DRIVE CIRCUIT FOR MAGNETIC IMPEDANCE EFFECT ELEMENT

PROBLEM TO BE SOLVED: To accurately detect pulse voltage of MI elements by using sample- hold circuits or peak-hold circuits as detection circuits. SOLUTION: First and second sample-hold circuits 8, 9 sample and hold, with fixed timing, peak voltage across first and second linear magnetic bodies 1, 2, respectively. Output signals from the two sample-hold circuits 8, 9 are inputted into and differentially amplified by an operational amplifier 10. The hold timing of the sample-hold circuits 8, 9 is given by rear edges of pulses of an element drive circuit 6. By thus providing the first sample-hold circuit 8 and the second sample-hold circuit 9 instead of smoothing parts used in the past, peak values of waveforms can be accurately held according to a clock signal inputted thereinto. Because pulse voltages of MI elements are held, detection errors are reduced and the reliability is enhanced.