RU2101751C1 - Reference voltage source - Google Patents

Abstract

FIELD: electric engineering. SUBSTANCE: device has pulses which is connected between power supply line and output terminal, first resistor, which is connected between output terminal and connection point of base of first transistor and first terminal of second resistor, second transistor, which emitter is connected to output terminal and which joined base and collector are connected to collector of first transistor. In addition device has stabilizing diode which cathode is connected to emitter of first transistor and anode is connected to common line. In addition device has third resistor which is connected between connection point of second resistor terminal and collector of third transistor and common line. Emitter of third transistor is connected to output terminal. Base of third transistor is connected to base of second transistor. EFFECT: increased functional capabilities. 2 dwg

Description

 The invention relates to electrical engineering and can be used as a voltage reference source.

Known sources of reference voltage (ION), containing a current source and a zener diode, characterized by maximum simplicity [1]
The disadvantage of such an ION is the impossibility of changing the output voltage over a wide range, the relatively high output resistance and, as a result, the low stabilization coefficient.

The closest technical solution adopted for the prototype is an ION containing a current source connected between the power bus and the output terminal, a transistor whose collector is connected to the output terminal, a first resistor connected between the collector and the base of the transistor, and a second resistor connected between the base of the transistor and a common bus, a zener diode connected by a cathode to the emitter of the transistor, and an anode to a common bus [2]
The disadvantage of the prototype is the high output impedance and low stabilization coefficient.

 To reduce the output resistance and increase the stabilization coefficient in the prototype circuit, containing a current source connected between the power bus and the output terminal, the first resistor connected between the output terminal and the connection point of the first output of the second resistor with the base of the first transistor, a zener diode connected to the emitter of the first the transistor, and the anode to the common bus, introduced a third resistor connected between the second terminal of the second resistor and the common bus, the second transistor connected by the emitter to the output glue IU and the combined base and collector to the collector of the first transistor, the third transistor, an emitter connected to the output terminal and the base to the connection point of the first transistor collector and the collector and base of the second transistor, the collector of the third transistor is turned on to the point of connection of the second and third resistors.

 The prototype diagram is shown in figure 1, and the proposed ION in figure 2.

 The proposed ION (figure 2) contains a current source 1 connected between the power bus and the output terminal, the first resistor 2 connected between the output terminal and the connection point of the base of the first transistor 3 with the first output of the second resistor 4, the second transistor 5 connected by the emitter to the output the terminal, and the combined base and collector to the collector of the first transistor 3, a zener diode 6 connected by a cathode to the emitter of the first transistor 3, and an anode to a common bus, a third resistor 7 connected between the connection point of the second output of the resistor 4 s ollektorom third transistor 8 and the common bus, the emitter of the transistor 8 is connected to the output terminal and the base of transistor 8 to the base of transistor 5.

 Before you consider the work of the proposed device, consider the operation of the prototype circuit (figure 1), as it is necessary for comparative analysis.

где U_ст напряжение стабилизации стабилитрона VD1; U_бэ - напряжение база-эмиттер транзистора VT1; R₁, R₂ сопротивление резисторов R1 и R2 соответственно. Выходное сопротивление r_пр можно найти, продифференцировав выходное напряжение по току источника тока

где I_э ток эмиттера транзистора VT1; I_пр ток источника тока G1. Тогда

где r_эпр и r_стпр дифференциальные сопротивления эмиттера транзистора VT1 и стабилитрона VD1 соответственно.Provided that the current gain of the base β of the transistor VT1 (Fig. 1) is much greater than unity, the output voltage of the prototype circuit can be represented by the well-known expression [2]

where U _article stabilization voltage of the Zener diode VD1; U _BE - voltage base-emitter of the transistor VT1; R ₁ , R _{2 the} resistance of the resistors R1 and R2, respectively. The output resistance r _pr can be found by differentiating the output voltage by current of the current source

where I _e the emitter current of the transistor VT1; _{I direct} current I of the current source G1. Then

where r _epr and r _{stpr are the} differential resistances of the emitter of transistor VT1 and zener diode VD1, respectively.

где4 U_ст напряжение стабилизации стабилитрона 6; U_бэ - напряжение база-эмиттер транзистора 3; R_i сопротивление i-го резистора. Выходное сопротивление r_вых можно представить в виде

где r_э и r_ст дифференциальные сопротивления эмиттера транзистора 3 и стабилитрона 6 соответственно.Consider the operation of the device (Fig. 2). Using transistors 5 and 8, acting as a "current mirror", a positive feedback is introduced into the ION. With close parameters of transistors 5 and 8, which is possible with their integral design, the current I _{8 of the} collector of transistor 8 can be considered equal to the current of the collector of transistor 3 and for β> 1 the current I _{3 of the} emitter of transistor 3. The output voltage U _o can be defined as

where4 U _article stabilization voltage of the zener diode 6; U _BE - voltage base-emitter of the transistor 3; R _{i is the} resistance of the i-th resistor. The output resistance r _o can be represented as

where r _e and r _{article the} differential resistance of the emitter of the transistor 3 and the zener diode 6, respectively.

При этом коэффициент стабилизации K, равный

где r_ит внутреннее дифференциальное сопротивление источника тока; E_n напряжение шины питания, обращается в бесконечность. В случае приближенного выполнения равенства (6) выходное сопротивление заявляемого ИОН оказывается в десятки и сотни раз ниже, чем в схеме прототипа, а коэффициент стабилизации выше.From the analysis of expression (5) it follows that in order to obtain an output resistance equal to zero, it is necessary

Moreover, the stabilization coefficient K, equal to

where r _{it is the} internal differential resistance of the current source; E _{n the} voltage of the power bus, goes to infinity. In the case of approximate fulfillment of equality (6), the output resistance of the claimed ION is tens and hundreds of times lower than in the prototype circuit, and the stabilization coefficient is higher.

Claims (1)

 A voltage reference source comprising a current source connected between the power bus and the output terminal, a first resistor connected between the output terminal and the connection point of the base of the first transistor with the first output of the second resistor, a zener diode connected by a cathode to the emitter of the first transistor, and the anode to the common bus, characterized in that a third resistor is inserted into the device, connected between the second terminal of the second resistor and the common bus, the second and third transistors, the emitters of which are connected to the output terminal, and the base to the point compound collectors of the first and second transistors, the collector of the third transistor is turned on to the point of connection of the second and third resistors.

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