RU2475948C1 - Selective amplifier - Google Patents

Abstract

FIELD: radio engineering, communication.

SUBSTANCE: selective amplifier is proposed, which comprises the first input transistor, the emitter of which via the first current-stabilising dipole is connected with the first bus of a power supply source, the base is connected to the first source of additional voltage, and the collector is connected with the emitter of the matching transistor, the second source of additional voltage, connected with the base of the matching transistor, an output transistor, the collector of which is connected to the second bus of the power supply source, the emitter is connected with a potential output of the device, and the base is connected with the collector of the matching transistor and via the first auxiliary resistor it is connected with the second bus of the power supply source, the second current-stabilising dipole connected with the potential output of the device, a source of input voltage. The source of input voltage is connected with the collector of the first input transistor via the first frequency-setting capacitor, the common unit of the potential output and the second source of reference current is connected with the emitter of the first input transistor via the second frequency-setting capacitor.

EFFECT: higher quality of amplifier amplitude-frequency characteristic and its amplification ratio by voltage at quasi-resonance frequency.

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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 (DIs) (RC filters) is accompanied by significant energy losses, which are mainly used to ensure the static mode of a sufficiently large number of auxiliary transistors forming an operational amplifier of the microwave range [1, 2]. In this regard, the task of constructing highly specialized microwave selective amplifiers on three to four transistors, providing the selection of a 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 schemes cascode selective amplifiers (DUTs) with an output emitter follower [3-7], which provide the formation of the amplitude-frequency characteristics of the voltage gain (AFC) in a given frequency range Δf = -f _to -f _n . 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 the input correction capacitor.

The closest prototype of the claimed device is a selective amplifier, presented in patent ES 2.079.397 fig.9. It contains the first 1 input transistor, the emitter of which is connected through the first 2 current-stabilizing bipolar to the first 3 bus of the power supply, the base is connected to the first 4 additional voltage source, and the collector is connected to the emitter of the matching transistor 5, the second additional voltage source 6 connected to the matching base transistor 5, the output transistor 7, the collector of which is connected to the second 8 bus of the power source, the emitter is connected to the potential output of the device 9, and the base is connected to the collector transistor 5 and through the first auxiliary resistor 10 is connected to the second 8 bus power supply, the second 11 current-stabilizing two-terminal connected to the potential output of the device 9, the input voltage source 12.

амплитудно-частотной характеристики (АЧХ) и коэффициент усиления по напряжению K₀>1 на частоте квазирезонанса (f₀=1÷5 ГГц).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 frequency of quasi-resonance (f ₀ = 1 ÷ 5 GHz).

The main objective of the invention is to increase the quality factor 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 emitter of which is connected through the first 2 current-stabilizing bipolar to the first 3 bus of the power supply, the base is connected to the first 4 additional voltage source, and the collector is connected to the emitter of the matching transistor 5, the second additional voltage source 6 connected to the base of the matching transistor 5, the output transistor 7, the collector of which is connected to the second 8 bus of the power source, the emitter is connected to potential output of the device 9, and the base is connected to the collector of the matching transistor 5 and through the first auxiliary resistor 10 is connected to the second 8 bus of the power source, the second 11 is a current-stabilizing bipolar connected to the potential output of the device 9, the input voltage source 12, new elements and connections are provided - input voltage source 12 is connected to the collector of the first 1 input transistor through the first 13 frequency-setting capacitor, a common node of the potential output 9 and second 11 of the reference current source An emitter of the first 1 input transistor through the second 14 frequency-setting capacitor.

A diagram of a selective prototype amplifier is shown in FIG. Figure 2 presents a diagram of the inventive device in accordance with claim 1 of the claims.

Figure 3 shows a diagram of the DUT of figure 2 in accordance with claim 2.

Figure 4 shows a diagram of the inventive DUT of figure 3 in a Cadence environment on SiGe models of integrated transistors.

In Fig.5 shows the dependence of the voltage gain on the frequency of the DUT of Fig.4 on a large scale, and Fig.6 is the frequency dependence of the gain of the DUT of Fig.4 on a smaller scale.

The selective amplifier of Fig. 2 contains a first 1 input transistor, the emitter of which is connected through the first 2 current-stabilizing bipolar to the first 3 bus of the power supply, the base is connected to the first 4 additional voltage source, and the collector is connected to the emitter of the matching transistor 5, the second additional voltage source 6, connected to the base of the matching transistor 5, the output transistor 7, the collector of which is connected to the second 8 bus of the power source, the emitter is connected to the potential output of the device 9, and the base with dinene with the collector of the matching transistor 5 and through the first auxiliary resistor 10 is connected to the second 8 bus of the power source, the second 11 current-stabilizing two-terminal connected to the potential output of the device 9, the input voltage source 12. The input voltage source 12 is connected to the collector of the first 1 input transistor through the first 13 frequency-setting capacitor, a common node of the potential output 9 and second 11 of the reference current source is connected to the emitter of the first 1 input transistor through the second 14 frequency-setting con ensator.

In Fig. 3, in accordance with claim 2, the collector of the first 1 input transistor is connected to the emitter of the matching transistor 5 through the first 15 additional resistor, and the emitter of the output transistor 7 is connected to the potential output of the device 9 through the second 16 additional resistor.

Consider the operation of the DUT 3.

The input signal source 12 (u _I ) through a differentiating input circuit (the first 15 additional resistor and the first 13 frequency-setting capacitor) changes the emitter current of the matching transistor 5. The proportionality of the conversion of this current to its collector voltage, due to the resistance of the first 10 auxiliary resistor, changes the output voltage of the DUT (output 9) according to the integrating law, which is implemented by the output RC circuit (second 16 additional resistor and second 14 frequency-setting capacitor). That is why the shape of the frequency response and phase response of the circuit of Fig. 3 corresponds to a selective circuit whose quasi-resonance frequency (f ₀ ) is determined by the ratio of the time constants of the input (R ₁₅ , C ₁₃ ) and output (R ₁₆ , C ₁₄ ) RC circuits. The transfer of part of the output signal by converting the output voltage of the DUT through the capacitor C ₁₄ to the emitter current of the first 1 input transistor into the collector circuit of the matching transistor 5 provides an integrated feedback loop. Due to the fact that the input circuit of the DUT (the first 13 frequency-setting capacitor and the first 15 additional resistor) in this circuit functions as an integrating RC circuit, and the integrating circuit of the input signal transmission path (C ₁₄ , R ₁₆ ) functions as a differentiating conversion of the feedback signal, The type of frequency response and phase response of the IU feedback ratio corresponds to the characteristics of the band-pass type. That is why the action of the feedback loop is aimed at increasing the quality factor Q and the gain of the DUT at the frequency of its quasi-resonance f ₀ , which does not depend on the depth of this feedback. Thus, with increasing frequency, the emitter current of transistor 1 increases, and at f> f ₀ its collector voltage (due to the influence of capacitor C ₁₃ decreases. For f <f ₀ , the opposite occurs. Thus, in the indicated frequency ranges, the feedback is not real and approaches reactive, and the depth of the material feedback (f = f ₀ ) is directly determined by the coefficient of conversion of the collector current of the matching transistor 5 into its collector voltage.

Let us show analytically that higher values of K ₀ and Q in the operating frequency range are implemented in the scheme of figure 3.

Indeed, as a result of the analysis, we can find that the complex voltage transfer coefficient of the DUT of FIG. 2 is determined by the formula

Where

τ ₁ = C ₁₃ (R ₁₅ + h _11.5 ); τ ₂ = C ₁₄ (R ₁₆ + h _11.7 + h _11.1 )

α _i - current transfer coefficient of the emitter of the transistor of the i-th transistor.

Thus, the numerical values of the resistances R ₁₀ and R ₁₆ regardless of the ratio of time constants τ ₁ and τ ₂ , i.e. from f ₀ provide the necessary values of the quality factor Q and the gain K ₀ .

The most important property of the proposed scheme is the possibility of parametric optimization of the dynamic range, which requires the equality τ ₁ = τ ₂ at a relatively high quality factor. As can be seen from (4) and (3), when C ₁₄ = C ₁₃ , R ₁₅ = R ₁₆

At the same time, its sensitivity coefficients:

At the same time, the frequency of quasi-resonance (2) and its parametric sensitivity remain unchanged.

As can be seen from the drawing of Fig. 4, which shows the practical implementation of the circuit of Fig. 2, the conditions formulated above are easily realized by choosing the ratio between R ₁₅ , R ₁₆ and h _11.7 , h _11.1 by means of current mode current sources.

These theoretical conclusions confirm the graphs of Fig.5, Fig.6.

Thus, the claimed circuit solution is characterized by higher values of the gain K ₀ at the frequency of quasi-resonance f ₀ and increased values of the quality factor Q, characterizing its selective properties.

BIBLIOGRAPHIC LIST

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 developing promising micro- and nanoelectronic systems. - 2010. Proceedings / under the total. ed. Academician of the Russian Academy of Sciences A.L. Stempkovsky. - M .: IPPM RAS, 2010. - P.583-586.

3. ES patent 2.079.397, fig. 9.

4. Patent application US 2010/0283543, fig. 1.

5. Patent application US 2010/0283542, fig.2.

6. Patent US 7.633.344, fig. 1.

7. Ezhkov Yu.A. “Handbook of amplifier circuitry”, M .: IP “Radiosoft”, 2002, p. 113, Fig. 6.18.

Claims (2)

1. A selective amplifier containing the first (1) input transistor, the emitter of which is connected through the first (2) current-stabilizing two-terminal to the first (3) bus of the power supply, the base is connected to the first (4) additional voltage source, and the collector is connected to the emitter of the matching transistor (5), the second additional voltage source (6) connected to the base of the matching transistor (5), the output transistor (7), the collector of which is connected to the second (8) bus of the power source, the emitter is connected to the potential output of the device (9) and the base is connected to the collector of the matching transistor (5) and through the first auxiliary resistor (10) is connected to the second (8) bus of the power source, the second (11) current-stabilizing two-terminal connected to the potential output of the device (9), the input voltage source (12 ), characterized in that the input voltage source (12) is connected to the collector of the first (1) input transistor through the first (13) frequency-setting capacitor, the common node of the potential output (9) and the second (11) reference current source is connected to the emitter of the first (1 ) input nzistora through the second (14) frequency control capacitor. 2. The selective amplifier according to claim 1, characterized in that the collector of the first (1) input transistor is connected to the emitter of the matching transistor (5) through the first (15) additional resistor, and the emitter of the output transistor (7) is connected to the potential output of the device (9 ) through the second (16) additional resistor.

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