SU915216A1 - Amplifying device with adaptive pulse-width modulation - Google Patents

Description

The invention relates to radio engineering and can be used in hydroacoustic power amplifiers.

A device for amplification with adaptive PWM is known, comprising a pulse generator, an input signal connected in series, an adder, a relay element, and a push-pull key power amplifier in series, a low-pass filter (LPF) and a load, and the output of the low-pass filter through a feedback circuit connected to the second input of the adder 113.

However, the known device for amplification with adaptive PWM has increased distortion.

The purpose of the invention is to reduce the distortion of the amplified signal.

To do this, the device for amplifying with adaptive PWM additionally introduced elements AND, OR-NOT, OR, the first and second counting triggers, and the output of the pulse generator is connected to the counting input of the first trigger, the inverting output of which is connected to the counting input of the second trigger, 5 To-inputs of which are connected respectively with the outputs of the elements AND and OR-NOT, the inputs of the 10

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the power amplifier and the inputs of the OR element, the output of which is connected to the K input of the first trigger, and the inputs of the AND and OR-NOT elements are pairwise connected to the output of the relay element and the second trigger.

The drawing shows a schematic diagram of a device for amplification with adaptive PWM.

A device for amplification with adaptive PWM contains a source of an amplified signal, an adder 2, a relay element 3, an AND 4 element, an OR-NOT 5 element, an OR 6 element, a push-pull power key amplifier 7, a low-pass filter 8, a load 9, a reverse circuit 10 connection, generator 11 short pulses, triggers 12 and 13 with a counting input.

Device for amplification with adaptive PWM works as follows.

When a source 1 signal arrives at the input of the adder 2., · due to the existence of negative feedback, which is fundamental in adaptive PWM amplifiers, it is compared with the output signal and, if the first exceeds the second, the relay element 3 and the corresponding arm of the amplifier 7 power included (in avi3

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status of trigger state 13). After the output signal exceeds the input, the relay element 3 and the power amplifier key 7 are turned off. Consequently, the output signal of the amplifier will repeat the signal amplified during the amplification of one half-wave, due to the operation of only one arm of the power amplifier 7.

So the amplifier works until the pause of the voltage at the output of the relay element (after the element OR 6) does not exceed twice the period of the signal of the pulse generator 11, which occurs when the level decreases or the frequency of the amplified signal (source 1) increases. In this case, the output The trigger 12 is formed by a positive voltage drop, which translates the trigger 13 into another state. The trigger 13 switches the shoulders of the key power amplifier 7 with the help of the AND 4 and OR-NOT 5 elements.

Thus, at small signal values, the shoulders of the key power amplifier turn on in turn, and the minimum switching frequency is limited, which ensures small distortions of the output signal in a wide range of amplitudes and frequencies of the amplified signals without degrading the power characteristics of the amplifier. So, if a well-known amplifier has a distortion factor of the output signal in the dynamic range of 30 dB and frequency up to 10 kHz of the order of 10-15%, then the proposed one has distortions of no more than

3-5%.

Thus, a device for amplifying with adaptive PWM has less distortion than the well-known amplifiers with adaptive PWM.

Claims (1)

Claim Device for amplification with adaptive PWM, containing a pulse generator, serially connected input source, adder, relay element, as well as serially connected push-pull key power amplifier, low pass filter and load, and the output of the lower frequency filter through the feedback circuit is connected to the second an adder input, characterized in that, in order to reduce distortion, AND, OR-NOT, OR first and second counting triggers are additionally introduced into it, and the output of the pulse generator is dklyuchen to the count input of the first flip-flop, the inverting output of which is connected to the counting input of the second flip-flop, 3- and K-inputs of which are connected respectively to the outputs of the AND and NOR _λ key inputs of the power amplifier and the inputs of OR element whose output is connected to the K by the input of the first trigger, and the inputs of the AND and OR-NOT elements are connected in pairs with the output of the relay element and the second trigger. . . .