Low voltage brushless DC motor drive circuit

Circuit working principle: The structure of the motor is shown in Figure C. The rotor is
a permanent magnet with the same pair of radial magnetic poles; the three sets of coils are wound at 120 degrees. The stator core is distributed
on the stator core; the light-emitting diodes and photosensitive tubes are distributed on both sides of the light-blocking ring. The light-blocking ring
cooperates with the components of the circuit in Figure a to complete the current commutation task of the stator winding. Its function
is equivalent to the mechanical commutator of an ordinary DC motor. Assume that the rotor is initially in
the position shown in Figure e, then when the circuit is energized, T. , the internal resistance to light becomes smaller, T. And the gate
potential of Ta3 increases, causing L to cut off and T. When it is turned on, the potential of point A drops to close to the ground potential; while Tb1 and Tc1. Neither of them are exposed to light, so the potentials of point S and point C are close to the potential of the positive electrode of the power supply . The three points A, y, and C are connected to the three ends of the stator winding La, Lb, and Lc respectively . The other end of the stator winding is connected together as point 0, as shown in Figure b. At this time, the current flows from both ends B and C. End A, so L. The stator magnetic pole corresponding to the winding is N pole, the other two poles are S pole, and the rotor rotates 120 degrees clockwise. . The rotor completes 120 turns. Finally, Tb1 receives light. In the same way, the rotor will rotate 120 degrees clockwise. . As this process continues , the motor can continue to run clockwise.