| 摘要 |
<p>A speed control circuit (20) for use in a motor speed regulation loop for a washing machine or similar device comprises an output node (Vramp) for providing a control signal to be applied to the motor representative of the motor speed and acceleration, a clocked counter (22), a digital-to-analog (D/A) converter (24) coupled to the counter for providing a signal to the output node which is adjusted in steps in response to the count of the counter, step control means (28) coupled to the D/A converter for controlling the size of the steps in response to a step control signal applied to an input (slope-control) thereof whereby the step size determines the acceleration rate of the motor, and speed control means (26) coupled to the clocked counter and to the output node and having an input for receiving a speed control signal (Vdistri-start, Vdistri-end) having a value corresponding to a predetermined speed, the speed control means for detecting when the control signal at the output node is equal to the speed control signal, and in response thereto for resetting the clocked counter and for providing a signal representative of the predetermined speed to the output node which is combined thereat with the signal from the digital-to-analog converter. <IMAGE></p> |
