RU2469466C1 - Selective amplifier - Google Patents

Abstract

FIELD: radio engineering.

SUBSTANCE: selective amplifier includes the first (1) input transistor the base of which is connected to the first signal source (2), and emitter is connected through the first (3) current-stabilising bipole to the first (4) power supply bus, the second (5) input transistor the emitter of which is connected to the first (4) power supply bus through the second (6) current-stabilising bipole, and collector is connected to the second (7) power supply bus, the first (8) frequency-determining resistor connected between output of device (9) and the second (7) power supply bus, the first (10) correcting capacitor connected between emitters of the first (1) and the second (5) input transistors. Collector of the first (1) input transistor is connected to output (9) of device through the first (11) p-n junction made on the basis of emitter-base junction of bipolar transistor, collector of the first (1) input transistor is connected to base of additional transistor (12) the emitter of which is connected to the first (4) power supply bus through the third (13) current-stabilising bipole and connected to output (9) of the device through the second (14) correcting capacitor, the third (15) correcting capacitor is connected parallel to the first (8) frequency-determining resistor; at that, output (9) of device is connected as to alternating current to base of the second (5) input transistor.

EFFECT: improving the Q factor of amplitude-frequency response of the amplifier and its voltage amplification factor at quasi-resonance frequency f₀.

6 cl, 11 dwg

Description

The present invention relates to the field of radio engineering and communications and can be used in microwave filtering devices of radio signals from cellular communication systems, satellite television, radar, etc.

Integrated operational amplifiers with special RC correction elements that form the amplitude-frequency characteristic of the resonance type are widely used today in the problems of extracting high-frequency and microwave signals [1, 2]. However, the classical construction of such selective amplifiers (RC filters) is accompanied by significant energy losses, which are mainly used to ensure the static mode of a sufficiently large number of transistors forming an operational amplifier of the microwave range [1, 2]. In this regard, the task of constructing microwave selective amplifiers on two or three transistors, providing the selection of a narrow spectrum of signals with a sufficiently high quality factor of the resonance characteristic Q = 2-10 and f ₀ = 1 ÷ 5 GHz, is quite relevant.

Known amplifier circuits integrated into the architecture of RC filters based on two or three transistors that provide the formation of the amplitude-frequency characteristics of the voltage gain (AFC) in a given frequency range Δf = f _to -f _n [3-28]. Moreover, their upper cutoff frequency f _{in is} sometimes formed by the inertia of the transistors of the circuit (capacitance per substrate), and the lower f _n is determined by a correction capacitor.

The closest prototype of the claimed device is a selective amplifier, presented in the patent of Philips Cor. WO / 2006/077525. It contains the first 1 input transistor, the base of which is connected to the first signal source 2, and the emitter is connected through the first 3 current-stabilizing two-terminal to the first 4 bus of the power supply, the second 5 input transistor, the emitter of which is connected to the first 4 bus of the power supply through the second 6 current-stabilizing two-terminal and the collector is connected to the second 7th bus of the power source, the first 8th frequency-setting resistor connected between the output of the device 9 and the second 7th bus of the power source, the first 10 correction capacitor, included nny between the emitters of the first 1 and second 5 input transistors.

амплитудно-частотной характеристики (АЧХ) и коэффициент усиления по напряжению К₀>1 на частоте квазирезонанса (f₀).A significant disadvantage of the known device is that it does not provide high quality factor

amplitude-frequency characteristics (AFC) and voltage gain K ₀ > 1 at the quasi-resonance frequency (f ₀ ).

The main objective of the invention is to increase the quality factor Q of the frequency response of the amplifier and its voltage gain at the frequency of quasi-resonance f ₀ . This allows in some cases to reduce the total power consumption and to implement a high-quality microwave device with f ₀ = 1 ÷ 5 GHz.

The problem is solved in that in the selective amplifier of figure 1, containing the first 1 input transistor, the base of which is connected to the first signal source 2, and the emitter is connected through the first 3 current-stabilizing two-terminal to the first 4 bus of the power source, the second 5 input transistor, the emitter of which connected to the first 4 bus of the power source through the second 6 current-stabilizing bipolar, and the collector is connected to the second 7 bus of the power source, the first 8 frequency-setting resistor connected between the output of the device 9 and the second 7 by a power supply bus, the first 10 correction capacitor connected between the emitters of the first 1 and second 5 input transistors, new elements and connections are provided - the collector of the first 1 input transistor is connected to the output 9 of the device through the first 11 pn junction, based on the emitter-base junction a bipolar transistor, the collector of the first 1 input transistor is connected to the base of the additional transistor 12, the emitter of which is connected to the first 4 bus of the power supply through the third 13 current-stabilizing bipolar IR and connected to the output 9 of the device through the second 14 correction capacitor, parallel to the first 8 frequency-setting resistor, the third 15 correction capacitor is connected, and the output 9 of the device is connected by alternating current to the base of the second 5 input transistor.

The amplifier circuit of the prototype is shown in the drawing of figure 1. The drawing of figure 2 presents a diagram of the inventive device in accordance with claim 1 and claim 2 of the claims.

The drawing of figure 3 shows a diagram of the DUT in accordance with paragraph 3 and paragraph 4 of the claims.

In the drawing of figure 4 shows a diagram of the DUT corresponding to paragraph 5 of the claims.

The drawing of figure 5 shows a diagram of the DUT in accordance with claim 6.

The drawing of Fig.6 shows a diagram of the DUT of Fig.3 in the Cadence computer simulation environment on SiGe models of integrated process transistors SGB25VD.

The drawing of Fig.7 shows the logarithmic amplitude-frequency characteristic of the voltage gain of the DUT of Fig.6 (enlarged scale), and the drawing of Fig.8 shows the logarithmic amplitude and phase-frequency characteristics of the DUT of Fig.6 (small scale).

The drawing of Fig. 9 shows a DUT scheme in a Cadence computer simulation environment (SiGe transistors: npnVs, W = 2, L = 2, SGB25VD process technology, Ik.max = 6 mA), in which the number of transistors Q 6, Q11 connected in parallel changed ( m ₁₂ = 1, m ₁₂ = 2, m ₁₂ = 3) (12 - figure 2).

The figure 10 shows the logarithmic amplitude-frequency characteristics of voltage gain of the DUT 9 for different values of m parallel-connected transistors _12, 12 and 11 on the drawing - the logarithmic amplitude and phase frequency characteristics of the DUT 9 when m ₁₂ = 1, m ₁₂ = 2, m ₁₂ = 3.

The selective amplifier of figure 2 contains the first 1 input transistor, the base of which is connected to the first signal source 2, and the emitter is connected through the first 3 current-stabilizing two-terminal to the first 4 bus of the power source, the second 5 input transistor, the emitter of which is connected to the first 4 bus of the power source through the second 6 is a current-stabilizing two-terminal device, and the collector is connected to the second 7 bus of the power source, the first 8 frequency-setting resistor connected between the output of the device 9 and the second 7 bus of the power source, the first 10 is correct a capacitor connected between the emitters of the first 1 and second 5 input transistors. The collector of the first 1 input transistor is connected to the output 9 of the device through the first 11 pn junction based on the emitter-base junction of the bipolar transistor, the collector of the first 1 input transistor is connected to the base of the additional transistor 12, the emitter of which is connected to the first 4 bus of the power supply through the third 13 current-stabilizing two-terminal device and connected to the output 9 of the device through the second 14 correction capacitor, parallel to the first 8 frequency-setting resistor included the third 15 correction condensate Oh, and the output 9 of the device is connected by alternating current to the base of the second 5 input transistor.

In the drawing of FIG. 2, in accordance with claim 2, the additional transistor 12 is made in the form of a composite transistor containing m ₁₂ ≥1 bipolar transistors connected in parallel.

In the drawing of figure 3, in accordance with claim 3 of the claims, a second 16 frequency-determining resistor is connected in series with the first 10 correction capacitor.

In addition, in the drawing of figure 3, in accordance with paragraph 4 of the claims, the output 9 of the device is connected by alternating current to the base of the second 5 input transistor through an additional buffer amplifier 17.

In the drawing of figure 4, in accordance with paragraph 5 of the claims, the base of the second 5 input transistor is connected by alternating current to the output 9 of the device through the second 14 correction capacitor.

In the drawing of FIG. 5, in accordance with claim 6, a common node of the first 10 correction capacitor and the second 16 frequency setting resistor is connected to the second input 18 of the device through the fourth 19 correction capacitor.

The drawing of Fig.6 shows a diagram of the inventive DUT of Fig.2 on SiGe models of integrated transistors.

The drawing of Fig.7 shows the amplitude-frequency characteristic of the DUT of Fig.6 on a large scale.

The drawing of Fig. 8 shows the amplitude and phase frequency characteristics of the DUT of Fig. 6 on a smaller scale.

Based on the circuit of FIG. 9 corresponding to the drawing of FIG. 2, the effect of the number of transistors Q 6, Q 11 (transistor 12, FIG. 2) and the capacitance of capacitors C5 (capacitor 14, FIG. 2) in parallel on the amplitude-frequency characteristic was investigated.

The graphs of Fig. 10 characterize changes in the frequency response of the DUT of Fig. 9 on a large scale from changes in the number of transistors Q 6 and Q 11 connected in parallel (m ₁₂ = 2 ÷ 3), as well as the capacitance of capacitor C5 (C5 = 0, C5 ≠ 0).

The graphs of Fig. 11 characterize changes in the frequency response of the DUT of Fig. 9 on a smaller scale from changes in the number of transistors Q 6 and Q 11 connected in parallel (m ₁₂ = 2 ÷ 3), as well as the capacitance of the capacitor C5 (C ₅ = 0, C ₅ ≠ 0 )

Consider the operation of the DUT figure 2.

The source of the variable input signal u _I (2) changes the collector and emitter currents of the first 1 input transistor. The complex nature of the conductivity of its emitter circuit, formed by the first 10 correcting capacitors and the resistance of the emitter junctions of the first 1 and second 5 input transistors (r _e1 ≈h _11.1 , r _e5 ≈h _11.5 ), ensures the transmission of this signal through the emitter of the first 1 input transistor to output 9 the circuit of the device, which is implemented on the basis of the third 15 correction capacitor and the first 8 frequency-setting resistor. The complexity of the impedance of this circuit (C ₁₅ , R ₈ ) and the nature of the change in the collector current of the transistor 1 provide a resonant form of the amplitude-frequency characteristic of the DUT. The feedback loop introduced into the DUT, formed by connecting the base of the second 5 input transistor to the output of device 9, is reactive in the low frequency region (f << f ₀ ) due to the complex conductivity of the emitter circuits of the second 5 and first 1 input transistors. This feature keeps constant the frequency of the quasi-resonance of the DUT (f ₀ ) at any depth of this feedback and allows to increase the quality factor Q of the DUT and its gain in voltage K ₀ at a given value of the impedance in the output circuit of the device (capacitor C ₁₅ and resistor resistance R ₈ ) .

Let us show analytically that higher values of K ₀ and Q in the high frequency range are implemented in the scheme of figure 2.

As a result of the analysis of the circuit of FIG. 2, it can be obtained that the complex voltage transfer coefficient of the DUT of FIG. 2 is determined by the formula:

Where

τ ₁ = C ₁₀ (h _11.1 + h _11.5 );

τ ₂ = C ₁₅ R ₈ ,

where h _21.i = α _i , h _11.i - low-signal h - parameters of the i-th transistor in the circuit with a common base; K _i - current transfer coefficient from the collector of transistor 1 to resistor 8 in the operating frequency range of the DUT, when the influence of the capacitor 14 on the operation of the circuit can be neglected, moreover:

where m ₁₂ is the number of emitters connected in parallel in the structure of transistor 12.

Thus, it follows from (1) - (5) that the proposed QI can implement a given Q factor, regardless of the chosen quasi-resonance frequency f ₀ .

Similarly, it can be shown that the voltage gain (K ₀ ), f ₀ and the quality factor (Q) of the modified selective amplifier circuit of FIG. 3 (with a voltage gain of the buffer amplifier 17 K _at 17 = 1) are determined by the formulas:

τ ₁ = C ₁₀ (R ₁₆ + h _11.1 + h _11.5 );

τ ₂ = C ₁₅ R ₈ ,

If you choose R ₁₆ >> h _11.1 ≈h _11.5 and τ ₁ = τ ₂ , then the quality factor of the claimed DUT and the coefficient K _{0 of the} device of figure 3 will be determined by the proposed formulas:

Where

Choosing (with R ₈ = R ₁₆ ) in formula (9) these or other values of the factor 1 + m ₁₂ (for example, 1 + m ₁₂ = 1.8-1.999), which depends on the ratio of the areas of the emitter junctions of transistors 11 and 12, you can get almost any given value of the quality factor Q and gain K ₀ .

These theoretical conclusions are confirmed by the graphs of Fig. 7, Fig. 8, obtained as a result of modeling the circuit of Fig. 6, as well as the graphs of Fig. 10, Fig. 11, which allow to determine the effect of parameter m ₁₂ on the frequency response.

The introduction of a frequency-setting resistor 16 (claim 3 of the claims) allows to weaken the influence of the static mode of transistors 1 and 5 and its instability on the main parameters of the DUT: Q, K ₀ , f ₀ .

The introduction of matching buffer amplifier 17 (claim 4 of the claims) solves the problem of matching static potentials in the circuit of the claimed device and optimizing the dynamic range of the DUT.

When implementing the DUT according to the scheme of Fig. 5 (claim 6 of the claims), conditions are created for more coarse signal suppression in the low-frequency region f << f ₀ .

Indeed, minimizing the asymptotic attenuation in the DUT at a frequency f << f ₀ can be achieved by using the fourth correction capacitor 19 (Fig. 5). In this case:

τ ₁ = (C ₁₀ + C ₁₉ ) (R ₁₆ + h _11.1 + h _11.5 );

τ ₂ = C ₁₅ R ₈ ,

Thus, the obtained parametric degree of freedom of the capacitor 19 (C ₁₉ ) can be additionally used to implement the necessary relationship between Q and K ₀ . Such requirements are typical for the integration of DUT into SF blocks (for example, frequency filters with additional interconnection).

Thus, the claimed circuitry solutions are implemented on npn transistors, for example, the SGB25VD process technology and are characterized by higher values of the voltage gain at the frequency of the quasi-resonance f ₀ , as well as increased Q factors Q, which determines the selective properties.

Information sources

1. Design of Bipolar Differential OpAmps with Unity Gain Bandwidth up to 23 GHz / N.Prokopenko, A. Budyakov, K.Schmalz, C.Scheytt, P. Ostrovskyy // Proceeding of the 4-th European Conference on Circuits and Systems for Communications - ECCSC'08 / - Politehnica University, Bucharest, Romania: July 10-11, 2008. - pp. 50-53.

2. Microwave SF blocks of communication systems based on fully differential operational amplifiers / Prokopenko NN, Budyakov AS, K. Schmalz, S.Scheytt // Problems of Developing Advanced Micro- and Nanoelectronic Systems - 2010. Proceedings / under the general. ed. Acad. RAS A.L. Stempkovsky. - M .: IPPM RAS, 2010. - P.583-586.

3. Patent WO / 2006/077525.

4. Patent US 4.267.518, fig. 6

5. Patent RU 2101850, fig. 1.

6. Patent WO / 2007/022705.

7. Patent application US 2006/0186951, fig. 3.

8. Patent application US 2007/0040604, fig. 3.

9. Patent WO / 03052925A1, fig. 3.

10. Patent US 6.011.431, fig. 4.

11. Patent US 5.331.478, fig. 3.

12. Patent US 4.885.548, fig. 9.

13. Patent US 4.974.916, fig. 1.

14. Patent application US 2008/0122530, fig. 4.

15. Patent US 5.298.802.

16. Patent US 2009/0261899, fig. 3.

17. Patent CN 101204009.

18. Patent EP 1844547.

19. Patent UA 17276.

20. Patent US 2009/0289714, fig. 4.

21. Patent US 7.202.762.

22. Patent US 6.188.272.

23. Patent US 5.847.605.

24. Patent US 7.116.961.

25. Patent application US 2011/0109388, fig.2.

26. Patent application US 2006/0186951, fig.2.

27. Patent US 5.012.201, fig. 2.

28. Patent application US 2010/0201437, fig.2

Claims (6)

1. A selective amplifier containing the first (1) input transistor, the base of which is connected to the first signal source (2), and the emitter is connected through the first (3) current-stabilizing two-terminal to the first (4) bus of the power source, the second (5) input transistor, the emitter of which is connected to the first (4) bus of the power supply through a second (6) current-stabilizing two-terminal device, and the collector is connected to the second (7) bus of the power supply, the first (8) frequency-setting resistor connected between the output of the device (9) and the second ( 7) power supply bus, first th (10) correction capacitor connected between the emitters of the first (1) and second (5) input transistors, characterized in that the collector of the first (1) input transistor is connected to the output (9) of the device through the first (11) pn junction made on Based on the emitter-base junction of the bipolar transistor, the collector of the first (1) input transistor is connected to the base of the additional transistor (12), the emitter of which is connected to the first (4) bus of the power supply through the third (13) current-stabilizing two-terminal device and connected to the output (9) of the devicethrough the second (14) correction capacitor, parallel to the first (8) frequency-setting resistor, a third (15) correction capacitor is connected, and the output (9) of the device is connected via alternating current to the base of the second (5) input transistor. 2. The selective amplifier according to claim 1, characterized in that the additional transistor (12) is made in the form of a composite transistor containing m ₁₂ > 1 bipolar transistors connected in parallel. 3. The selective amplifier according to claim 1, characterized in that a second (16) frequency setting resistor is connected in series with the first (10) correction capacitor. 4. The selective amplifier according to claim 2, characterized in that the output (9) of the device is connected via alternating current to the base of the second (5) input transistor through an additional buffer amplifier (17). 5. The selective amplifier according to claim 2, characterized in that the base of the second (5) input transistor is connected via alternating current to the output (9) of the device through the second (14) correction capacitor. 6. The selective amplifier according to claim 2, characterized in that the common node of the first (10) correction capacitor and the second (16) frequency-setting resistor is connected to the second input (18) of the device through the fourth (19) correction capacitor.

Images