SU866666A1 - Voltage converter - Google Patents

Description

(54) VOLTAGE CONVERTER

-f The invention relates to a measurement technique, in particular, DC / AC voltage converters, used in DC voltage and current meters, generators, etc. A known constant-voltage-to-voltage converter contains transistor switches, the inputs of which are connected to the input bus, their control inputs are connected to the output of the multivibrator, and the outputs are connected to the output bus tl. The disadvantage of this converter is low accuracy. Closest to the present invention is a constant-to-alternating voltage converter containing an operational amplifier, the driver of which is connected to the input of a multivibrator, the filter whose output is connected to the output bus I2l. A disadvantage of the known converter is low accuracy, stability and resolution. The purpose of the invention is to improve accuracy, stability and resolution. The goal is achieved by the fact that the converter containing the operational amplifier, the driver, the output of which is connected to the input of the multivibrator, the filter whose output is connected to the output bus, are connected in series and connected between the output of the multivibrator and the input of the filter, the pulse amplitude limiter, a summing unit, a selective AC amplifier with unipolar pulse amplification, as well as a source of reference voltage, the driver input being connected to the input bus, the outputs of the reference voltage source and the op amp are connected to the corresponding inputs of the summing unit, the inverting input of the op amp is connected to the input bus, and the non-inverts are connected to the common bus. FIG. 1 shows a diagram of the device proposed in FIG. 2 temporary diagrams for the device operation. The device contains a switching amplifier 1, a driver 2, a multivibrator 3, a filter 4, a pulse amplitude limiter 5, a summing block b, an alternating current selective amplifier 7 with a unipolar pulse amplification, a reference voltage source 8.

The device works as follows.

The input alternating signal of a sinusoidal or rectangular shape of a constant frequency and duty cycle (Fig. 2, a) is fed to the input of a form 2, from the output of which (Fig. 2, b) is fed to the input of the multivibrator 3, which can work both in standby and and in the self-oscillating mode. The output signals of the multivibrator 3 (Fig. 2,) are fed to the input of the limiter of the pulse amplitude 5 where the amplitude of the pulses is limited and at the output of the limiter 5 of the amplitude of the pulses a stable amplitude (Fig. 2.1) is generated and the first input of the sum of the module 6, to the second input of which a stabilized direct current voltage is supplied from the source 8 of the supply voltage of such magnitude that the alternating square-shaped signal at the output of the central unit b is in the negative area with the input voltage and operational surge amplifier 1, equal to zero (Fig. 2, E, e).

When a constant voltage is applied to the input of the operational amplifier 1 to be converted into a variable Ugy O (Fig. 2, a), an amplified signal appears at its output; The direct current, which is fed to the third input of the routing unit 6, shifts its input alternating signal into the positive region in such a way that this offset is proportional to and (Fig. 2, e). The output of summing unit 6 is fed to the input of a selective amplifier 7 of an alternating current with a unipolar pulse amplification, which suppresses the alternating signal of the negative polarity, and amplifies the pulses of positive polarity. Its output signal of a constant frequency and duty ratio (Fig. 2) is applied to the load.

With a pulse duty cycle & 2, this signal is fed to the input of filter 4, the output of which is a sinusoidal signal that is applied to the load. The summing unit 6 is made on passive elements, i.e. resistors and capacitors or

. contains 1-2 operational amplifiers operating in a repetition mode with a transmission coefficient of one, i.e. practically without drift As an operational amplifier 7, an integrated amplifier with MDM - type conversion or with direct coupling with a small drift and deep negative feedback is used, which eliminates the drift and performs conversion of the DC signal of very small equations ( for example, a microvolt range) to a variable with high accuracy, linearity and stability, while the gain of amplifier 1 does not require large, since the selective amplifier 7 must have a large oeffitsient gain.

The pulse amplitude limiter 5 is designed to eliminate outliers and drift of the output alternating voltage of the multivibrator 3, mainly due to the instability of the saturation voltage of the keys of the multivibrator.

Claims (2)

Invention Formula about A voltage converter containing an operational amplifier, a driver, the output of which is connected to the CQ input of a multivibrator, a filter whose output is connected to the output bus, characterized in that, in order to increase accuracy, stability and resolution | it is connected in series and connected between the output. a multivibrator and a filter input, a pulse amplitude limiter, a summing unit, an AC alternating current amplifier with unipolar pulse amplification, and a voltage source, the input of the imager is connected to the input bus, the outputs of the reference voltage source and the operational amplifier are connected to the corresponding the inputs of the summing unit, the inverting input of the operational amplifier is connected to the input bus, non-inverting - to the common bus .. Sources of information taken into account in the examination 1, USSR Author's Certificate 312368, cl. H 03 F 1/00, 1971. 2. Patent ShA 3622800, cl. 307-229, pub. 1971. TO of-A A a "T