor turns on by the base current which is input when the second Zener diode is turned on.