Controlled selective amplifier

FIELD: radio engineering, communication.

SUBSTANCE: controlled selective amplifier comprises an input signal source, two input transistors, two current-stabilising two-terminal elements, a power supply, a current mirror, two balancing capacitors, a resistor and a buffer amplifier. The input transistors used are field-effect transistors, whose sources correspond to the emitter, the drain to the collector and the gate to the base of a bipolar transistor.

EFFECT: lower overall power consumption owing to higher attenuation of the input signal in the low frequency range with high stability of the Q factor of the amplitude-frequency characteristic of the selective amplifier and voltage gain at quasi-resonance frequency f₀.

8 dwg

The present invention relates to the field of radio and communication and can be used in filtration devices radio, television, radar, etc.

In the tasks of separating high-frequency signals are now widely used integrated operational amplifiers with special items RC-correction form of the amplitude-frequency characteristic of the resonance type [1, 2]. However, the classical construction of such election amplifiers (in-amps) is accompanied by significant energy losses, which go primarily to ensure the static mode, a sufficiently large number of secondary transistors constituting the operational amplifier [1, 2]. In this regard, it is highly important task of building electoral amplifiers on two or three transistors, providing a selection of narrow-spectrum signal with a sufficiently high quality factor (Q) of the resonance characteristics (Q=2÷40) with low power consumption.

Known schemes Yiwu integrated into the architecture of the RC-filter based on bipolar transistors, which provide the formation of the amplitude-frequency characteristics of the gain of the voltage in a given range of frequencies Δf=f_in-f_n[3-10]. And their top f_inand lower f_nthe cutoff frequency are formed special adjust what they condensers.

The closest prototype of the proposed device is the selective amplifier presented in the patent US 4843343, figure 1. It contains the input source 1 connected to the first base 2 of the input transistor, the second 3 input transistor, the base of which is connected with the output 4 of the device, and the emitter is connected to the emitter of the first 2 input transistor and through the first 5 dakotabilities dvukhpolosnykh associated with the first 6-bus power source, current mirror 7, consistent with the second 8-bus power supply, the output of which 9 through the second 10 dakotabilities dvukhpolosnykh connected with the first 6-bus power supply, the first 11 correction capacitor AC current between the output 9 of the current mirror 7 and the total bus power sources 12, 13 second correction capacitor.

Significant disadvantages of Yiwu prototype figure 1 are as follows:

- to provide a large attenuation of the output signal in the low frequency range (<<f₀in the structure of PS 1, you must use the connection of the signal source 1 to the first 2 of the input transistor through a special decoupling capacitor, whose capacity must be significantly greater than the capacities of the frequency-setting circuit (the first 11 and second 13 correction capacitors). In addition, in this case, the necessary facilities is hydrated regionalise resistor in the base circuit of the input transistor 2;

for cascading (Daisy chain) of such schemes in Yiwu bandpass filters must use an additional buffer amplifiers;

- the structure is difficult to obtain high dobrotnosti. When implementing large dobrotnosti (Q=3...10) it is necessary to use a large value of resistance dakotabilities of dvukhpolosnykh 10, which increases in proportion to the impact on the operation of the circuit parasitic capacitance of the collector junction of the transistor 3 and the output capacitance of the current mirror. This ultimately limits the operating frequency range Yiwu prototype.

The main objective of the present invention is to increase the attenuation of the output signal in the low frequency range at high and quite stable quality factor Q of the amplitude-frequency characteristics (AFC) Yiwu and high gain voltage (K₀on the frequency of quasiresonance f₀.

The problem is solved in that in the election amplifier figure 1, containing the input source 1 connected to the first base 2 of the input transistor, the second 3 input transistor, the base of which is connected with the output 4 of the device, and the emitter is connected to the emitter of the first 2 input transistor and through the first 5 dakotabilities dvukhpolosnykh associated with the first 6-bus power source, a current mirror is about 7, consistent with the second 8-bus power supply, the output of which 9 through the second 10 dakotabilities dvukhpolosnykh connected with the first 6-bus power supply, the first 11 correction capacitor AC current between the output 9 of the current mirror 7 and the total bus power sources 12, 13 second correction capacitor, there are new elements and relationships - as the first 2 and second 3 input transistors are field-effect transistors, the source of which corresponds to the emitter, drain - to the collector and the gate - base bipolar transistor, and the drain of the second 3 of the input transistor is connected to the input 14 of the current mirror 7, the output 9 of the current mirror 7 is connected with the input of buffer amplifier 15, the output of which is connected to the output device 4 through 13 second correction capacitor, the drain of the first 2 input transistor associated with the second 8-bus power source, and the output device 4 are shunted by AC additional resistor 16.

The amplifier circuit of the prototype is shown in figure 1. Figure 2 presents the diagram of the inventive Yiwu in accordance with the invention.

Figure 3 presents a diagram of the PS 2 with a specific implementation of the current mirror 7 and the buffer amplifier 15.

Figure 4 shows a diagram of the PS 3 in the environment of computer simulation Cadence on models SiGe and TerraLink transistors.

Figure 5 shows the logarithmic amplitude-frequency characteristic Yiwu figure 4 in the frequency range of 0.2 to 5 GHz for different values of current I₀dakotabilities of dvukhpolosnykh 5.

Figure 6 shows the logarithmic phase response Yiwu figure 4 in the frequency range of 0.2 to 5 GHz for different values of the current 1₀dvukhpolosnykh 5.

7 and 8 shows the amplitude-frequency (Fig.7) and phase (Fig) characteristics Yiwu figure 4 in the frequency range of 0.5-2 GHz at different values of current dvukhpolosnykh 20 (I₂₀=I_to).

Controlled selective amplifier includes an input signal source 1 is connected to the base of the first 2 input transistor, the second 3 input transistor, the base of which is connected with the output 4 of the device, and the emitter is connected to the emitter of the first 2 input transistor and through the first 5 dakotabilities dvukhpolosnykh associated with the first 6-bus power source, current mirror 7, consistent with the second 8-bus power supply, the output of which 9 through the second 10 dakotabilities dvukhpolosnykh connected with the first 6-bus power supply, the first 11 correction capacitor AC current between the output 9 of the current mirror 7 and a common bus sources power supply 12, 13 second correction capacitor. As the first 2 and second 3 input transistors are used floor is the first transistors, the source which corresponds to the emitter, drain - to the collector and the gate - base bipolar transistor, and the drain of the second 3 of the input transistor is connected to the input 14 of the current mirror 7, the output 9 of the current mirror 7 is connected with the input of buffer amplifier 15, the output of which is connected to the output device 4 through 13 second correction capacitor, the drain of the first 2 input transistor associated with the second 8-bus power source, and the output device 4 are shunted by AC additional resistor 16.

Figure 3 current mirror 7 is implemented by transistors 17 and 18, and an additional buffer amplifier 15 includes a transistor 19 and a current source 20. In the circuit of the drain of the transistor 2 is turned on, the transistor 21, which increases the symmetry of the schema.

Consider the work of the proposed Yiwu based on the analysis of the private choices of its construction (figure 3).

The input signal u_I(1) changes the currents of the sources (drains) of the MOS transistors 2 and 3. The drain current of the transistor 3 changes the base current and the emitter of the transistor 17. A similar change in the collector current of transistor 17 because of the nature of its collector load leads to the amplification of signals of lower frequencies and the attenuation of high frequency signals in the base circuit of the transistor 19. The conversion of the voltage drop on dvukhpolosnykh 10 and the capacitor 11 in the voltage emitter circuit t is ancestor 19 provides (due to the differentiating properties of the chain, formed by the series connection of capacitor 13 and resistor 16) the dependence of the output voltage Yiwu (node 4), corresponding to the characteristic of the selective amplifier. Thus, the regenerative feedback circuit PS 3 form its maximum depth of only a single frequency coinciding with the frequency of quasiresonance election amplifier (f₀). The specified property Yiwu provides increased realizable quality factor (Q) and gain (K₀) without changing the f₀.

The complex transmission coefficient of Yiwu as the ratio of the output voltage u_o=u_wyh(output 4) to the input voltage u_Iamplifier 2 is determined by a formula, which can be obtained by using methods of analysis of electronic circuits

$$K{\left(jf\right)}_{12}=\frac{u_{\mathrm{in}sx.4}}{u_{\mathrm{in}x}}=K_0\frac{jf\frac{f_0}{Q}}{f_0^2-f^2+jf\frac{f_0}{Q}},\left(1\right)$$

where f is the frequency of the input signal;

f₀frequency quasiresonance Yiwu;

Q - q AFC electoral amp;

To₀the gain of the DUT voltage at a frequency of quasiresonance f₀. And

$$f_0=\frac{1}{2\pi \sqrt{C_{13}{C}_{11}{R}_{10}\left(R_{\mathrm{in}sx15}+R_{16}\right)}},\left(2\right)$$

$$Q^{-1}=d_p=\sqrt{\frac{C_{11}{R}_{10}}{C_{13}\left(R_{16}+R_{\mathrm{in}sx15}\right)}}+\sqrt{\frac{C_{13}\left(R_{16}+R_{\mathrm{in}sx15}\right)}{C_{11}{R}_{10}}}\left(1-S\frac{R_{16}{R}_{10}}{R_{16}+R_{\mathrm{in}sx15}}\right),\left(3\right)$$

$$K_0=Q\cdot S\sqrt{R_{16}{R}_{10}}\sqrt{\frac{C_{13}}{C_{11}}}\frac{\mathrm{}}{\sqrt{1+\raisebox{1ex}{$R_{\mathrm{in}sx15}$}\!\left/ \!\raisebox{-1ex}{$R_{16}$}\right.}},\left(4\right)$$

where R_wyhS - the output impedance of buffer amplifier 15 and the steepness of the current mirror 7.

The peculiarity of the structure Yiwu figure 2 allows to choose the optimal parameter values of the circuit elements

R₁₆=kR_wyh,

$$m_{opt}=\frac{1}{2}{d}_p;k_{opt}=\frac{1}{4}{d}_p^2$$

Then for scheme 3

$$R_2\approx 2\frac{h_{11.17}}{{\alpha }_{17}}\frac{1+k}{k},\left(7\right)$$

Therefore, the choice m=m_optthrough the ratio of the capacitances of the capacitors C₁₃and C₁₁

$$\raisebox{1ex}{$C_{11}$}\!\left/ \!\raisebox{-1ex}{$C_{13}$}\right.=n,\left(8\right)$$

if$$\raisebox{1ex}{$C_{10}$}\!\left/ \!\raisebox{-1ex}{$C_{16}$}\right.=l$$can be found

$$n=1l\left(1+\raisebox{1ex}{$1$}\!\left/ \!\raisebox{-1ex}{$k$}\right.\right)\frac{d_p^2}{4}.\left(9\right)$$

For example, choosing k≈3, we get l≈3/k and$$n=\frac{d_p^2}{3}$$easy to implement parametric conditions.

The combination of structural and parametric characteristics diagram of the inventive device allows to adjust its frequency quasiresonance f₀. So, to control the frequency of quasiresonance f₀by changing the output resistance of the buffer amplifier 15 is necessary to ensure the dependence of R_wyh=φ_T/I_to(figure 3). Given that R₁₆=kR_wyhimplementation of Ogre is Iceni (6) leads to the following additional parametric condition:

$$R_2=2h_{11.17}\cdot \frac{1+k}{{\alpha }_{17}k}\left(1-\frac{1}{4}{d}_p^2\right)=\frac{1}{2}{h}_{11.17}\left(4-d_p^2\right)\frac{1+k}{{\alpha }_{17}k}\approx \frac{2h_{11.17}}{{\alpha }_{17}}\cdot \frac{1+k}{k},\left(10\right)$$

where α₁₇h_11.17- small-signal parameters of the transistor 17.

For example, to change the f₀±10% should have

$$k\approx \mathrm{3,}{R}_2\approx \frac{8}{3}{h}_{11.17}\approx 3h_{11.17}.\left(11\right)$$

Then the parameters of the d_pand$$m_{opt}=\frac{1}{2}{d}_p$$(if$$\frac{R_{10}}{R_{16}}=1$$) set the "bias" of tanks_p/S₁₃=n while maintaining relationships

$$\frac{n{R}_{10}}{R_{mn>\; 16}+R_{\mathrm{in}sx15}}=nl\cdot \frac{1}{1+1/k}=nl\frac{k}{1+k}=\frac{1}{4}{d}_p^2,\left(12\right)$$

$$n=\frac{1}{l}\left(1+\raisebox{1ex}{$1$}\!\left/ \!\raisebox{-1ex}{$k$}\right.\right)\frac{d_p^2}{4}$$.

For the case when$$k\approx 3$$and$$l\approx \frac{3h_{11.17}}{k{R}_{\mathrm{in}sx15}}\approx \frac{3}{k}$$

get that

$$n=\frac{1}{3}\left(k+1\right)\frac{d_p^2}{4}\approx \frac{4}{3}\frac{d_p^2}{4}=\frac{d_p^2}{3}.\left(13\right)$$

Configure the schema to the desired value of the quality factor Q is carried out in accordance with relation (3) change of slope S through the source of constant current I₅. For scheme 3, the parameter S=α₁₇/h_11.17≈φ_T/I₀the, as can be seen from the relation (2), modal dependence of the steepness of S does not change the values of f₀.

Thus, the proposed circuit decision provides reiteration setting process PS while maintaining a high asymptotic attenuation in the lower frequencies (f<<f₀and zero regime (constant) input and output voltages of the circuit. Additionally, we note that the choice (implementation) of the above parameters does not require a significant voltage power source.

Presented in figure 5-8 the simulation results of the proposed Yiwu confirm these properties.

Thus, the claimed circuit decision Yiwu characterized by higher values of the gain K₀the frequency of quasiresonance f₀an elevated values of quality factor Q, which characterizes its selective properties, as well as the higher attenuation of the output signal in the low frequency range.

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. SHF SF-blocks of communication systems on the basis of the fully differential operational amplifiers./ Prokopenko N. N., Budakov A.S., K. Schmalz, .Scheytt. // Problems of development of the future development of the main micro - and nanoelectronic systems 2010. Collected works / under the General editorship of academician Alemannische. - M.: IPPM RAS, 2010. - S-586.

3. Patent US 4843343.

4. Patent US 4590435, fig.5.

5. Patent US 4999585, fig.2.

6. Patent US 6307438, fig.2.

7. Patent US 4267518, fig.4.

8. Patent WO 03052925.

9. Patent application US 2008/0246538, fig.3.

10. Patent application US 2010/0201437.

Controlled selective amplifier containing the input source 1 connected to the first base 2 of the input transistor, the second 3 input transistor, the base of which is connected with the output 4 of the device, and the emitter is connected to the emitter of the first 2 input transistor and through the first 5 dakotabilities dvukhpolosnykh associated with the first 6-bus power source, current mirror 7, consistent with the second 8-bus power supply, the output of which 9 through the second 10 dakotabilities dvukhpolosnykh connected with the first 6-bus power supply, the first 11 correction capacitor AC current between the output 9 of the current mirror 7 and a shared bus power sources 12, 13 second correction capacitor, characterized in that theas the first 2 and second 3 input transistors are field-effect transistors, the source of which corresponds to the emitter, drain - to the collector and the gate - base bipolar transistor, and the drain of the second 3 of the input transistor is connected to the input 14 of the current mirror 7, the output current of the mirror 7 is connected with the input of buffer amplifier 15, the output of which is connected to the output device 4 through 13 second correction capacitor, the drain of the first 2 input transistor associated with the second 8-bus power source, and the output device 4 are shunted by AC additional resistor 16.