THERMALLY STABLE POWER AMPLIFIER

• US 3,863,170 A
• Filed: 02/21/1973
• Issued: 01/28/1975
• Est. Priority Date: 02/21/1973
• Status: Expired due to Term

• Current Assignee: SWEN Sonics Corporation
• Original Assignee: Henry Kevin Ratcliff
• Inventors: Ratcliff, Henry Kevin
• Primary Examiner(s): Smith, Alfred E.
• Assistant Examiner(s): Dahl, Lawrence J.
• Application Number:
  US05/334,517
• Time in Patent Office: 706 Days
• Field of Search: 307/261,263,268,280 328/22,223 330/21,23,26,28,31,196 331/113R,165,166
• US Class Current: 330/298
• CPC Class Codes: H03F 3/2176 Class E amplifiers
• CPC Class Codes: H03F 3/245 with semiconductor devices only
• CPC Class Codes: H03F 3/42 Amplifiers with two or more amplifying elements having their dc paths in series with the load, the control electrode of each element being excited by at least part of the input signal, e.g. so-called totem-pole amplifiers

Abstract

An alternating current amplifier includes a first transistor for controlling an operational signal derived from an input signal and a voltage to develop a sinusoidal output signal upon passing through a load. A second transistor is connected to the first transistor and the input signal for controlling the interval of time during which the input signal and voltage are communicated to the first transistor to reduce their simultaneous presence therein and prevent thermal energy from being created which would materially affect the operation of the first transistor.

Claims

1. A transistor power amplifier comprising:

switching means connected between a voltage source and a ground for controlling an operational signal derived from an input signal supplied by a source of electrical current;

shaping means located between said switching means and said voltage source for sequentially presenting said input signal and said voltage to said switching means;

resonant means connected to said switching means for transmitting said operational signal at a predetermined frequency to a load;

matching means connected to said resonant means and said voltage source for isolating the input signal from the operational signal to develop a sinusoidal output signal upon passing the operational signal through said load; and

control means connected to said switching means and said ground for preventing the creation of thermal energy in the switching means by substantially eliminating the instantaneous and simultaneous presence of the input signal and voltage source therein to thereby stabilize the frequency of said operational signal over an extended period of time.

2. The transistor power amplifier, as recited in claim 1, wherein said switching means includes:

a first transistor having a first base connected to receive said input signal, a first collector connected to receive said voltage source, and a first emitter connected to the ground; and

a second transistor having a second base connected to receive said input signal simultaneously with said first base, a second collector connected to receive said voltage source, and a second emitter connected to the ground, said first and second collectors dividing the electrical potential from said voltage source to reduce the overall development time of said operational signal.

3. The transistor power amplifier, as recited in claim 2, wherein said control means includes:

a third transistor having a third base connected to receive said input signal simultaneously with said first and second bases of the first and second transistors respectively, a second collector connected to said first and second emitters For receiving the output therefrom, and a third emitter connected to the ground, said third transistor reacting to said input signal faster than said first and second transistors to limit the simultaneous presence of said input means and said voltage in the first and second transistors to less than 2 microseconds.

4. The transistor power amplifier, as recited in claim 3, wherein said control means further includes:

a diode shunting means located between the third transistor and ground for providing a balanced load on the input signal and for shaping the input signal to prevent a distorted output from the transistor switching means resulting in time delays caused during the derivation of the operational signal from the input signal.

5. The transistor power amplifier, as recited in claim 4, wherein said first and second transistors are high voltage devices capable of developing a high gain to produce the operational signal and said third transistor in a low voltage device capable for controlling fall time to prevent the creation of thermal energy in said first and second transistors.

6. The transistor power amplifiers, as recited in claim 1, wherein said switching means includes:

a first transistor having a first base connected to receive said input signal, a first collector connected to receive said voltage source, and a first emitter connected to the ground; and

a second transistor having a second base connected to said first emitter, a second collector connected to said voltage source and a second emitter connected to said control means, said first transistor driving said second transistor to produce said operational signal.

7. The transistor power amplifier, as recited in claim 6, wherein said control means includes:

a third transistor having a third base connected to said first emitter, a third collector connected to said second emitter, and a third emitter connected to ground, said third transistor controlling the time said input signal and said voltage are present in said first and second transistors to reduce the creation of thermal energy in said first and second transistors.

8. The transistor power amplifier, as recited in claim 7, wherein said control means further includes:

a diode shunting means located between the third transistor and ground for providing a balanced load on the input signal and for shaping the input signal to prevent a distorted output from the transistor switching means resulting in time delays caused during the derivation of the operational signal from the input signal.