| 摘要 |
PURPOSE:To obtain the direction detecting device of an automobile, etc., eliminates the need for troublesome arithmetic processing and is tolerant to a DC drift due to temperature characteristics, etc., of a circuit element by obtaining an AC detection signal without using any rotary mechanism. CONSTITUTION:This device is equipped with the 1st and the 2nd since wave generating circuits which generate 90 deg. out-of-phase signals, the 1st and the 2nd magnetic detecting elements 9 and 13 which generate signal proportional to the geometric product of a control current and magnetic flux density based upon an external magnetic field to a detection shaft, differential amplifiers 23 and 24 supplied with outputs of magnetic detecting elements, and a phase comparing means which compares phases of differential outputs of those differential amplifiers with the phases of the 1st and the 2nd sine wave signals. The detection axes of the 1st and the 2nd magnetic detecting elements are set crossing each other at right angles; and the 1st sine wave signal is supplied to the 1st magnetic detecting element as the control current and the 2nd sine wave signal which is 90 deg. out of phase with the 1st sine wave signal is supplied to the 2nd magnetic detecting element as a control current respectively. Then, the phase of the differential output between the magnetic detecting elements is compared with the phase of the 1st or the 2nd sine wave signal to detect the direction of the external magnetic field. |
