SU1415419A1 - Low-frequency amplifier - Google Patents

Abstract

The invention relates to radio engineering and can be used in various types of electronic devices. The purpose of the invention is to increase efficiency when working on a complex load. N-1 fourth diodes 1416, N-1 fifth diodes 17-19, diodes 20-22, N-2 second key elements 27, 28, key elements 29-31, N-1 capacitors 32-34, the source of negative voltage 36. With the help of capacitors 32-34, it was possible to implement the principle of energy recovery in the low-frequency amplifier itself. During the operation of the negative stages of the supply voltage, the capacitors are charged from the energy stored in the load, and during the operation of the positive stages of the supply voltage, the capacitors are discharged, giving energy to the load. 2 Il.

Description

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The invention relates to a radio operator and can be used in electronic devices for various purposes.

The purpose of the invention is to increase the efficiency when working on a complex load.

FIG. Figure 1 shows a low-frequency structural electrical circuit; in fig. 2 - diagrams of Ha of stresses and currents, explaining the principle of operation of the amplifier.

The low-frequency amplifier (Fig. I) contains a preamplifier I with a paraphase output, an output stage performed on the first 2 and second 3 transistors, output 4 and controlling 5 transformers, a multi-level comparator 6, resistors 7. the first 8 and second 9 diodes of third N diodes 10–13, N – 1 fourth diodes 14–16, N – 1 fifth diodes 17–19, sixth 20, seventh 21, eighth 22 diodes, N first key elements 23–26, N – 2 second the key elements 27 and 28, the third 29, the fourth 30, the fifth 31 key elements, N-1 capacitors 32-34, power supply 35, source 36 negative voltage stress.

Curve I of the load current and curve II, the supply voltage applied to the middle point of the primary winding of the output transformer 4, correspond to the case with a capacitive character

load (Fig. 2a).

Curve III corresponds to the load current, curve IV shows the changes in the voltage across the collection /: interval: the p-emitter of one of the transistors of the g-cascade during one period of the signal voltage variation (phi 2b).

The low-frequency amplifier works as follows.

The essence of the technical solution lies in the inclusion of recuperating capacitors, which allow the formation of recuperative negative levels of supply voltages.

The amplified signal is fed to the input of preamplifier 1, where it is amplified to the level necessary for normal operation of the output stage.

Transistors 2 and 3 of the output stage operate in mode B or AB, their power is supplied from power supply 35, to the key elements via the midpoint of the first

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the primary winding of the output transformer 4.

There are times in time (Fig. 2a) at which the load current does not coincide in phase with the voltage. At these times, the low-frequency amplifier does not operate. It consumes energy from the sources of power supply unit 35, but due to the energy stored in the load.

The low frequency amplifier is powered at these times from negative and zero levels of supply voltage. The negative steps of the supply voltage are automatically generated by the use of capacitors 32-34. It happens as follows. The initial moment of time corresponds to the off state of all the key elements (Fig. 2a), except for the key elements 29 and 30. The low frequency amplifier is powered from the lower stage of the supply voltages generated by / by the capacitor 34, which is charged at that time. At that moment, when the difference between the voltages of the capacitor 34 and the signal decreases to a predetermined level, the key element 28 is switched on, connected to the midpoint of the primary winding of the output transformer 4, the next negative level of the supply voltage generated by the capacitor The key element of the zero voltage supply stage is that all capacitors are charged. With this key element 31, all capacitors are connected to the housing with the negative plates.

The return of energy to the load is destroyed when the corresponding capacitors are discharged during the operation of the positive supply voltage levels. In order to realize the energy return through the positive supply voltage levels, it is necessary to connect each capacitor to the corresponding power supply unit 35. Diodes 14-16 are designed to isolate charge currents and discharge currents of the respective capacitors 32-34, as a result, the charge current flows through diodes 17-19, the discharge current through diodes 14-16.

Thus, with the help of capacitors 32-34 managed to

the principle of energy recovery in the low-frequency amplifier itself. During the operation of the negative stages of the supply voltage, the capacitors are charged from the energy stored in the load: - ke, and during the operation of the positive stages of the supply voltage, the accumulators are discharged, giving energy to the load. The capacitors are discharged to the voltage level of the respective sources of the power supply unit 35. This means that the levels of the negative supply voltage levels are symmetrical about the zero levels of the corresponding positive supply voltage levels.

The diodes 20 and 21 are designed to protect the transistors 2 and 3 of the output stage from the inverse current flow through the emitter-collector gap. The key elements 29 and 30 are intended to be connected to the input of a comparator 6 of that secondary half winding of a control transformer 5. which is located in the shoulder of the currently operating transistor. From these semi-windings, the load voltage is applied to the input of the comparator 6.

Diodes 8 and 9 - rectifier diodes. The multi-level comparator 6 controls the key elements as follows. Each key element is included with. when the voltage of the signal in the primary winding of the output transformer 4 reaches a value smaller by a predetermined value of the previous operating stage, and remains in an on state until the voltage of the signal drops below a predetermined value.

Claims (1)

Invention Formula A low-frequency amplifier containing a series-connected preamplifier with a paraphase output, whose input is the input of a low-frequency amplifier, an output stage performed on the first and second transistors connected in a common emitter circuit and having the same structure, output: i control transformers, primary windings. And K V Topbrx are connected in parallel, and also a multi-path comparator, the signal input of which is connected to the first pin of the resistor and to the cathodes  The first and second diodes, the anodes of which are connected to the PCR terminals of the first and second secondary semi-windings of the control transformer, respectively, N inputs for the reference voltage of a multi-level combiner are connected to the corresponding outputs of the N power supply unit sources connected to the first terminals of the N circuits of the first connected the key element and the third diode, the second terminals of which are combined and connected to the midpoint of the primary 5 windings of the output transformer, while the N outputs of the multilevel comparator are connected to the control inputs of the corresponding N first key elements, distinguished0 so that, in order to improve efficiency when operating on a complex load, N-2 second key elements, N-1, are introduced capacitors, NI fourth diodes, N-1 pty diodon, 5 seventh, eighth, third, fourth, fifth key elements, a source of negative voltage, with the third and fourth key elements included between; 0 and the second terminals, respectively, of the first and second secondary windings of the control transformer, the control inputs of the third and fourth key elements are connected to the bases of the first and second transistors, respectively, whose collectors are connected in the forward and right direction to the corresponding The outputs of the primary winding of the output transformer, the first plates of N-1 capacitors are combined, through the fifth key element they are connected to the common length, and through the eighth diode included in g forward direction, with the midpoint of the primary winding of the output transformer, with the second lining of the i-th capacitor connected to the anode of the i-ro fourth diode and the cathode i-ro p g of that diode, and the anodes of N-2 fifth diodes through the corresponding N -2 second key elements are connected to the common busbar, with which the anode (Nl) -ro of the fifth diode is connected, to the i-ro tod g of the fourth diode is connected to the output i-ro power supply source, and o multilevel comparator is made with 2N-1 outputs, of which N-I outputs are connected respectively to the inputs five Control N-2 second key -vj. controls and the input control of the fifth class) of the head element, while the second Jh 9ig.2 The lead of the resistor is connected to the output of a negative voltage source.