Datasheet

INTRODUCTION

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2.4 Speed Adjust Potentiometer (R1)

The speed adjust potentiometer (Spd_Adj) can be found in Figure 8. The potentiometer adjusts the duty

cycle of the PWM signal which will in turn adjust the speed of the motor. In order to lower the duty cycle

and in turn lower the speed, turn the potentiometer counter-clockwise. In order to increase the duty cycle

and in turn increase the speed, turn the potentiometer clockwise.

Figure 8. Speed Adjust Potentiometer

The onboard PWM signal for the DRV10866 is generated by a circuit based upon the Texas Instruments

TLC555 low power timer. It is capable of an approximately 25-kHz output that can be adjusted from 5% to

95% duty cycle. This square output signal will switch from 0 V to VCC.

In order to provide an external PWM signal to the DRV10866, first remove the 0-Ω resistor (R6). Next,

connect the external PWM signal to the “PWM” surface mounted test point. For more information on the

PWM input required by the DRV10866 please refer to the datasheet.

DRV10866EVM User’s Guide SBVU020A–November 2012–Revised December 2012

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