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US 4,542,399 AGranted
Feed forward Darlington circuit
AssigneeNational Semiconductor Corporation
InventorDennis M. Monticelli
Life of this patent
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Abstract
A Darlington output stage is shown in which the saturation voltage is substantially reduced by the incorporation of a complementary transistor. An IC form of the circuit is shown in detail.
Claims9
A Darlington transistor circuit stage having a pair of like conductivity bipolar transistors coupled together as output and driver devices with their collectors commonly connected, means coupling the emitter of said driver transistor to the base of said output transistor and means coupling the base of said driver transistor to an input terminal, said circuit comprising:
- a transistor, of complementary construction to that of said driver transistor, having a base coupled to said commonly connected collectors, a collector coupled to said emitter of said driver transistor and an emitter coupled to said base of said driver transistor.
An integrated circuit comprising:
- a substrate semiconductor wafer having a first surface and of a first conductivity type;
- a first region of the opposite conductivity type extending from said surface into said semiconductor to create an output transistor base;
- a second region of said opposite conductivity type closely adjacent to and separate from said first region and extending from said surface into said semiconductor to create a driver transistor base;
- a third region of said first conductivity type extending within the confines of said first region and part way therethrough to create an output transistor emitter;
- a fourth region of said first conductivity type extending within the confines of said second region and part way therethrough to create a driver transistor emitter;
- and
- means for coupling said output and driver transistor into a Darlington pair configuration whereby the relationship between said first and second regions produces a merged lateral transistor that is complementary to said output and driver transistors and said lateral transistor acts to drive said output transistor into saturation thereby lowering the voltage drop across said Darlington pair in saturation.
4 more elements
Dependencies are inferred from the claim text.