RU2449464C1 - Differential operational amplifier with paraphase output - Google Patents

Abstract

FIELD: radio engineering.

SUBSTANCE: differential operational amplifier with a paraphrase output comprises the first and second input transistors, from the first to the fourth current-stabilising dipoles, the first and second current mirrors, the first and second additional transistors, the first and second additional resistors.

EFFECT: development of conditions, under which the output static cophased voltage of the DA will have high stability and value close to zero.

3 cl, 10 dwg

Description

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

Known circuits of classical two-stage differential operational amplifiers (DU) with paraphase output, which became the basis of many serial analog circuits [1-16]. Remote controls of this class are also actively used in bridge power amplifiers, implemented on the basis of various technologies, including SiGe.

The closest prototype (figure 1) of the claimed device is a differential operational amplifier according to patent US 6.657.465, containing the first 1 and second 2 input transistors, the first 3 current-stabilizing bipolar connected between the emitter of the first 1 input transistor and the first 4 bus power source, second 5 current-stabilizing two-terminal connected between the emitter of the second 2 input transistor and the first 4 bus power supply, the first current mirror 6, matched with the second 7 bus power supply, the input of the first 6 t the shunt mirror is connected to the collector of the first 1 input transistor, and the current output through the third 8 current-stabilizing two-terminal device is connected to the first 4 bus of the power source, the second 9 current mirror, matched to the second 7 bus of the power source, and the input of the second 9 current mirror is connected to the collector of the second 2 input transistor, and the current output through the fourth 10 current-stabilizing two-terminal is connected to the first 4 bus power source.

A significant drawback of the known remote control is that it has an unstable output common-mode voltage level, depending on the parameters of the third 8 and fourth 10 current-stabilizing two-terminal devices. This greatly complicates its coordination with subsequent functional units.

The main objective of the invention is to create conditions under which the output static common-mode voltage of the remote control will have high stability and a value close to zero. In this case, a wider range of variation of the output signal of the remote control is also realized.

The problem is solved in that in the differential operational amplifier with a paraphase output of Fig. 1, containing the first 1 and second 2 input transistors, the first 3 current-stabilizing bipolar connected between the emitter of the first 1 input transistor and the first 4 bus power source, the second 5 current-stabilizing bipolar, connected between the emitter of the second 2 input transistor and the first 4 bus power supply, the first current mirror 6, consistent with the second 7 bus power source, and the input of the first 6 current mirror the la is connected to the collector of the first 1 input transistor, and the current output through the third 8 current-stabilizing two-terminal is connected to the first 4 bus of the power source, the second 9 current mirror, matched with the second 7 bus of the power source, and the input of the second 9 current mirror is connected to the collector of the second 2 input transistor, and the current output through the fourth 10 current-stabilizing bipolar is connected to the first 4 bus power supply, new elements and communications are provided - the first 11 and second 12 additional trans side, the collectors of which are connected to the second 7 bus of the power source, the emitter of the first 11 additional transistor is connected to the emitter of the first 1 input transistor, the emitter of the second 12 additional transistor is connected to the emitter of the second 2 input transistor, the current output of the first 6 current mirror is connected to the combined bases of the first 11 and the second 12 additional transistors through the first 13 additional resistor, and the current output of the second 9 current mirrors is connected to the combined bases of the first 11 and second 12 additional x transistor 14 via a second additional resistor.

In Fig.1 shows a diagram of the remote control prototype.

Figure 2 shows a diagram of the inventive device in accordance with claim 1, and figure 3 - paragraph 2 of the claims with a specific implementation of the current mirrors 6 and 9.

In Fig.4 shows a diagram of the claimed remote control of Fig.3 in the environment of computer simulation PSpice on models of integrated transistors FSUE NPP Pulsar.

Figure 5 and figure 6 presents the dependence of the voltages of the remote control for its outputs on the input sinusoidal voltage with an amplitude of U _in = 1 mV (Fig. 5) and U _in = 5 mV (Fig. 6). The graphs of FIG. 5, FIG. 6 show that the claimed remote control has two out-of-phase output voltages and a zero level of output common-mode static voltage (U _synf ≈0.6 mV).

In Fig.7 shows the frequency dependence of the gain of the remote control circuit of Fig.4.

On Fig is a diagram of the inclusion of the proposed remote control in the structure of the differential driver of the communication line (or bridge power amplifier). In this case, the driver has an output common-mode voltage U _synf = 22 μV.

Figure 9 shows the dependence of the driver output voltages in the large signal mode at U _in = 30 mV.

Figure 10 shows the frequency dependence of the differential gain of the driver of Fig. 8.

The differential operational amplifier with a paraphase output of FIG. 2 contains the first 1 and second 2 input transistors, the first 3 current-stabilizing two-terminal connected between the emitter of the first 1 input transistor and the first 4 bus of the power source, the second 5 current-stabilizing two-terminal connected between the emitter of the second 2 input transistor and the first 4 bus power source, the first current mirror 6, consistent with the second 7 bus power source, and the input of the first 6 current mirror is connected to the collector of the first 1 input of the transistor, and the current output through the third 8 current-stabilizing two-terminal device is connected to the first 4 bus of the power supply, the second 9 current mirror is matched to the second 7 bus of the power supply, and the input of the second 9 current mirror is connected to the collector of the second 2 input transistor, and the current output through the fourth 10 current-stabilizing bipolar is connected to the first 4 bus power supply. The first 11 and second 12 additional transistors are introduced into the circuit, the collectors of which are connected to the second 7 bus of the power supply, the emitter of the first 11 additional transistors is connected to the emitter of the first 1 input transistor, the emitter of the second 12 additional transistors is connected to the emitter of the second 2 input transistor, the current output of the first 6 of the current mirror is connected to the combined bases of the first 11 and second 12 additional transistors through the first 13 additional resistor, and the current output of the second 9 current mirror is connected to the combined bases of the first 11 and second 12 additional transistors through the second 14 additional resistor.

The current mirrors 6 and 9 in the circuit of FIG. 2 are based on transistors 16, 18 and two-terminal 15, 17, which ensures their high current gain.

In Fig. 3, in accordance with claim 2, the current output of the first 6 current mirrors is connected to the combined bases of the first 11 and second 12 additional transistors through the first 19 additional buffer amplifier and the first 13 additional resistor connected in series, and the current output of the second 9 current mirror connected to the combined bases of the first 11 and second 12 additional transistors through sequentially connected second 20 additional buffer amplifier, the second 14 additional resistor.

In accordance with paragraph 3 of the claims, the current transfer coefficient of the first 6 and second 9 current mirrors in the circuit of FIG. 2 significantly exceeds unity (K _i12 >> 1). As buffer amplifiers 19 and 21, classic emitter repeaters can be used.

As current-stabilizing two-terminal devices 3, 5, 8, 10, 15, 17, the authors recommend the use of classical sources of reference current on transistors or relatively high-resistance resistors.

Consider the operation of the remote control of Fig.3.

The static current mode of the transistors of the proposed remote control is set by bipolar 3, 5, 15, 17, 8 and 10. Moreover, the collector (I _ki ) and emitter (I _ei ) currents of the transistors 1, 2, 11, 12, 14, 18 are determined by the formulas:

where I ₀ is the set value of the static current, for example 1 mA.

The static voltage U _{o. 1} at the output of O. 1 and U _{o. 2} at the output of O. 2 remote control at a zero input signal (u _in = 0) can be found from the equations:

.

.

where U _eb. 1 = U _eb . ₂ = U _eb . ₁₁ = U _{eb. 12} - emitter-base voltage of transistors 1, 2, 11, 12 at an emitter current I _ei = I ₀ ;

I _b11 , I _b12 - components of the base currents of transistors 11 and 12 in resistors 13 and 14.

Thus, with typical values of the base current of transistors 11 and 12, as well as with R ₁₃ = R ₁₄ = 500 ÷ 1000 Ω, the in-phase output voltage of the remote control of Fig. 3 is practically zero in a wide range of temperature and radiation influences, as well as changes in supply voltages. This is very important for the coordination of the claimed remote control with the subsequent functional units of electronic equipment, has a positive effect on the range of variation of the amplitudes of the output sinusoidal voltage of the remote control.

With a common-mode voltage variation at the inputs Vx.1 and Bx.2, the common-mode voltages at the outputs Output 1, Output 2 also change. However, the emitter (collector) currents of the transistors of the circuit remain constant. Therefore, the attenuation coefficient of the input common-mode voltages in the claimed remote control is quite high, since the current mode of its transistors does not change.

и отрицательной

полярностей близки к сумме напряжений первого 4 (Е₄) и второго 7 (Е₇) источников питания

, что является одной из ее замечательных особенностей.In the circuit of FIG. 3, which differs from the circuit of FIG. 2 by the presence of additional buffer amplifiers 19 and 20, the requirements for the resistance values of the feedback resistors 13 and 14 are significantly reduced, which makes it possible to obtain zero levels of static voltages at outputs 1 and 2. regardless of the static parameters of these additional buffer amplifiers 19 and 20. However, in the circuit of Fig. 3, corresponding to claim 2 of the claims, in the low-impedance load connected between the outputs of Ex. 1 and Ex. 2, significantly higher powers can be obtained that determine are provided with the properties of additional buffer amplifiers 19 and 20. In addition, in the architecture of FIG. 3, the maximum amplitudes of the output voltages are positive

and negative

polarities are close to the sum of the voltages of the first 4 (E ₄ ) and second 7 (E ₇ ) power sources

That is one of its wonderful features.

Thus, the proposed remote control has significant advantages in comparison with the prototype.

Information sources

1. US patent application No. 2005/0218983.

2. US Patent Application No. 2006/0139098.

3. US Patent Application. No. 2006/0006910, fig. 1.

4. US patent No. 6.657.465.

5. US patent No. 6.831.513, fig.4.

6. US patent No. 6.844.781.

7. US Patent Application No. 2008/0032656, fig. 6.

8. US Patent No. 6,657.465.

9. US patent No. 6.538.513.

10. US patent application No. 2003/0132803, fig.4.

11. US patent No. 6.882.185, fig.1.

12. US Patent No. 7,649,418, fig.3A.

13. US patent No. 7.701.290, fig.6.

14. US patent No. 7.777.568, fig.2.

15. US patent No. 5.225.791, fig.2.

16. Auth. St. USSR No. 459780.

Claims (3)

1. A differential operational amplifier with a paraphase output, comprising the first (1) and second (2) input transistors, the first (3) current-stabilizing two-terminal device connected between the emitter of the first (1) input transistor and the first (4) power supply bus, and the second (5 ) a current-stabilizing two-terminal connected between the emitter of the second (2) input transistor and the first (4) bus of the power source, the first current mirror (6), coordinated with the second (7) bus of the power source, and the input of the first (6) current mirror is connected to the collector first (1) input transistor, and the current output through the third (8) current-stabilizing two-terminal device is connected to the first (4) bus of the power source, the second (9) current mirror, matched with the second (7) bus of the power source, and the input of the second (9) the current mirror is connected to the collector of the second (2) input transistor, and the current output through the fourth (10) current-stabilizing two-terminal device is connected to the first (4) bus of the power source, characterized in that the first (11) and second (12) additional transistors are introduced into the circuit whose manifolds are connected To the second (7) bus of the power supply, the emitter of the first (11) additional transistor is connected to the emitter of the first (1) input transistor, the emitter of the second (12) additional transistor is connected to the emitter of the second (2) input transistor, the current output of the first (6) the current mirror is connected to the combined bases of the first (11) and second (12) additional transistors through the first (13) additional resistor, and the current output of the second (9) current mirror is connected to the combined bases of the first (11) and second (12) additional transistors through tue A second (14) additional resistor. 2. The differential operational amplifier with a paraphase output according to claim 1, characterized in that the current output of the first (6) current mirror is connected to the combined bases of the first (11) and second (12) additional transistors through the additional buffer amplifier connected in series to the first (19) and the first (13) additional resistor, and the current output of the second (9) current mirror is connected to the combined bases of the first (11) and second (12) additional transistors through a second buffer amplifier connected in series to the second (20) a second (14) additional resistor. 3. The differential operational amplifier with a paraphase output according to claim 1, characterized in that the current transfer coefficient of the first (6) and second (9) current mirrors significantly exceeds unity.

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