| 摘要 |
PURPOSE:To obtain a compact, light weight, digital rotation detector which can detect the rotary position highly accurately, by arranging four Hall effect elements so as to face a permanent magnet rotor in such a way that every two pieces are attached with a phase difference of pi/2 being provided respectively. CONSTITUTION:Hall elements 10a and 10b and 11a and 11b are arranged so as to face a permanent magnet rotor R with a phase difference of pi/2 being provided. Currents i1 and i2 are applied to current terminals 10ai and 10bi and 11ai and 11bi of the Hall elements. Then, voltages V1a and V1b and V2a and V2b, which are proportional to the product of a magnetic flux density and the current values, are generated at voltage terminals 10av and 10bv and 11av and 11bv. The voltages V1a and V2a are added in an adder 12. The voltages V1b and V2b are subtracted in a subtractor 13. Outputs Va and Vb are multiplied by the outputs of a cosine wave generator 14a and a sine wave generator 14b in multipliers 16a and 16b. The difference between their outputs Va' and Vb' is obtained by a control circuit 17. The output is counted by a counter 20 through a voltage controlled oscillator 18. Thus a rotary position signal is detected highly accurately through a latch circuit 19. |
