| 摘要 |
PROBLEM TO BE SOLVED: To provide a control drive circuit for a constant-current chopper stepping motor, capable of suppress a current flowing through a stepping motor driver, using a positive temperature characteristic thermistor instead of a current detection resistance. SOLUTION: Tx1, Tx2 in Fig. are positive temperature characteristic thermistors, in which when a voltage value becomes higher than a prescribed voltage value, temperature rises and a resistance value increases at the same time. In this circuit, when an overcurrent flows into the Tx1 or Tx2, the resistance value increases, which suppresses the current flowing through itself. When an abnormal current flows due to a short circuit in the motor or a harness, or a breakdown of the stepping motor, the resistance value of the Tx1 or Tx2 increases up to almost infinity, so that the current value decreases to approximately zero, which prevents damages to the circuit and the motor, and smoke from them. Furthermore, a monitoring circuit monitors the voltages of the Tx1 and Tx2, thus detecting an abnormality of the control drive circuit for the constant current chopper stepping motor. COPYRIGHT: (C)2005,JPO&NCIPI |
