| 摘要 |
PURPOSE:To prevent fluctuation of torque due to influence of other phase even under chopper control and to prevent lowering of torque margin by providing current routes individually for coils, which are subjected to overlapped driving, and providing respective current routes with current detecting resistors. CONSTITUTION:An exciting signal is fed to an exciting signal transmission circuit 4 in order to drive MOSFETs 3a-3d thus feeding coils 1a-1d with driving currents. A current chopper circuit 5 detects phase A and phase B driving currents IA, IB through current detecting circuits 50, 51 and the driving currents IA, IB are then compared with the reference voltage (reference current) of a reference voltage supply 56 through comparators 52, 53. When the driving current reaches the reference current, OFF commands are fed to current chopper control circuits 57, 58 in order to turn the chopper signal OFF for a predetermined time. Since the chopper signal is fed to the exciting signal transmission circuit 4 in order to modulate the exciting signal thus driving the MOSFETs 3a-3d, the phase A and phase B driving currents are subjected to chopper control. |
