| 摘要 |
PURPOSE:To simplify a current detecting circuit and lower a cost, by switching the polarities of the current signals of respective arms based on the rotor position signal of a motor, and by detecting the respective phase current values of the motor. CONSTITUTION:By current detecting resistors 51, 52, 53, each current flowing to U, V, W-phases is detected as voltage signal, and the input of the current to the input terminals X, Y, Z of respective analog SW 71, 72, 73 is provided. The input of respective rotor position signals S, T, R to the respective control terminals A, B, C of the analog SW is provided. Then, the polarities of the current signals of respective arms are switched based on the rotor position signals S, T, R of a motor. By using inversion buffers 81, 82, a differential amplifier 84, and a buffer 83, and by taking the arithmetic sum of current signals, the respective phase current values of the motor are detected. |
