| 摘要 |
PURPOSE:To protect a transistor against the damage and a pulse motor against burnout at an erroneous operation time by constructing the drive circuit of the motor with a leading edge differentiator. CONSTITUTION:A leading edge differentiator 4 is provided in a drive circuit of a transistor Q2 which supplies a high voltage V2 to a pulse motor. Thus, when a microprocessor Z1 erroneously operates and an output signal A becomes a high level, the differentiator 4 drops toward a low level at the time constant C1.R13. Accordingly, even if the output signal A remains high level, the output signal A' of the differentiator 4 drops toward the low level. Thus, a current I1 flowed to the motor temporarily flow in a large amount, but the current then drops. Therefore, it can protect the drive circuit against damage or the motor against burnout. |
