SU746864A1 - Power amplifier - Google Patents

Description

(54) POWER AMPLIFIER

I

The invention relates to electronic technology and can be used as a mosfle transformer cascade low-frequency amplifier.

A bridge power amplifier is known, a power transistor in each arm, whose base is connected to a collector or emitter of its own control transistor, and an additional transistor, while in one pair of base arms, they are interconnected by means of resistors their collector is connected to the bases of the power transistors, in the other pair of shoulders each of the additional transistors of one shoulder is connected to the base of the control transistor of the other shoulder by means of a corresponding resistor, and their collectors are also connected Linked to the bases of their .force transistors 0-3.

The disadvantage of such an amplifier is its low efficiency and low reliability. The power amplifier, known as a four-shoulder bridge, is also known. In which two arms are formed by input transistors with collector loads, and l: in the other ± LH1Lech, adjacent to the specified ones, are formed respectively by power and additional transistors connected together in each arm, with the emitter section - the collector of the power transistor through the diode included in the conductive voltage shunts the collector load of the input transistor 10 of the adjacent shoulder, the terminals for connecting the connection of the parallel to the corresponding conductive junction point between a diode and a power transistor, a power source is turned diagonally

15 four-shoulder bridge.

The disadvantage of this power amplifier is its low efficiency and low reliability of its operation, due to the possibility of the flow of through currents.

The purpose of the invention is to increase the efficiency and reliability of the amplifier by eliminating the flow of through currents.

Claims (2)

746864 The goal is achieved by the fact that the opposite shoulders are made on transistors of different conductivity types, the power and additional transistors of each shoulder are connected according to the scheme, with a common emitter, and the collector load of each of the IWFs of the shoulder transistors, to the middle of which is connected the base of the additional transistor from the adjacent shoulder, the collector of which is connected through a resistor to the collector of the power transistor from the other shoulder, in which the collector is an additional transis torus is connected through a resistor to the collector of another power transistor. The drawing shows the electrical diagram of the proposed first unit. The collectors of the input power transistors 1 and 2 of the first pair of shoulders are connected through resistors 3 and 4 to the databases of additional transistors 5 and 6 of the second pair of shoulders. The collectors of additional transistors 5 and 6 are connected to the bases of the Transformer Power Transistors 7 and 8 directly and through resistors 9 and 1O to the switches of the transistors 7 and 8 of the adjacent shoulders of the same pair. The bases of the additional transistors 5 and 6 are connected via resistors 11 and 12 to the power source 13, and the emitters of the transistors 5, 6, 7 and 8 of the second pair are connected to the power source 13 . The load 14 is connected to the collectors of the power transistors 7 and 8 of the second pair of shoulders directly, through diodes 15 and 16. with the collectors of input transistors 1 and 2, and through diodes 17 and 18 with a common bus 19. The emitters of input transistors 1 and 2 are connected with a common bus 19. Transistors 5, 6, 7, 8 second pair of shoulders.,. „Have polarity opposite to transistors 1 and 2 of the first pair of shoulders. At the base of the transistors I and 2 provide input signals in the opposite phase. For example, a negative half-wave input voltage is applied to the base of transistor 1, and a positive half-wave is based on the base of transistor 2. In this case, transistors 1, 5, 8 are open and transistors 2, 6, 7 are closed. On the emitt- a circuit of the transistor 1 - diode 15 - load 14 - the collector-emitter of transistor 8 will flow current. When the phase of the input signal changes, transistors 2, 6, 7 open, and transistors 1, 5, 8 close. The current through the load will flow in the opposite direction along the emitter-collector circuit of transistor 2, diode 16 — load 14 — collector of transistor 7. When transistor 2 is opened while it is still in the active region, diode 16 is closed. In this case, the load of transistor 2 is a transistor 6 connected through an bias circuit formed by resistors 4 and 12. The parameters of the amplifier are chosen so as to ensure the operation of the transistor 6 and the cut-off of transistor 8 while the transistor 2 is in the active region. The current through the load decreases to zero. Prothetic: direct current through the load in the opposite direction will become possible only when transistor 1 approaches the cut-off region. Thus, in the described amplifier it is always possible to create a zone when there are no currents through the load. The duration of the determination of the parameters of the amplifier and the duration of the edges of the input signals. As a result, the flow of the SCW031WH currents is eliminated, and the reliability of the amplifier increases. With the resistor settings correctly selected, the amplifier transistors will operate in cut-off or saturation mode. Diodes 17 and 18 are designed to dampen the reverse surge with inductive load 14. In the proposed amplifier, all the voltage of the power supply source is applied to the load, and its efficiency is higher than that of known local amplifiers. The transistors of the second pair of shoulders are in a lightweight mode compared to the known amplifier, which, together with the elimination of the flow of through currents, increases the reliability of the amplifiers. The invention The power amplifier, made in the form of a four-shoulder bridge, in which two arms are formed by input transistors with collector loads, and the two other arms adjacent to these are formed by power and additional transistors, respectively, but included in the KfixatOKi shoulder and the emitter section -Six transistor collector through a diode connected in the conducting direction, shunts the collector load of the input transistor of the adjacent arm, the terminals for connecting the load are connected to the corresponding etstvuyuschi soedinen1 points between a diode and a power transistor, a power source included in the bridge diagonal chetyrehllechogo, characterized in that, in order to increase koeffshshenta. efficiency and reliability of operation by eliminating the flow of squared currents, in it the opposite arms are made on transistors of different conductivity types, the power and additional transistors of each arm are connected according to the circuit with a common emitter, 4 and the collector load of each shoulder voltage The center of which is connected to the base of the additional extension of the transistor from the adjacent shoulder, the colletstor of which is connected to the collector of the power transistor through a resolution of the transistor and the other arm, wherein the manifold further tranzistbra soodyyon through another resistor to the collector of the power transistor. Sources of information taken into account during the examination 1. USSR USSR Certificate of Authorship 32OO14, cl. H 03 F 3 / 2O, 197O. 2. USSR author's certificate No. 340059, cl. H 03 F 3/20, 197a (prototype).