SU1336196A1 - Power amplifier - Google Patents

Abstract

The invention relates to amplifier technology. The purpose of the invention is to reduce nonlinear distortion and increase the gain in power for large signals. The power amplifier contains transistors 1-4 and 12, power supply buses 5, 7, 9, and 11, a diode 6, and a bias circuit 8 and 10. The use of transistor 12 ensures that the input impedance of the power amplifier is constant for both small and large instantaneous values of the input signal, which contributes to an increase in the linearity of the circuit, as well as to an increase in its power gain factor for large signals. 1 il. (L WITH WITH 35 O5

Description

This invention relates to an amplifier technique and can be used in an economical low frequency power amplifier.

The purpose of the invention is to reduce nonlinear distortion and increase the power gain with large signals.

The drawing shows a basic electrical power amplifier circuit.

The power amplifier contains the first 1, second 2, third 3 and fourth

4 transistors, the first bus 5 signal source, which helps to increase

linear circuit, as well as an increase in its power gain for large signals.

Claims (1)

Invention Formula a power supply, a diode 6, a second power supply bus 7, a first bias circuit 8, a third power supply bus 9, a second bias circuit 10, a fourth power supply bus 11, and a five transistor 12. The power amplifier works as follows. . In the initial state, with zero input signal, the fifth transistor 12 is saturated, the first 1 and third 3 transistors are locked, and the second and fourth transistors are either locked (mode B) or operate with some quiescent currents (mode AB). At small instantaneous values of the input signal, the currents of the second 2 and fourth 4 transistors increase. The current in the load flows from the second bus 7 of the power source through the diode 6 and the fourth transistor 4. As the input signal rises above the voltage on the third power supply bus 9, the emitter junction of the first transistor 1 begins to open. As a result, the third transistor 3 is opened, and the load current is added from the emitter current of the third transistor a 3 flowing from the first bus 5 of the power supply and from the emitter current of the fourth transistor 4. A further increase in the input and output signals leads to a gradual decrease in the current flowing from the fourth power supply busbars 11 through second bias circuit 10; neither, and ultimately, to the complete locking of p of the transistor 12. In this case, the fourth transistor 4 is also locked, and its collector is disconnected from the second bus 7 due to the locking 30 35 20 The power amplifier containing the first and second transistors of one structure, the trunks and the fourth transistors of the opposite structure, the emitters of the first, second and third, fourth transistors are connected in pairs and are respectively the input and output of the power amplifier, the collectors of the first and second transistors are connected to the bases of the third and fourth transistors, the collector of the third transistor is connected to the first power supply bus, the collector of the fourth transistor, through a diode connected to the The direction of the first transistor is connected to the third power supply bus and the second bias circuit, the first output of which is connected to the fourth power supply bus, characterized in that, in order to reduce non-linear distortions and an increase in the power gain at large signals, a five transistor is introduced, whose structure coincides with that of the third transistor, while the emitter and collector of the fifth transistor are connected respectively, to the third emitter and the second transistor base, and the base of the fifth transistor is connected to the second output of the second bias circuit. 40 45 50 55 vnkigm Order 4054/54 Edition 901 Random polygons pr-tie, Uzhgorod, st. Project, 4 Neither diode 6. The unlocking of the third transistor 3 and the locking of the fourth transistor 4 takes place at a voltage across the load close to the voltage on the second bus 7 of the power supply, after which the output current of the power amplifier is determined only by the current of the third transistor 3. The use of the fifth transistor 12 makes it possible to ensure the constancy of the input impedance of the power amplifier both at small and high instantaneous values of the input 0 five The power amplifier containing the first and second transistors of one structure, the trunks and the fourth transistors of the opposite structure, the emitters of the first, second and third, fourth transistors are connected in pairs and are respectively the input and output of the power amplifier, the collectors of the first and second transistors are connected to the bases of the third and fourth transistors, the collector of the third transistor is connected to the first power supply bus, the collector of the fourth transistor, through a diode connected to the The direction of the first transistor is connected to the third power supply bus and the second bias circuit, the first output of which is connected to the fourth power supply bus, characterized in that, in order to reduce non-linear distortions and an increase in the power gain at large signals, a five transistor is introduced, whose structure coincides with that of the third transistor, while the emitter and collector of the fifth transistor are connected respectively to the emitters of the third and to the base of the second transistor and the base of the fifth transistor connected to the second terminal of the second bias circuit. 0 five 0 five Subscription