JPS54134545A - Pulse generator circuit - Google Patents

Abstract

PURPOSE: To generate output pulses which has a high-speed rise characteristic and are obtained by adding a fixed pulse width to an input pulse width, by constant-current and constant-voltage driving.

CONSTITUTION: Though transistors Q₁ to Q₅ are turned off normally, Q₁ and Q₂ are turned on simultaneously when the trigger pulse of pulse width T₁ caused by noise, etc., is applied to input terminal 8. When Q₂ is turned on, Q₄ and Q₅ are turned on similarly. Then, when Q₅ is turned on, capacitor C₁ is charged because capacitor C₁ is connected to connection point 12 of resistances R₈ and R₉, and the potential of connection point 12 does not become zero immediately but lowers with a time constant, which is determined by resistances R₉ and R₂ and capacitor C₁, even if input pulses disappear, Consequently, the collector potential of Q₃ rises immediately through the path of Q₁ turning-on and Q₃ turning-on when input pulses are applied; and even if input pulses disappear, conduction is continued until the potential of connection point 12 becomes a value below threshold voltage VBE of Q₃, so that pulses of pulse width T₁+T₀ can be obtained at output terminal 9. Pulse width T₀ is determined by resistances R₉ and R₂ and capacitor C₁.

COPYRIGHT: (C)1979,JPO&Japio