Accelerated switching input circuit

Claim 1

Switching input circuit comprising: a stage of the emitter coupled logic (ECL) type having first and second transistors, the first transistor receiving at its base an input signal and the second transistor receiving at its base a control signal which is generated by a control circuit responsive to a signal from a collector of the first transistor, in order to obtain at a collector of the second transistor an output signal switching faster than the input signal, wherein the control circuit comprises a third transistor whose collector is connected to a voltage supply source and whose base is connected to the collector of the first transistor, a first resistor, a second resistor and a third resistor connected in series between an emitter of the third transistor and a reference point to which is connected a reference voltage source and a first reference current source, means connecting a point common to the first resistor and the second resistor to a second reference current source, and a point common to the second resistor and the third resistor supplying said control signal and being connected to the base of the second transistor.