SU508900A1 - Push-pull Pulse Width Modulated Amplifier - Google Patents

Description

pa 12, the second input of which is connected to the generator that: who (output pulses 6. The second converter 5 of the input signal into the pulse duration is similar to the first converter 4 of the input signal into the pulse duration. The input of the operational amplifier of the second converter of the input signal into the duration is connected to the output 3 sources 1 of the input signal, the outputs of both converters 4 and 5 of the input signal in the pulse duration are connected to the inputs of the push-pull power amplifier 7, and the resistors 10 and 14 their time settings are R The C-circuits are connected to a source of power supply 8 that feeds a push-pull pulse power amplifier 7. Each of the transducers 4 and 5 of the input signal into a pulse duration converts the input voltage of only one polarity (according to the variant shown in Fig. 1, this polarity is positive.) A push-pull amplifier with pulse-width modulation works as follows: C: the arrival of the trigger pulse (Fig. 2, a) from the clock generator 6 to the input of the trigger 12 is set to the first stable of PICs, whereby the transistor 13 is turned off and the capacitor 9 is charged exponentially through resistor 10 from the power source 8; U, -L (l - l) where and c is the voltage on the condenser 10; t RC is a time constant, where R is a resistor 10; C - capacitor 9; f / n is the supply voltage. If the voltage t / on the capacitor 9 and the voltage f / in the positive field of the non-certifying input of the operational amplifier are equal And the latter switches the trigger 12 to the second steady state, the transistor 13 opens and discharges the capacitor 9 for a short period of time ( Fig. 2.6). At the output of the input-to-pulse converter, a rectangular pulse is formed, the duration of which is proportional to the input signal level ((FIG. 2, d). When the input signal is negative, the voltage on the capacitor 9 at the non-inverting input of the operational amplifier remains zero. Despite the fact that the transistor 13 is turned off by the signal from the trigger 12 (Fig. 2, b and d). The operation of the input signal converter 5 in the pulse duration is similar to the operation of the input signal converter 4 in the duration pulse pattern. The appearance of a series of mono-angular pulses at the outputs of converters 4 and 5 of input signals: in the duration of the pulses (Fig. 2, d and e) alternates in accordance with the signal of a positive polarity at the inputs of their operational amplifiers. The pulses (Fig. 2, d and e) are alternately fed to two separate independent | Symy inputs of the push-pull power amplifier 7. The voltage form on the load of the push-pull power amplifier 7 is shown in fig. 2, e. The pulse duration on the load of the push-pull power amplifier 7, as well as on the outputs of the input-to-pulse converter, is determined by the expression: / 2 (2) The mean value of the voltage on the load where T. is the pulse following period. Substituting expression (2) into expression (3), we define f / cp and From expression (4) it can be seen that the average value of the voltage on the load does not depend on the voltage of the power source of the push-pull power amplifier, and therefore does not depend on changing this stress. Thus, stabilization of the gain of a push-pull amplifier with pulse-width modulation with a change in the voltage of the power source is achieved. Invention of the invention A push-pull amplifier with 1-modulation pulse-width, containing a push-pull converter of the input signal to a pulse duration, the outputs of which are connected to the inputs of a push-pull pulse power amplifier, an input source and a power source, characterized in that the purpose of increasing the stabilization of the gain when the voltage of the power source is varied, the antiphase outputs of the input voltage source are connected to the Nv1N | rotary inputs of two-cycle operational amplifiers The converter is an input signal into a pulse duration, the resistors of which drive circuits are connected to a power source of a push-pull pulse amplifier. POWER I.

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