Apparatus and method for a wide-band direct-coupled transistor amplifier
First Claim
1. A wide-band direct-coupled transistor amplifier circuit having a feedback network, said amplifier circuit comprising:
- an input means receiving an input signal and providing intermediate signals, said input means including;
a first pair of complementary transistors having base terminals thereof coupled together, said coupled first transistor pair base terminals having said input signal applied thereto, anda second pair of complementary transistors having emitter terminals thereof coupled together, each base terminal of said second pair of transistors coupled to an emitter terminal of an associated one of said first pair of transistors;
an output means for providing an output signal, said output means including a third pair of complementary transistors having collector terminals thereof coupled together, said coupled third transistor pair collector terminals providing said output signal, wherein a base terminal of each of said third transistor pair is coupled to a collector terminal of an associated one of said second transistor pair; and
a feedback means including;
transistor means coupled between said second transistor pair base terminals,first series transistor means coupled to an emitter terminal of a first transistor of said third transistor pair and responsive to current through said first transistor of said third transistor pair,second series transistor means coupled to an emitter terminal of a second transistor of said third transistor pair and responsive to current through said second transistor of said third transistor pair,a biasing transistor,constant current source coupled to a collector terminal of said biasing transistor, wherein said biasing transistor collector terminal is coupled to a control terminal of said transistor means, a base terminal of said biasing transistor being coupled to said first and said second series transistor means, wherein a change in current through said third transistor pair causes a change in voltage of said biasing transistor collector terminal.
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Accused Products
Abstract
In a wide-band direct-coupled transistor amplifier, the current through the power output stage must be stabilized to prevent fluctuations in the amplifier output signal. To stabilize the output stage current, a negative feedback loop is established providing a bias control for the amplifier input stage. In the past, voltage feedback apparatus, typically including operational amplifiers, has been utilized. In the present invention, a current feedback path, which avoids the voltage level translation inherent in the prior art, is used to provide the feedback bias control for the input stage of the amplifier. A technique for the compensation of temperature drift and for voltage offset is described.
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Citations
19 Claims
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1. A wide-band direct-coupled transistor amplifier circuit having a feedback network, said amplifier circuit comprising:
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an input means receiving an input signal and providing intermediate signals, said input means including; a first pair of complementary transistors having base terminals thereof coupled together, said coupled first transistor pair base terminals having said input signal applied thereto, and a second pair of complementary transistors having emitter terminals thereof coupled together, each base terminal of said second pair of transistors coupled to an emitter terminal of an associated one of said first pair of transistors; an output means for providing an output signal, said output means including a third pair of complementary transistors having collector terminals thereof coupled together, said coupled third transistor pair collector terminals providing said output signal, wherein a base terminal of each of said third transistor pair is coupled to a collector terminal of an associated one of said second transistor pair; and a feedback means including; transistor means coupled between said second transistor pair base terminals, first series transistor means coupled to an emitter terminal of a first transistor of said third transistor pair and responsive to current through said first transistor of said third transistor pair, second series transistor means coupled to an emitter terminal of a second transistor of said third transistor pair and responsive to current through said second transistor of said third transistor pair, a biasing transistor, constant current source coupled to a collector terminal of said biasing transistor, wherein said biasing transistor collector terminal is coupled to a control terminal of said transistor means, a base terminal of said biasing transistor being coupled to said first and said second series transistor means, wherein a change in current through said third transistor pair causes a change in voltage of said biasing transistor collector terminal. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A feedback transistor amplifier circuit comprising:
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an input stage including a first and a second complementary transistor, said first and said second complementary transistors having base terminals thereof coupled together for receiving an input signal; an intermediate stage including a third and a fourth complementary transistor, said third and said fourth complementary transistors having emitter terminals thereof coupled together, wherein an emitter terminal of said first transistor is coupled to a base terminal of said third transistor and an emitter terminal of said second transistor is coupled to a base terminal of said fourth transistor; an output stage including a fifth and a sixth complementary transistor, said fifth and said sixth transistors having collector terminals thereof coupled together, wherein a collector terminal of said third transistor is coupled to a base terminal of said fifth transistor and wherein a collector terminal of said fourth transistor is coupled to a base terminal of said sixth transistor; first feedback means coupled to collector terminals of said fifth and sixth transistors for applying a signal to emitter terminals of said third and fourth transistors; first current source means coupled to said emitter terminal of said first transistor; second current source means coupled to said emitter terminal of said second transistor; feedback transistor means coupled between said third and said fourth transistor base terminals; and second feedback means for monitoring current through said fifth and said sixth transistors, wherein an output signal from said second feedback means is coupled to a control terminal of said feedback transistor means; wherein said first and said second current source means each include means for compensating for at least a one of voltage offset and temperature drift parameters. - View Dependent Claims (11)
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12. A feedback transistor amplifier circuit comprising:
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an input stage including a first and a second complementary transistor, said first and said second complementary transistors having base terminals thereof coupled together for receiving an input signal; an intermediate stage including a third and a fourth complementary transistor, said third and said fourth complementary transistors having emitter terminals thereof coupled together, wherein an emitter terminal of said first transistor is coupled to a base terminal of said third transistor and an emitter terminal of said second transistor is coupled to a base terminal of said fourth transistor; an output stage including a fifth and a sixth complementary transistor, said fifth and said sixth transistors having collector terminals thereof coupled together, wherein a collector terminal of said third transistor is coupled to a base terminal of said fifth transistor and wherein a collector terminal of said fourth transistor is coupled to a base terminal of said sixth transistor; first feedback means coupled to collector terminals of said fifth and sixth transistors for applying a signal to emitter terminals of said third and fourth transistors; first current source means coupled to said emitter terminal of said first transistor; second current source means coupled to said emitter terminal of said second transistor; feedback transistor means coupled between said third and said fourth transistor base terminals; and second feedback means for monitoring current through said fifth and said sixth transistors, wherein an output signal from said second feedback means is coupled to a control terminal of said feedback transistor means;
wherein said second feedback means includes;a current source; and a control transistor having a collector terminal coupled to said current source, said current source providing a high impedance load for said control transistor, said control transistor collector terminal being coupled to said control terminal of said feedback transistor means. - View Dependent Claims (13, 14, 15, 16, 17, 18, 19)
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Specification