| 摘要 |
PURPOSE:To provide a general purpose brushless motor drive circuit at low cost by integrating systems employing two and three Hall elements, respectively, and selecting one of the systems through switching according to the application. CONSTITUTION:A selection is made between two and three Hall elements through a switch 16. When three Hall elements are selected, the Hall elements Hu1, Hv2, Hw14 detect the polarity of a field magnet and produce an output signal waveform corresponding to an operation timing chart. Consequently, upper stage transistors Q1, Q3, Q5 and lower stage transistors Q2, Q4, Q6 are conducted continuously to rotate a motor. When two Hall elements are employed and the Hall element Hw is not connected, the Hall elements Hu1, Hv2 produce an A3 output signal, which lags by 4/3pi behind the Hall signal waveform of phase U, through amplifiers A1, A2 and an inverted amplifier A3. |
