Abstract A high power, high efficiency transistor amplifier is disclosed having an input drive signal in the form of a square wave with a square wave or saturated voltage output. This amplifier drives a tuned or reactive load with the result that the output current wave form is sinusoidal or some form other than a square wave. A current transformer or other current sensing device is connected into the output circuit, and a portion of the output current is fed back to the input in such sense that resulting sinusoidal voltage pulses are added to each square wave input pulse. Where the output transistors are connected in push-pull in a grounded emitter configuration, resistors are normally connected in the emitter circuit. A sinusoidal voltage is developed across these resistors which subtracts from the input drive square wave voltage pulses. This results in a degradation in the drive signal which may cause the output transistors to drop out of saturation which then causes them to try to deliver excessive power with resulting danger of burning them out. By feeding back a sinusoidal voltage which is added to the base drive, saturation is maintained throughout the length of the drive pulse. In another embodiment a plurality of identical amplifiers are connected into a common output such that their square wave voltage output signals are displaced slightly in time and algebraically added to produce a sine wave synthesis output signal across the load which, in this case, may be either reactive or resistive. A similar current sensing or voltage sensing device connected into the load circuit provides a similar feedback signal to each amplifier to assure saturation.
Inventors
👤 B Shaw
Bibliographic Details
Application Number—
JurisdictionUS
Data Sourcegoogle_patents
Last Synchronized2026-10-29 20:45
CPC Classifications
H; H03; H03K; H03K5/00; H03K5/01; H03K5/02
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
116 words
A high power, high efficiency amplifier having output transistors arranged in push-pull and having their collectors connected to supply power to a load, with resistors connected between the emitters of said transistors and ground, and each of said transistors being biased to saturation during its conductive half cycle, base drive means for supplying input signals to said transistors having a square wave voltage characteristic, current sampling means connected between said output transistors and said load device for sensing output current to said load, and means responsive to said current sampling means for supplying a voltage resulting from said sensed current to said base drive means in such sense as to add to said base drive voltage.
Claim 2
Dependent Claim
116 words
A high power, high efficiency amplifier having output transistors arranged in push-pull and having their collectors connected to supply power to a load, with resistors connected between the emitters of said transistors and ground, and each of said transistors being biased to saturation during its conductive half cycle, base drive means for supplying input signals to said transistors having a square wave voltage characteristic, current sampling means connected between said output transistors and said load device for sensing output current to said load, and means responsive to said current sampling means for supplying a voltage resulting from said sensed current to said base drive means in such sense as to add to said base drive voltage.
Claim 3
Dependent Claim
37 words
An amplifier as set forth in claim 1 wherein said amplifier includes an output transformer having a primary winding connected to said collectors, and said current sampling means is connected between said output transformer and said load.
Claim 4
Dependent Claim
65 words
An amplifier as set forth in claim 1 including a plurality of output transformers having their secondary windings connected in series across said load, a plurality of separate amplifier circuits connected to the primary windings of said output transformers, said amplifier circuits having their outputs displaced in time such that the voltage across said load is added algebrically to form a sine synthesis output waveform.
Claim 5
Dependent Claim
36 words
An amplifier as set forth in claim 1 wherein at least four of said output transistors are arranged in push-pull, parallel and resistors are connected between the emitters of each of said output transistors and ground.
Claim 6
Dependent Claim
37 words
An amplifier as set forth in claim 4 wherein said amplifier includes an output transformer having a primary winding connected to said collectors, and said current sampling means is connected between said output transformer and said load.