CN102412052A

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Info

Publication number: CN102412052A
Application number: CN2011102438854A
Authority: CN
Inventors: 蔡描; 李平梁
Original assignee: Shanghai Hua Hong NEC Electronics Co Ltd
Current assignee: Shanghai Huahong Grace Semiconductor Manufacturing Corp
Priority date: 2011-08-24
Filing date: 2011-08-24
Publication date: 2012-04-11
Anticipated expiration: 2031-08-24
Also published as: CN102412052B

Abstract

The invention discloses a circuit model of a radio frequency inductor, which comprises a PI type circuit, wherein a low-frequency inductor in the PI type circuit is connected with two sub-circuit modules in series, and the two sub-circuit modules are used for simulating the skin effect of a radio frequency inductor metal coil; the circuit model structure of the second sub-circuit module is completely the same as that of the first sub-circuit module; the element parameter value of the second sub-circuit module is correlated with the element parameter value of the first sub-circuit module; the main branch current is changed by different element parameter values to simulate the influence of current proximity effect at high frequency. According to the invention, two sub-circuit modules for describing the skin effect of the radio frequency inductor are connected in series, so that the influence of the current proximity effect on the radio frequency inductance characteristic can be effectively simulated, the physical property of the inductance model is improved, and the high-frequency fitting precision of the inductance model is improved.

Description

The circuit model of radio frequency inductive

Technical field

The present invention relates to a kind of circuit model, be specifically related to a kind of circuit model of radio frequency inductive.

Background technology

The radio frequency inductive device is the critical elements of RF CMOS or BiCMOS integrated circuit, is widely used in the various RF circuit modules such as voltage controlled oscillator and low noise amplifier.

Because electric current is tending towards the Surface runoff at metallic resistance when high frequency, thereby has increased the high-frequency electrical resistance, has reduced the quality factor of inductance, this phenomenon is referred to as the skin effect of resistance.Have this characteristic of skin effect for resistance, the solution that proposes from the model angle is a lot, and common method is parallel connection one or more current branch at the D.C. resistance two ends, and this current branch comprises an inductance and a resistance series connection.

The circuit model structure of existing radio frequency inductive is as shown in Figure 1, parallel connection one or more current branch at D.C. resistance Rmain two ends, and this current branch comprises the inductance Rs and the resistance Ls of mutual series connection.

This circuit model has mainly been considered the influence that the skin effect of resistance when high frequency brought inductance characteristic.Wherein Ls1, Ls2 and Rs1, Rs2 are the element of simulation skin effect.

But,, need to adopt the wire coil of the more number of turns in order to obtain the radio frequency inductive of big sense value.And the inductance of many circles, particularly the differential inductance of many circles can receive the influence of electric current approach effect.

The principle of electric current approach effect is: two current branch of facing mutually during high frequency can interact, and influence electric current and DISTRIBUTION OF MAGNETIC FIELD.As shown in Figure 2, the formed downward the action of a magnetic field of the electric current of outer ring wire coil is in the wire coil of inside, and the wire coil generation eddy current at inner ring causes the current density of inner ring to change.Inner ring receives the influence of eddy current, causes near inboard and unequal near the current density of Outboard Sections.In some cases, the eddy current value can balance out most of forward current, and the effective length of inductance is reduced, and effective sense value of radio frequency inductive is reduced, and the quality factor of inductance are reduced.Show that according to statistics because the influence of electric current approach effect, the inductance that width is big is compared with the little inductance of width, the quality factor of inductance descend faster after the number of turns increases.

The circuit model of existing radio frequency inductive is for the not simulation well of electric current approach effect.

Summary of the invention

Technical problem to be solved by this invention provides a kind of circuit model of radio frequency inductive, its analog current approach effect influence that inductive is brought exactly.

For solving the problems of the technologies described above, the technical solution of the circuit model of radio frequency inductive of the present invention is:

Comprise PI type circuit, low frequency inductance L main and two sub-circuit modules in the said PI type circuit are one another in series, and two sub-circuit modules are used for the skin effect of analog radio frequency inductance wire coil; The first electronic circuit module comprises D.C. resistance R₁₁, D.C. resistance R₁₁The first current branch of parallel connection in two ends, this current branch comprises the first inductance L s1 and the first skin resistance Rs1 of mutual series connection; The two ends of skin resistance Rs1 on said current branch are current branch of parallel connection again, and this current branch comprises another inductance and another skin resistance of mutual series connection; The circuit model structure of the second electronic circuit module and the first electronic circuit module are identical;

The device parameter values of the second electronic circuit module is relevant mutually with the device parameter values of the first electronic circuit module; Raw parameter value R, Rs, the Ls of the device parameter values of the first electronic circuit module when not considering the electric current approach effect multiply by alpha and obtains, and raw parameter value R, Rs, the Ls of the device parameter values of the second electronic circuit module when not considering the electric current approach effect multiply by (1-α) and obtain; Change main branch current through different device parameter values, with the influence of electric current approach effect under the simulation high frequency;

Wherein, the span of alpha is 0＜α＜1.

Said PI type circuit is two PI type circuit or single PI type circuit.

Parallelly connected again current branch at the two ends of said first skin resistance (Rs1), this current branch comprises second inductance (Ls2) and second skin resistance (Rs2) of mutual series connection; Parallelly connected again current branch at the two ends of said second skin resistance (Rs2), this current branch comprises the 3rd inductance (Ls3) and the 3rd skin resistance (Rs3) of mutual series connection; Parallelly connected again current branch at the two ends of said the 3rd skin resistance (Rs3), this current branch comprises the 4th inductance (Ls4) and the 4th skin resistance (Rs4) of mutual series connection.

The size of said alpha is adjusted according to the size of electric current approach effect, with the electric current approach effect of the different sizes of match.

Little to can ignore the time when the influence of electric current approach effect, said α value is 0.5.

The technique effect that the present invention can reach is:

The present invention is cascaded two electronic circuit modules of describing the radio frequency inductive skin effect, and the circuit form of two modules is in full accord, and just the coefficient of component parameters is different.

The present invention's analog current approach effect influence that the radio frequency inductance characteristic is brought effectively improves the inductor models physical property, thereby improves its high frequency fitting precision.

The present invention can describe the skin effect of resistance and the common influence of electric current approach effect.

Description of drawings

Below in conjunction with accompanying drawing and embodiment the present invention is done further detailed explanation:

Fig. 1 is the circuit model structural representation of prior art radio frequency inductive;

Fig. 2 is that the electric current approach effect influences sketch map in radio frequency inductive;

Fig. 3 is the sketch map of the circuit model of radio frequency inductive of the present invention.

Description of reference numerals among the figure:

Lmain is the low frequency inductance, and R is a D.C. resistance,

Ls is an inductance, and Rs is a skin resistance.

Embodiment

As shown in Figure 3, the circuit model of radio frequency inductive of the present invention comprises PI type circuit, low frequency inductance L main in the PI type circuit and two sub-circuit modules 1., 2. be one another in series, two sub-circuit modules are used for the skin effect of analog radio frequency inductance wire coil;

1. the first electronic circuit module comprises D.C. resistance R₁₁, D.C. resistance R₁₁The first current branch of parallel connection in two ends, this current branch comprises the inductance L s1 and the skin resistance Rs1 of mutual series connection; Parallelly connected again current branch at the two ends of skin resistance Rs1, this current branch comprises the inductance L s2 and the skin resistance Rs2 of mutual series connection; By that analogy, parallelly connected again current branch at the two ends of skin resistance Rs2, this current branch comprises the inductance L s3 and the skin resistance Rs3 of mutual series connection;

The second electronic circuit module circuit model structure and the firstelectronic circuit module 2. is 1. identical, but its device parameter values is different;

The device parameter values of two sub-circuit modules is relevant mutually; Raw parameter value R, Rs, the Ls of first electronic circuit moduledevice parameter values 1. when not considering the electric current approach effect multiply by alpha and obtains, and raw parameter value R, Rs, the Ls of second electronic circuit moduledevice parameter values 2. when not considering the electric current approach effect multiply by (1-α) and obtain.Change of the influence of main branch current through different device parameter values with electric current approach effect under the simulation high frequency.

Wherein, the span of alpha is 0＜α＜1.

1. the first electronic circuit module representes the current density of wire coil near the inboard, and 2. the second electronic circuit module representes the current density of wire coil near the outside, the firstelectronic circuit module 1. with the secondelectronic circuit module 2. under both actings in conjunction, form new electric current.

According to the size of electric current approach effect, can adjust the size of alpha, thus the electric current approach effect of the different sizes of match; Little to can ignore the time when the influence of electric current approach effect, the α value is 0.5, this moment two D.C. resistance R_{11* α}With R_{11* (1-α)}Equate the element inductance R of the simulation skin effect parallelly connected with it_{S* α}With resistance L_{S* α}Also respectively with inductance R_{S* (1-α)}With resistance L_{S* (1-α)}Equate.

Be illustrated in figure 3 as two PI type circuit; Each low frequency inductance L main wherein connects respectively two and simulates the electronic circuit module of skin effect; Wherein Lmain1 connect the firstelectronic circuit module 1. with the second electronic circuit module 2.; Lmain3 connect the 3rd electronic circuit module 3. with the 4th electronic circuit module 4., form the precircuit that two PI patterns are intended differential inductances.

Can certainly be single PI type circuit, low frequency inductance L main is connected with the electronic circuit module of two simulation skin effects.

Two D.C. resistance R among the present invention_{11* α}, R_{11* (1-α)}Sum is the initial value R when not considering the electric current approach effect₁₁, promptly be equivalent to D.C. resistance Rmain of the prior art, to compare with existing radio frequency inductive model, circuit model of the present invention is corresponding with physical effect, has stronger physical property.

Claims

1. the circuit model of a radio frequency inductive comprises PI type circuit, it is characterized in that: the low frequency inductance (Lmain) in the said PI type circuit is one another in series with two sub-circuit modules, and two sub-circuit modules are used for the skin effect of analog radio frequency inductance wire coil;

The first electronic circuit module comprises D.C. resistance (R₁₁), D.C. resistance (R₁₁) the first current branch of parallel connection in two ends, this current branch comprises first inductance (Ls1) and first skin resistance (Rs1) of mutual series connection; The two ends of the skin resistance on said current branch (Rs1) are current branch of parallel connection again, and this current branch comprises another inductance and another skin resistance of mutual series connection;

The circuit model structure of the second electronic circuit module and the first electronic circuit module are identical;

The device parameter values of the second electronic circuit module is relevant mutually with the device parameter values of the first electronic circuit module; The raw parameter value (R, Rs, Ls) of the device parameter values of the first electronic circuit module when not considering the electric current approach effect multiply by alpha and obtains, and the raw parameter value (R, Rs, Ls) of the device parameter values of the second electronic circuit module when not considering the electric current approach effect multiply by (1-α) and obtain;

Change main branch current through different device parameter values, with the influence of electric current approach effect under the simulation high frequency;

Wherein, the span of alpha is 0＜α＜1.

2. the circuit model of radio frequency inductive according to claim 1 is characterized in that: said PI type circuit is two PI type circuit or single PI type circuit.

3. the circuit model of radio frequency inductive according to claim 1 and 2; It is characterized in that: parallelly connected again current branch at the two ends of said first skin resistance (Rs1), this current branch comprises second inductance (Ls2) and second skin resistance (Rs2) of mutual series connection; Parallelly connected again current branch at the two ends of said second skin resistance (Rs2), this current branch comprises the 3rd inductance (Ls3) and the 3rd skin resistance (Rs3) of mutual series connection; Parallelly connected again current branch at the two ends of said the 3rd skin resistance (Rs3), this current branch comprises the 4th inductance (Ls4) and the 4th skin resistance (Rs4) of mutual series connection.

4. the circuit model of radio frequency inductive according to claim 1, it is characterized in that: the size of said alpha is adjusted according to the size of electric current approach effect, with the electric current approach effects of the different sizes of match.

5. the circuit model of radio frequency inductive according to claim 1 is characterized in that: little to can ignore the time when the influence of electric current approach effect, said α value is 0.5.