SU824164A1

SU824164A1 - Reference voltage source

Info

Publication number: SU824164A1
Application number: SU792792464A
Authority: SU
Inventors: Эркки Раймундович Круусе
Original assignee: Предприятие П/Я Г-4934
Priority date: 1979-07-05
Filing date: 1979-07-05
Publication date: 1981-04-23

Description

Изобретение относится к электроизмерительной технике и может применяться в качестве двухполярного источника постоянного напряжения, например, в автоматических измерительных системах.The invention relates to electrical engineering and can be used as a bipolar constant voltage source, for example, in automatic measuring systems.

Известны источники напряжений, используемые в радиотехнических установках и· приборах для создания опорных напряжений [1] .Known voltage sources used in radio installations and · devices for creating reference voltages [1].

Наиболее близким по технической сущности к предлагаемому является источник опорного напряжения, содержащий мостовую схему cq стабилитронами в двух противоположных плечах и резисторами в двух других плечах и два операционных усилителя, поочередно подключаемые к выходной клемме источника. Первый усилитель инвертирующим входом соединен с анодом и выходом - с катодом одного ИЗ! ста-’ билитронов, а второй усилитель инвертирующим входом соединен с катодом И выходом - с анодом другого стабилитрона мостовой схемы Г2 J.The closest in technical essence to the proposed one is a reference voltage source containing a bridge circuit with qq zener diodes in two opposite arms and resistors in two other arms and two operational amplifiers, alternately connected to the output terminal of the source. The first amplifier with an inverting input is connected to the anode and output - to the cathode of one of the FMs! st ’bilitrons, and the second amplifier is connected by an inverting input to the cathode AND output to the anode of another zener diode of the bridge circuit G2 J.

В известном источнике опорного напряжения температурная погрешность в основном определяется температурными погрешностями стабилитронов.In a known reference voltage source, the temperature error is mainly determined by the temperature errors of the zener diodes.

' .· ² ''. · ² '

Добиться уменьшения температурной погрешности можно либо термостатированием схемы, либо созданием схем температурной компенсации, применяя элементы с малыми температурными коэффициентами. Если пользоваться термостатированием схемы, то возрастают габариты и потребляемая мощность источника, а также возрастает время выхода на режим и ухудшается временная стабильность источника. Применение элементов с малыми температурными коэффициентами неэффективно, так как нужен выбор элементов с одинаковыми температурными коэффициентами.You can achieve a reduction in temperature error either by thermostating the circuit, or by creating temperature compensation circuits using elements with low temperature coefficients. If you use the temperature control circuit, then the dimensions and power consumption of the source increase, as well as the time to enter the mode increases and the temporary stability of the source deteriorates. The use of elements with low temperature coefficients is inefficient, since a selection of elements with the same temperature coefficients is needed.

Цель изобретения- уменьшение тем-. пературной погрешности выходного напряжения 'источника, при этом не ухудшая временной стабильности выходного напряжения.The purpose of the invention is the reduction of. the temperature error of the output voltage of the source, while not compromising the temporal stability of the output voltage.

Поставленная цель достигается тем, что источник опорного напряжения, содержащий мост со стабилитронами в двух противоположных плечах и резисторами в двух других плечах, клемму подключения источника управляющего напряжения, два операционных усилителя, выходы которых являются выходами устройства и подключены к двум противоположным вершинам моста, неинвертирующие входы'присоединены к клемме подключения источника управляющего напряжения, имеет также два дополнительных операционных усилителя, неинвертирующие входы которых подключены через цепочки из двух последовательно включенных дополнительных резисторов к выходам устройства и к другим противоположным вершинам моста, выходы дополнительных усилителей присоединены к своим инвертирующим входам и к инвертирующему входу первого и второго, соответственно, основных операционных усилителей, а также через дополнительные диоды разного направления к точкам соединения дополнительных резисторов последовательных резистивных цепей.This goal is achieved by the fact that the reference voltage source, containing a bridge with zener diodes in two opposite arms and resistors in the other two arms, a control voltage source connection terminal, two operational amplifiers, the outputs of which are device outputs and are connected to two opposite bridge vertices, non-inverting inputs '' connected to the control voltage source connection terminal, also has two additional operational amplifiers, the non-inverting inputs of which are connected Through a chain of two series-connected additional resistors to the outputs of the device and to other opposite vertices of the bridge, the outputs of the additional amplifiers are connected to their inverting inputs and to the inverting input of the first and second, respectively, main operational amplifiers, as well as through additional diodes of different directions to the connection points additional resistors in series resistive circuits.

На чертеже изображена электрическая схема предлагаемого источника опорного напряжения.The drawing shows an electrical diagram of the proposed reference voltage source.

Источник опорного напряжения выполнен на основе мостовой схемы, в противоположных плечах которой включены два стабилитрона 1 и 2 и два резистора 3 и 4. К выходной клемме 5 положительных выходных напряжений подключены выход операционного усилителя 6, Одна клемма резистора 4 и катод стабилитрона 1, к выходной клемме 7 отрицательных выходных напряжений подключены выход операционного усилителя 8, одна клемма резистора 3 и анод стабилитрона 2. Клемма 9 подключения управляющего напряжения присоединена к неинвертирующему входу операционных усилителей б и 8. Неинвертирующие входы дополнительных операционных усилителей 10 и 11 подключены через два тфсЛедОвательно включенных резистора, соответственно 12, 13 и 14, 15 к выходу 5 и через два последовательно включенных резистора, соответственно 16, 17 и 18, 19 - к выходу 7. Выходы дополнительных усилителей 10 и 11 присоединены прямо к своим инвертирующим входам, и к инвертирующим входам основных операционных усилителей 6 и 8, соответственно, а. также через дополнительные диоды разного направления 2Q и 21.или 22 и 23 к точкам соединения дополнительных резисторов последовательных резистивных цепей 12, 13 иЛб, 17 или 14, 15 и 18, 19, соответственно.The reference voltage source is based on a bridge circuit, on the opposite shoulders of which two zener diodes 1 and 2 and two resistors 3 and 4 are connected. The output of operational amplifier 6 is connected to the output terminal 5 of the positive output voltages. One resistor 4 terminal and the zener diode 1 cathode are connected to the output the terminal 7 of the negative output voltages is connected to the output of the operational amplifier 8, one terminal of the resistor 3 and the anode of the zener diode 2. Terminal 9 connecting the control voltage is connected to the non-inverting input of the operating voltage she’s b and 8. The non-inverting inputs of the additional operational amplifiers 10 and 11 are connected through two tfs Ice-connected resistors, respectively, 12, 13 and 14, 15 to output 5, and through two series-connected resistors, respectively 16, 17 and 18, 19, to output 7 The outputs of the additional amplifiers 10 and 11 are connected directly to their inverting inputs, and to the inverting inputs of the main operational amplifiers 6 and 8, respectively, a. also through additional diodes of different directions 2Q and 21.or 22 and 23 to the connection points of additional resistors of series resistive circuits 12, 13 and Lb, 17 or 14, 15 and 18, 19, respectively.

Все используемые операционные усилители 6, 8, 10 и 11 охвачены глубокой отрицательной обратной связью, и поэтому для упрощения анализа можно считать, что напряжение на обоих выходах усилителей фактически равны и их температурные дрейфы на порядок меньше температурных коэффициентов стабилитронов.All used operational amplifiers 6, 8, 10, and 11 are covered by deep negative feedback, and therefore, to simplify the analysis, we can assume that the voltage at both outputs of the amplifiers is practically equal and their temperature drifts are an order of magnitude lower than the temperature coefficients of the zener diodes.

На выходе усилителя 6 формируется стабилизированное положительное постоянное напряжение U^, а на выходе усилителя 8 отрицательное стабилизированное постоянное напряжение ^U-7At the output of amplifier 6, a stabilized positive constant voltage U ^ is formed, and at the output of amplifier 8, negative stabilized constant voltage ^U -7

Uj-(T) = г и₇(т) = и;Uj- (T) = r and ₇ (t) = u;

где U₄ , (О10 ^U9 = U. (Т)+ Ug ,where U ₄ , (O10 ^U 9 = U. (T) + Ug,

- U_a(T),- U _a (T),

- падения напряжения на стабилитронах 1 и 2, соответственно*,- voltage drops at zener diodes 1 and 2, respectively *,

- напряжение управляющего источника 9;- voltage control source 9;

- температура.- temperature.

ЗдЧерез стабилитроны 1 иZd through zener diodes 1 and

ТT

Токи 3^ , равны □ ^ую(т) .The currents 3 ^ are equal to □ ^y ω (t).

С ^ч~ R, ⁺ β~ о---- >C ^h ~ R, ⁺ β ~ o ---->

ί (ту- < UaaCnί (tu- <UaaCn

J) где ^U2o’ ^U21 ’ ^U2i’ ^ϋ2?Γ ^RrJ) where ^U 2o ' ^U 21' ^U 2i ' ^ϋ 2? Γ ^R r

- падения напряжения стабилитронов 1 и 2, соответственно;- voltage drops of zener diodes 1 and 2, respectively;

падения напряжения диодов 20-23. сопротивления резисторов 3, 4, 13, 16, 14 и 18. Выходные напряжения U_, U_T и тост абили.тронов 3_γ , З_а имеют темпе30 ί КИ ратурную зависимость. При изменении температуры от Т₄ до изменяется . падение напряжения стабилитронов на величину δ (Т) и ди а (т) ;voltage drop of diodes 20-23. the resistances of resistors 3, 4, 13, 16, 14, and 18. The output voltages U_, U _T, and the toast of the abili trons 3 _γ , З _а have a temperature of 30 ί KI temperature dependence. When the temperature changes from T ₄ to changes. Zener voltage drop by δ (T) and di a (t);

ди^Т) = ϋ₇. (^) - 1¼. (Ь,)_; ди_а(т) = (tJ ) - и_а (tJ) , ⁽³/ которые и вызывают изменения выходных напряжений. Чтобы выходные напряжения остались неизменными, надо изменитьтоки через стабилитроны Ц, и так, чтобы ди, (т) = 0 иd ^ T) = ϋ ₇ . (^) - 1¼. (B,) _; di _a (t) = (tJ) - and _a (tJ), ⁽³ / which cause changes in the output voltages. In order for the output voltages to remain unchanged, it is necessary to change the currents through the zener diodes C, and so that di, (t) = 0 and

AUzj. (Т) = 0.AUzj. (T) = 0.

Далее рассмотрим как уменьшается температурная погрешность выходного напряжения отрицательной полярности. Для упрощения анализа предположим, что напряжение управляющего источника равняется нулю и при увеличении температуры от до Т_а падение напряжения стабилитрона Уменьшается. Чтобы 1М (Т₄) = U_a (Т_а), т.е.Next, we consider how the temperature error of the output voltage of negative polarity decreases. To simplify the analysis, assume that the control voltage source is zero, and when the temperature increases from T to _a zener voltage drop decreases. To 1M (T ₄ ) = U _a (T _a ), i.e.

-ΑΙΙχ (Т) = 0, надо-увеличить ток За стабилитрона .2 так, чтобы приращение тока составило . '1 ₍₄) где R_CT - дифференциальное сопротивление стабилитрона 2 при токе 3 2. (Т) .-ΑΙΙχ (Т) = 0, it is necessary to increase the current Zener diode .2 so that the current increment is. '1 ₍₄ ) where R _CT is the differential resistance of the Zener diode 2 at a current of 3 2. (T).

Выбирая ток через резистор 18Selecting current through resistor 18

6(Т) = аЗ^(Т), получаем соответствующую компенсацию напряжения стабилитрона 2 (Т) =0 так, чтобы при изменений температуры выходное напряжение оставалось стабиль5 ным. Величина сопротивления резистора 18,выбирается соотношением _й 18' ДЭ₄(Т) ’ (5) где U,2j (Tj ) и U₂₃ (Т^) - напряжения, диода 23 при температурах, Tj и ^соответственно.6 (Т) = аЗ ^ (Т), we obtain the corresponding compensation of the voltage of the zener diode 2 (Т) = 0 so that, with temperature changes, the output voltage remains stable5. The value of resistor 18 is selected by the relation _d 18 'DE ₄ (T)' (5) where U, 2j (Tj) and ₂₃ U (T ^) - voltage diode 23 at temperatures, Tj and ^ respectively.

Чтобы исключить температурную койкой точности выходного напряжения исключить из источника дорогостоящий термостат и, кроме того, благодаря исключению термостата, время готовности прибора к работе умень. шается с 45-60 мин до 5-10 мин, что дает потребителю выигрыш во времени на 10% при 8-ми часовом режиме эксплуатации прибора.In order to exclude the accuracy of the output voltage by the temperature bed, to exclude the expensive thermostat from the source and, in addition, due to the exclusion of the thermostat, the readiness time for operation of the device is reduced. It takes from 45-60 minutes to 5-10 minutes, which gives the consumer a 10% gain in time with an 8-hour operation mode of the device.

пенсацию выходного напряжения ниже температуры выбираем сопротивление резистора 19 ·compensation of the output voltage below the temperature, select the resistance of the resistor 19

R - ^ио.СЦ)~ Uxb(Tj) 19 (Ь).R - ^and o.S.C.) ~ Uxb (Tj) 19 (b).

Если при возрастании температуры наблюдается увеличение падения напряжения стабилитрона 2,. то соответствующую компенсацию тока стабилитрона получаем, уменьшая ток ре- 20 зистора 14. При расчете можно применять формулы (!) - (5), если в них диод 23 заменить диодом 22, резистор 18 - резистором 14, а резистор 19 - резистором 15.If with increasing temperature there is an increase in the voltage drop of the Zener diode 2 ,. then we obtain the corresponding compensation of the zener diode current by reducing the current of the resistor of resistor 14. In the calculation, you can use formulas (!) - (5), if the diode 23 is replaced by diode 22, resistor 18 is replaced by resistor 14, and resistor 19 is replaced by resistor 15.

Таким образом, при помощи резисторов 18 и 19, а также диода 23 получаем линейную компенсацию тока стабилитрона 2 отрицательным температурным коэффициентом напряжения в интервале температур от до Ъ-, а при помощи резисторов 14 и 15 и диода 22 получаем линейную компенсацию тока стабилитрона 2 в области положительного температурного коэф- -j. фициента напряжения.Thus, using resistors 18 and 19, as well as diode 23, we obtain linear compensation of the Zener diode current 2 by a negative temperature coefficient of voltage in the temperature range from b-, and using resistors 14 and 15 and diode 22 we obtain linear compensation of the Zener diode 2 in the region positive temperature coefficient -j. stress factor.

’ Аналогично этой процедуре выраба тывается и положительное выходное напряжение’A positive output voltage is generated in the same way.

При правильном выборе номиналов резисторов получен суммарный темпе- .40 ратурный коэффициент напряжения в интервале температур от + 10 до + 50°С не более 0,002%, т.е. предлагаемое схемное решение уменьшает температурный коэффициент напряжения 45 источника на порядок.With the correct choice of resistor values, the total temperature coefficient of .40 temperature coefficient in the temperature range from + 10 to + 50 ° C is not more than 0.002%, i.e. the proposed circuit solution reduces the temperature coefficient of voltage of the source 45 by an order of magnitude.

Благодаря уменьшению температурной погрешности согласно предлагаемому техническому решению можно, при обеспечении определенной высо-By reducing the temperature error according to the proposed technical solution, it is possible, while ensuring a certain high

Claims

one . V The invention relates to electrical measuring equipment and can be used as a two-pole source of constant voltage, for example, in automatic measuring systems. Voltage sources are known that are used in radio engineering installations and devices for creating reference voltages ClJ. The closest in technical essence to the proposed invention is the source of the reference voltage, which contains the bridge circuit cq with stabilizers in two opposite shoulders and resistors in the other two shoulders and two operational amplifiers, alternately connected to the output terminal of the source. The first amplifier is connected to the anode and output by an inverting input with the cathode of one of the stabilizers, and the second amplifier is connected to the cathode by an inverting input and the output from the anode of the other zener diode of the bridge circuit 121. The temperature error is mainly determined by the reference voltage source. inaccuracies of zener diodes. Reducing the temperature error can be achieved either by thermostating the circuit, or by creating temperature compensation circuits using elements with low temperature coefficients. If the temperature control of the circuit is used, the size and power consumption of the source increase, and also the time to reach the mode increases and the time stability of the source deteriorates. The use of elements with small temperature coefficients is inefficient, since a choice of elements with the same temperature coefficients is needed. . The purpose of the invention is to reduce the themes. The perioperative error of the output voltage of the source, while not impairing the temporal stability of the output voltage. The goal is achieved by the fact that a voltage source, containing a bridge with zener diodes in two opposite arms and resistors in two other arms, a connection terminal for a control voltage source, two operational amplifiers, whose outputs are device outlets and are connected to two opposite peaks the motor / non-inverting inputs are connected to the terminal for connecting the source of control voltage; it also has two additional operational amplifiers, the non-inverting inputs of which are connected through the chains of two series-connected additional resistors to the device's outputs and to other opposite vertices of the bridge, the outputs of additional amplifiers are connected to their inverter inputs and to the inverter input of the first and second, respectively, main operational amplifiers, as well as through additional diodes of different directions to the connection points of additional resistors of series resistive circuits. The drawing shows an electrical circuit of the proposed reference voltage source. The reference voltage source is made on the basis of a bridge circuit, in the opposite arms of which two Zener diodes 1 and 2 and two resistors 3 and 4 are connected. The output terminal 5 of positive output voltages is connected to the output of operational amplifier 6, one terminal of resistor 4 and the zener diode 1, the output of the operational amplifier 8, one terminal of the resistor 3 and the anode of the zener diode 2 are connected to the output terminal 7 of the negative output voltages. The terminal 9 for connecting the control voltage is connected to the non-inverting input of the operating currents Both b and B. The non-inverting inputs of the additional operational amplifiers 10 and 11 are connected via two r resistors of the connected resistors, respectively 12, 13 and 14, 15 to the output 5 and through two resistors connected in series, respectively 16, 17 and 18, 19 to the output 7. The outputs of the additional amplifiers 10 and 11 are connected directly to their inverting inputs, and to the inverting inputs of the main operational amplifiers b and 8, respectively, a. also through additional diodes of different directions 29 and 21. or 22 and 23 to the points of connection of additional resistors of the following resistor resistance circuits 12, 13 and 9.6, 17 or 14, 15 and 18, 19, respectively. All used operational amplifiers 6, 8, 10, and 11 are covered by a deep negative feedback, and therefore, to simplify the analysis, we can assume that the voltage at both outputs of the amplifiers is actually equal and their temperature drifts are an order of magnitude smaller than the temperature coefficients of the zener diodes . At the output of the amplifier 6, a stable positive constant voltage U is formed, and at the output of the amplifier 8 a negative stable constant voltage Uj-d) u. (T) + Ug,) Up - u, (t). where and, and are the voltage drops at the zener diodes 1 and 2, respectively, j and „, the voltage of the control source 9j T is the temperature. The currents L of the rear through the zener diodes 1 and 2 are equal to J (t) .l adill Uao (g) 4 th R O T6 3 (T) -M114.-M2l (T) ... R-X, - fall for example. nor the zener diodes 1 and 2, respectively; jn - Jt 2 crashes down 1 22.. diodes 20-23. one/-,. RX Rjln resistance / 3 (b (4 18 zistor 3, 4, 13, 16, 14 and 18. Output voltages and, -, U and Zener diodes 3, have a temperature dependence. When the temperature changes from T to T, it changes The voltage of the zener diodes is applied to the magnitude of li., (T) and di, (T); li (T) and (T) - i. (1,2.); /, 4 li (T) U2 (T., ) - and., (T), which also cause changes in the output voltages. In order for the output voltages to remain unchanged, you need to change the current through the zener diodes 1 3-2, so that di (T) O and li (T) 0. Next Let us consider how the temporal error of the output aperture of the negative sex decreases. To simplify the analysis, suppose that the voltage of the control source is zero and as the temperature rises from T to T: the voltage drop of the zener diode Ua. decreases. To u / i (T) and / g (T,;,), i.e. dUvj (tG o, it is necessary to increase the current a of the zener diode .2 so that the current increment is uUi (T) 1 - the differential resistance of the zener diode 2 at the current 3 2. (T). Choose the current through the 18 L resistor (T ) AZ (T), we obtain the corresponding compensation of the voltage of the tabilitron 2 di. (T) 0 so that when the temperature changes, the output voltage remains stable. The resistance value R of resistor 18 is selected by the ratio o -.MbihM fo dz (TT- where U, 2j (T) and ()) voltage of diode 23 at temperatures, T and responsibly. To exclude temperature compensation of the output voltage below temperature T choose the resistance of the resistor 19. S f-ib Y.-ССГ-,} 19 TsaSh, If with an increase in temperature an increase in the voltage drop of Zener diode 2 is observed, then the corresponding compensation of the current of the Zener diode Z. is obtained by decreasing the current of the resistor 14. the formulas () - (5), if in them diode 23 is replaced by a diode 22, resistor 18 is resistor 14, and resistor 19 is resistor 15. Thus, using resistors 18 and 19, as well as diode 23, we obtain linear current compensation for Zener diode 2 by a negative temperature coefficient of voltage in the temperature range from T to T, and With the help of resistors 14 and 15 and diode 22, we obtain a linear compensation of the current of Zener diode 2 in the region of a positive temperature coefficient of voltage. Similar to this procedure, a positive output voltage U, is generated. With the correct choice of resistor values, the total temperature coefficient of voltage was obtained in the temperature range from + 10 to + no more. 0.002%, i.e. The proposed circuitry reduces the temperature coefficient of the source voltage by an order of magnitude. By reducing the temperature error according to the proposed technical solution, it is possible to exclude a costly thermostat from the source while ensuring a certain high accuracy of the output voltage and, moreover, due to the elimination of the thermostat, the device availability time is reduced from 45-60 minutes to 5 -10 min, which gives the consumer a time gain of 10% with 8-hour operation of the device. Claims of the Invention Source A voltage source containing a bridge with zener diodes in two opposite shoulders and resistors in two other arms, a terminal. Connecting a control voltage source, two operational amplifiers, the outputs of which are device outputs and are connected to two antipole axes of the bridge non-inverting inputs are connected to a terminal for connecting a source of control voltage / characterized in that, in order to reduce the temperature error of the output voltages, the source of the reference voltage Equipped with two additional operational amplifiers, the non-inverting inputs of which are connected to the other two opposite the top of the bridge and through the chains of two series-connected additional resistors to the device outputs, the outputs of the additional amplifiers are connected to their inverting inputs and the second , respectively, the main operational amplifiers, as well as through additional diodes of different directions to the points of connection of additional resistors after ovatelnyh resistive circuits. . Sources of information taken into account during the examination 1.Weigerovsky L.V. and Weinstein A.Kh. Precision semiconductor stabilizers. M., Energie, 1974.

2. USSR author's certificate No. 445037, cl. G 05 F 1/56.