CN102684634B - Transmitting/receiving circuit and impedance correcting method thereof - Google Patents

Abstract

The invention discloses a transmitting/receiving circuit and an impedance correcting method thereof. The impedance correcting method of the transmitting/receiving circuit is used on a transmitting/receiving circuit and comprises the steps of: inputting a first current into a transmitter to generate a first output voltage, wherein the first current is generated according to the ratio of a preset voltage to an inner resistance of a chip; inputting a second current into the transmitter to generate a second output voltage, wherein the second current is generated according to the ratio of the preset voltage to a preset resistance; and adjusting a first variable impedance module according to the first output voltage and the second output voltage.

Description

Transmission/reception circuit and the bearing calibration of transmission/reception circuit impedance

Technical field

The present invention relates to transmission/reception circuit and relevant transmission/reception circuit impedance bearing calibration, the element particularly using transmission/reception circuit itself to comprise is to do the transmission/reception circuit of impedance matching and relevant transmission/reception circuit impedance bearing calibration.

Background technology

In network communicating system, transmission path all needs the problem considering impedance matching.Because the resistance of chip internal has the situation of drift, so need a circuit that can correct impedance matching to accomplish impedance matching accurately.Wherein a kind of way is, provides a quite accurate correcting circuit to reach the object correcting impedance.But in order to reach accurate correction, correcting circuit must occupy sizable area.For example, namely U.S. Patent number US6734302 discloses this type of alignment technique.

Summary of the invention

Therefore, an object of the present invention is the method providing a transmission/reception circuit and correct this transmission/reception circuit, impedance in transmission/reception circuit can be corrected by the element in transmission/reception circuit, avoid correcting circuit in prior art to occupy the problem of larger area.

One embodiment of the invention disclose a kind of impedance correction method of transmission/reception circuit, are used on a transmission/reception circuit.The method comprises: one first electric current input conveyor is produced one first output voltage, and wherein this first electric current produces according to the ratio of an internal resistance of a predetermined voltage and a chip; One second electric current is inputted this conveyer and produces one second output voltage, wherein this second electric current produces according to the ratio of this predetermined voltage and a predetermined resistance; And adjust this first variableimpedance module according to the difference of this first output voltage and this second output voltage.

Another embodiment of the present invention discloses a kind of transmission/reception circuit, comprising: a conveyer, one receiver, wherein this conveyer and a receiver are arranged in a chip, one first variableimpedance module: and a control unit, flow into this receiver in order to control one first electric current and produce one first output voltage, wherein this first electric current produces according to the ratio of an internal resistance of a predetermined voltage and this chip, this control unit also flows into this receiver in order to control one second electric current and produces one second output voltage, wherein this second electric current produces according to the ratio of this predetermined voltage and a predetermined resistance, and this control unit also adjusts this first variableimpedance module according to the difference of this first output voltage and this second output voltage.

Another embodiment of the present invention discloses a kind of impedance correction method of transmission/reception circuit, is used on a transmission/reception circuit.This impedance correction method comprises: one first electric current is inputted this conveyer and produces one first output voltage, and wherein this first electric current produces according to the ratio of this internal resistance of this predetermined voltage and this chip; One second electric current is inputted this conveyer and produces one second output voltage, wherein this second electric current corresponds to this first electric current; And adjust this second variableimpedance module according to the difference of this first output voltage and this second output voltage.

One more embodiment of the present invention discloses a kind of transmission/reception circuit, comprising: a conveyer; One receiver, wherein this conveyer and a receiver are coupled to a chip; One first variableimpedance module: and a control unit, flow into this receiver in order to control one first electric current and produce one first output voltage, wherein this first electric current produces according to the ratio of this internal resistance of this predetermined voltage and this chip, this control unit also controls one second electric current and flows into this receiver and produce one second output voltage, wherein this second electric current corresponds to this first electric current, and this control unit more adjusts this second variableimpedance module according to the difference of this first output voltage and this second output voltage.

The embodiment of above, the impedance of transmission/reception inside circuit can be utilized reach must impedance matching, therefore can to save in prior art middle impedance matching mechanisms occupied area.

Accompanying drawing explanation

Fig. 1 shows transmission/reception circuit according to an embodiment of the invention.

Fig. 2 shows the impedance correction method of the transmission/reception circuit of the embodiment of corresponding diagram 1.

Fig. 3 shows a wherein example of the detailed construction of the transmission/reception circuit shown in Fig. 1.

Fig. 4 shows transmission/reception circuit according to another embodiment of the present invention.

Fig. 5 shows a wherein example of the detailed construction of the transmission/reception circuit shown in Fig. 4.

Fig. 6 shows the situation of the transmission/reception open circuit shown in Fig. 5.

Fig. 7 shows a wherein example of the detailed construction of the transmission/reception circuit shown in Fig. 4.

Fig. 8 shows the situation of the transmission/reception open circuit shown in Fig. 7.

Fig. 9 shows transmission/reception circuit according to another embodiment of the present invention.

Figure 10 shows the impedance correction method of the transmission/reception circuit of the embodiment of corresponding diagram 9.

Main element symbol description

100,300 transmission/reception circuit 101,301 conveyers

103,303 receiver 105,305,309 variableimpedance modules

107,307 connection gasket 221,311 switch elements

201,203,204,205,402 resistance

207 inverter 209,401 amplifiers

211 analog-digital converter 213 control units

215 current switching unit 217,219 current sources

403,405 transistor 407 variable resistors

409 analog-digital converter 411 signal attenuators

Embodiment

Some vocabulary is employed to censure specific element in the middle of specification and follow-up claim.Those skilled in the art should understand, and hardware manufacturer may call same element with different nouns.This specification and follow-up claim are not used as the mode of distinguish one element from another with the difference of title, but are used as the criterion of differentiation with element difference functionally." comprising " mentioned in the middle of specification and follow-up claim is in the whole text an open term, therefore should be construed to " including but not limited to ".In addition, " couple " word comprise directly any at this and be indirectly electrically connected means.Therefore, if describe a first device in literary composition to be coupled to one second device, then represent this first device and directly can be electrically connected in this second device, or be indirectly electrically connected to this second device by other device or connection means.

Fig. 1 shows transmission/reception circuit 100 according to an embodiment of the invention.As shown in Figure 1, transmission/reception circuit 100 comprises conveyer 101, receiver 103, variableimpedance module 105, and wherein conveyer 101 and receiver 103 are arranged in a chip.Chip carrys out transmission signal by conveyer 101 and connection gasket 107, and carrys out Received signal strength by receiver 103 and connection gasket 107.

And the transmission/reception circuit impedance correction mechanism disclosed by the present invention, as shown in Figure 2, can comprise:

Step 2001

By one first current Ib input conveyor 101 in V _oplace's generation one first output voltage V _ob.Wherein I _bproduce according to the ratio of an internal resistance of a predetermined voltage and chip.In one embodiment, v _bgfor the predetermined voltage do not changed along with variations in temperature and processing procedure drift, R _polythe internal resistance of the chip set by conveyer 101 and receiver 103, and K ₁for adjustment I _bone parameter of value, also can be 1.

The internal resistance of chip includes variform.More common is polycrystalline resistor (poly resistor) and diffusion resistance (diffusion resistor).Polycrystalline resistor is by the polycrystalline material in chip as polysilicon (poly silicon) etc. is formed, and diffusion resistance formed by the region had in chip through DIFFUSION TREATMENT (diffusion process).And in actual example of the present invention, be all illustrate with polycrystalline resistor, and being not used to limit the present invention, the concept disclosed by the present invention also can be used in the internal resistance of other form.

Step 2003

By one second electric current I _bxinput conveyor 101 is in V _oplace's generation one second output voltage V _obx.Wherein I _bxaccording to a predetermined voltage and a predetermined resistance R _extratio and produce.In one embodiment, wherein R _extit is the resistance value (or being called the accurate resistance of chip exterior) of a predetermined resistance.Wherein, K ₁and K ₂in order to adjust I _band I _bxratio poor.For example, R _polyand R _extit may be varying number level (such as, 10 ²with 10 ⁴), therefore by K ₁and K ₂adjust I _band I _bx.

Step 2005

According to the first output voltage V _oband the second output voltage V _obxdifference adjust the first variableimpedance module 105.In one embodiment, by the first output voltage V _obwith the second output voltage V _obxvalue be sent to analog-digital converter in receiver 103 (ADC, not shown), solve D respectively _aand D _axvalue.Then can according to D _aand D _axdifference calculate the internal resistance R of chip _polydrift value.Due in this embodiment, internal resistance R _polyfor polycrystalline resistor, and the material of variableimpedance module 105 is identical with the material of internal resistance.Therefore the drift value of variableimpedance module 105 and internal resistance R _polydrift value identical, therefore a control signal (such as: control code) resistance value of variableimpedance module 105 can be adjusted, be the resistance value of expectation.For example, if internal resistance R _polydrifted about 10%, then variableimpedance module 105 also can adjust 10% to compensate its drift value.

In one embodiment, step 2001 can be performed by a control unit or a control code to 2005.

Fig. 3 shows a wherein example of the detailed construction of the transmission/reception circuit 100 shown in Fig. 1.In the circuit framework shown in Fig. 3, transmission/reception circuit 100 represents with the situation of small signal model.It is noted that, the circuit framework shown in Fig. 3 and function mode thereof only in order to citing, and are not used to limit the present invention.As shown in Figure 3, conveyer 101 comprises an amplifier 202.And resistance 204 is equivalent to the internal resistance R of chip _poly.Receiver 103 comprise resistance 201,203, amplifier 209 and analog-digital converter 211.In this embodiment, Ib electric current can make the output point T of conveyer 101 _xthe value at place equals previously described V _oband amplifier 209 output point R _xmagnitude of voltage can equal-V _bg.Then, I is made _bxelectric current flows into conveyer 101, can make the output point T of conveyer 101 _xthe value at place equals V _obx, and amplifier 209 output point R _xmagnitude of voltage can equal-V _obx.Then, as previously mentioned can by-V _bgwith-V _obxbe sent to analog-digital converter 211 and calculate relative D respectively _out, to calculate chip internal resistance R _polydrift value, and then adjust variableimpedance module 105 with a control signal CS.The input impedance that note that due to receiver compare in variableimpedance module 105 be quite high input impedance.Therefore, the voltage at variableimpedance module 105 two ends is equal in fact, so Vo can be placed in variableimpedance module 105 right-hand member also can be positioned at variableimpedance module 105 left end, it does not affect the follow-up identity about Vo.In this embodiment, can comprise a current switching unit 221, the control signal of its reception control unit 213 is at two current source 217(I _b) and 219(I _bx) between switch, and control unit 213 receives the D from digital analog converter 211 _outwith the switching action of carrying out current source, namely meaning carries out switching action for current switching unit 215, and according to D _outexport control signal CS and adjust variableimpedance module 105.

Fig. 4 shows transmission/reception circuit 400 according to another embodiment of the present invention.Compared to the transmission/reception circuit 100 shown in Fig. 1, transmission/reception circuit 400 is except conveyer 301, receiver 303 and variableimpedance module 305, and also comprising in this example of another variableimpedance module 309(is a variable resistor) and a switch element 311.When conveyer 301 does not operate, conveyer 301 can cut out, and makes switch 311 conducting, makes can produce a guiding path between variableimpedance module 309 and receiver 303, impedance module 309 is provided must impedance matching.Can save by this allow conveyer 301 maintain running institute palpus energy.But the situation that variableimpedance module 309 also can have impedance drift because element processing procedure is different, therefore also needs the mechanism corrected.

In this instance, be after first variableimpedance module 305 having been adjusted according to aforesaid Regulation mechanism, then variableimpedance module 309 is adjusted.Its Regulation mechanism can as shown in Figure 10, comprise:

Step 1001

By one first electric current I _binput conveyor and produce one first output voltage V _ob.Wherein I _bproduce according to the ratio of an internal resistance of a predetermined voltage and chip.In one embodiment, v _bgbe a predetermined voltage, R _polythe internal resistance of the chip set by conveyer 101 and receiver 103, and K is adjustment I _bone parameter of value, also can be 1.

Step 1003

By one second electric current I _bxinput conveyor and produce one second output voltage V _obx, wherein the second electric current corresponds to the first electric current.In one embodiment, the value of the second electric current is equal to the 50%I in Fig. 2 _b+ 50%I _bxvalue.

Step 1005

According to the first output voltage V _oband the second output voltage V _obxdifference adjust variableimpedance module 309.In one embodiment, by the first output voltage V _obwith the second output voltage V _obxthe analog-digital converter (ADC) that is sent in receiver 303 of value solve D _band D _bx.Then can according to D _band D _bxcalculate the internal resistance R of chip _polywith the difference value of predetermined resistance, and adjust variableimpedance module 309 with a control signal (such as: control code).

Why output voltage V will be explained in detail in Fig. 5 _oband V _obxthe resistance drift conditions of variableimpedance module 309 can be reflected.When after the resistance drift conditions learning impedance module 309, variableimpedance module 309 can be adjusted according to this.

Fig. 5 shows a wherein example of the detailed construction of the transmission/reception circuit shown in Fig. 4.In the circuit framework shown in Fig. 5, transmission/reception circuit 300 represents with the situation of small signal model.It is noted that, the circuit framework shown in Fig. 5 and function mode thereof only in order to citing, and are not used to limit the present invention.In this embodiment, conveyer 301 comprises an amplifier 401, is a P-type mos transistor in this example of transistor 403() and transistor 405, resistance 402 is the resistance R of emulation chip inside _poly.Variableimpedance module 305 comprises a variable resistor 407, and in this example, control signal CS inputs to variable resistor 407.Receiver 303 comprises analog-digital converter 409 and signal attenuator 411.

In this embodiment, because resistance 402(R _poly) the order of magnitude be K, and resistance 407(R _a) be also equivalent to the resistance that the order of magnitude is K due to following derivation (2), and resistance 309 is in order to impedance matching when conveyer cuts out, so resistance 309(R _b) and resistance 407 be with different resistance strings composition, so just need additional corrections resistance 309.And resistance 309 will be corrected into and external transmission line impedance R _lunanimously (usually in Ethernet field, R _l=50ohm).And in order to be predicted the drift [R of resistance 309 by output voltage _b(real)=R _b(design)* (1+y)], following condition must be met in one embodiment:

(1) I _infor 50%I _badd 50%I _bx.If I _bbe set to I _bxequivalent, can obtain I _in=K*V _bg* [1+1/ (1+x)], wherein (x is internal resistance drift value).

Its derivation is as follows:

$\mathrm{Ib}=K_1\×\frac{\mathrm{Vbg}}{\mathrm{Rpoly}}$

$I_{\mathrm{bx}}=K_2\×\frac{\mathrm{Vbg}}{\mathrm{Rext}}$

Will $K_1\×\frac{\mathrm{Vbg}}{\mathrm{Rpoly}}=K_2\×\frac{\mathrm{Vbg}}{\mathrm{Rext}}$ Be set to K, can obtain:

I _in=K*V _bg*[1+1/(1+x)]。

(2) R _a=R _l* (1+N), output impedance=transmission line impedance (R _l).

(3) R _amust first be corrected.Its bearing calibration can R as the aforementioned _abearing calibration.

(4) R _polythe selection of palpus " suitably ".Such as R _poly=R _l* N.

Beneath will explanation in detail works as R _acorrect, R corrected _btime, why output voltage values V _o(the V shown in Fig. 9 _oband V _obx) can R be contained _bthe information of drift value " y ".And about in this embodiment, aforesaid mode can be adopted why to correct R _a, also will illustrate in Fig. 6.

V _X=I _in×R _poly

$I_{\mathrm{in}}+\frac{V_X-V_O}{R_A}=I_M$

$\frac{V_O-V_X}{R_A}+\frac{V_O}{R_B}=N\×I_M$

The wherein ratio of the magnitude of current that provides for transistor 403 and 405 of N.

$\frac{V_O-V_X}{R_A}+\frac{V_O}{R_B}=N\×[I_{\mathrm{in}}+\frac{V_x-V_o}{R_A}]$

$\⇒V_o\×[\frac{1+N}{R_A}+\frac{1}{R_B}]=I_{\mathrm{in}}\×R_{\mathrm{poly}}\×[\frac{1+N}{R_A}+\frac{N}{R_{\mathrm{poly}}}]$

$\⇒\frac{\mathrm{Vo}}{\mathrm{Iin}}=\frac{\frac{R_{\mathrm{poly}}\×(1+N)}{R_A}+N}{\frac{1+N}{R_A}+\frac{1}{R_B}}$

Therefore, I can be learnt _inand V _orelational expression can by R _a, R _band R _polyrepresent.

If will and R _poly=R _l× N × (1+x) substitutes into aforementioned I _inand V _outrelational expression can obtain following relationship.Wherein R _lfor the transmission line impedance found out from 307.R ideally _polyr should be equaled _l, but in fact have the drift of x, and because the electric current of transistor 405 is N times of transistor 403, therefore can be derived from R according to the principle of circuitry _poly=R _l× N × (1+x).The R about why _a=R _l× (1+N), will describe in addition.

$V_o=I_{\mathrm{in}}\×\frac{\frac{R_{\mathrm{poly}\left(\mathrm{real}\right)}\×(1+N)}{R_A}+N}{\frac{1+N}{R_A}+\frac{1}{R_{B\left(\mathrm{real}\right)}}}=K\×V_{\mathrm{bg}}\×[1+\frac{1}{1+x}]\×\frac{\frac{R_L\×N\×(1+x)\×(1+N)}{R_L\×(1+N)}+N}{\frac{1+N}{R_L\×(1+N)}+\frac{1}{R_{B\left(\mathrm{design}\right)}(1+y)}}=$

$K\×V_{\mathrm{bg}}\×[1+\frac{1}{1+x}]\×\frac{N\×[1+(1+x)]}{\frac{1}{R_L}+\frac{1}{R_{B\left(\mathrm{design}\right)}(1+y)}}=$

$K\×V_{\mathrm{bg}}\×N\×R_L\×[1+\frac{1}{1+x}+(1+x)+1]\×\frac{1}{1+\frac{1}{(1+y)}}$

When x much smaller than 1 time,

Therefore following relationship can be obtained

$=K\×V_{\mathrm{bg}}\×N\×R_L\×[1+(1-x)+(1+x)+1]\×\frac{1}{1+\frac{1}{(1+y)}}$

$=K\×V_{\mathrm{bg}}\×N\×R_L\×4\×\frac{1}{1+\frac{1}{(1+y)}}$

$=\mathrm{cons}\tan t\×\frac{1}{1+\frac{1}{(1+y)}}$

Output voltage V as can be seen here _oin can with R _bthe information of side-play amount y.

Under why R will be described _a=R _l× (1+N).

Referring again to Fig. 5, if hypothesis Iin ground connection and Vx is 0, there is an I _outflow into from 307, then can obtain following relationship:

V _X=0

$\frac{V_X}{R_{\mathrm{poly}}}+\frac{\mathrm{Vx}-\mathrm{Vo}}{R_A}=I_M$

$\frac{V_O-V_X}{R_A}=N\×I_M+I_{\mathrm{out}}$

$\frac{V_o}{R_A}=N\×\left[\frac{-V_o}{R_A}\right]+I_{\mathrm{out}}\⇒V_o\×\frac{1+N}{R_A}=I_{\mathrm{out}}\⇒\frac{V_O}{I_{\mathrm{out}}}=\frac{R_A}{1+N}$

Output impedance is R _l, therefore $\frac{V_O}{I_{\mathrm{out}}}=R_L\⇒R_A=R_L\×(1+N)$

Fig. 6 shows the situation of the transmission/reception open circuit shown in Fig. 5, and it only corrects R in order to key diagram 5 _atime, why input I respectively _band I _bxelectric current, can allow output voltage contain R _athe information of drift value x.

Output voltage in Fig. 6 can be as follows.

$\left\{\begin{array}{c}{V}_x=I_{\mathrm{in}}\×R_{\mathrm{poly}}\\ I_M+N\×I_M=I_{\mathrm{in}}\\ V_{\mathrm{out}}=V_x+N\×I_M\×R_A\end{array}\right.$

$V_{\mathrm{out}}=I_{\mathrm{in}}\×R_{\mathrm{poly}}+N\×\frac{I_{\mathrm{in}}}{N+1}\×R_A=I_{\mathrm{in}}\×(R_{\mathrm{poly}}+\frac{N}{N+1}\×R_A)$

R _polyand R _afor the resistance of same kind (type), so drift about during processing procedure " x " is identical.

$V_{\mathrm{out}}=I_{\mathrm{in}}\×[R_{\mathrm{poly}\left(\mathrm{design}\right)}\×(1+x)+\frac{N}{N+1}\×R_{A\left(\mathrm{design}\right)}\×(1+x)]=I_{\mathrm{in}}\×(1+x)\×(R_{\mathrm{poly}\left(\mathrm{design}\right)}+\frac{N}{N+1}\×R_{A\left(\mathrm{design}\right)})$

Work as I _inpour into I _belectric current, because of I _b=K*V _bg/ [R _poly], so output voltage is definite value.

If work as I _inpour into I _bxelectric current, because of I _bx=K*V _bg/ R _ext, so output voltage is proportional to (1+x).Therefore, I is filled with out respectively _band I _bxtime, output voltage can reflect R _polythe information of drift.

Except the circuit framework described in Fig. 5, the transmission/reception circuit of this case also as shown in Figure 7, only can have a transistor 403, and does not have transistor 405.Fig. 8 shows the situation of the transmission/reception open circuit shown in Fig. 7.

Output voltage in fig. 8 can following relation represent:

V _out=V _x=I _in×R _poly

If R _polyduring processing procedure, drift is " x "

Then V _out=I _in× R _{poly (design)}× (1+x)

According to the description of Fig. 6, work as I _inpour into I _belectric current, because of I _b=K*V _bg/ [R _poly* (1+x)], so output voltage is definite value.

If work as I _inpour into I _bxelectric current, because of I _bx=K*Vb _g/ R _ext, so output voltage is proportional to (1+x).

And in figures 7 and 8, how to obtain R _bdrift information can represent by following equation:

When the electric current of input conveyor is twice Ib, output voltage Vo and R _bdrift " y " relation lead card as follows,

Rpoly resistance has drift " x " → R _poly(real)=R _poly(design)* (1+x).

R _abe corrected, so do not have drift phenomenon, in the case, R _a=R _l.

R _bresistance has drift " y " → R _b(real)=R _b(design)* (1+y)=R _l* (1+y).

$V_{\mathrm{out}}=I_{\mathrm{in}}\×R_{\mathrm{poly}\left(\mathrm{real}\right)}\×\frac{R_{B\left(\mathrm{real}\right)}}{R_{A\left(\mathrm{design}\right)}+R_{B\left(\mathrm{real}\right)}}=I_{\mathrm{in}}\×R_{\mathrm{poly}\left(\mathrm{real}\right)}\×(1+x)\×\frac{R_L\×(1+y)}{R_L+R_L\×(1+y)}$

$=(K_1\×V_{\mathrm{bg}}\×\frac{2}{1+x})\×R_{\mathrm{poly}\left(\mathrm{real}\right)}\×(1+x)\×\frac{R_L\×(1+y)}{R_L+R_L\×(1+y)}=2\×K_1\×V_{\mathrm{bg}}\×R_{\mathrm{poly}\left(\mathrm{real}\right)}\×\frac{(1+y)}{1+(1+y)}$

So output voltage values V _outcontaining R _bthe information of drift " y ".

Fig. 9 shows transmission/reception circuit 900 according to another embodiment of the present invention.Compared to the embodiment shown in Fig. 4, Fig. 9 only has variableimpedance module 309 and eliminates variableimpedance module 305.And its impedance correction method can be as shown in Figure 10.Because the step of Figure 10 has been specified in, therefore do not repeat them here.

The embodiment of above, the impedance of transmission/reception inside circuit can be utilized reach must impedance matching, therefore can to save in prior art middle impedance matching mechanisms occupied area.

The foregoing is only preferred embodiment of the present invention, all equalizations done according to the present patent application the scope of the claims change and modify, and all should belong to covering scope of the present invention.

Claims (17)

1. an impedance correction method for transmission/reception circuit, is used on a transmission/reception circuit, and described transmission/reception circuit to be arranged in a chip and to comprise one first variableimpedance module, a conveyer and a receiver, and described method comprises:

One first electric current is inputted described conveyer and produces one first output voltage, wherein, described first electric current has the ratio of the internal resistance of drift value according to one of a predetermined voltage and described chip and produces;

One second electric current is inputted described conveyer and produces one second output voltage, wherein, described second electric current produces according to the ratio of described predetermined voltage and a predetermined resistance; And

Calculate this drift value of this internal resistance according to described first output voltage and described second output voltage, and adjust described first variableimpedance module according to this drift value.

2. impedance correction method according to claim 1, wherein, described first variableimpedance module is identical with the material of described internal resistance.

3. impedance correction method according to claim 1, wherein, described transmission/reception circuit also comprises one second variableimpedance module, and one end of described second variableimpedance module couples described conveyer and described receiver, and described impedance correction method comprises:

One the 3rd electric current is inputted described conveyer and produces one the 3rd output voltage, wherein, described 3rd electric current produces according to the ratio of described predetermined voltage and described internal resistance;

One the 4th electric current is inputted described conveyer and produces one the 4th output voltage; And

Described second variableimpedance module is adjusted according to described 3rd output voltage and described 4th output voltage.

4. impedance correction method according to claim 3, wherein, the value that the value of described 4th electric current equals described 3rd electric current adds the value of one the 5th electric current, and wherein, described 5th electric current produces according to the ratio of described predetermined voltage and described predetermined resistance.

5. impedance correction method according to claim 3, also comprises:

When described conveyer transmission signal, described second variableimpedance module and described receiver is made not to produce guiding path; And

When described conveyer not transmission signal time, close described conveyer and make the second variableimpedance module and described receiver produce a guiding path.

6. the impedance correction method of a transmission/reception circuit, be used on a transmission/reception circuit, and described transmission/reception circuit comprises a variableimpedance module, a conveyer and a receiver, one first end of described variableimpedance module couples described conveyer and described receiver, and one second end of described variableimpedance module couples an earth potential, and the described conveyer of described transmission/reception circuit and described receiver are arranged in a chip, described impedance correction method comprises:

One first electric current is inputted described conveyer and produces one first output voltage, wherein, described first electric current has the ratio of the internal resistance of drift value according to one of a predetermined voltage and described chip and produces;

One second electric current is inputted described conveyer and produces one second output voltage, wherein, described second electric current and described first current in proportion; And

Calculate this drift value of this internal resistance according to the difference of described first output voltage and described second output voltage, and adjust described variableimpedance module according to this drift value.

7. impedance correction method according to claim 6, wherein, the value that the value of described second electric current equals described first electric current adds the value of one the 3rd electric current, and wherein, described 3rd electric current produces according to the ratio of described predetermined voltage and a predetermined resistance.

8. a transmission/reception circuit, described transmission/reception circuit is arranged in a chip, and described transmission/reception circuit comprises:

One conveyer;

One receiver;

One first variableimpedance module, couples described conveyer and described receiver: and

One control unit, flow into described conveyer in order to control one first electric current and produce one first output voltage, wherein, described first electric current has the ratio of the internal resistance of drift value according to one of a predetermined voltage and described chip and produces, described control unit also flows into described conveyer in order to control one second electric current and produces one second output voltage, wherein, described second electric current produces according to the ratio of described predetermined voltage and a predetermined resistance, and described control unit more calculates this drift value of this internal resistance according to the difference of described first output voltage and described second output voltage, and adjust described first variableimpedance module according to this drift value.

9. transmission/reception circuit according to claim 8, wherein, described first variableimpedance module is identical with the material of described internal resistance.

10. transmission/reception circuit according to claim 8, wherein, described conveyer comprises:

One the first transistor, has a drain electrode of the first end being coupled to described first variableimpedance module.

11. transmission/reception circuit according to claim 10, wherein, described conveyer also comprises:

One transistor seconds, has a drain electrode of one second end being coupled to described first variableimpedance module.

12. transmission/reception circuit according to claim 8, wherein, described transmission/reception circuit also comprises one second variableimpedance module, and one end of described second variableimpedance module couples described conveyer and described receiver;

One the 3rd electric current is inputted described conveyer and produces one the 3rd output voltage by wherein said control unit, and wherein, described 3rd electric current produces according to the ratio of described predetermined voltage and described internal resistance;

One the 4th electric current is inputted described conveyer and produces one the 4th output voltage by described control unit; And

Described control unit adjusts described second variableimpedance module according to the difference of described 3rd output voltage and described 4th output voltage.

13. transmission/reception circuit according to claim 12, wherein, the value that the value of described 4th electric current equals described 3rd electric current adds the value of one the 5th electric current, and wherein, described 5th electric current produces according to the ratio of described predetermined voltage and described predetermined resistance.

14. transmission/reception circuit according to claim 12, wherein, described control unit is when when described conveyer transmission signal, described second variableimpedance module and described receiver is made not to produce guiding path, and when described conveyer not transmission signal time, close described conveyer and make the second variableimpedance module and described receiver produce a guiding path.

15. 1 kinds of transmission/reception circuit, described transmission/reception circuit is arranged in a chip, and described transmission/reception circuit, comprising:

One conveyer;

One receiver;

One variableimpedance module, couples described conveyer and described receiver; And

One control unit, flow into described receiver in order to control one first electric current and produce one first output voltage, wherein, described first electric current has the ratio of the internal resistance of drift value according to one of predetermined voltage and described chip and produces, described control unit also controls one second electric current and flows into described receiver and produce one second output voltage, wherein, described second electric current and described first current in proportion, and described control unit also calculates this drift value of this internal resistance according to the difference of described first output voltage and described second output voltage, and adjust described variableimpedance module according to this drift value.

16. transmission/reception circuit according to claim 15, wherein, the value that the value of described second electric current equals described first electric current adds the value of one the 3rd electric current, and wherein, described 3rd electric current produces according to the ratio of described predetermined voltage and a predetermined resistance.

17. transmission/reception circuit according to claim 15, described control unit is when when described conveyer transmission signal, described variableimpedance module and described receiver is made not to produce guiding path, and when described conveyer not transmission signal time, close described conveyer and make described variableimpedance module and described receiver produce a guiding path.