SU572919A1 - Voltage-to-frequency signal converter - Google Patents

Description

one

The invention relates to the field of impulse technology and electrical measurements, namely, voltage to frequency converters, and can be applied in digital measuring devices and information measuring systems.

A voltage to frequency converter is known, comprising an integrating circuit, a comparator and a metering device 1.

The disadvantage of these converters is the complexity of their implementation.

A voltage to frequency converter is known that contains a passive integrating circuit and an operational amplifier, the non-inverting input of which is connected via a resistor to the first input bus and the inverting input to the output of the passive integrated circuit whose input is connected to the second input bus 2.

In the known device, between the converter output and the output of the passive integrating circuit, a dosing device is switched on.

The disadvantages of a known health system are the complexity caused by the use of a metering device in it, and the inability to convert voltage voltages into a frequency signal, which limits the range of application.

In order to simplify the device and expand its functionality, two diodes and a capacitor connected between the output are introduced into the proposed converter.

the operational amplifier and its non-siding input; the inverting input of the operational amplifier is connected to the anode of the first diode, the cathode of which is connected to the output of the operational amplifier, and the non-inverting input of the operational amplifier is connected to the common bus.

The drawing shows a diagram of the proposed voltage to frequency converter.

The converter contains a passive integrating circuit 1, an operating siliconizer 2, a capacitor 3, a first diode 4, a second diode 5, a resistor 6, input buses 7 and 8. At the same time, the output of the passive integrating circuit 1 is connected to a noninputing input of amplifier 2, between which inverting input and its output includes a capacitor 3, between the inverting input of amplifier 2 and its output is connected to the first diode 4, the second diode 5 is connected between the common terminal and the non-inverting input of the operational amplifier, which is connected to resistor 6 through

Claims (2)

first, input bus 7, and the input of the integrated circuit of the coupler is connected with the second input bus 8. The converter works as follows. In the initial state, diodes 4 and 5 are closed, and amplifier 2 is in a state of positive saturation. The input voltage U from the second input bus 8 is fed to the input of the integrating circuit 1, the voltage from the output of which is fed to the inverting input of the amplifier 2. When the voltage on the inverting input of the operational amplifier is equal to the voltage on its non-inverting input, which is equal to the input voltage 1 on the first input bus 7, the output voltage of the operational amplifier 2 begins to decrease, and the negative pulse through the capacitor 3 opens the diode 5, the voltage at the non-winding input of the amplifier 2 becomes close to zero. Resistor 6 protects the input source -U when diode 5 is open. When the output voltage of amplifier 2 reaches the value of f / i, diode 4 is opened. The capacitor of the passive integrating circuit 1 begins to discharge through the output resistance of the operational amplifier 2, covered by the open first diode 4, with 100% negative feedback. the circuit is discharged to a voltage close to the magnitude of the bias zero of the amplifier 2. Thus, the effect of instability of this magnitude, i.e. the zero drift, is eliminated. At the end of the discharge, diodes 4 and 5 are closed and the cycle is repeated. When f / 2 f / i, the circuit generates stable oscillations, the frequency of which, if not reading the nonlinearity of the output voltage of the passive integrating circuit 1, is defined by the following expression where J and C are the resistance and capacitance values of the capacitor of the passive integrating circuit. Thus, the output frequency signal of the converter is proportional to the voltage ratio. Introduction to the device of two diodes and a capacitor expands the functionality of the converter with a simpler circuit, in addition, this device solves the important problem of eliminating the influence of the zero drift of the operational amplifier. When using special measures to reduce the magnitude and instability of the residual voltage on diode 5, the device can be used as a high-precision low-level voltage converter during the period or pulse frequency. Claims The voltage converter is a frequency signal containing a passive integrating circuit and an operational amplifier, the non-inverting input of which is connected via a resistor to the first input bus and the inverting input to the output of the passive integrating circuit whose input is connected to a second input bus, characterized in that In order to simplify and expand the functional capabilities, two diodes and a capacitor connected between the output of the operational amplifier and its non-inverting input are inserted into it, and the inverter The input of the operational amplifier is connected to the anode of the first diode, the cathode of which is connected to the output of the operational amplifier, and the non-inverting input of the operational amplifier is connected to the cathode of the second diode, the anode of which is connected to the common bus. Sources of information taken into account during the examination 1. V. D. Makhianov, N. T. Milokhin. Frequency device and pulse conversion time. En 1970, p. 54. 2. Orpatin V.V. Voltage to frequency converter on an operational amplifier, Zh. “Instruments and Experimental Technique, 1974, Mg 1, p. 8 / -88. P 6 / X.