SU1192142A1 - Voltage-to-frequency converter - Google Patents

Abstract

A VOLTAGE CONVERTER TO A FREQUENCY, containing a comparison unit, a timing capacitor, a series-connected voltage source and a current stabilizer, the output of which is connected to the first input of the comparison unit, and the first plate of the master capacitor, the second facing of which is connected to the common bus of the device, that, in order to extend the functionality, a rectangular pulse generator, a switch, a one-shot and a key connected in parallel to the time specifying the cond To the transmitter, the output of the comparison unit is connected to the first input of the switch via a one-shotgate, to the second input of which a square pulse generator is connected, the output of the switch is connected to the control input of the key, and the input source is connected to the second input of the comparison unit. ZJ Phi 1

Description

one

The invention relates to a pulse technique and electrical measurements, namely, voltage-to-frequency converters, and can be applied in digital measuring devices and information-measuring systems.

The aim of the invention is to enhance the functionality as well as increase the accuracy of the conversion.

Achievement of the goal is caused by the fact that with simple means the device operates both in the mode of voltage conversion to the pulse frequency and in the mode of the pulse-width modulator (pwm). At the same time, due to the possible implementation of a comparison unit on a high-speed operational amplifier and a discharge device at the field effect transistor, the conversion accuracy is improved.

Figure 1 shows the functional scheme of the device; 2 and 3 are time diagrams of the device operation.

The voltage to frequency converter contains a comparison unit 1, a time specifying a capacitor 2, a series 7 voltage supply 3 in series, and a current regulator 4, the output of which is connected to the first input of the comparison unit 1 and the time of the setting capacitor 2 to the first plate, the second plate of which is connected to common bus device, and also contains a generator of 5 rectangular pulses, a switch 6, a single vibrator 7 and a switch 8, connected in parallel to the time of the setting capacitor 2, the output of the comparison unit 1 via a single vibrator 7 the first input of the switch 6, to the second input of which is connected a generator of rectangular pulses, the output of switch 6 is connected to a control input of the key 8, and the input signal source 9 is connected to the second input of the comparing unit I.

In Fig. 2, the following designations are accepted: a is the signal for the time of the driving capacitor 2; b - signal at the output of the comparison block 1; in - signal at the output of the one-shot 7.

In FIG. 3, the following symbols are accepted: a - a signal at the output of the generator of rectangular pulses 5; b - sy1-

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For a time, the capacitor is set to 1 - the signal at the output of the comparison unit 1.

The device works as follows.

Using switch 6, either the one-shot 7 is connected to the control input of the key 8 and the device operates in a voltage-to-pulse voltage converter mode, or a square-wave generator 5 is connected and the device operates in PWM mode.

In the mode of converting the input 5 voltage to the pulse frequency

(Fig. 2, after supplying the supply voltage from the source 3, the time of the setting capacitor 2 begins to charge with the current provided by the current regulator 4. The voltage for the time of the setting capacitor 2 increases linearly to a value equal to the voltage applied to the inverting input of the comparison unit 1 from source 9

25 (FIG. 2a).

With the voltage equal to the time of the driving capacitor and the voltage to be converted, applied to the second input of the comparison unit 1 through the terminals

30 of source 9, the signal level at the output of Comparison Unit 1 (Fig. 2b) varies. The key 8 for the time of the pulse of the single vibrator 7 (Fig. 2B opens, and the time of the setting capacitor 2 is discharged. After the level of the signal at the output of the comparison unit 1 changes, the key 8 is locked, the time of the setting capacitor 2 is charged through the current stabilizer 4, and the process is repeated. In the PWM mode of FIG. 3), the key 8 is controlled by pulses from the generator 5 of rectangular pulses (FIG. 3 a), and in the absence of pulses intervals the capacitor 2

Gfig. Zb) is charged, and in the presence intervals it is discharged. At the output of the comparison unit 1, a pulse signal is generated, the duration of which is controlled by the voltage applied to the source terminal 9.

The device in the PWM mode, in particular, can be used in power converting technology in thyristor converter control devices, thus generating a pulse control signal from the network. Using PWM allows you to reduce

the asymmetry of the control angles of the thyristors, i.e. to minimize the inequality of the control angles of the individual thyristors included in the thyristor converter. Reducing the asymmetry of the steering angles eliminates the self-oscillation mode and reduces the ripple in the output voltage.

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Claims (1)

VOLTAGE TRANSFORMER In FREQUENCY, comprising a comparison unit, a timing capacitor, a voltage source and a current regulator connected in series, the output of which is in order to expand the functionality, a rectangular pulse generator, a switch, a one-shot and a key connected in parallel with a timing capacitor, the output of the comparison unit h Through a single vibrator, it is connected to the first input of the switch, to the second input of which a square-wave pulse generator is connected, the output of the switch is connected to the control input of the key, and the input signal source is connected to the second input of the comparison unit. Thebes 1 ZHZ6 ίί