| 摘要 |
PURPOSE:To realize PWM drive of a load with an accuracy equivalent to that of current drive system using a simple circuit similar to that of a voltage drive system. CONSTITUTION:A load 16 is subjected to current drive by delivering a PWM pulse having duty ratio, corresponding to a current designation D from a control means 44, to a drive means 40 from a PWM means 60. At the time of calibration, a calibration means 70 delivers a reference current designation Dr corresponding to a reference current Ir in order to measure the driving current Is of the load 16. When the measured current Is does not match the reference load current Ir, the current designation W is regulated to determine a current designation Ds for matching the currents Ir and Is thus determining a correction coefficient K=Ds/Dr for the current designation. A correcting means 75 corrects a current designation D delivered from the control means 44 using the correction coefficient K determined by the calibration means 70 and delivers the corrected to the PWM means 60. |
