| 摘要 |
PURPOSE:To prevent the saturation of an output transistor (TR) by connecting a diode between a constant current path of a level shift stage and collectors of a phase inverting TR and the output stage TR. CONSTITUTION:In a conversion circuit comprising an ECL input stage CS, a level shift stage LS, and an output stage OP, the diode D1 is connected between a collector of the phase inverting TRQ6' and a node n4 of a constant current path where TRs Q12', Q14' of the shift stage LS and a resistor R21' are connected in series. Thus, when the TRQ6' is turned on, the potential of a node ns is decreased by the collector resistor and the TRQ6' approaches the saturation, a current flows from the node n4 to the node ns through a diode D1. Then the potential of the node n4 is decreased, the base potential is decreased and the saturation of the TRQ6' is prevented. The collector of an output TRQ9 of the output stage OP is connected to the other constant current path via diodes D2, D3 to prevent the saturation. As a result, the delay in the output is avoided without using a Schottky type TR and the leading is made steep to prevent the occurrence of the oscillation. |
