RU2519419C1 - Broadband voltage repeater - Google Patents

Abstract

FIELD: radio engineering, communication.

SUBSTANCE: broadband voltage repeater comprises an input transistor (1), the control terminal (2) of which is connected to an input signal source (3), the injecting terminal (4) is connected to a first (5) power supply bus through a current-stabilising two-terminal element (6) and is connected to the main output of the device (7), and the charge-collecting terminal (8) is connected to a second (9) power supply bus, wherein the main output of the device (7) is alternating current-shunted by an equivalent load capacitor (10). The circuit includes an additional voltage repeater (11), the input of which is connected to the main output of the device (7), the output is connected to the additional output (12) of the device and through a balancing capacitor (13) to the input of an additional non-inverting current repeater (14), the current output of which is connected to the main output of the device (12).

EFFECT: wide operating frequency range of the broadband voltage repeater when there is a capacitance Cn at the output, which can be reduced for objective reasons, shorter time for establishing a transient process with pulsed variation of the input voltage.

3 cl, 8 dwg

Description

The present invention relates to the field of radio engineering and communication and can be used in various analog devices on field and bipolar transistors as an output (buffer) amplifier.

The basic unit of modern analog devices is a broadband voltage follower (SPN), which is implemented as a circuit with a common drain (in the field) or as a circuit with a common collector on bipolar transistors. This structure (Fig. 1) [1-25] is widely used both in analog (class H03F) and digital (class H03K) devices. In the latter case, the tap-changer acts as a driver — a cascade for controlling communication lines or a matching circuit. As a rule, the load of the known SCNs [1-25] contains the active resistance R _H and the capacitance C _n , which negatively affects the low-signal range of operating frequencies and the speed with a pulse change in the input signal of large amplitude.

The closest prototype of the claimed device is a classic voltage follower, described in patent US 6.043.690 fig.1. It contains an input transistor 1, the control terminal of which 2 (gate) is connected to the input signal source 3, the injection terminal 4 (source) is connected to the first 5 bus of the power source through a current-stabilizing two-terminal 6 and connected to the main output of the device 7, and the charge-collecting terminal 8 (drain) is connected to the second 9 bus of the power source, and the main output of the device 7 is shunted by alternating current with an equivalent, as a rule, stray load capacitor 10.

A significant disadvantage of the known device is that it has a relatively narrow range of operating frequencies for a small signal, which is determined by the time constant of the load circuit (τ _in ).

Indeed, in a first approximation, the upper cutoff frequency f _in (at the level of -3 dB) of the classical tap-changer of Fig. 1 is not better than

$$f_{\mathrm{at}}\le \frac{\mathrm{one}}{2\pi {\tau }_{\mathrm{at}}},\left(\mathrm{one}\right)$$

where τ _in - time constant of the load circuit. Moreover

$${\tau }_{\mathrm{at}}\approx \left(\frac{\mathrm{one}}{S}|\; |\; ||\; |\; |R_n\right)C_n,\left(2\right)$$

where S is the slope of the input field-effect transistor of the tap-type prototype of figure 1;

R _n - equivalent load resistance;

C _n - equivalent load capacity. The main objective of the invention is the expansion of the range of operating frequencies of the tap-changer in the presence of a capacitance at the output C _n , which cannot be reduced for objective reasons, is an integral part of the load circuit, for example, a piezoceramic transducer, etc.

An additional task is to reduce the time it takes to establish a transient process with a pulse change in input voltage.

This object is achieved in that in the broadband voltage follower of FIG. 1, containing an input transistor 1, the control terminal of which 2 is connected to an input signal source 3, the injection terminal 4 is connected to the first 5 power supply bus through a current-stabilizing two-terminal device 6 and connected to the main output of the device 7, and the charge collecting terminal 8 is connected to the second 9 bus of the power source, the main output of the device 7 being shunted by alternating current with an equivalent load capacitor 10, new cells are provided communications and communications - an additional voltage follower 11 is introduced into the circuit, the input of which is connected to the main output of the device 7, the output is connected to the additional output of the device 12 and connected through the correction capacitor 13 to the input of the additional non-inverting current follower 14, the current output of which is connected to the main output of the device 12.

In the drawing of figure 1 shows a diagram of the BPC prototype.

The drawing of figure 2 presents a diagram of the inventive device in accordance with claim 1 and claim 2 of the claims.

The drawing of figure 3 presents a diagram of the inventive broadband voltage follower of figure 2 on a field effect transistor in a computer simulation environment Cadence.

The drawing of figure 4 presents the logarithmic amplitude-frequency characteristics of the voltage gain (K _y ≤1) of the tap-changer of figure 3 for different values of the capacitance of the correction capacitor 13 (figure 2). From these graphs it follows that the operating frequency range of the inventive device extends to 6.4 GHz, while the upper cut-off frequency of the CAP prototype (at -3 dB) has a value of 44 MHz.

The drawing of Fig. 5 shows the transient process of the output voltage of the tap-changer of Fig. 3 when the input pulse rises with an amplitude of 1 V and shows the values of the transient establishment time (t _set ) on the tap-changer output of Fig. 3 when the capacitance of the correction capacitor 13 (Sk ) These graphs show that in the proposed scheme of figure 3, the speed increases to 47.5 ps, which is 138 times better than in the CAP prototype.

The drawing of Fig. 6 shows the transient process of the tap-changer of Fig. 3 with a decreasing input pulse and shows the values of the transient _settling time (t _yst.dec .) At the tap-changer output at different values of the capacitance of the correction capacitor 13 (Ck).

The drawing of Fig.7 shows a diagram of the inventive device of Fig.2 on a bipolar p-n-p transistor in accordance with claim 3 of the claims.

The circuit in the drawing of FIG. 8 is implemented on a p-n-p composite transistor 1, which includes a bipolar transistor 16 and a resistor 17.

The broadband voltage follower of FIG. 2 contains an input transistor 1, the control terminal of which 2 is connected to the input signal source 3, the injection terminal 4 is connected to the first 5 bus of the power source through a current-stabilizing two-terminal 6 and connected to the main output of the device 7, and the charge-collecting terminal 8 is connected with a second power supply bus 9, the main output of the device 7 being shunted by alternating current with an equivalent load capacitor 10. An additional voltage follower 11 is introduced into the circuit, the input of which oedinen the main output device 7 output is connected to an additional output 12 of the device and through the compensation capacitor 13 is connected to the noninverting input of the additional current mirror 14, the current output of which is connected to the main output of the apparatus 12.

In the drawing of FIG. 2, in accordance with claim 2, a field effect transistor is used as the input transistor 1, the gate of which corresponds to the control terminal 2, the source to the injection terminal 4, and the drain to the charge collecting terminal 8 of the input transistor 1.

In the drawing of Fig. 7, in accordance with claim 3, a bipolar n-p-n transistor is used as the input transistor 1, the base of which corresponds to control terminal 2, the emitter to the injection terminal 4, and the collector to the charge-collecting terminal 8 of the input transistor 1.

The circuit in the drawing of FIG. 8 is implemented on a p-n-p composite transistor 1, which includes a bipolar transistor 16 and a resistor 17.

Consider the operation of the circuit of figure 2.

The static mode of the input transistor 1 is set in a particular case by a two-pole 6. An additional voltage follower 11 and an additional non-inverting current follower 14 in this case do not affect the statics of the circuit.

передается в цепь нагрузкиInput voltage change

transmitted to the load circuit

Where $${\mathrm{<figure-callout\; id="0"\; label="K"\; filenames="00000029.png,00000030.png"\; state="\{\{state\}\}">K</figure-callout>}}_0=\frac{\mathrm{one}}{\mathrm{one}+\frac{\mathrm{one}}{S_{\mathrm{one}}{R}_{n.\mathrm{uh}\mathrm{to}\mathrm{at}}}}=\frac{{\dot{U}}_{\mathrm{at}sx.7}}{{\dot{U}}_{\mathrm{at}x}},\left(\mathrm{four}\right)$$

$${\tau }_n=C_{10}{R}_{\mathrm{fifteen}}\Vert \frac{\mathrm{one}}{S_{\mathrm{one}}},\left(5\right)$$

Rn.ekv = R15 - equivalent load resistance;

- крутизна входного биполярного транзистора, где r_э1 - сопротивление эмиттерного перехода биполярного транзистора).S ₁ - the steepness of the input (field) transistor (or $$S_{\mathrm{one}}=r_{\mathrm{uh}\mathrm{one}}^{-\mathrm{one}}$$

- the steepness of the input bipolar transistor, where r _e1 is the resistance of the emitter junction of the bipolar transistor).

передается на выход дополнительного повторителя напряжения 11, что создает входной ( $${\dot{I}}_{13}$$

), а затем выходной ( $${\dot{I}}_{14}$$

) токи дополнительного усилителя тока 14:Voltage

transmitted to the output of the additional voltage follower 11, which creates an input ( $${\dot{I}}_{13}$$

) and then output ( $${\dot{I}}_{\mathrm{fourteen}}$$

) currents of the additional current amplifier 14:

$${\dot{I}}_{13}=\frac{{\dot{U}}_{\mathrm{at}sx.7}{\dot{\mathrm{TO}}}_{\mathrm{at}\mathrm{eleven}}}{\mathrm{one}/\mathrm{<figure-callout\; id="13"\; label="j\; \omega \; C"\; filenames="00000033.png,00000034.png"\; state="\{\{state\}\}">j\; </figure-callout>}\omega C_{}{}_{13}},\left(6\right)$$

. $${\dot{I}}_{\mathrm{fourteen}}=j{\dot{K}}_{i\mathrm{fourteen}}{\dot{K}}_{y\mathrm{eleven}}\mathrm{<figure-callout\; id="13"\; label="\omega \; C"\; filenames="00000033.png,00000034.png"\; state="\{\{state\}\}">\omega \; </figure-callout>}{C}_{}{}_{13}.\left(7\right)$$

.

- комплекс коэффициента передачи по току дополнительного неинвертирующего повторителя тока 14;Where $${\dot{K}}_{i\mathrm{fourteen}}$$

- complex current transfer coefficient of an additional non-inverting current follower 14;

- комплекс коэффициента передачи по напряжению дополнительного повторителя напряжения 11; $${\dot{K}}_{y\mathrm{eleven}}$$

- a complex of the transmission coefficient for voltage of the additional voltage follower 11;

) и выходного (

) напряжений ШПН можно записать следующие уравнения:In linear mode for input complexes (

) and output (

) of the voltage of the tap-changer, the following equations can be written

$${\dot{U}}_{\mathrm{at}sx.7}=\frac{{\dot{Z}}_H{\dot{I}}_{u\mathrm{one}}}{\mathrm{one}-j\omega C_{13}{\dot{K}}_{i\mathrm{fourteen}}{\dot{K}}_{y\mathrm{eleven}}}.\left(8\right)$$

$${\dot{U}}_{\mathrm{at}x}={\dot{U}}_{\mathrm{at}sx.7}+{\dot{U}}_{s\mathrm{and}},\left(9\right)$$

- комплекс напряжения затвор-исток полевого транзистора 1;Where $${\dot{U}}_{s\mathrm{and}}={\dot{I}}_{u\mathrm{one}}/S_{\mathrm{one}}$$

- voltage complex gate-source field-effect transistor 1;

S1 is the slope of the field effect transistor 1;

- комплекс эквивалентного сопротивления нагрузки, причем $${\dot{Z}}_H$$

- a complex of equivalent load resistance, and

$${\dot{Z}}_H=\frac{R_n}{\mathrm{one}+j\omega C_n{R}_n}.\left(10\right)$$

As a result of solving equations (6) - (9), it can be obtained that in the claimed circuit of the silos, the complex voltage transfer coefficient

$${\dot{K}}_y=\frac{{\dot{U}}_{\mathrm{at}sx.7}}{{\dot{U}}_{\mathrm{at}x}}=\frac{\mathrm{one}}{\mathrm{one}+\frac{\mathrm{one}}{S_{\mathrm{one}}{R}_n}+j\omega {\tau }_{\mathrm{at}}},\left(\mathrm{eleven}\right)$$

Where $${\dot{\tau }}_{\mathrm{at}}=\left[{\mathrm{FROM}}_{10}-C_{13}{\dot{K}}_{y\mathrm{eleven}}{\dot{K}}_{i\mathrm{fourteen}}\right]S_{\mathrm{one}}^{-\mathrm{one}}-\mathrm{to}\mathrm{about}mPle\mathrm{to}\mathrm{from}n\mathrm{but}\mathrm{I\; am}P\mathrm{about}\mathrm{from}t\mathrm{about}\mathrm{I\; am}nn\mathrm{but}\mathrm{I\; am}\mathrm{at}Remen\mathrm{and}ceP\mathrm{and}n\mathrm{but}gR\mathrm{at}s\mathrm{to}\mathrm{and}.\left(12\right)$$

, $${\dot{K}}_{i14}=1$$

, то условием уменьшения влияния емкости нагрузки С₁₀ на амплитудно-частотную характеристику ШПН фиг.2 будут равенстваIf you provide $${\dot{K}}_{y\mathrm{eleven}}=\mathrm{one}$$

, $${\dot{K}}_{i\mathrm{fourteen}}=\mathrm{one}$$

, then the condition for reducing the influence of the load capacitance C ₁₀ on the amplitude-frequency characteristic of the tap-changer of FIG. 2 will be equal

$$\{\begin{array}{l}{\tau }_{\mathrm{at}}=0\\ \frac{C_{13}}{C_{10}}{K}_{y\mathrm{eleven}}{K}_{i\mathrm{fourteen}}=\mathrm{one}\end{array}.\left(13\right)$$

Therefore, with a first approximation, the capacitances of the capacitors 13 and 10 must satisfy the condition C ₁₃ ≤C ₁₀ .

Thus, in the claimed circuit, conditions are created for a significant expansion of the low-signal range of operating frequencies, which in practice will be determined (and limited) by the inertia of the additional non-inverting current amplifier 14 and the additional voltage follower 11. However, these functional units can be performed at higher frequencies (than field) bipolar transistors, since their construction does not require high input impedances and other properties that are unacceptable for input nzistor 1 (low noise, near-zero input conductivity, a wide range of linear operation, etc.).

The analysis performed above, as well as the results of computer simulations show that in the claimed circuit one of the problems of modern analog microcircuitry is solved - expanding the frequency range of the source (emitter) voltage followers with a small input signal.

In addition, as follows from the graphs of Fig. 5, Fig. 6, in the inventive circuit, with capacitive load, the response speed in the large signal mode is significantly increased - the time of establishment of the transient process and the slew rate of the output voltage improve by tens to hundreds of times.

Thus, the claimed device has significant advantages in the range of operating frequencies (on a small signal) and speed (with a pulse change in the input voltage).

BIBLIOGRAPHIC LIST

1. Patent US 6.919.743 fig. 9

2. Patent US 7.898.339 fig. 4

3. US patent 6.727.729 fig.5B

4. US patent 7.733.182 fig. 1

5. Patent US 6.043.690 fig. 1, fig. 2

6. Patent US 3.678.402 fig. 2, fig. 7

7. Patent US 4.855.625 fig. 1

8. Patent US 5.469.085 fig.2

9. Patent US 4,492,932 fig. 4a

10. Patent US 4.092.701

11. Patent US 4.698.526 fig.2

12. US Pat. No. 6,469,562 fig.A, fig.2A

13. US Patent 6.154.580

14. Patent US 8.248.161

15. Patent US 7.304.540

16. Patent US 7.944.303 fig. 1

17. Patent US 8.148.962 fig.2

18. US Pat. No. 4,123,723 fig. 2, fig. 3

19. Patent US 5.083.095 fig. 4

20. Patent US 5.045.808

21. Patent US 4.101.788 fig.2

22. Patent US 3.436.672

23. Patent US 4.168.471

24. Patent 5.365.19

25. Patent US 5.666.070.

Claims (3)

1. A broadband voltage follower containing an input transistor (1), the control terminal of which (2) is connected to an input signal source (3), the injection terminal (4) is connected to the first (5) bus of the power source through a current-stabilizing two-terminal device (6) and connected with the main output of the device (7), and the charge collecting terminal (8) is connected to the second (9) bus of the power source, and the main output of the device (7) is shunted by alternating current with an equivalent load capacitor (10), characterized in that an additional voltage follower (11) is introduced into the circuit, the input of which is connected to the main output of the device (7), the output is connected to the additional output (12) of the device and is connected through the correction capacitor (13) to the input of the additional non-inverting current follower (14), the current output which is connected with the main output of the device (12). 2. A broadband voltage follower according to claim 1, characterized in that a field effect transistor is used as the input transistor (1), the gate of which corresponds to the control terminal (2), the source to the injection terminal (4), and the drain to the charge collecting terminal (8) ) input transistor 1. 3. A broadband voltage follower according to claim 1, characterized in that a bipolar transistor is used as the input transistor (1), the base of which corresponds to the control terminal (2), the emitter to the injection terminal (4), and the collector to the charge-collecting terminal (8) ) input transistor (1).

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