| 摘要 |
PURPOSE:To prevent the effect of a delay in rise of driving current based on a signal from rotor position-sensing elements at the time of a high-speed rotation by providing plural sets of said rotor position-sensing elements of brushless motor at a specified phase difference angle in the direction of rotation of a rotor. CONSTITUTION:An apparatus is provided with a first system of rotor position- sensing Hall elements 1-a, 1-b, 1-c and a second system of Hall elements 2-a, 2-b, 2-c with a fitting phase advancing more than said first system. One of binary signals of said second system is inputted as a rotation signal to a rotation detection circuit 6, and when the rotational speed of a motor reaches a specified speed, a switching signal is given to switch the output of a multiplexer 5 from the first system to the second system. The output of a decoder 7 is given by a suitable combination to the gate electrode of driving current- supplying transistors 8-u, 8-v 8-w and 9-u, 9-v, 9-w connected with three-phase exciting coils U, V, W to supply driving current successively. |
