PURPOSE: To always generate a pulse with constant width and with fast responsiveness even for the fluctuation of a source voltage or temperature change by operating all of the elements of an emitter follower, a constant current circuit, and a current mode logic circuit in an unsaturated current area.
CONSTITUTION: When the comparators of transistors TrQ14 and Q15 perform switching operations, the change of the collector voltage of the TrQ14 at the time of changing the voltage Va with a change rate (α) can be expressed as {Va(1+α)-VBE(Q20)}.R9/(R15+R16). Meanwhile, when a circuit consisting of a diode-connected TRQ21 and a variable resistor VR is remarked and it is assumed that the intermediate terminal part of the variable resistor VR is set at resistance values RV2 and RV1, the base voltage of a TrQ6 goes to {Va(1+α)-VBE(Q21)}.RV2/RV1+RV2). Here, assuming VBE(Q20)=VBE(Q21) =VBE, the collector voltage of the TrQ14, that is, the base voltage of a TrQ12 and that of the TrQ6 are set at an irrelevant state since the fluctuation of the power source and the temperature change of the VBE of the TR can be negated with each other.
IWATA NAOMICHI
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