Lead angle value setting method, motor driving control circuit, and brushless motor

A method for setting a lead-angle value of a motor drive control circuit that drives a winding, with an energizing timing obtained based on a stored lead-angle value set in advance, of a brushless motor comprising a stator wound with the winding, and a rotor disposed rotatably and confronting the stator, the method comprising steps of:

• rotating the rotor at a predetermined rpm;
• energizing and driving the winding while switching the lead-angle value during the rotation at the rpm;
• calculating an average value of current amount that energizes the winding with a correlation established to each of lead-angle values being switched;
• calculating a total value of the average value corresponding to one of the lead-angle values and other average values before and after the average value, the total value being calculated for each of the lead-angle values;
• finding a smallest total amount among the total values;
• and
• setting a lead-angle value corresponding to the smallest total value as the stored lead-angle value applied to the rpm.