Self-balancing push pull amplifier

Claim 2

A self-balancing push pull amplifier comprising a push pull stage including first and second transistors connected in push pull relationship, each of said transistors having an input electrode, an output electrode and a reference electrode, input means connected between the input electrodes of said first and second transistors for deriving first input signals for said first transistor and second input signals of opposite phase for said second transistor from signals input to said amplifier, output means connected between the output electrodes of said first and second transistors for combining first amplified signals provided by said first transistor and second amplified signals provided by said second transistor to provide output signals for said push pull stage, means for providing a fixed DC bias potential for the reference electrodes of said first and second transistors and an AC signal coupling network connected between the reference electrodes of said first and second transistors for coupling negative feedback signals from the reference electrode of one of said transistors to the reference electrode of the other one of said transistors whenever the amplitude of the amplified signals provided by said one transistor is greater than the amplitude of the amplified signals provided by said other transistor to thereby maintain the amplitude of said first amplified signals substantially the same as the amplitude of said second amplified signals.

Claim 3

A self-balancing push pull amplifier as set forth in claim 1 in which said input means includes a first transformer, a second transformer, and an input transformer for coupling said amplifier input signals to said first and second transformers, said input transformer having a winding with one end connected to a point of reference potential thrOugh a winding of said first transformer and another end connected to the point of reference potential through a winding of said second transformer whereby first input signals coupled to said first transformer are opposite in phase with second input signals coupled to said second transformer, and signal means connected between said first and second transformers and the input electrodes of said first and second transistors for extending the first input signals to said first transistor and the second input signals to said second transistor.

Claim 4

A self-balancing push pull amplifier as set forth in claim 2 in which said signal means includes a push pull input stage including third and fourth transistors connected in push pull relationship for amplifying said first and said second input signals to provide first and second amplified input signals, said third and fourth transistors each having an input electrode, an output electrode and a reference electrode, the input electrode of said third transistor being connected to said first transformer, the input electrode of said fourth transistor being connected to said second transformer, means for coupling said first amplified input signals to the input electrode of said first transistor, means for coupling said second amplified input signals to the input electrode of said second transistor, and a further AC signal coupling network connected between the reference electrodes of said third and said fourth transistors for coupling negative feedback signals from the reference electrode of one of said transistors to the reference electrode of the other one of said transistors whenever the amplitude of the amplified input signals provided by said one transistor is greater than the amplitude of the amplified input signals provided by said other transistor to thereby maintain the amplitude of said first amplified input signals substantially the same as the amplitude of said second amplified input signals.

Claim 5

A self-balancing push pull amplifier as set forth in claim 1 in which said AC signal coupling network includes means for adjusting the frequency response of said push pull stage.

Claim 6

A self balancing push pull amplifier as set forth in claim 1 in which said output means includes an output transformer, a first transformer for coupling said first amplified signals to said output transformer and a second transformer for coupling said second amplified signals to said output transformer, said output transformer having a winding with one end connected to a point of reference potential through a winding of said first transformer and another end connected to the point of reference potential through a winding of said second transformer whereby said first amplified signals and said second amplified signals are combined across said output transformer winding.

Claim 7

A push pull amplifier comprising, a push pull circuit including first and second transistors connected in push pull relationship, a first transformer having a first winding and means for coupling input signals derived from said first winding to said first transistor, a second transformer having a second winding and means for coupling input signals derived from said second winding to said second transistor, a phase splitting transformer including an input circuit over which signals are received and an output winding connected in series with said first and second windings, and means for connecting a point of reference potential to the junction of said first and second windings whereby the input signals coupled to said first transistor are opposite in phase with the input signals coupled to said second transistor.

Claim 8

A push pull amplifier comprising, a push pull circuit including first and second transistors connected in push pull relationship, a first transformer having a first winding and means for coupling input signals derived from said first winding to said first transistor, a second transformer having a second winding and means for coupling input signals derived from said second winding to said second transistor, a phase splitting transformer including an input circuit over which signals are received and an output winding connected in series with said first and second windings, and means for connecting a point of reference potential to the junction of said first and second windings whereby the input signals coupled to said first transistor are opposite in phase with the input signals coupled to said second transistor.

Claim 9

A push pull amplifier as set forth in claim 6 and further including an output transformer having at least one winding, a third transformer having a third winding and means for coupling first amplified signals derived from said third winding to said output transformer winding, a fourth transformer having a fourth winding and means for coupling second amplified signalS derived from said fourth winding to said output transformer winding, said third and fourth windings being connected in series across the output of said push pull circuit and means for connecting said point of reference potential to the junction of said third and fourth windings whereby the first amplified signals coupled to said output transformer winding are in phase with the second amplified signals coupled to said output transformer winding.

Claim 10

A self-balancing push pull amplifier comprising a push pull stage including first and second transistors connected in push pull relationship, said first and second transistors each having an input electrode, an output electrode and a control electrode, input means including a first transformer connected to the input electrode of said first transistor, a second transformer connected to the input electrode of said second transistor and an input transformer for coupling signals input to said amplifier to said first and second transformers to provide oppositely phased input signals for said first and said second transistors, output means connected between the output electrode of said first transistor and the output electrode of said second transistor for combining first amplified signals provided by said first transistor and second amplified signals provided by said second transistor, means for providing a fixed DC potential for the reference electrodes of said first and second transistors, a first AC signal coupling network connected between the reference electrode of said first transistor and the reference electrode of said second transistor to provide negative feedback signals for maintaining the amplitude of the first amplified signals substantially the same as the amplitude of the second amplified signals, and a second AC signal coupling network connected between the output electrode of said first transistor and the output electrode of said second transistor for coupling negative feedback signals from the output electrode of said first transistor to the output electrode of said second transistor for maintaining the gain of said push pull amplifier substantially constant over a predetermined frequency range.

Claim 11

A self-balancing push pull amplifier comprising a push pull stage including first and second transistors connected in push pull relationship, said first and second transistors each having an input electrode, an output electrode and a control electrode, input means including a first transformer connected to the input electrode of said first transistor, a second transformer connected to the input electrode of said second transistor and an input transformer for coupling signals input to said amplifier to said first and second transformers to provide oppositely phased input signals for said first and said second transistors, output means connected between the output electrode of said first transistor and the output electrode of said second transistor for combining first amplified signals provided by said first transistor and second amplified signals provided by said second transistor, means for providing a fixed DC potential for the reference electrodes of said first and second transistors, a first AC signal coupling network connected between the reference electrode of said first transistor and the reference electrode of said second transistor to provide negative feedback signals for maintaining the amplitude of the first amplified signals substantially the same as the amplitude of the second amplified signals, and a second AC signal coupling network connected between the output electrode of said first transistor and the output electrode of said second transistor for coupling negative feedback signals from the output electrode of said first transistor to the output electrode of said second transistor for maintaining the gain of said push pull amplifier substantially constant over a predetermined frequency range.