SU1690180A1 - Push-pull pulse power amplifier - Google Patents

Abstract

The invention relates to radio engineering and pulse technology and can be used in amplifying devices. The purpose of the invention is to expand the field of application by reducing phase distortion and improving reliability by applying overload protection. At the end of the input pulse, the accelerating switch 1 (2) is triggered at the corresponding input of the amplifier, ensuring that the blocking voltage is applied to the base of the lockable switching transistor 11 (12), thereby forming the process of absorption of excess charge. The protection unit 18 blocks the passage of control input signals at elevated currents flowing through the current sensor 13. 2 Il.

Description

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The invention relates to radio engineering and pulse technology and can be used in amplifying devices.

The purpose of the invention is to expand the field of application by reducing phase distortion and improving reliability by applying overload protection.

Figure 1 shows the structural diagram of the amplifier; 2 is a schematic diagram of a protection unit.

The push-pull switching power amplifier contains accelerating switches 1 and 2, elements AND-HE 3 and 4, resistors 5-8, capacitors 9 and 10, switching transistors 11 and 12, current sensor 13, transformer 14 with primary windings 15 and 16, secondary winding 17, block 18 protection. The protection unit 18 contains comparators 19-21, resistors 22 and 23, capacitors 24 and 25, and diodes 26 and 27.

The input terminals of the amplifier are connected to the first inputs of the elements AND-NOT 3 and 4 and the inputs of the accelerating switches 1 and 2, the outputs of which through the corresponding resistors 5 and 7 are connected to the outputs of the corresponding elements AND-NOT 3 and 4 and through the capacitors 9 and 10 with the bases the corresponding switching transistors 11 and 12, the emitters of which are connected to one power bus through the current sensor 13, the collectors through the corresponding primary windings 15 and 16 of the transformer 14 are connected to another power bus, the output of the protection unit 18 is connected to the second inputs of the NAND elements, The outputs of which through the corresponding resistors 6 and 8 are connected to the bases of the switching transistors 11 and 12, the emitters of which are connected to the input of the block 18 protection.

The amplifier works as follows.

When a logical unit signal is applied to the first input of the amplifier, the accelerating switch 1 closes, the logical zero level appears at the output of the NE-HE element 3, ensuring the flow of the base-emitter-current of the switching transistor 11, which starts to open, the capacitor 9 is charged. At the end of the input pulse, the accelerating key 1 is forcedly unlocked and connects the output of capacitor 9 to the power bus, ensuring that the blocking voltage is applied to the base of the transistor 11. At the same time, the level of the logical unit is set at the output of the AND-HE element 3. As a result, accelerated resorption of minority carriers in the base of transistor 11 and its fast locking are ensured. Similar

Processes occur when the input signal is fed to another input of the amplifier.

By alternately opening the transistors 11 and 12, voltage pulses are generated on the current sensor 13. In this case, at the moments of overlapping of the open states of the transistors 11 and 12, pulsed voltage spikes appear. The trigger voltage of the comparator 19 is selected

such that it only works during these voltage spikes. In this case, pulses are generated on the capacitor 24, whose amplitude does not exceed the response voltage of the comparator 20. When overloads occur, the voltage on the current sensor 13 increases, the voltage on the capacitor 24 increases due to an increase in the pulse duration at the comparator 19 output and the comparator operation threshold 20 exceeds The comparator 20 is triggered, and the capacitor 25 is forcedly charged through diode 27. The comparator 21 is triggered, and the input signals of the amplifier are disabled, the transistors 11 and 12 are locked by stopping the power supply to the load. The comparators 19 and 20 are reset, and the capacitor 25 is discharged through a resistor 23. When the voltage on the capacitor 25 drops below the threshold, the comparator 21 returns to its original state. When overload is removed, protection is automatically disabled.

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Claims (1)

Invention Formula A push-pull switching power amplifier comprising first and second switching transistors, the emitters of which are interconnected, the collectors are connected to the corresponding first terminals of the first and second primary windings of the transformer, the second terminals of which are connected to the first power bus, the transformer secondary leads are connected to the output terminals of the amplifier, the first, second, third and fourth resistors, the first terminals of which are interconnected in pairs, the first and second capacitors, characterized in that, in order to expand the field of application by reducing phase distortion and increasing reliability by applying overload protection, it is entered into the first and second elements of NAND, the first and second accelerating keys, the protection unit and the current sensor, the first inputs of the first and second elements of NAND and the inputs of the accelerating keys are connected to the input terminals of the amplifier, the second inputs of the first and second I-NOT elements are connected to the output of the protection unit, the input of which is connected to the emitters of the switching transistors and through the current sensor to the second power bus, the outputs of the first and second accelerating switches are connected via the corresponding first and third resistors to the outputs oL / on.f 19 I 20 Comparator Computer - rotor 6 + Ј /  FIG. 2 corresponding to the first and second elements of the NAND and through the corresponding first and second capacitors with the bases of the corresponding first and second switching transistors and the second terminals of the corresponding second and fourth resistors. 21, Comparator -  one