RU2568384C1 - Precision operational amplifier based on radiation resistant bipolar and field process - Google Patents

Abstract

FIELD: radio engineering, communication.

SUBSTANCE: precision operational amplifier based on the radiation resistant bipolar and field process contains the input differential stage (1) the common emitter circuit of which is matched with the first (2) power supply bus, the first (3) current output of the input differential stage (1), the emitter of the first (4) output transistor, the first (5) auxiliary resistor, the second (6) power supply bus, the second (7) current output of the input differential stage (1), the emitter of the second (8) output transistor, the second (9) auxiliary resistor, the first (10) current-stabilizing two-pole network, the second (11) current-stabilizing two-pole network, the output buffer amplifier (12). The circuit is added by the first (13) and the second (14) additional field transistors with the control p-n transition and the additional current mirror (16).

EFFECT: decrease of zero shift voltage for improvement of precision of the operational amplifier.

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Description

The invention relates to the field of radio engineering and can be used as a precision device for amplifying the signals of various sensors.

In modern electronic equipment, operational amplifiers (op amps) using field-effect and bipolar transistors based on the architecture of the “bent cascode” [1-14] are used. Their main advantages are the extended frequency range, as well as the effective use of the supply voltage.

To work in outer space, experimental physics requires radiation-resistant opamps with a low zero bias voltage (U _cm ) and a high voltage gain (100-120 dB). World experience in designing devices of this class shows that the solution to these problems is possible using a bipolar field process [15], which provides the formation of p-channel field and high-quality npn bipolar transistors with radiation resistance up to 1 Mrad and a neutron flux up to 10 ¹³ n / cm ² . However, for such an op-amp, a special circuitry is needed that takes into account the limitations of bipolar field technology [15].

The closest prototype (Fig. 1) of the claimed device is an operational amplifier according to the patent US 5.422.600 fig. 1. It contains (Fig. 1) the input differential stage 1, the common emitter circuit of which is matched with the first 2 bus of the power supply, the first 3 current output of the input differential stage 1, connected to the emitter of the first 4 output transistor and through the first 5 auxiliary resistor connected to the second 6 bus power supply, the second 7 current output of the input differential stage 1 connected to the emitter of the second 8 output transistor and through the second 9 auxiliary resistor connected to the second 6 bus power source, the first 10 current-stabilizing two-terminal connected between the collector of the first 4 output transistor and the first 2 bus power supply, the second 11 current-stabilizing two-terminal connected between the collector of the second 8 output transistor and the first 2 bus power source, the output buffer amplifier 12, and the base of the first 4 and second 8 output transistors are connected to each other.

A significant drawback of the known op-amp is that in the operating range, especially low temperatures, and also when exposed to a neutron flux, it has increased zero bias voltage (U _cm ) (several tens of millivolts). Ultimately, this reduces the precision of the known opamp. In addition, its voltage gain (K _y ) is small.

The main objective of the invention is to reduce the bias voltage of zero.

The first additional task is to increase the gain of the op-amp differential signal in the open state to the level of 130-140 dB.

The second additional task is to increase the attenuation coefficient of the input common-mode signals of the op-amp.

The objectives are achieved in that in the operational amplifier of FIG. 1, containing the input differential stage 1, the common emitter circuit of which is matched with the first 2 bus of the power source, the first 3 current output of the input differential stage 1, connected to the emitter of the first 4 output transistor and through the first 5 auxiliary resistor connected to the second 6 bus of the power source, the second 7 current output of the input differential stage 1, connected to the emitter of the second 8 output transistor and through the second 9 auxiliary resistor connected to the second 6 bus power source, the first 10 current-stabilizing two-terminal connected between the collector of the first 4 output transistor and the first 2 bus power supply, the second 11 current-stabilizing two-terminal connected between the collector of the second 8 output transistor and the first 2 bus power source, the output buffer amplifier 12, and the base of the first 4 and second 8 output transistors are connected to each other, new elements and connections are provided - the first 13 and second 14 additional field-effect transistors with a control pn junction, combined sources of a cat are introduced into the circuit They are connected to the bases of the first 4 and second 8 output transistors and are connected to the first 2 bus of the power source through an additional current-stabilizing two-terminal 15, the drain of the first 13 additional field transistor is connected to the input of the additional current mirror 16, matched with the second 6 bus of the power source, and the drain of the second 14 additional field-effect transistor connected to the output of the additional current mirror 16 and the input of the output buffer amplifier 12.

In FIG. 1 shows a diagram of an op-amp prototype, and in FIG. 2 is a diagram of the inventive device in accordance with the claims.

In FIG. 3 shows a diagram of FIG. 2 with a specific embodiment of the output buffer amplifier 12.

In FIG. 4 is a diagram of the opamp of FIG. 2 in a computer simulation environment PSpice on integrated transistor models ABMK_1_3 of NPO Integral (Minsk).

In FIG. 5 shows the frequency response of the opamp of FIG. 4 at 100% negative feedback.

In FIG. 6 shows the frequency response of an open op amp of FIG. 4, from which it follows that the proposed circuit of FIG. 4 has an increased voltage gain close to 140 dB (Ku = 100.000.000).

In FIG. 7 shows the dependence of the zero bias voltage (U _cm ) of the op-amp circuit of FIG. 4 from the neutron flux.

In FIG. 8 shows the dependence of the zero bias voltage of the op-amp circuit of FIG. 4 in the temperature range from -60 ÷ + 80 ° C.

A precision operational amplifier based on a radiation resistant bipolar field process of FIG. 2 contains an input differential stage 1, the common emitter circuit of which is matched with the first 2 bus of the power source, the first 3 current output of the input differential stage 1, connected to the emitter of the first 4 output transistor and through the first 5 auxiliary resistor connected to the second 6 bus of the power source, the second 7 current output of the input differential stage 1, connected to the emitter of the second 8 output transistor and through the second 9 auxiliary resistor connected to the second 6 bus of the power source, the first 10 t Ostabilizing two-terminal connected between the collector of the first 4 output transistor and the first 2 bus of the power supply, the second 11 current-stabilizing two-terminal connected between the collector of the second 8 output transistor and the first 2 bus of the power supply, output buffer amplifier 12, with bases of the first 4 and second 8 output transistors connected to each other. The first 13 and second 14 additional field-effect transistors with a control pn junction are introduced into the circuit, the combined sources of which are connected to the bases of the first 4 and second 8 output transistors and are connected to the first 2 power supply bus via an additional current-stabilizing two-terminal 15, the drain of the first 13 additional field-effect transistor is connected with the input of the additional current mirror 16, consistent with the second 6 bus power source, and the drain of the second 14 additional field-effect transistor is connected to the output of the additional Shackle mirror 16 and the input of the output buffer amplifier 12.

In addition, in FIG. 2, the input differential stage 1 is implemented on the input field-effect transistors 17 and 18, the reference current source 19 and the resistor 20, which simulates the operation of the input differential stage 1 when working with input common-mode signals. The output of the device 21 is the output of the buffer amplifier 12.

In FIG. 3 is a diagram corresponding to FIG. 2, in which the inverting output buffer amplifier 12 is implemented as an output transistor 22 according to a common emitter circuit, a current source 23, and a non-inverting stage 24.

Consider the operation of the opamp of FIG. 2.

The static mode of the transistors of the circuit of FIG. 2 is set by reference current sources made in the form of current-stabilizing two-terminal 10, 11 and 19. In this case, the drain currents and collector currents of the transistors of the circuit are determined by the equations

where I ₁₀ , I ₁₁ , I ₁₉ - currents of two-terminal networks 10, 11, 19.

The voltage gain of the op-amp circuit of FIG. 2 is determined by the work

where u _out. - increment opamp output voltage caused by a change of the input voltage (u _Rin.);

- коэффициент преобразования входного напряжения ОУ (u_вх) в напряжение между узлами Σ1, Σ2 (u_Σ1-Σ2);

- the coefficient of conversion of the input voltage of the OS (u _I ) to the voltage between the nodes Σ1, Σ2 (u _Σ1-Σ2 );

- коэффициент передачи дифференциального напряжения между узлами Σ1, Σ2 на вход буферного усилителя 12 (Σ₃);

- transmission coefficient of the differential voltage between the nodes Σ1, Σ2 to the input of the buffer amplifier 12 (Σ ₃ );

u _Σ1-Σ2 - voltage increment between the high-impedance nodes Σ1 and Σ2;

- коэффициент передачи по напряжению буферного усилителя 12;

is the voltage transfer coefficient of the buffer amplifier 12;

u _Σ3 is the voltage increment in the high-impedance node Σ3.

Moreover

where R _{equiv. Σ1-Σ2} is the equivalent differential resistance between the high impedance nodes Σ1 and Σ2;

R _{equiv. Σ3} is the equivalent resistance in the high impedance node Σ3;

S ₁₃ , S ₁₄ , S ₁₇ , S ₁₈ - steepness of the gate-gate characteristic of the corresponding field-effect transistors (13, 14, 17, 18).

The numerical value of the equivalent resistance R _equiv . _{Σ1-Σ2 is} close to the resistances of the closed collectors of transitions of the output transistors 4 and 8, and the resistance is R _equiv . _{Σ3 is} determined mainly by the input impedance of the buffer amplifier 12. As a result, due to the creation in FIG. 2 of three high-impedance nodes (Σ1, Σ2, Σ3), the voltage gain of the open op amp of FIG. 2 it turns out quite large (130-140 dB) and is several orders of magnitude higher than K _for the prototype circuit (Fig. 1).

In the claimed op-amp circuit (in comparison with the prototype), the attenuation coefficient of the input common-mode signals is also increased. This effect is explained by the increased symmetry of the op amp circuit of FIG. 2 and the introduction of negative common-mode feedback (transistors 13 and 14). Due to the high symmetry of the op-amp circuit and the use of field-effect transistors 13, 14, the zero bias voltage of the claimed op-amp is measured by microvolts (Fig. 7, Fig. 8).

Thus, the claimed device has significant advantages compared to the op-amp prototype.

BIBLIOGRAPHIC LIST

1. US Patent No. 5,422,600, FIG. 2.

2. US Patent No. 4,406,990, FIG. four.

3. US patent No. 5.952.882.

4. US patent No. 4.723.111.

5. US patent No. 4.293.824.

6. US patent No. 5.323.121.

7. US Patent No. 5,420,540 fig. one.

8. Patent RU No. 2,354.041 C1.

9. US patent application No. 2003/0201828 fig 1, fig 2.

10. US patent No. 6.825.721 fig 1, fig 2.

11. US Patent No. 6,542,030 fig. one.

12. US Pat. No. 6,456,162, fig. 2.

13. Patent US 6.501.333.

14. Patent US 6.717.466.

15. The element base of radiation-resistant information-measuring systems: monograph. / N.N. Prokopenko, O.V. Dvornikov, S.G. Krutchinsky; under the general. ed. Doctor of Technical Sciences prof. N.N. Prokopenko; FSBEI HPE “South-Ros. state un-t economics and service. " - Mines: FSBEI HPE "URGUES", 2011. - 208 p.

Claims (1)

A precision operational amplifier based on a radiation-resistant bipolar field process containing an input differential stage (1), the common emitter circuit of which is matched with the first (2) bus of the power source, the first (3) current output of the input differential stage (1) connected to the emitter of the first (4) output transistor and through the first (5) auxiliary resistor connected to the second (6) bus of the power supply, the second (7) current output of the input differential stage (1) connected to the emitter horn (8) of the output transistor and through the second (9) auxiliary resistor connected to the second (6) bus of the power source, the first (10) current-stabilizing two-terminal device connected between the collector of the first (4) output transistor and the first (2) bus of the power source, second (11) a current-stabilizing two-terminal connected between the collector of the second (8) output transistor and the first (2) bus of the power source, the output buffer amplifier (12), and the bases of the first (4) and second (8) output transistors are connected to each other, different the fact that in the circuit introduced the first (13) and second (14) additional field effect transistors with a pn junction control, the combined sources of which are connected to the bases of the first (4) and second (8) output transistors and are connected to the first (2) power supply bus through an additional current-stabilizing two-terminal device (15), the drain of the first (13) additional field-effect transistor is connected to the input of the additional current mirror (16), matched with the second (6) bus of the power source, and the drain of the second (14) additional field-effect transistor is connected to the output of the additional Yelnia current mirror (16) and the input of the output buffer amplifier (12).

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