| 摘要 |
PURPOSE:To prevent counter torque from being generated and improve the efficiency of a motor, by generating a non-electrical-conduction section with a binary level comparator. CONSTITUTION:A motor driving circuit is composed of a phase-detecting Hall element HS, an operational amplifier OP, a comparator CP, an inverter N, an AND gate AD, a NOR gate NR, a transistor T, and a switch Sw, and the output of voltage in proportion to the strength of the magnetic field of bias current flowing to the Hall element HS is generated. The voltage is compared with previously set upper and lower reference values (binary level), and upper and lower side output amounts are separated from each other. When the detected output is set to come between the upper side reference value and the lower side reference value, then electrical conduction to the coils L0, L1 of a motor is stopped by an electrical conduction stopping means. Then, by setting a non-electrical-conduction voltage section between the reference voltage section, counter torque can be prevented from being generated. |
