CN212163278U - Ultra-wideband low-noise amplifier and feedback pre-input stage circuit thereof - Google Patents

Abstract

The utility model relates to an ultra wide band low noise amplifier and leading input stage circuit of feedback thereof belongs to radio frequency integrated circuit technical field. The input stage circuit comprises a first capacitor, an active amplification unit and a feedback branch circuit, wherein one end of the first capacitor is connected with the amplification input end of the active amplification unit, one end of the feedback branch circuit is connected to the amplification output end of the active amplification unit and serves as a connection node connected with a rear stage circuit, and the other end of the feedback branch circuit is connected with the other end of the first capacitor and serves as a signal input end of the input stage circuit. The utility model discloses can obviously optimize the low frequency input and match to can reduce the size of on-chip condenser under the prerequisite that does not influence the circuit performance.

Description

Ultra-wideband low-noise amplifier and feedback pre-input stage circuit thereof

Technical Field

The utility model belongs to the technical field of the radio frequency integrated circuit, especially indicate an ultra wide band low noise amplifier and leading input stage circuit of feedback thereof.

Background

With the continuous upgrade of mobile communication services, the upgrade of devices increasingly takes into account the constraints of factors such as size, integration, etc., which are highly cost-related, in addition to performance. The ultra-wideband technology solves the problem that a single device supports multiple communication standards and various applications, and can create a reusable hardware platform.

As a first stage active circuit of a front end of a wireless transceiver, a Low Noise Amplifier (LNA) or a Power Amplifier (PA) plays a very important role in a wireless transceiver system, by which an input signal can be sufficiently amplified and a desired signal-to-noise ratio or power can be achieved at an output terminal. However, for the ultra-wideband low noise amplifier for multimode multistandard application, the prior art focuses on the three aspects of bandwidth expansion of gain and matching, noise suppression and low power consumption. For example:

jonathan Borrowans, Piet Wambacq, Charlotte Sonns et al propose an Active Feedback LNA in "Low-Area Active-Feedback Low-Noise Amplifier Design in Scaled Digital CMOS" in IEEE JSSC2008, 2422-2433. The LNA only adopts a Cascode unit and is matched with an active feedback technology, and the LNA shows the broadband performance of 0.5-6.5 GHz under lower power consumption. However, the input and output of the LNA have no on-chip blocking capacitors, and external capacitors are needed in use, so that the LNA is not suitable for occasions with high requirements on integration level and cost.

A Dual RLC Branch Input Matching Network for an LNA is proposed in an article of Analysis and Design of a CMOS UWB LNA With Dual-RLC-branched Input Matching Network, page 287 and 296, by Yo-Sheng Lin, Chang-Zhi Chen, Hong-Yu Yang et al, IEEE TMTT 2010, and 287 and 296, and the working bandwidth of the LNA can reach 1.3-12.1 GHz, but the problem of low frequency Matching cannot be solved by the scheme, and the problem of the blocking capacitance also exists.

An ultra-Wideband LNA with an Input DC blocking capacitor is proposed in an article of Analysis and Design of a 1.6-28GHz Compact Wideband LNA in 90-nm CMOS Using a pi-Match Input Network of Hsien-Ku Chen, Yo-sheng Lin, Shey-Shi Lu at IEEE TMTT 2010, 2092 and 2104, but the LNA cannot give consideration to the circuit performance of frequencies below 1.6 GHz.

The utility model discloses a self-biased ultra wide band low power consumption low noise amplifier, which is disclosed in the utility model patent No. 201510220400.8, by Yangering, xu Shilong, Du Keming et al, an ultra wide band LNA based on active device as load and resistance negative feedback technology, but the LNA still has the aforementioned blocking capacitance problem.

The utility model discloses a high octave ultra wide band input matching circuit for a low noise amplifier, which is proposed in the utility model patent with application number 201920979820.8 of Yangming, Quming, Chengminghui et al, but when the circuit is used in LNA design, the influence after adding an on-chip DC blocking capacitor needs to be reevaluated.

Therefore, the LNA and the ultra-wideband LNA in the prior art generally lack the blocking capacitor, and the problem that low-frequency matching performance cannot be considered after the blocking capacitor is introduced into the ultra-wideband LNA is solved.

SUMMERY OF THE UTILITY MODEL

In view of this, the utility model provides an ultra wide band low noise amplifier and leading input stage circuit of feedback thereof, the utility model discloses it has blocking capacitor to integrate, and can compromise ultra wide band LNA's low frequency matching performance.

In order to realize the purpose, the utility model discloses a technical scheme be:

feedback preposed input for ultra-wideband low-noise amplifierA stage circuit including a first capacitor C₁The active amplification unit and the feedback branch circuit; a first capacitor C₁One end of the feedback branch is connected with the amplifying input end of the active amplifying unit, one end of the feedback branch is connected with the amplifying output end of the active amplifying unit and is used as a connecting node connected with a post-stage circuit, and the other end of the feedback branch is connected with the first capacitor C₁Is connected to serve as a signal input terminal of the input stage circuit.

Further, the feedback branch comprises a second capacitor C connected in series_FAnd a resistor R_F。

Further, the active amplification unit includes a transistor M₁And an inductance L₁Said transistor M₁The grid of the transistor M is the amplifying input end of the active amplifying unit, the drain of the transistor M is the amplifying output end of the active amplifying unit₁Source and inductor L₁Is connected to one end of an inductor L₁And the other end of the same is grounded.

Furthermore, the utility model provides an ultra wide band low noise amplifier, including input stage circuit, biasing circuit, load network and back stage circuit, the input stage circuit be as above arbitrary the leading input stage circuit of feedback, back stage circuit is connected with the connected node of input stage circuit, the one end and the power of load network are connected, and the other end is connected with the connected node of input stage circuit, biasing circuit's one end and power are connected, and the other end is connected with the amplification input of active amplification unit.

Compared with the prior art, the utility model beneficial effect who has lies in:

1) the utility model provides an input stage structure is leading to signal input part with the feedback point of feedback branch road, can obviously optimize the low frequency input and match, and does not influence input stage circuit's noise performance hardly.

2) The utility model discloses an input stage circuit is leading with the feedback point, can reduce the size of on-chip condenser under the prerequisite that does not influence the circuit performance to the performance that causes when having avoided on the ultra wide band low noise amplifier with the input stage integration and the problem that the size can't be compromise, be favorable to improving ultra wide band low noise amplifier's integrated level.

Drawings

Fig. 1 is a schematic diagram of a feedback pre-input stage circuit in an embodiment of the present invention;

fig. 2(a) is a schematic diagram of an ultra-wideband low noise amplifier with a preferred feedback pre-input stage circuit according to an embodiment of the present invention;

fig. 2(b) is a schematic diagram of an ultra-wideband low noise amplifier with a non-forward feedback branch corresponding to fig. 2 (a);

fig. 3 is a small-signal equivalent circuit corresponding to the feedback pre-input stage circuit in fig. 2 (a).

FIG. 4 is S of FIGS. 2(a) and 2(b)₁₁And (4) comparing simulation curves with graphs.

FIG. 5 is a graph comparing NF simulation curves of FIGS. 2(a) and 2 (b).

Detailed Description

The present invention will be described in detail with reference to the accompanying drawings.

As shown in FIG. 1, a feedback pre-input stage circuit for an ultra-wideband low noise amplifier comprises a first capacitor C₁The active amplification unit and the feedback branch circuit; a first capacitor C₁One end of the feedback branch is connected with the amplifying input end of the active amplifying unit, one end of the feedback branch is connected with the amplifying output end of the active amplifying unit and is used as a connecting node connected with a post-stage circuit, and the other end of the feedback branch is connected with the first capacitor C₁Is connected to serve as a signal input terminal of the input stage circuit.

Further, the feedback branch comprises a second capacitor C connected in series_FAnd a resistor R_FA second capacitor C_FAnd a resistor R_FThe series connection of (A) is not described in any order.

Fig. 2(a) shows an ultra-wideband low noise amplifier including a preferred feedback pre-input stage circuit. In particular, the ultra-wideband low noise amplifier comprises a transistor M₁A resistance R_FAn inductance L₁A bias circuit, a load network, two capacitors C₁、C_FAnd a subsequent stage circuit. Wherein:

transistor M₁The grid of the active amplifying unit is an amplifying input end of the active amplifying unit, and the drain of the active amplifying unit is an amplifying output end of the active amplifying unit. Capacitor C_FOne terminal of (1) and a resistor R_FOne end of the first and second branches is connected in series to serve as a feedback branch. Capacitor C₁One terminal of and a capacitor C_FAnd the other ends of the two are connected and then used as signal input ends. Resistance R_FIs connected to the transistor M at the other end₁Of the substrate. Capacitor C₁Is connected to the transistor M at the other end₁A gate electrode of (1). Transistor M₁Source and inductor L₁Is connected to one end of an inductor L₁And the other end of the same is grounded. One terminal of the bias circuit is connected to the transistor M₁And the other end of the grid is connected to a power supply V_DD. One end of the load network is connected to the transistor M₁And the other end of the drain is connected to a power supply V_DD. The drain of the transistor serves as a connection node connected to a subsequent stage circuit.

In the ultra-wideband low noise amplifier, the bias circuit, the load network and the post-stage circuit are all common knowledge of those skilled in the art, and are not described herein again.

FIG. 3 is a small signal equivalent circuit of the feedback pre-input stage circuit of FIG. 2(a), where R_gIs a transistor M₁Gate parasitic resistance of C_gsIs a transistor M₁Parasitic capacitance of gate and source, C_gdIs a transistor M₁Parasitic capacitance of gate and drain, g_mIs a transistor M₁Transconductance of, V_gsIs a transistor M₁Gate-source voltage of C_LIs the input equivalent capacitance of the circuit of the later stage. The analysis of fig. 2 shows that the feedback pre-input stage circuit of the ultra-wideband low-noise amplifier can obviously optimize low-frequency input matching, and hardly influences the inherent mechanism of the circuit noise performance. The specific analysis is as follows:

let P₁、Q₁、X₁、Y₁Comprises the following steps:

where s is j ω, j is an imaginary unit, and ω is an angular frequency, the input impedance Z is set to be lower when the operating frequency of the input stage circuit is relatively low_inSatisfies the following formula

Therefore, the input impedance of FIG. 2(a)

Comprises the following steps:

where G is the gain of the input stage circuit.

In the normal case where the feedback branch is not leading, as shown in FIG. 2(b), P in the formula (1)₁、Q₁、X₁、Y₁Is changed to P'₁、Q’₁、X’₁、Y’₁：

Thus, the input impedance of FIG. 2(b)

Comprises the following steps:

comparing the equations (3) and (5), it can be seen that the on-chip capacitor C is not located in the feedback branch under the normal condition₁The value of (a) needs to be infinitely large to achieve the effect of matching the front end of the feedback branch. In practice, the on-chip capacitance cannot be made infinite, limited by the chip area, and therefore, for the same size C₁Feedback ofThe branch-forward scheme can achieve better low-frequency input matching than the non-forward conventional scheme.

FIG. 4 shows the input matching parameters S for the circuits of FIGS. 2(a) and 2(b)₁₁And (4) comparing simulation curves with graphs. It can be seen from the comparison of the simulation curves that the low frequency input matching performance of the circuit of fig. 2(a) is better than that of the circuit of fig. 2(b) with the non-preceding feedback branch, and therefore, the simulation result is consistent with the result of theoretical analysis.

Noise figure F of FIG. 2(a) from the noise equation of the two-port network^(a)Comprises the following steps:

wherein, γ and g_d0Is the characteristic constant of the transistor itself, K and C are respectively:

K＝[1+(g_m+sC_gs)sL₁]，C＝C_gs+C_gd (7)

since the size of C is of the order of fF and C₁Is of the order of pF, and therefore equation (6) can be rewritten as:

noise figure F of FIG. 2(b) from the noise equation of the two-port network^(b)Comprises the following steps:

as can be seen from comparing equation (8) and equation (9), the scheme of feedback preamble is almost the same as the general scheme of non-preamble in terms of noise performance.

Fig. 5 is a graph comparing simulated noise figure curves for the circuits of fig. 2(a) and 2 (b). From the comparison of the simulation curves, it can be seen that the noise performance of the circuit of fig. 2(a) is comparable to the noise performance of the circuit of fig. 2(b) in which the feedback branch is not advanced, and therefore, the simulation result is consistent with the result of theoretical analysis.

The above theoretical analysis and simulation result prove that the feedback prepositive input stage circuit of the ultra-wideband low-noise amplifier of the utility model is effective.

It should be noted that the above embodiments are only specific examples of the implementation schemes of this patent, and do not cover all the implementation schemes of this patent, and therefore, the scope of protection of this patent cannot be considered as limited; all the implementations which belong to the same concept as the above cases or the combination of the above schemes are within the protection scope of the patent.

Claims (4)

1. A feedback pre-input stage circuit for ultra-wideband low noise amplifier, comprising a first capacitor(s) ((C ₁) The active amplification unit and the feedback branch circuit; a first capacitor (C ₁) One end of the feedback branch is connected to the amplifying output end of the active amplifying unit and serves as a connection node connected with a later stage circuit, and the other end of the feedback branch is connected with a first capacitor: (C ₁) Is connected to serve as a signal input terminal of the input stage circuit.

2. The feedback pre-input stage circuit for an ultra-wideband low noise amplifier according to claim 1, wherein the feedback branch comprises a second capacitor (in series), (b) and (c)C _F) And a resistor (R _F）。

3. Feedback pre-input stage circuit for an ultra-wideband low noise amplifier according to claim 1, characterized in that the active amplifying unit comprises a transistor (M)₁) And an inductance (L)₁) Said transistor (M)₁) A gate electrode of the transistor (M) is an amplification input end of the active amplification unit, a drain electrode of the transistor (M) is an amplification output end of the active amplification unit, and a transistor (M)₁) Source and inductor (L)₁) Is connected to one end of an inductor (L)₁) Is grounded at the other end。

4. An ultra-wideband low noise amplifier, comprising an input stage circuit, a bias circuit, a load network and a post-stage circuit, wherein the input stage circuit is a feedback pre-input stage circuit according to any one of claims 1 to 3, the post-stage circuit is connected to a connection node of the input stage circuit, one end of the load network is connected to a power supply, the other end of the load network is connected to a connection node of the input stage circuit, one end of the bias circuit is connected to the power supply, and the other end of the bias circuit is connected to an amplification input end of an active amplification unit.

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