| 摘要 |
PURPOSE:To provide a brushless motor drive circuit in which spike noise is suppressed and the motor is driven stably, by a constitution wherein the control signal for a semiconductor switching circuit is varied slowly before and after function of the semiconductor switching circuit for providing the motor coil with a driving power supply. and the control signal is varied rapidly at other times. CONSTITUTION:A FET 2 is applied with a servo voltage Vs on the drain thereof to ground the source thereof through a motor coil Ln and the FET 2 controls the voltage VM to be applied onto the motor coil LM according to a gate voltage V1 thus feeding a predetermined driving current. Transistors 4, 6 have same characteristics as the transistor 2 wherein the gate-drain are connected in series and applied with a predetermined gate voltage V through 8 resistor 8 thus forming voltage references VREF1, VREF2 by the use of gate-source voltage. The circuitry is constituted such that the gate voltage V1 varies slowly before and after switching of the transistor 2 and the gate voltage V1 varies rapidly at other times with reference to the voltages VREF1, VREF2. |
