| 摘要 |
PURPOSE:To suppress noise and to prevent error by switching a second inner input terminal from connection with a first input terminal to connection with an inner terminal grounded through a predetermined resistor. CONSTITUTION:Switches 1, 2, an inverter 3 and a resistor 12 are additionally provided in order to switch a gate control signal between low potential side NMOS transistors 5, 7 constituting an H bridge circuit in correspondence to input terminals 51, 52 and an inner terminal 54. In other words, when a step motor is stopped, high level side NMOS transistors 4, 6 are turned OFF prior to turn OFF of all NMOS transistors 4-7 in the H bridge circuit thus sustaining ON state of the low level side NMOS transistors 5, 7 for several tens to several hundreds mus. According to the constitution, enegy stored in the motor is dissipated to a ground point and thereby noise is avoided. |
