SU1241450A1 - Voltage-to-frequency converter - Google Patents

Abstract

This invention relates to the field of radio engineering. It can be used to convert voltage to frequency. The aim of the invention is to improve the accuracy of the conversion. The converter contains paraphase cascade 1, sources 2 and 3 of constant voltage, sources 4 and 5 of direct current, made on transistors 6 and resistors 7, diode bridge 8, capacitor 10. To achieve this goal, the converter also includes , inverter 15, comparison unit 12, containing operational amplifier 13, capacitor 14. The voltage difference between the emitters of the transistors 6 is maintained with a high accuracy equal to the input voltage. At the same time change of current sources. 4 and 5 under the influence of various destabilizing factors does not affect the stability of the output frequency of the converter. 1 il. with S (L gN tN5 u ate Output

Description

one

The invention relates to radix-15 and can be used to convert a voltage to a frequency.

The purpose of the invention is to increase the accuracy of the conversion.

The drawing shows a structural electrical circuit for converting voltage to frequency.

The voltage to frequency converter contains a paraphase cascade 1, the first 2 and second 3 sources of constant voltage, first 4 and second 5 current sources, made respectively on transistors 6 and resistors 7 connected between sources 2 and 3 of constant voltage and emitters transistors 6 sources 4 and 5 current ring diode bridge 8, one diagonal of which is connected to the collector of transistors 6 sources 4 and 5 current, trigger 1 1 1midta, input and output of which are connected to another diagonal ring diode bridge 8, the first condenser a 10 connected between a common bus and Schmidt trigger 9 input connected in series differential amplifier 11, the inputs of which are connected to the emitters of transistors 6 of current sources 4 and 5, comparison unit 12, made on the operational amplifier (OA) 13, in the negative feedback circuit The capacitor 14 is turned on, and the non-terminating input of the op-amp 13 is the input of a voltage to frequency converter, and the inverter 15, the output of which is connected to the input of a paraphase cascade 1..

The voltage to frequency converter operates as follows.

Suppose that at the output of the Schmidt trigger 9 there is a positive potential. Then the capacitor 10 is charged through the ring diode bridge 8 from the current source 4.

At the point in time when the voltage on the capacitor 10 reaches the positive threshold of the Schmidt trigger 9, the latter trips and a negative potential is generated at its output, which disconnects using an annular diode bridge 8: the current source I1 connects 4 the capacitor 10 to the source 5 of the current flowing. Capacitor 10 begins to recharge before the time when the voltage across it reaches the negative threshold.

the triggering of trigger 9 (Lmidt. Next, the process repeats.

The charge of the capacitor 10 is linear.

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where and

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voltage on the time of the master capacitor 10; current sources 4 and 5; the charge time of the capacitor 10 to the trigger threshold of Schmidt trigger 9; the capacitance of the capacitor 10. The conversion of voltage to frequency is carried out by changing the current I as follows.

The constant voltage from the emitters of the transistors 6 is supplied through the differential amplifier 11, the transmission coefficient of which can be chosen to be equal (unit to the inverting input of the op-amp 13 of the comparison unit 12, is compared with the input voltage and 15 and paraphase

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cascade 1 changes the currents of the sources of the currents 4 and 5 in such a way that the difference in voltage at the inputs of the comparison unit 12 becomes zero.

Let the voltage at some point in time at the non-inverting input –СУ 13 become its inverter input. OU 13 reinforces this difference. In this case, the voltage at the output of the op-amp 13 can have a positive polarity, and at the output of the inverter 15 - negative. Then the current flowing through the cs (gz paraphasic cascade 1j decreases. The currents of the transistors 6 of the current sources 4 and 5 are correspondingly reduced, which leads to a decrease in the voltage drop across the resistors 7 and, accordingly, to an increase in the same voltages relative to the total bus i.e. at the inputs of the differential amplifier 11, and therefore to an increase in voltage at the inverting input of the op-amp 13. A similar control process occurs when the voltage at the inputs of the op-amp 13 has a different relative sign.

Thus, the voltage difference between the emitters of the transistors 6 is maintained with high accuracy equal to the input voltage. At the same time, changes in the currents of current sources 4 and 5 under the action of various destabilization factors do not affect the stability of the output current.

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frequency converter that higher-; no conversion accuracy.

Claims (1)

Invention Formula Voltage to frequency converter containing the first and second sources of direct voltage, paraphase cascade, first and second sources, currents made on transistors of different conduction types, the bases of which are connected to the corresponding outputs of the paraphase cascade between the emitters of source transistors DC voltage sources and outputs include resistors, a ring diode bridge, one diagonal of which is connected to the collectors of current source transistors, Schmidt trigger, the input and output of which dklyucheny to the other diagonal kolor M. Nedoluzhenkr 3612/54 Compiled by C, Lebedev Tehred L. Oleinik Cor Pod Circulation 816. VNIIPI USSR State Committee for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab., d. / 5 Production and printing company, Uzhgorod, st. Project 4 304 The first diode bridge, and the first capacitor, is connected between the common pshnaya and the Schmidt trigger input, the output of which is the output of a voltage to frequency converter, which means that, in order to improve the accuracy of the conversion, an inverter and a series-connected differential amplifier are inserted, the inputs of which are connected to the emitters of the respective transistors of the current sources, and the comparison unit, made on the operational amplifier, in the negative feedback circuit of which the second capacitor is connected, while non-inverting input of the operational amplifier is an input voltage in the converter frequency, and between the output of the comparison unit and the input of the inverter included parafaznogo- cascade. Proofreader E. Subscription