RU2488955C1 - Non-inverting current amplifier-based selective amplifier - Google Patents

Abstract

FIELD: radio engineering, communication.

SUBSTANCE: non-inverting current amplifier-based selective amplifier has an input voltage source (1), a voltage-to-current converter (2), an output transistor (3), an auxiliary voltage source (4), a first (7) and second (8) balancing capacitor, a second (9) frequency-setting resistor.

EFFECT: high Q-factor of the amplitude-frequency curve of the selective amplifier and its voltage gain at quasi-resonance frequency f₀.

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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 resonant 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 _in -f _n [3-20]. 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 US 5304946, Fig.24. It contains an input voltage source 1, connected to a voltage-current converter 2, an output transistor 3, the base of which is connected to an auxiliary voltage source 4, and a collector through the first 5 frequency-setting resistor is connected to the first 6 bus of the power source, the first 7 and second 8 correction capacitors, the second 9 frequency-setting resistor.

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 $$Q\approx \frac{f_0}{f_{\mathrm{at}}-f_n}$$

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, figure 1, containing an input voltage source 1, connected to a voltage-current converter 2, an output transistor 3, the base of which is connected to an auxiliary voltage source 4, and the collector through the first 5 frequency-setting resistor connected to the first 6 bus of the power source, the first 7 and second 8 correction capacitors, the second 9 frequency-setting resistor, new elements and connections are provided - the output of the voltage-current converter 2 is connected to the collector output about transistor 3 and is connected via alternating current to the common bus of power supplies 10 through the first 7 correction capacitor, as well as through the second 8 correction capacitor connected to the input of the additional current mirror 11, and the non-inverting output 12 of the additional current mirror 11 is connected to the emitter of the output transistor 3 and the output of the device 13 through the second 9 frequency-setting resistor, and the emitter of the output transistor 3 is connected to the first additional current-stabilizing two-terminal 14.

The amplifier circuit of the prototype is shown in figure 1.

Figure 2 presents a diagram of the inventive device in accordance with claim 1, claim 2 and claim 3 of the claims.

Figure 3 shows a diagram of the DUT of figure 2 in a Cadence computer simulation environment on SiGe models of integrated transistors (SG25Hl process technology).

Figure 4 shows the logarithmic amplitude-frequency (LAC) and phase-frequency (PFC) characteristics of the DUT of figure 3 in a wide frequency range from 1 kHz to 100 GHz with Rvar = R1 = 70 Ohms, Cvar = C6 = C7 = 250 fF.

Figure 5 shows the LACH and phase response of the DUT of figure 3 in a narrower frequency range from 100 MHz to 10 GHz with Rvar = R1 = 70 Ohms, Cvar = C6 = C7 = 250 fF.

Figure 6 presents the dependence of the quality factor Q on the resistance Rvar of the DUT of figure 3.

7 shows the dependence of the Q factor Q and the resonant frequency f _{0 of the} DUT of FIG. 3 on the parameter Cvar.

The selective amplifier of FIG. 2 contains an input voltage source 1 connected to a voltage-current converter 2, an output transistor 3, the base of which is connected to an auxiliary voltage source 4, and a collector through the first 5 frequency-setting resistor is connected to the first 6 bus of the power source, the first 7 and the second 8 correction capacitors, the second 9 frequency-setting resistor. The output of the voltage-current converter 2 is connected to the collector of the output transistor 3 and connected via alternating current to the common bus of the power sources 10 through the first 7 correction capacitor, and also through the second 8 correction capacitor connected to the input of the additional current mirror 11, and the non-inverting output 12 additional current mirror 11 is connected to the emitter of the output transistor 3 and the output of the device 13 through the second 9 frequency-setting resistor, and the emitter of the output transistor 3 is connected to the first additional ohm current-stabilizing two-terminal 14.

In Fig. 2, in accordance with claim 2, between the input of the additional current mirror 11 and the first 6 bus of the power source, a second 15 additional current-stabilizing two-terminal device is included.

In addition, in FIG. 2, in accordance with claim 3, the inverting output 16 of the additional current mirror 11 is connected to the additional output of the device 17 and is connected to the first 6 bus of the power source through an auxiliary resistor 18. The current mirror 11 is based on a transistor 19 and a pn junction 20.

Consider the operation of the circuit of figure 2.

The input signal source (u _I ) 1 through the voltage-current converter 2 changes the current of the load circuit formed by the resistors 5, 9 and capacitors 8, 10. Due to the capacitive divider implemented on the capacitors 10 and 8, the current flowing through the resistor 9 has frequency response that matches the frequency response of the resonant DUT. Moreover, its maximum value is achieved at the frequency of quasi-resonance f ₀ , determined by the ratio of only passive elements of the specified circuit. The output current of the aforementioned frequency-dependent circuit (current through resistor 9) determines the change in the current of the emitter and collector of the output transistor 3 and the current of the additional current mirror 11, which ensure the implementation of the complex feedback loop. Due to the above properties of the load circuit of the output transistor 3, this feedback is real at the frequency of the quasi-resonance of the dc f ₀ and, therefore, its action is aimed at increasing the quality factor Q and the gain K ₀ . The depth of the loop specified feedback is determined by the number m of emitters of the transistor 19 of the current mirror 11.

The complex transfer coefficient of the DUT (Fig. 2) as the ratio of the output voltage (output of the device 13) to the input voltage u _in is determined by the formula, which can be obtained using methods of analysis of electronic circuits:

$$K\left(jf\right)=\frac{u_{13}}{u_{\mathrm{at}x}}=K_0\frac{jf\frac{f_0}{\mathrm{<figure-callout\; id="0"\; label="Q\; f"\; filenames="00000014.png,00000015.png"\; state="\{\{state\}\}">Q\; </figure-callout>}}}{f_{}^{}},\left(\mathrm{one}\right)$$

where f is the signal frequency;

f ₀ is the frequency of quasi-resonance;

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

$${\mathrm{<figure-callout\; id="0"\; label="f"\; filenames="00000014.png,00000015.png"\; state="\{\{state\}\}">f</figure-callout>}}_0\approx \frac{\mathrm{one}}{2\pi \sqrt{C_8{C}_{10}{R}_5\left({\mathrm{<figure-callout\; id="9"\; label="R"\; filenames="00000012.png"\; state="\{\{state\}\}">R</figure-callout>}}_9+h_{11.20}+h_{11.3}\right)}},\left(2\right)$$

where C ₈ , C _10, R _5, R ₉ are the parameters of the elements of the circuit 8, 10, 5 and 9;

h _11.i is the input resistance of the i-th transistor in a circuit with a common base.

The quality factor of the DUT is determined by the formula

$$Q^{-\mathrm{one}}={\mathrm{<figure-callout\; id="0"\; label="D"\; filenames="00000014.png,00000015.png"\; state="\{\{state\}\}">D</figure-callout>}}_0+\sqrt{\frac{C_8}{C_{10}}}\sqrt{\frac{R_5}{{\mathrm{<figure-callout\; id="9"\; label="R"\; filenames="00000012.png"\; state="\{\{state\}\}">R</figure-callout>}}_9+h_{11.20}+h_{11.3}}}\left[\mathrm{one}-{\alpha }_3\left(2+m\right)\right],\left(3\right)$$

where α _i is the current transfer coefficient of the emitter of the i-th transistor;

m is the number of pn junctions of the multi-emitter transistor 19 in the current mirror 11;

$${\mathrm{<figure-callout\; id="0"\; label="D"\; filenames="00000014.png,00000015.png"\; state="\{\{state\}\}">D</figure-callout>}}_0=\left(\sqrt{\frac{C_8}{{\mathrm{<figure-callout\; id="10"\; label="C"\; filenames="00000012.png,00000014.png"\; state="\{\{state\}\}">C</figure-callout>}}_{10}}}+\sqrt{\frac{C_{10}}{C_8}}\right)\sqrt{\frac{{\mathrm{<figure-callout\; id="9"\; label="R"\; filenames="00000012.png"\; state="\{\{state\}\}">R</figure-callout>}}_9+h_{11.20}+h_{11.3}}{{\mathrm{<figure-callout\; id="5"\; label="R"\; filenames="00000012.png"\; state="\{\{state\}\}">R</figure-callout>}}_5}}$$

- 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

$$K_0=-Q\cdot \left(-S_2\right)\cdot \sqrt{\frac{C_8}{C_{10}}\frac{R_5}{R_9+h_{11.19}+h_{11.3}}},\left(\mathrm{four}\right)$$

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

An important feature of the circuit is the ability to optimize the use of equiminal elements of the passive circuit. Indeed, as follows from relation (3) under the conditions R = R ₅ = R ₉ , C ₈ = C ₁₀ = C:

$$Q^{-\mathrm{one}}=\left[3-{\alpha }_3\left(2+m\right)\right]+\frac{h_{11.3}+h_{11.20}}{R}\left[\mathrm{one}+{\alpha }_3\left(\mathrm{one}+m/2\right)\right].\left(5\right)$$

Действительно,The necessary value of Q can be set structurally by choosing the number of emitter junctions m of the transistor 19 and parametric selection of the operating currents I ₁₄ and $${\mathrm{<figure-callout\; id="0"\; label="I"\; filenames="00000014.png,00000015.png"\; state="\{\{state\}\}">I</figure-callout>}}_0^{*}$$

Really,

$$h_{11.3}\approx {\varphi }_t/I{}_0,h_{11.20}\approx {\varphi }_t/{\mathrm{<figure-callout\; id="0"\; label="I"\; filenames="00000014.png,00000015.png"\; state="\{\{state\}\}">I</figure-callout>}}_{0.}^{*}\left(6\right)$$

, а изменением тока источника тока 14 - ток I₀.By changing the resistance of the current-setting resistor 15, the current is controlled $${\mathrm{<figure-callout\; id="0"\; label="I"\; filenames="00000014.png,00000015.png"\; state="\{\{state\}\}">I</figure-callout>}}_0^{*}$$

, and by changing the current of the current source 14 - current I ₀ .

Presented in figure 4-7, the simulation results of the proposed IU, figure 3, confirm these properties.

Thus, the claimed circuit solution of the DUT is characterized by higher values of the gain K ₀ at the frequency of quasi-resonance f ₀ , as well as 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. Ezhkov Yu.S. Reference book on circuitry amplifiers. - 2nd ed., Revised. - M., IP RadioSoft, 2002. - P. 21, Fig. 1.10c.

4. Volgin L.I. Synthesis and circuitry of analog electronic devices in the elemental basis of amplifiers and current repeaters / L.I. Volgin, A.I. Zarukin; ed. L.I. Volgina. - Ulyanovsk: UlSTU, 2005. - P.33, Fig. 27.

5. Patent US 5304946 fig. 22.

6. Patent US 7113043.

7. Patent US 7598810.

8. Patent application US 2005/0146389, fig. 3.

9. Patent application US 2008/0231369, fig. 2.

10. Patent US 7110742, fig. 5.

11. Patent US 6515547, fig. 4a.

12. Patent US 7633344, fig. 7.

13. Patent US 7847636, fig.4a.

14. Patent US 7786807.

15. Patent application US 2007/0296501.

16. Patent application US 2008/0018403.

17. US 3351865.

18. Patent US 7737790.

19. Patent US 4151483, fig. 2.

20. Patent application JP 2003011396.

Claims (3)

1. A selective amplifier based on a non-inverting current amplifier containing an input voltage source (1) connected to a voltage-current converter (2), an output transistor (3), the base of which is connected to an auxiliary voltage source (4), and the collector through the first (5) frequency setting resistor is connected to the first (6) bus of the power source, the first (7) and second (8) correction capacitors, the second (9) frequency setting resistor, characterized in that the output of the voltage-current converter (2) is connected to the output trans collector a resistor (3) and is connected via alternating current to a common bus of power sources (10) through the first (7) correction capacitor, as well as through the second (8) correction capacitor connected to the input of the additional current mirror (11), and the non-inverting output (12) an additional current mirror (11) is connected to the emitter of the output transistor (3) and the output of the device (13) through a second (9) frequency-setting resistor, and the emitter of the output transistor (3) is connected to the first additional current-stabilizing two-terminal device (14). 2. A selective amplifier based on a non-inverting current amplifier according to claim 1, characterized in that between the input of the additional current mirror (11) and the first (6) bus of the power source, a second (15) additional current-stabilizing two-terminal device is included. 3. A selective amplifier based on a non-inverting current amplifier according to claim 1, characterized in that the inverting output (16) of the additional current mirror (11) is connected to the additional output of the device (17) and is connected to the first (6) through an auxiliary resistor (18) power supply bus.

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