| 摘要 |
PURPOSE:To prevent a transistor from damaging due to an erroneous operation of a microcomputer by inputting an inverted signal of a driving signal to a driving circuit as an input signal together with an output signal of a monostable multivibrator through a NAND circuit. CONSTITUTION:Assume that a state of '0' level is continued due to an erroneous operation, etc., of a microcomputer in a pulse motor driving signal 101. In this case, one of the signal 101 is inverted to an inverted signal 103, and the other is input to a monostable multivibrator 4. The output signals 102, 103 of the multivibrator are passed through a NAND circuit 5. The signal 103 is reset after a predetermined period of time. The output signal 104 of the NAND circuit 5 is inputted to a driving circuit as an input signal. Thus, even if the signal 101 continuously becomes '0' level, the signal 102 is returned to a reset state ('0' level) after a predetermined period (Tw) of time is elapsed. Therefore, the transistor of the driving circuit is prevented. |
