RU2383100C1 - Radiation-resistant voltage-to-current converter - Google Patents

Abstract

FIELD: physics; radio.

SUBSTANCE: invention relates to radio engineering and communication and can be used as a device for converting analogue signals in the structure of analogue microcircuits for different functional purposes (for example operational amplifiers, voltage multipliers, comparators etc). The radiation-resistant voltage-to-current converter has a signal source (1) connected between bases of a first (1) and a second (2) input transistor, first (4) and second (5) current stabilising two-terminal circuits connected to emitters of corresponding first (2) and second (3) input transistors, a scaling resistor (6) connected between emitters of the first (2) and second (3) input transistors, a load circuit (7) connected to collectors of the first (2) and second (3) input transistors and first (8) and second (9) current outputs of the device. The circuit includes first (10), second (11), third (12) and fourth (13) additional transistors. The base of the first (10) additional transistor is connected to the base of the first (2) input transistor. The emitter of the first (10) additional transistor is connected to the emitter of the first (2) input transistor. The base of the second (11) additional transistor is connected to the first (8) current output of the device. The emitter of the second (11) additional transistor is connected to the collector of the first (10) additional transistor. The collector of the second (11) additional transistor is connected to the power supply (14). The base of the third (12) additional transistor is connected to the base of the second (3) input transistor. The emitter of the third (12) additional transistor is connected to the emitter of the second (3) input transistor. The base of the fourth (13) additional transistor is connected to the second (9) current output of the device. The emitter of the fourth (13) additional transistor is connected to the collector of the third (12) additional transistor. The collector of the fourth (13) additional transistor is connected to the power supply (14).

EFFECT: reduced conversion errors under radiation conditions.

2 cl, 9 dwg

Description

The invention relates to the field of radio engineering and communication and can be used as a device for converting analog signals in the structure of analog microcircuits for various functional purposes (for example, operational amplifiers, voltage multipliers, comparators, etc.).

Known schemes of classical voltage-current converters (PNT) based on differential stages with a symmetrical load in the form of resistors (or pn junctions) and local negative feedback, which are widely used in modern analog microcircuits [1-22], for example, mixers and multipliers of signals.

The closest prototype (figure 1) of the claimed device is a voltage-current converter described in US patent No. 6531920, figure 1, containing a signal source 1 connected between the bases of the first 1 and second 2 input transistors, the first 4 and second 5 current-stabilizing two-terminal connected to the emitters of the corresponding first 2 and second 3 input transistors, a scaling resistor 6 connected between the emitters of the first 2 and second 3 input transistors, a load circuit 7 connected to the collectors of the first 2 and second 3 input transistors s 8 and the first and second current outputs 9 of the device.

A significant drawback of the known device is that the error in converting the input voltage u _I to the output current (I ₈ , I ₉ ) depends on the numerical values of the current gain of the base (β) of the input transistors, which decreases by 5 ÷ 10 times when exposed neutron flux (F) and according to the literature at F = 10 ¹³ ÷ 10 ¹⁴ n / s · cm ² for bipolar npn transistors reaches β _min = 5 ÷ 10.

The main objective of the invention is to reduce the error of converting the input voltage to the output current in radiation conditions. This allows you to create on the basis of such PNT precision analog signal multipliers, for example, for microwave communication systems.

This goal is achieved by the fact that in the known Converter of figure 1, containing a signal source 1 connected between the bases of the first 1 and second 2 input transistors, the first 4 and second 5 current-stabilizing two-terminal connected to the emitters of the corresponding first 2 and second 3 input transistors, scaling a resistor 6 connected between the emitters of the first 2 and second 3 input transistors, a load circuit 7 connected to the collectors of the first 2 and second 3 input transistors and the first 8 and second 9 current outputs of the device, before new elements and connections are examined - the first 10, second 11, third 12 and fourth 13 additional transistors are introduced into the circuit, the base of the first 10 additional transistor is connected to the base of the first 2 input transistor, the emitter of the first 10 additional transistor is connected to the emitter of the first 2 input transistor, base the second 11 additional transistor is connected to the first 8 current output of the device, the emitter of the second 11 additional transistor is connected to the collector of the first 10 additional transistor, the collector of the second 11 additional the power transistor is connected to the power source 14, the base of the third 12 additional transistor is connected to the base of the second 3 input transistor, the emitter of the third 12 additional transistor is connected to the emitter of the second 3 input transistor, the base of the fourth 13 additional transistor is connected to the second 9 current output of the device, the emitter of the fourth 13 additional transistor is connected to the collector of the third 12 additional transistor, the collector of the fourth 13 additional transistor is connected to a power source fourteen.

Figure 1 presents a diagram of a prototype device. The circuit of the claimed device and its static currents are shown in figure 2.

FIG. 3 shows a diagram of FIG. 2 and current increments caused by an input signal.

Figure 4 shows the circuit of figure 2 for the case when the transistors 2 and 10, as well as 3 and 12 are made in the form of two-collector transistors with a common emitter circuit.

5 shows a voltage-current converter circuit in which negative feedback is introduced due to additional differential stages 17 and 18, which provides a further increase in the conversion point

u _Rin in scheme i _O 2.

Figure 6 shows a diagram of the PNT prototype in the environment of computer simulation PSpice on models of integrated transistors of FSUE NPP Pulsar.

Figure 7 shows a diagram of the inventive device in a computer simulation environment PSpice on models of integrated transistors of FSUE NPP Pulsar.

The results of computer simulation of the circuits of Figs. 6 and 7 are shown in Figs. 8 and 9. Moreover, in Fig. 8 β = 40, and in Fig. 9 β = 4.

The voltage-current Converter of figure 2 contains an input signal source 1, connected between the bases of the first 1 and second 2 input transistors, the first 4 and second 5 current-stabilizing two-terminal connected to the emitters of the corresponding first 2 and second 3 input transistors, a scaling resistor 6, connected between the emitters of the first 2 and second 3 input transistors, a load circuit 7 connected to the collectors of the first 2 and second 3 input transistors and the first 8 and second 9 current outputs of the device. The first 10, second 11, third 12 and fourth 13 additional transistors are introduced into the circuit, the base of the first 10 additional transistor is connected to the base of the first 2 input transistor, the emitter of the first 10 additional transistor is connected to the emitter of the first 2 input transistor, the base of the second 11 additional transistor is connected to the first 8 current output of the device, the emitter of the second 11 additional transistor is connected to the collector of the first 10 additional transistor, the collector of the second 11 additional transistor is connected to and power supply 14, the base of the third 12 additional transistor is connected to the base of the second 3 input transistor, the emitter of the third 12 additional transistor is connected to the emitter of the second 3 input transistor, the base of the fourth 13 additional transistor is connected to the second 9 current output of the device, the emitter of the fourth 13 additional transistor is connected to the collector of the third 12 additional transistor, the collector of the fourth 13 additional transistor is connected to the power source 14.

In the circuit of FIG. 2, in accordance with claim 2, the load circuit 7 is connected to the collectors of the first 2 and second 3 input transistors through the first 15 and second 16 pn junctions.

In the circuit of FIG. 5, by introducing differential stages 17 and 18, the influence of the resistances of the emitter and the base of transistors 2, 10 and 3, 12 on the error of conversion of u _input to output current is minimized.

Consider the operation of the inventive device of figure 2 in static mode, and then the circuit of figure 3 on alternating current.

In the circuit of figure 2, with u _in = 0, the output currents I ₈ and I _{9 are} composed of several components

where I _{e. i} (I _{b. i} ) is the emitter static current (base current) of the i-th transistor.

Moreover

where β _i is the static current gain of the base of the i-th transistor;

I ₄ , I ₅ - currents of two-terminal networks 4 and 5.

Thus, taking into account (3), we can find

From (4) and (5) it follows that a significant (but identical) degradation of β transistors 11 and 2, 13 and 3 does not lead to an additional static error δI of converting u _input to currents I ₈ and I ₉

Where

In the PNT prototype of figure 1

If we assume that with increased radiation β transistors decreases (β ₂ = β ₃ = 10), then the relative conversion error in PNT figure 1 reaches 10%, and in the inventive device at least an order of magnitude less.

Similar conclusions about the conversion error _Rin u ac can make the result of analysis circuit 3, for which when R ₆ »r ≈r _{E2 E3} variable components of output currents

Where

R ₆ is the resistance of the resistor 6;

- сопротивления эмиттерных переходов транзисторов 2 и 3.

- resistance of the emitter junctions of transistors 2 and 3.

Thus, the alternating currents of outputs 8 and 9

Therefore, the relative error of the steepness of the conversion of u _in to i _out in the scheme of Fig. 3 is quite small

The theoretical conclusions obtained above coincide with the results of computer simulation of the scheme of Fig. 7 - the absolute error of the current conversion through the resistor 6, proportional to u _in , into the output current of the proposed PNT is 7-10 times less than in the PNT prototype. The effect of radiation in the circuits was modeled by a significant decrease in β transistors (Fig. 8 - β = 40, Fig. 9 - β = 4).

In the particular case, the collectors of transistors 11 and 13 can be used as additional current outputs PNT.

BIBLIOGRAPHIC LIST

1. US patent No. 56666888.

2. US Patent No. 5767741.

3. Patent application 20020053935.

4. US Patent No. 5550.512.

5. US patent 5256984.

6. US patent No. 4439696.

7. A. St. USSR 600545.

8. US patent 5389893.

9. US patent 5914639.

10. US patent 5521544.

11. US patent No. 4721920.

12. Patent application 20040251965 A1.

13. US patent No. 5065112.

14. US patent No. 5521544.

15. US patent No. 4288707.

16. US Patent No. 5774020.

17. US patent No. 4498053.

18. US patent No. 5610547, Fig.19.

19. US patent No. 6369618, figure 2.

20. US patent No. 6111463, figure 1.

21. US patent No. 5610547.

22. U.S. Patent 4,385,364.

Claims (2)

1. A radiation-resistant voltage-current converter containing a signal source (1) connected between the bases of the first (1) and second (2) input transistors, the first (4) and second (5) current-stabilizing two-terminal connected to the emitters of the corresponding first (2) and second (3) input transistors, a scaling resistor (6) connected between the emitters of the first (2) and second (3) input transistors, a load circuit (7) connected to the collectors of the first (2) and second (3) input transistors and the first (8) and second (9) current outputs of the device, exc characterized in that the first (10), second (11), third (12) and fourth (13) additional transistors are introduced into the circuit, the base of the first (10) additional transistor is connected to the base of the first (2) input transistor, the emitter of the first (10 ) an additional transistor is connected to the emitter of the first (2) input transistor, the base of the second (11) additional transistor is connected to the first (8) current output of the device, the emitter of the second (11) additional transistor is connected to the collector of the first (10) additional transistor, the collector of the second ( 11) add the transistor is connected to the power source (14), the base of the third (12) additional transistor is connected to the base of the second (3) input transistor, the emitter of the third (12) additional transistor is connected to the emitter of the second (3) input transistor, the base of the fourth (13) additional the transistor is connected to the second (9) current output of the device, the emitter of the fourth (13) additional transistor is connected to the collector of the third (12) additional transistor, the collector of the fourth (13) additional transistor is connected to the source m of food (14). 2. The device according to claim 1, characterized in that the load circuit (7) is connected to the collectors of the first (2) and second (3) input transistors through the first (15) and second (16) p-n junctions.

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