Motor control device

A motor control device comprising:

• an acquisition unit that acquires an analog signal indicating a rotational position of a motor;
• an AD conversion unit that AD-converts the analog signal to generate a digital value;
• a calculation unit that estimates a slope of a waveform of the analog signal by using a plurality of the digital values and obtains an intersection timing at which a straight line corresponding to the estimated slope intersects with a threshold;
• and
• a drive control unit that controls driving of the motor according to a rotation cycle obtained from a plurality of the intersection timings,
• wherein the AD conversion unit AD-converts the analog signal at a plurality of sampling timings at which levels of the analog signal are arranged across the threshold to generate the plurality of digital values, and
• the calculation unit estimates the slope of the analog signal waveform by using the plurality of generated digital values,
• the calculation unit includes
• a holding unit that holds a first digital value received at a first sampling timing and a second digital value received at a second sampling timing,
• a determination unit that determines a magnitude relation between the first digital value and the threshold to generate a first determination result and determines a magnitude relation between the second digital value received at the second sampling timing and the threshold to generate a second determination result, and
• an estimation unit that estimates the slope of the analog signal waveform by using the first digital value and the second digital value according to the first determination result and the second determination result,
• the holding unit supplies the first digital value and the second digital value to the estimation unit in a case where the first determination result is different from the second determination result.