RU2475947C1 - 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, the first output of which is connected with the emitter of the output transistor, and the second output is connected to the first bus of the power supply source. Between the collector of the first input transistor and the common bus of power supply sources there is the first correcting capacitor connected by AC, and between the first output of the second source of reference current and the emitter of the first input transistor there is the second correcting capacitor connected, besides, the common unit of the second correcting capacitor and the first output of the second source of reference current is connected with the current input of the device.EFFECT: higher quality of amplifier amplitude-frequency characteristic and its amplification ratio by voltage at quasi-resonance frequency.2 cl, 8 dwg

Description

The invention relates to the field of radio engineering and communication 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 tasks 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, universal transistors forming an operational amplifier of the microwave range [1, 2]. In this regard, quite urgent is the task of constructing microwave highly specialized selective amplifiers on three to four transistors, which provide 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.

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 _in -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 2079397, 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, 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 according to a switching transistor 5 and through a first auxiliary resistor 10 is connected to the second 8 bus of the power source, the second 11 is a current-stabilizing two-terminal device, the first terminal of which is connected to the emitter of the output transistor 7, and the second terminal is connected to the first 3 bus of the power source.

- амплитудно-частотной характеристики (АЧХ) и коэффициент усиления по напряжению К₀>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 supply, the second 11 is a current-stabilizing two-terminal device, the first output of which is connected to the emitter of the output transistor 7, and the second output is connected to the first 3 bus power supply, new elements and connections are provided - between the collector of the first 1 input transistor and the common bus of power supplies, the first 12 correction capacitor is turned on by alternating current, and between rvym terminal of the second reference current source 11 and the emitter of the first transistor 1 is turned on the second input 13 of the correction capacitor and the common node of the second correction capacitor 13 and a first terminal of the second reference current source 11 is connected to the current input 14 of the apparatus.

A diagram of a selective prototype amplifier is shown in FIG. 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 shows a diagram of the DUT of figure 2 in accordance with claim 2 of the claims.

The drawing of FIG. 4 shows the DUT of FIG. 3, in which a converter 11 of the input voltage u _in to the input current i _{in of the} device is used, and also a specific embodiment of the sources of additional voltages 4, 6 is shown.

The drawing of Fig. 5 shows the DUT of Fig. 4 (Fig. 3), in which the converter 11 of the input voltage u _in to the input current of the device i _{in is} made on the basis of a differential stage (elements 20, 21, 22).

The drawing of Fig.6 shows a diagram of the inventive DUT of Fig.5 in a Cadence environment on SiGe models of integrated transistors.

The drawing of Fig.7 shows the dependence of the voltage gain on the frequency of the DUT of Fig.6 on a large scale, and the drawing of Fig.8 is the frequency dependence of the gain of the DUT of Fig.6 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 matching one with the collector of the transistor 5 and through the first auxiliary resistor 10 is connected to the second power supply bus 8, the second two-pole tokostabiliziruyuschy 11, a first terminal of which is connected to the emitter of the output transistor 7, and a second terminal connected to the first power source bus 3. The first 12 correction capacitor is connected alternately to the collector of the first 1 input transistor and the common bus of the power supplies, and the second 13 correction capacitor is connected between the first output of the second 11 reference current source and the emitter of the first 1 input transistor, and the common node of the second 13 correction capacitor and the first the output of the second 11 source of reference current is connected to the current input 14 of the device.

In the drawing of 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 first output of the second 11 current-stabilizing two-terminal is connected to the emitter of the output transistor 7 through the second 16 additional resistor .

The figure 4 shows the DUT 3, which uses the input voltage of inverter 11 (u _Rin, 19) in the input current i _Rin device, and shows a specific execution of additional voltage sources 4, 6, in the special case that are implemented on pn transitions 17 and resistor 18.

The figure 5 shows the DUT 4 (3), wherein the input voltage converter 11 (u _Rin, 19) in the input device current (i _Rin) is based on a classical differential stage (elements 20, 21, 22) .

Consider the operation of the DUT figure 2.

The input source of the driving current i _Rin by the input of the differentiating circuit formed by capacitor 13 and the input impedance of transistors 1 and 7, modifies the emitter current of the input transistor 1, load circuit of which, consisting of capacitor 12 and input transistor resistance 5, provides its integrating transform in the increment of the emitter and collector current of the transistor 5. The active load resistance of the transistor 5 implements a large-scale conversion of this increment into the input voltage the base and current of the base of the transistor of the output circuit 7. The capacitive nature of the emitter (output) circuit of the circuit, together with the above transformations of the input signal, ensures the realization of the band-pass characteristic of the DUT, the amplitude-frequency characteristic of which has a maximum at the frequency of quasi-resonance f ₀ . The interaction of the output circuit 9 with the isolation capacitor 13 and, therefore, the emitter circuit of the transistor 1 contributes to the organization of the regenerative feedback loop, which in the low frequency region (f << f ₀ ) (due to the nature of the conductivity of the capacitor 13) is reactive and blocking properties of the capacitor 12 in the high frequency region (f >> f ₀ ) retains its reactive properties. Thus, the feedback turns out to be real only at the frequency of quasi-resonance, which explains the increase in the quality factor of the circuit Q and its gain K ₀ . Due to the large-scale conversion of the collector current of the transistor 5 into the input current of the transistor 7, the depth of this material feedback not only does not affect the quasi-resonance frequency of the DUT, but also directly determines the numerical value of Q and K ₀ .

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

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 f is the signal frequency;

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

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

Analysis of the circuit of figure 2 leads to the following relationships:

τ ₁ = C ₁₂ h _11.5 , τ ₂ = C ₁₃ (h _11.1 + h _11.7 )

where h _11.i is the input resistance of the i-th transistor;

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

As can be seen from (4) and (3), the ratio between R ₁₀ and h _11.5 provides the implementation of any necessary value of the Q factor and gain K ₀ of the DUT circuit while maintaining a constant value of the frequency of quasi-resonance f ₀ . One of the important properties of the DUT of FIG. 2 is the possibility of parametric optimization of its sensitivity with limited Q factors. As can be seen from (4), when the condition R ₁₀ = h _{11.5 is} realized (replacing R ₁₀ with a forward biased transition)

Therefore, the implementation of the condition

provides

With parametric sensitivities

In addition, the circuit of the DUT of FIG. 2 can have τ ₁ = τ ₂ , which helps to increase its dynamic range. In this case

Therefore, the fulfillment of the condition R ₁₀ = 2h _11.5 (two forward-biased transitions are used in the collector circuit of transistor 5) provides high quality factor

which is determined by the static current gain of the base β of the transistors used.

An important feature of the circuit is the possibility of modifying its quasi-resonance frequency f ₀ . As can be seen from (2) provided that h _11.i ≈φ _t / I _e

where I _i is the current of the i-th current-stabilizing two-terminal network.

As can be seen from the obtained ratio, the currents I ₂ and I ₁₁ can also be used for circuits for the implementation of a tunable DUT with correction of the control law.

In this case, the frequency of quasi-resonance (2) and its parametric sensitivity remain unchanged.

As seen from the figure 3, which shows a practical implementation of the circuit 2, the conditions set forth above can be easily implemented based on the input converter "voltage-current" (differential stage), which provides the input voltage u transform _Rin during the input current i _{input 1} selective amplifier.

These theoretical conclusions confirm the graphs of Fig.7, Fig.8.

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, S.Scheytt \\ Problems of developing 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. ES patent 2079397, fig. 9.

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

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

6. Patent US 7633344, fig. 1.

7. Ezhkov Yu.A. “Handbook of amplifier circuitry”, M.: RadioSoft IE, 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 network, the first output of which is connected to the emitter of the output transistor (7), and the second terminal is connected to the first (3) bus of the power source, characterized in that between the collector of the first (1) input transistor and the common bus of the power sources, the first (12) correction capacitor is turned on by alternating current, and between the first terminal of the second (11) source oporn of the current and the emitter of the first (1) input transistor includes a second (13) correction capacitor, and the common node of the second (13) correction capacitor and the first output of the second (11) reference current source is connected to the current input (14) of the device. 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 first output of the second (11) current-stabilizing two-terminal device is connected to the emitter of the output transistor (7) through the second (16) additional resistor.

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