| 摘要 |
Traditionally, controllers for brushless, sensorless direct current (DC) motors (in, for example, Hard Disk Drive applications) would use one of the phases of the DC motor to measure a back electromotive force (back-EMF) voltage. This measurement would generally cause a discontinuity in the current waveform for a motor operating at a generally constant rotational speed (i.e., at “run speed”), which would result in poor acoustic performance (i.e., audible hum). Here, however, an integrated circuit (IC) is provided that uses coil current and applied voltage measurements to substantially maintain a predetermined phase difference between the phase of the applied voltage and back-EMF voltage, eliminating the need for a back-EMF voltage measurement and improving the acoustic performance.
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