| 摘要 |
PURPOSE:To obtain a drive circuit in which a sole power source is operated and the number of power transistors is reduced by connecting the coils of a 2-phase brushless motor to two sets of bridge circuits which are energized in phase difference of 90 deg., and driving the motor in full wave. CONSTITUTION:Power transistors 28, 29 are driven by a small signal transistor 32, and power transistors 30, 31 are driven by a small signal transistor 33 which inputs a signal through a rectifier 20 from rotary position detectors 18, 19. When the output 24 of a switching signal generator 23 is L level, a current flows in a direction from a point C to a point B in armature coils 16 (16a, 16b), and when the output 25 is L level, a current flows in a direction form the point B to the point C. Similarly, the transistors 30, 34 are driven by a small signal transistor 36, and power transistors 35, 29 are driven by a small signal transistor 37. When the output 26 of the generator 26 is L level, a current flows in a direction from a point D to the point C in armature coils 17 (17a, 17b), and when the output 27 is L level, a current flows in a direction from the point C to the point D. |
