Circuit for controlling a transistor static switch for d.c. loads with high turn-on current

Claim 1

A switch and control circuit for a D. C. load requiring a turn-on current of a first magnitude and an operating current of a second lower magnitude, said switch arranged in series between said load and a supply voltage source and comprising a first output transistor of a first conductivity type and a second driver transistor of said first conductivity type, said transistors arranged in a Darlington configuration; said circuit comprising first and second current generators respectively connected to the bases of said first and second transistors and further comprising a switching means operatively respectively connected between said first and second current generators and said first and second transistor bases for simultaneously interrupting the flow of current from said current generators to their respective transistor bases; said circuit still further comprising a unidirectional current flow means, arranged between the base and collector of said second transistor, said current flow means oriented so that current supplied by said second current generator may be shunted away from the base of said second transistor and wherein said current flow means is an open circuit to current flow when said second transistor is in its active region.