DRIVE CIRCUIT OF DC BRUSHLESS FAN MOTOR

摘要

PROBLEM TO BE SOLVED: To provide a drive circuit of a low noise DC brushless fan motor in which generation of noise due to a steep discharge current is suppressed when a capacitor for absorbing a steep peak current and a peak current at the time of turning off conduction of a field coil or at the time of starting is provided. SOLUTION: In the drive circuit 41 of a DC brushless fan motor where a rotor (permanent magnet) is rotated by a rotating field being generated by turning conduction to a field coil on/off with a signal to the control terminal of switching elements T3 and T4 having switching parts connected in series with field coils L1 and L2, resistors R10 and R11 are connected between the field coils and the switching parts when capacitors C1 and C2 for absorbing peak current are connected in parallel with the switching parts of the switching elements T3 and T4 and the capacitors C1 and C2 are connected in parallel with the switching parts through the resistors. Current from the capacitor absorbing a peak current is discharged through the resistor when the switching element is turned on thus obtaining a peakless current.