RU2479110C1 - Selective amplifier - Google Patents

Abstract

FIELD: radio engineering, communications.SUBSTANCE: selective amplifier comprises a source of an input voltage (1), connected with an inlet of a "voltage-current" converter (2), an inlet transistor (3), the first (5) current-stabilising dipole, the first (7) and second (8) frequency-setting resistors, the first (9) correcting capacitor. A collector of the inlet transistor (3) is connected to the outlet of the "voltage-current" converter (2) via a forward-biased p-n transition (11) and is connected to a base of an additional transistor (12), an emitter of the additional transistor (12) is connected with the first (6) bus of the source of supply via the second (13) current-stabilising dipole and via the first (9) correcting capacitor is connected with the outlet of the "voltage-current" converter (2), which is connected with the second (10) bus of the source of supply via the first (7) frequency-setting resistor, the outlet of the "voltage-current" converter (2) is connected by AC with the common bus of sources of supply (14) via serially connected second (15), third (16) correcting capacitors, the common unit of which is connected to the output of the device (17) and via the second (8) frequency-setting resistor is connected with the emitter of the inlet transistor (3), besides, the collector of the additional transistor (12) is connected with the second (10) bus of the source of supply.EFFECT: higher quality of selective amplifier amplitude-frequency characteristic and its amplification ratio by voltage at quasiresonance frequency f.3 cl, 10 dwg

Description

The present invention relates to the field of radio engineering and communications and can be used in devices for filtering radio signals, 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 tasks of extracting high-frequency signals [1, 2]. However, the classical construction of such selective amplifiers (DUTs) is accompanied by significant energy losses, which are mainly used to ensure the static mode of a sufficiently large number of secondary transistors forming an operational amplifier [1, 2]. In this regard, it is very urgent to build selective amplifiers on bipolar transistors, which provide a narrow spectrum of signals with a sufficiently high quality factor (Q) of the resonance characteristic (Q = 2 ÷ 10) with low power consumption.

Known schemes are DUTs integrated into the architecture of RC filters based on bipolar transistors, which provide the formation of the amplitude-frequency characteristics of the voltage gain in a given frequency range Δf = f _a -f _n [3-11]. 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 patent RU 2421879, figure 2. It contains an input voltage source 1, connected to the input of the voltage-current converter 2, an input transistor 3, the base of which is connected to an auxiliary voltage source 4, the first 5 is a current-stabilizing two-terminal device connected between the emitter of the input transistor 3 and the first 6 power supply bus, the first 7 and second 8 frequency-setting resistors, the first 9 correction capacitor, the second 10 bus power supply.

амплитудно-частотной характеристики (АЧХ) и коэффициент усиления по напряжению K₀>1 на частоте квазирезонанса (f₀).A significant drawback of the known YiU prototype is that it does not provide high quality factor

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

The main objective of the invention is to increase the quality factor of the frequency response of the DUT and its voltage gain (K ₀ ) at the frequency of quasi-resonance f ₀ . This allows in some cases to reduce the overall energy consumption and implement a high-quality selective device.

The problem is solved in that in the selective amplifier, Fig. 1, containing an input voltage source 1, connected to the input of the voltage-current converter 2, an input transistor 3, the base of which is connected to an auxiliary voltage source 4, the first 5 current-stabilizing two-terminal device included between the emitter of the input transistor 3 and the first 6 bus power supply, the first 7 and second 8 frequency-setting resistors, the first 9 correction capacitor, the second 10 bus power supply, there are new elements and communications - the input transistor 3 collector is connected to the output of the voltage-current converter 2 through a direct biased junction 11 and connected to the base of the additional transistor 12, the emitter of the additional transistor 12 is connected to the first 6 bus of the power source through the second 13 current-stabilizing two-terminal and through the first 9 corrective the capacitor is connected to the output of the voltage-current converter 2, which is connected to the second 10 bus of the power source through the first 7 frequency-setting resistor, the output of the voltage-current converter 2 is connected alternating current with a common bus of power supplies 14 through series-connected second 15, third 16 correction capacitors, the common node of which is connected to the output of the device 17 and through the second 8 a frequency-setting resistor is connected to the emitter of the input transistor 3, and the collector of the additional transistor 12 is connected to the second 10 power supply bus.

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 of the claims.

The drawing of figure 3 presents a diagram of the inventive device in accordance with claim 2 and claim 3 of the claims.

The drawing of Fig. 4 is a diagram of the DUT, Fig. 3, in a Cadence environment on SiGe models of integrated transistors (SG25H1 manufacturing process).

The drawing of figure 5 shows the logarithmic amplitude and phase frequency characteristics of the DUT, figure 3, in a wide frequency range (from 1 kHz to 100 GHz) with R21 = 310 Ohms, C1 = 410 fF, C2 = 30 pF.

The drawing of Fig.6 shows the LACH and phase response of the DUT, Fig.3, in a narrower frequency range (from 100 MHz to 10 GHz) with R21 = 310 Ohms, C1 = 410 fF, C2 = 30 pF.

The drawing of Fig.7 illustrates the dependence of the Q factor Q and the frequency f _{0 of the} DUT, Fig.3, on the resistance of the resistor R21.

The drawing of Fig. 8 shows the dependence of the Q factor Q and the resonant frequency f ₀ on the parameter of the element C1 in the DUT circuit, Fig. 3.

The drawing of Fig.9 shows the dependence of the Q factor Q and the resonant frequency f ₀ from the parameter C2 of the DUT, Fig.3, varying from 0 to 200 pF.

The drawing of figure 10 shows the LAC of the DUT, figure 3, in the frequency range from 100 MHz to 10 GHz with R21-310 Ohm, C1 = 410 fF and three values of C2 = 0; 10 pF; 100 pF.

The selective amplifier, figure 2, contains an input voltage source 1, connected to the input of the voltage-current converter 2, an input transistor 3, the base of which is connected to an auxiliary voltage source 4, the first 5 is a current-stabilizing two-terminal connected between the emitter of the input transistor 3 and the first 6 bus power supply, the first 7 and second 8 frequency-setting resistors, the first 9 correction capacitor, the second 10 bus power supply. The collector of the input transistor 3 is connected to the output of the voltage-current converter 2 through a forward biased junction 11 and connected to the base of the additional transistor 12, the emitter of the additional transistor 12 is connected to the first 6 bus of the power source through the second 13 current-stabilizing two-terminal device and through the first 9 corrective the capacitor is connected to the output of the voltage-current converter 2, which is connected to the second 10 bus of the power source through the first 7 frequency-setting resistor, the output of the voltage-current converter 2 is connected alternating current with a common bus of power supplies 14 through series-connected second 15, third 16 correction capacitors, the common node of which is connected to the output of the device 17 and through the second 8 a frequency-setting resistor is connected to the emitter of the input transistor 3, and the collector of the additional transistor 12 is connected to the second 10 power supply bus.

In the drawing of FIG. 3, in accordance with claim 2, the collector of the second 12 additional transistor is connected to the second 10 bus of the power source through an auxiliary resistor 18 and connected to the first additional output of the device 19.

In addition, in the drawing of FIG. 3, in accordance with claim 3, between the output of the device 17 and the second additional output 20, a buffer amplifier 21 is included. As a voltage-current converter 2, classical amplifier stages (OB, OE) can be used , Remote control, etc.)

Consider the operation of the circuit of figure 3.

The input voltage source (1) through the voltage-current converter 2 changes the collector circuit current of the transistor 3. The collector load of this transistor, formed by resistors 7 and 8, as well as capacitors 15 and 16, converts this current into the current of the resistor 8 of the output circuit. Moreover, the presence of a capacitive divider formed by capacitors 15 and 16, provides a functional dependence of this current, corresponding to the frequency characteristics of the selective amplifier.

When the capacitor 9 (C ₉ >> C ₁₅ , C ₉ >> C ₁₆ ) the complex transfer coefficient of the DUT, Fig.2, as the ratio of the output voltage (output of the device 17) to the input voltage u _inx is determined by the formula, which can be obtained using methods of analysis of electronic circuits:

where f is the frequency of the input signal;

f ₀ is the frequency of the quasi-resonance of the DUT;

Q is the quality factor of the frequency response of the selective amplifier;

K ₀ is the gain of the DUT at the frequency of quasi-resonance f ₀ .

Moreover:

where C ₁₅ , C ₁₆ , R ₇ , R ₈ are the parameters of elements 15, 16, 7 and 8;

h _11.i is the h-parameter of the i-th transistor (pn junction 11 based on a bipolar transistor) in a circuit with a common base.

The quality factor of the DUT is determined by the formula:

where α ₃ is the current transfer coefficient of the emitter of transistor 3; m is the number of emitters in the transistor 12;

- эквивалентное затухание пассивной цепи.

- equivalent attenuation of the passive circuit.

By choosing the parameters of the elements included in the formula (3), it is possible to provide Q >> 1.

The formula for the gain K ₀ in the complex transfer coefficient (1) has the form:

where S ₂ - the steepness of the input Converter "voltage - current" 2.

An important feature of the circuit is the ability to optimize its parametric sensitivity.

The optimal ratio is the equality of the capacitance of the capacitors 15 and 16 (C ₁₅ = C ₁₆ ). In this regard, the necessary value of the quality factor Q can be realized both structurally (by choosing the number of emitter junctions (m) of transistor 12), and parametrically by establishing a given ratio between the resistances of resistors 7 (R ₇ ) and 8 (R ₈ ) ((R ₈ + h _11.3 ) / R ₇ = k). In this case, the parametric sensitivity

determined by the ratio of the resistors (coefficient k). In this case, the numerical value of the number m of emitters of transistor 12:

allows you to get the specified value of the quality factor Q, provided that the circuit is equally nominal (k = 1). Indeed, for m = 2, k = 1

and for m = 3

Note that the condition k = 1 is associated with minimizing the influence of the frequency properties of bipolar transistors on the frequency of the quasi-resonance of the DUT and its quality factor. As for the sensitivity (5), it affects the instability of the parameters of the DUT only through the error due to the non-identity of the resistive elements (ΔΘ _R ), which for modern technologies is much smaller than the relative deviations of these elements, which determine the stability of the frequency of quasi-resonance f ₀ .

The numerical values of the capacitor 9 (C ₉ ) should be chosen from the following considerations.

If C ₉ = 0, then in formulas (2) - (8) it should be assumed that m = 0. In practice, this means that the circuit of the DUT, Fig. 3, with C ₉ = 0, has practically no improvement in the parameters K ₀ and Q.

If C ₉ >> C ₁₅ , C ₉ >> C ₁₆ , then all formulas (2) - (8) are valid and the IE has elevated values of Q and K ₀ , which are in accordance with (2) - (8).

In practical schemes, the capacitance C ₉ can be commensurate with C ₁₅ and C ₁₆ (Fig. 9).

The graphs of Fig. 9 show that the capacitance of the capacitor 9 (Fig. 3) or the same C ₂ (Fig. 3) can also be used to form the parameters of the resonant characteristic of the DUT, if its values are within 2 ÷ 40 pF. However, the authors recommend choosing C ₉ (C ₂ ) = 40 ÷ 70 pF for the SG25H1 process technology.

In addition, all possible modifications of the claimed DUT are implemented on n-p-n transistors, which is their significant advantage, for example, when constructing radiation-resistant products that turn out to be more efficient in outer space.

Presented on the drawings of FIGS. 5 to 10, the simulation results of the proposed DUT, FIG. 3, confirm the indicated properties of the claimed circuit.

Thus, the proposed circuit solution of the DUT is characterized by higher values of the gain K ₀ at the frequency of the quasi-resonance f ₀ , as well as increased values of the quality factor Q, characterizing its 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, C.Scheytt // Problems of Development of Promising Micro- and Nanoelectronic Systems - 2010. Proceedings / under the general. ed. Academician of the Russian Academy of Sciences A.L. Stempkovsky. - M .: IPPM RAS, 2010. - P.583-586.

3. Patent US 4.267.518.

4. Patent WO 2003/052925 fig. 3.

5. Patent application US 2011/0169568 fig. 4.

6. Patent US 7.135.923.

7. Patent US 3.843.343.

8. Patent application US 2008/0122530.

9. Patent US 6.972.624, fig.6A.

10. Patent application US 2011/0109388.

11. Patent US 5.298.802.

Claims (3)

1. A selective amplifier containing an input voltage source (1) connected to the input of the voltage-current converter (2), an input transistor (3), the base of which is connected to an auxiliary voltage source (4), the first (5) current-stabilizing two-terminal device, connected between the emitter of the input transistor (3) and the first (6) bus of the power source, the first (7) and second (8) frequency-setting resistors, the first (9) correction capacitor, the second (10) bus of the power source, characterized in that the input collector transistor (3) connected to you an ode to the voltage-current converter (2) through a forward biased pn junction (11) and connected to the base of the additional transistor (12), the emitter of the additional transistor (12) is connected to the first (6) bus of the power source through a second (13) current-stabilizing two-terminal device and through the first (9) correction capacitor is connected to the output of the voltage-current converter (2), which is connected to the second (10) bus of the power source through the first (7) frequency-setting resistor, the output of the voltage-current converter (2) is connected via alternating current with common bus power supplies (14) through series-connected second (15), third (16) correction capacitors, the common node of which is connected to the output of the device (17) and through the second (8) frequency-setting resistor is connected to the emitter of the input transistor (3), and the collector is additional transistor (12) is connected to the second (10) bus of the power source. 2. The selective amplifier according to claim 1, characterized in that the collector of the second (12) additional transistor is connected to the second (10) bus of the power source through an auxiliary resistor (18) and connected to the first additional output of the device (19). 3. A selective amplifier according to claim 1, characterized in that a buffer amplifier (21) is connected between the output of the device (17) and the second additional output (20).

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