SU1385253A1 - Gated power amplifier - Google Patents

Abstract

The invention relates to radio engineering. The purpose of the invention is to increase the efficiency by reducing the through currents. The amplifier contains a push-pull output stage 1, an active-inductive load 2, controllable switches 3 and 4, a pulse modulator 5, threshold blocks 6 and 7 (block 6 with balanced outputs, switch 9. Current sensor 8 is inserted, controlled filter 10. When entering the amplifier input

Description

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position signal on. the output of the modulator forms a pulse. polarity The current in load 2 is zero. Block 7 generates a low-level signal. At the input of the filter 10, a signal of the modulator 5 is formed, past the switch 9. The filter 10 generates a negative signal. polarity, to-ry through block 6, connects the signal of the modulator 5 through the key 3 to the input of the cascade 1. This signal opens one of the keys of the cascade

1. The other key is in the locked state under the action of a signal from the output of the key 4. At the same time, current 2 flows through the load 2 and the sensor 8. When the current exceeds a predetermined value, block 7 generates a logic signal of a high level. Under the action of this signal, the switch 9 connects the sensor 8 to the filter 10. The bandwidth of the filter 10 expands, and the signal from the sensor 8 enters the block 6 without distortion. 1 il.

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The invention relates to radio engineering and can be used in low-frequency amplifiers, as well as in amplifiers for controlling electric drives.

The purpose of the invention is to increase the efficiency by reducing the through currents.

The drawing shows an electrical diagram of a key power amplifier.

The key power amplifier contains push-pull output stage 1 active-inductive load 2, first 3 and second 4 controlled keys, pulse modulator 5, first threshold unit 6 with balanced outputs, second threshold unit 7, current sensor 8, switch 9 and controlled filter 10.

Key power amplifier works as follows.

When a positive signal power amplifier arrives at the input of the key amplifier, a positive polarity pulse is generated at the output of the pulse modulator 5. At this moment, the current in the active-inductive load 2 is zero, while the second threshold unit 7 generates a logic signal of a low level. At the input of the controlled filter 10, a pulse modulator signal 5 is generated that passes the switch 9. The control filter 10 generates a negative polarity signal which, through the first threshold unit 6 with balanced outputs, provides the connection of the pulse modulator 5 signal

through the first controlled key 3 to the input of the push-pull output stage 1. This signal opens one of the keys of the push-pull output stage 1. His other key is in the locked state under the influence of the signal from the output of the second controlled key 4. Through the active-inductive load 2 and the current sensor 8 begins to flow current (in one direction) When the current exceeds a predetermined value, the second threshold unit 7 produces a high level logic signal at its output. Under the action of this signal, the switch 9 connects the output of current sensor 8 to the input of controllable filter 10. In this case, the passband of controllable filter 10 expands and the signal from the output of current sensor 8 goes to the first threshold unit 6 with balanced outputs without distortion. When a negative polarity signal appears at the output of the pulse modulator 5, the previously open key of the push-pull output stage 1 is locked and its other key remains in the same state. When the current in the active-inductive load circuit 2 decreases at the level of the second threshold unit 7, a low level logic signal is generated, under which the switch 9 connects the output of the pulse modulator 5 to the input of the controlled filter 10. At this moment, the time of the controlled filter 10 is equal to the time constant of active-inductive loading load 2. At

This input signal of the first threshold unit 6 with symmetrical outputs is close in its form to the output signal of current sensor 8 and ensures that the other switch of the push-pull output stage 1 remains unchanged until the current in the active-inductive load circuit 2 reaches zero. When a positive signal appears at the output of the controlled filter 10, which corresponds to the achievement of the active-inductive load 2 in the circuit, a zero value, the first threshold unit 6 with symmetrical outputs provides a signal from the pulse modulator through the second control key 4 5 to the input of another key of the push-pull output stage 2. At the output of the first control key 3, a negative level signal is generated, with the result that the other key of the push-pull output stage is unlocked. At the same time through the active-inductive load 2 and the current sensor 8 current flows in the opposite direction. Further work is carried out similarly.

Thus, at any values of the current in the circuit of the active-inductive load, the through current is absent, which results in an increase in efficiency.

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Claims (1)

Invention Formula A key power amplifier containing a two-stroke output stage, the output of which is connected to the first output of the active-inductive load, and its inputs through the first and second control keys are connected to the output of the pulse modulator, the input of which is the input of the key power amplifier, the control inputs of each the control key is connected to the corresponding output of the first threshold unit with symmetrical outputs, and the second threshold unit, characterized in that, in order to increase the efficiency by reducing the through-current In addition, a series-connected current sensor, connected to the second output of the active-inductive load, is additionally introduced; the switch, the second input of which is connected to the output of the pulse modulator, and a controllable filter, the control input of which is connected to the control input of the switch through the second threshold unit to the output of the current sensor, the second output of which is connected to the common bus, while the output of the controlled filter is connected to the input of the first threshold unit with balanced outputs.