| 摘要 |
PURPOSE: A brushless DC motor control circuit is provided to obtain electronic products small in size and light in weight by integrating DC power supply circuit with the motor driver circuit. CONSTITUTION: A brushless DC motor control circuit comprises a DC power supply circuit(100), and a motor driver circuit(200). The DC power supply circuit includes a power stabilizing unit(110) having a varistor(Z1) connected in parallel to an AC power input, and a film condenser(C1) connected to the AC power input; a current smoothing unit(120) having a bridge rectifying diode(BD) with an input connected to the AC power input, and a smoothing condenser(C3) connected in parallel to the output side of the bridge rectifying diode; an auxiliary power supply unit(130) having a film condenser(C2) connected to the varistor(Z1), rectifying diodes(D1,D2) connected in parallel with each other, and a resistance(R1) for applying the rectified power output from rectifying diodes to the motor driver circuit; and a voltage dividing unit(140) having resistances(R2,R3), a voltage dividing zener diode(ZD1) of which cathode side is connected to the resistance(R3) and a smoothing condenser(C4) connected in parallel to the zener diode. The motor driver circuit includes a magnetic pole sensor(300) for sensing the magnetic pole of a magnet(500) of a motor rotor(400); a protection resistance(R6) connected between the output side of the magnetic pole sensor and the gate of a field effect transistor(FET1); the field effect transistor(FET1) having a gate connected to the protection resistance, a drain connected to a coil(L1) and a source connected to the ground; a field effect transistor(FET2) having a gate connected to the output of the auxiliary power supply unit, a drain connected to a coil(L2) a source connected to the ground; a signal inverting transistor(DT1) having electrolytic condensers(C5,C6); a current limiting resistance(R4) connected to the input side of the magnetic pole sensor; a pull-up resistance(R5) connected between the output side of the magnetic pole sensor and the pull-up resistance; and a pull-up resistance(R7) of the signal inverting transistor.
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