| 摘要 |
PURPOSE:To generate a prescribed width of unipolar pulse signal of a prescribed width by providing a transformer having a secondary winding whose center tap is connected to a reference voltage Vref, a series resistance and two comparators, comparing a non-inverting and an inverting signal or a divided inverting signal and a divided non-inverting signal and keeping an identification point at nearly the center of amplitude change. CONSTITUTION:A divided inverting signal 18 crosses at a point S0 with a noninverting signal 12 when the reference voltage Vref is normal. If the reference voltage Vref is in variation, the noninverting signal 12 is moved in parallel vertically by + or -Vref depending on the increase/increase. A DC bias voltage is changed and the inverting signal 18 is moved in parallel vertically because of the change in the reference voltage fed to resistors 31, 32. The moving direction of the inverting signal 18 is the same as the changing direction of the noninverting signal 12 and cross points S1, S2 after the movement are kept at enarly the middle of the amplitude of the noninverting signal. Thus, the identification point is made constant and it is avoided that the output signal from a comparator 4 is subject to pulse width change by the power voltage fluctuation, that is, the reference voltage change.
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