DD203415A1 - CIRCUIT ARRANGEMENT WITH FALLING VOLTAGE TEMPERATURE CHARACTERISTICS - Google Patents

Abstract

The invention relates to a circuit arrangement with decreasing voltage-temperature characteristics taking advantage of the dependence of the Fluszspannung a operated in the flow direction semiconductor PN junction of the temperature, preferably for use in reference voltage sources and temperature measuring devices. The goal of significantly increasing the scope of use with relatively little overhead is achieved by the solution of the following problem: to provide a circuit arrangement with a voltage which is strictly linear with respect to the temperature. This is done by the addition of a further operated in the direction of flow semiconductor PN junction to the already known, the over the two semiconductor PN transitions resulting temperature-dependent Fluszspannungen of an intermediate arrangement according to a specific rule to a strictly linear over the temperature falling voltage are processed.

Description

Title of the invention

Circuit arrangement with decreasing voltage-temperature characteristics erist ils:

Field of application of the invention

The invention relates to a circuit arrangement with decreasing voltage T emperatur Charakt erist ik taking advantage of the dependence of the forward voltage of a flow-operated semiconductor PH junction of the temperature, preferably for use in reference voltage sources and temperature measuring.

Characteristic of the known technical solutions

Circuit arrangements are known, in which the semiconductor PH junction is supplied with a constant current. However, the resulting forward voltage has IT-non-linearities in its temperature dependence, so that such circuits are insufficient for cases with very high accuracy requirements. Circuit arrangements are used to reduce the nonlinearities in the relationship between forward voltage and temperature, in which the constant current supply by feeding the semiconductor PH transition is replaced with a temperature-proportional flow current I ₁₇ , the function

i _p (T) = I ₀ . ^Τ Λ, (D

j satisfies where I _{Q is} the reference value of this current at the

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Temperature T = T _Q is.

However, the course of the positive voltage as a function of the temperature occurring during such control of the flux current is still characterized by visual linearities. As a result, here too the accuracy of arrangements which refer to this falling voltage-temperature characteristic, and thus the scope of o. A. Circuitries limited.

For example, known band gap references generally do not achieve a lower temperature coefficient than some low-cost voltage references for analog circuits (Analog Dialogue ^{8/1974 / H.2, p.12} ). Furthermore, the supply of a semiconductor PIT junction with a square-wave with the temperature increasing flux flow is known (Pat O'jfeil, Carl Derrington: Transistors as temperature sensors, electronics 29/1980 / H. 11, p.81 - 84) «

Thereby, the non-linearity of the voltage-temperature characteristic can be further reduced, but not completely eliminated. In addition, arises in this supply variant of the Halbieiter-Pl junction a considerable circuit complexity.

Object of the invention

The aim of the invention is to provide a circuit arrangement with decreasing voltage-temperature characteristics, in which the range of application is significantly increased with relatively little extra effort.

Explanation of the essence of the invention

The invention is based on the object to provide a circuit arrangement with a strictly linear voltage dropping above the voltage.

According to the invention the object is achieved in that in addition to the known semiconductor PH junction, a second

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Semiconductor PN junction is arranged and the first semiconductor P ¥ junction with a current source, which is a current with a temperature dependence

and the second semiconductor PU junction with a current source having a current Ip with a temperature dependence

T ß I ₂ (T) = Iq ₂ (jjT-) v.2)

is connected, where Iq. or I _Q2 the reference values of the two currents at the temperature T = T ₀ and ei, Q exponents with the condition

Q-CaCέβ '(3)

The respective connection point of the current source to the associated semiconductor PH junction is in each case connected to a Bingang of an arrangement which is designed so that it is the rule

U = U ₁ -M + "3 * (U-Jj ₁₀ - υ -, -,) (4)

realized, where U ^ are the output voltage of the arrangement, UT _1. , or U- _o the am.Verbindungsnunkt the first and second semiconductor PH junction with the respective associated current source applied to the forward voltage of the semiconductor PIT junctions and for the Factor ~ £ the prescription

> o)

The effect of the circuit arrangement is based on the relationships explained in more detail below:

Over a semiconductor flux junction fed with a flux current I ™. arises the temperature-dependent forward voltage U ^ ₁ (T). For this flux voltage applies in a certain range of

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Current-voltage characteristic of semiconductor PFC junction the relationship

U _p = -U ₁ In J- , (6)

where U ₂ = IT (7)

the temperature voltage with the Boltzmann constant k, the Slementarladung q and the absolute temperature T and

I _Q = CT ^ exp ^ '(8)

the saturation current with the. Component parameters C, P and the band gap W is »

Equations (7) and (8) used in equation (6) lead to

: u w

from which the temperature behavior of the voltage Dp can be determined by deriving according to the temperature:

^(u V f ^

ar - r ^(u g- V -f ^ - ^ · ⁽¹⁰⁾

W where U = - ^. (11)

If we give a certain temperature dependence for the flux I ^, so that

T dl,

= const. , , (12)

applies, results as a solution for the differential equation (10)

U ^ = U. (u _ u) | _ -ι; 'ϋ _φ I- In I- (13)

not ^; ü_, ₀ = U ₅ , (2 = T ₀ ), (14)

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^υ το

T dip and υ '= χ) -? - 4 · ♦ (16)

In the case of the use according to the invention of two semiconductor PN junctions fed with currents according to equations (1) and (2), the resulting forward voltages t L,

- W Ij - »1 - *> ^u to

and U _M = U _g2 - (U _g2 - U ₁₀₂ )! jj - Co ₂ - / 3) U ₁₀ f. in | _, (18)

where the indexing with 1 and 2, respectively, indicates the affiliation of the corresponding quantities to the semiconductor PSF transitions 1 and 2, respectively.

The combination of equations (17) and (18) according to rule (4) provides

^Ü 3 "V ⁺ 'W -fer ⁰ "**' KV ^^ J} -1 "^ ₁ -d + T (^ ₂ - / 3 - O ₁ + ^) J n _T0 ψ ^ in | -. (19)

By setting the factor 0 according to the regulations

1

Vo A T ,,

from equation (19) a linear relationship between the voltage U, and the temperature T:

By suitable choice of the reference currents Iq. and the connection

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^U g2 " ^U g1" ^U K> 2 " ^U P01 (22)

with which from equation (21)

3 = ^ü g1

^U 3 = ^ü g1 ^{+ ί CU} _S 2 - V " ^(Ü S1" ¹ W 3 £ ⁽²³⁾

follows.

Highly favorable conditions result when using identical, for example integrated, semiconductor PlI transitions 1 and 2,

where 'S) _Λ = V ₀ = 13, (24)

• ^ü P01 =

applies

 This simplifies equation (21)

^U 3 ^U s - ^(U g - ^U P0 ^% '

whereby a strictly linear relationship between the voltage U, and the temperature T is given.

Äusführungsbeispiel

The invention will be explained in more detail in the following Äusführungsbeispiel.

According to the drawing, the circuit arrangement with linearly decreasing voltage-temperature characteristic consists of semiconductor PU junctions 1 j 2, current sources 3; 4, connection points 5? 6; .7 and an arrangement 8, the operational amplifier 9 with resistors 10; 11 contains and inputs 12; 13 as well as an outlet 14.-

The mode of operation of the circuit arrangement is the following: The semiconductor PiJ tibergänge 1 or 2 are fed by the current sources 3 and 4, respectively, which satisfy the equation (12) the currents

Ij = I ₀₁ = const. , (28)

or I ₂ = Iq ₂ ψ- (29)

which, for the present embodiment, yields the exponents ^ and / 3 from the equations (1) and (2) the values

oi = 0 · (30)

or / 3 = 1. (31)

accept.

The arrangement 8 contains to implement the regulation (4) a known operational amplifier circuit with the resistors 10 and 11 whose values R10 and R11 with

R10 = {tf- 1) R11 (32)

are fixed.

The value R11 is selected such that the current flowing through the resistor 11 to the connection point 5 is opposite to the current. · Current I _{1 is} negligibly small.

The further mode of operation of the circuit arrangement according to the invention is explained in the following material constants and freely selected reference values, wherein the implementation of the semiconductor-PIP junctions 1 and 2 is to take place by integrated silicon transistors whose collector-base junction is operated in the short circuit:

g1 ~ "g2 ~ g" ~ '

T ₀ = 300 K.

The used semiconductor PH junctions 15 2 should at this 3ezug3temperatur T _Q and a current

¹ FOI ^{= 1} FC ^ ^{= 1} FO " ⁰ ^ ² ^ a forward voltage

^Ü H) 1 ^{= ü} F02 ^{= U} P0 ⁼

respectively

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From equation (20) and relationships (30) and (31) one obtains

f = 3. (33)

This results in the 'resistors 10 and 11 of the context

RIO = 2 R11, (34)

in the exemplary embodiment with the values R10 = 20 kO. and R11 = 10k-Ω.

is realized.

At the output 14 of the circuit arrangement, a voltage U- is produced with respect to the connection point 7, according to equation (27), which in the present exemplary embodiment is represented by a temperature coefficient en Dm

_! k ^ 2 ₌ . _2mYr i ₍₃₅₎

is marked.

It is also conceivable to satisfy the relationship (4) with a factor / T according to equation (20), if for the two currents I. and Ip

I ₁ = I ₂ (36)

with oC = / 3 (37)

and the material constants VL and V ~ differ from each other.

Furthermore, it is possible to realize the arrangement 8 in a different way than described in the exemplary embodiment. For the current sources 3 and 4 can be used to achieve the effect of the invention generally conventional arrangements.

Claims (1)

2348 9 9 3 invention claim Circuit arrangement with decreasing voltage-temperature characteristics taking advantage of the dependence of the J ¹ IuB span of a semiconductor-PH junction operated in the direction of flight on the temperature, preferably for use in reference voltage sources and temperature measuring devices, characterized in that in addition to the known half-conductor PH Transition (1) a second semiconductor? H junction (2) is arranged and the first semiconductor PH junction (1) with a current source (3) having a current I-. with a temperature dependence and the second semiconductor PH junction (2) with a current source (4) having a current I ₂ with a temperature dependence I ₂ (T) = I ₀₂ (ψ-) where Iq ₁ or I _Q p are the reference values of the two currents at the temperature T = T _Q and ^, /? Exponents with the condition 0 * o <& j3 and the respective connection point (5; 6) of the current source (3; 4) with the assigned semiconductor PH junctions (1; 2) 'in each case with. an input (12; 13) of an assembly (8) which is designed to comply with the requirement realized, where U ^ the output voltage of the arrangement (8), U-Tj ₁ bzv /. UJ ₉ which at the connection point (5; β) of the first and second semiconductor-PlT transition (1; 2) with the respective associated current source (3; 4) adjacent. is residual and voltage, and for the factor T the prescription Q ^ "^ O holds. For this 1 page drawing