TW201238243A - Adaptive impedance matching - Google Patents

Abstract

A matching circuit for matching an impedance at a terminal. The matching circuit comprises at least one variable reactance element for dynamically adjusting values of a plurality of reactive components. The at least one variable reactance element is configured to: (a) perform a first adjustment of a value of one of the reactive components so as to one of minimize and maximize a feedback voltage at least approximately at resonance, and (b) perform a second adjustment of values of multiple reactive components while maintaining a predetermined relationship among the multiple reactive components as a constant so as to match the impedance.

Description

201238243 VI. Description of the invention: L Ming belongs to the ^^Technical system. The relevant application cross-references this patent application requesting the US Provisional Patent Application No. 61/436,768 filed on January 27, 2011 The entire content of which is incorporated herein by reference. FIELD OF THE INVENTION This invention relates generally to the field of transmission line impedance matching and, more particularly, to adaptive impedance matching techniques. t 冬好] Background of the Invention A loop antenna, such as a Near Field Communication (NFC) antenna, is typically coupled to a portable electronic device and/or terminal. The fixed tuning of loop antennas, including those used in NFC devices, results in an impedance mismatch resulting in 1^1? (: transmitter near-field power reflection. The resulting reflection complex can cause noise in the receiver, And the transmission error caused by the large load of the transmitter. The detuning caused by nearby metal objects further narrows the transmission range. In addition, the antenna tolerance can cause performance changes. Similar impedance matching problems exist in the inductance of power transmission. Aspects, such as inductive coupling via a power attenuator device. Therefore, fixed impedance tuning methods are not effective in overcoming impedance mismatch caused by nearby metal object detuning 'tolerance variations, and other variability factors.

However, there are currently methods for adaptive impedance matching, such as Automatic Impedance Matching for 13.56 MHz NFC 201238243 as in (10) mw, those methods discussed in IEEE (Association of Electrical and Electronics Engineers) (Copyright 2008) rely on phase information and, therefore, This results in considerable component complexity and implementation costs (eg, requiring a measurement circuit with a phase detector mode). Therefore, some people will pay attention to the further improvement of the antenna system. C Ming J Summary of the Invention A system, method and associated electrical topology for the need to adaptively match the impedance of a terminal by using voltage feedback to eliminate phase-dependent information. This results in a simplified circuit topology and reduced implementation cost due to production tolerance relaxation. 'Reliability increases due to reduced component count, increased communication range, increased communication reliability, increased stability of transmitter load regulation, and other advantages. In various embodiments, an antenna matching circuit is provided that utilizes a complex dynamic tunable reactive component 'and a voltage feedback circuit for adaptively matching the impedance of a terminal that is coupled to an antenna, such as a mobile device The close range §fL (NFC) loop antenna β In various embodiments, the matching circuit described herein relies on voltage feedback and uses a separate capacitor tuning network to adaptively match the impedance variations of the narrowband inductive antenna. Optionally, the split inductor tuning network is used for adaptive impedance matching of narrowband capacitive antennas. The matching circuit topology and related methods described herein can be used to dynamically match the steep impedance of many power components associated with inductive or capacitive coupling, including but not limited to antennas (including due to user and/or interaction). Easy-to-impedance mismatched mobile phone antenna), inductive power attenuator, radio frequency identification (RHD) converter (such as a key reader), F]v (for example, connecting a portable player to a Vehicle radio) and so on. 4 201238243 In one level, a system for matching the impedance of a terminal is provided. The system includes a signal generator, a matching circuit coupled to the signal generator, and a feedback circuit. The matching circuit includes at least one variable reactance element for dynamically adjusting a value of the plurality of reactive components, the at least one variable reactance element being configured to: (a) a reactive component of the reactive components One value performs a first adjustment to minimize or maximize a feedback voltage at least near resonance, and (b) performs a second adjustment on values of the plurality of reactive components while maintaining between the plurality of reactive components A predetermined relationship is a constant to match the impedance. The feedback circuit is coupled to the matching circuit and is configured to change the feedback voltage. In another aspect, a matching circuit for matching the impedance of a terminal is provided. The matching circuit includes at least one variable reactance component for dynamically adjusting a value of the plurality of reactive components, the at least one variable reactance component being configured to: (a) a reactive component of the reactive components One value performs a first adjustment to minimize or maximize a feedback voltage at least near resonance, and (b) performs a second adjustment on the values of the plurality of reactive components while maintaining between the plurality of reactive components A predetermined relationship is a constant to match the impedance. In yet another aspect, a method of matching the impedance of a terminal by adaptively adjusting the value of a plurality of reactive components of a matching circuit is provided. The method includes performing a first adjustment on one of the reactive components of the reactive components to minimize or maximize a feedback voltage at least near resonance, and performing a second adjustment on values of the plurality of reactive components While maintaining a predetermined relationship between the plurality of reactive components is a constant to match the impedance. BRIEF DESCRIPTION OF THE DRAWINGS The present invention and its advantages are fully understood from the following detailed description in conjunction with the accompanying drawings, in which: FIG. Embodiments, a schematic diagram of a circuit topology for adaptive impedance matching of an inductive load; FIG. 1B is a diagram illustrating an adaptive tuning step performed by a circuit topology of FIG. 1A, in accordance with an embodiment of the present invention A schematic diagram of a Smith chart; FIG. 1C is a schematic diagram showing a scatter diagram corresponding to the Smith chart of FIG. 1B according to an embodiment of the present invention; FIG. 1D is a diagram illustrating an embodiment of the present invention a schematic diagram of a Smith chart reflecting another adaptive tuning step performed via the circuit topology of FIG. 1A; FIG. 1E is a diagram showing a dispersion of the Smith chart corresponding to the 1D map according to an embodiment of the present invention FIG. 2A is a schematic diagram showing another circuit topology for adaptive impedance matching of an inductive load according to an embodiment of the present invention; FIG. 2B Is a schematic diagram showing a Smith chart reflecting an adaptive tuning step performed by the circuit topology of FIG. 2A in accordance with an embodiment of the present invention; FIG. 2C is a diagram illustrating an embodiment of the present invention, corresponding to A schematic diagram of a scatter plot of the Smith chart of FIG. 2B; FIG. 2D is a Smith chart of another adaptive tuning step performed by the circuit topology of FIG. 2A, in accordance with an embodiment of the present invention 6 201238243 2E is a schematic diagram showing a scatter diagram corresponding to the Smith chart of the 2D diagram according to an embodiment of the present invention; FIG. 3A is a diagram illustrating an embodiment of the present invention, A schematic diagram of another circuit topology for adaptive impedance matching of an inductive load; FIG. 3B is a schematic diagram of a Smith chart associated with the circuit topology of FIG. 3A, in accordance with an embodiment of the present invention; 3C is a schematic diagram showing another Smith chart associated with the circuit topology of FIG. 3A according to an embodiment of the present invention; FIG. 3D is a diagram showing an embodiment of the present invention, and FIG. 3A A schematic diagram of a scatter plot associated with one of the states of the tuned circuit; FIG. 3E is a schematic diagram of a Smith chart associated with the circuit topology of FIG. 3A, in accordance with an embodiment of the present invention; The figure is a schematic diagram showing another Smith chart associated with the circuit topology of FIG. 3A according to an embodiment of the present invention; FIG. 3G is a diagram illustrating tuning with FIG. 3A according to an embodiment of the present invention. A schematic diagram of a scatter plot associated with a circuit; FIG. 4A is a schematic diagram showing another circuit topology for adaptive impedance matching of an inductive load in accordance with an embodiment of the present invention; 4B, 4C Is a schematic diagram of a Smith chart associated with respective states of the circuit of FIG. 4A in accordance with an embodiment of the present invention; FIG. 4D is a diagram associated with FIG. 4C in accordance with an embodiment of the present invention A schematic diagram of a scatter parameter diagram; FIGS. 4E and 4F are schematic diagrams showing a Smith chart associated with respective states of the circuit of FIG. 4A according to an embodiment of the present invention; 201238243 FIG. 4G is a diagram According to one of the inventions Embodiments, a schematic diagram of a scatter parameter map associated with FIG. 4F; FIGS. 5A and 5B are diagrams showing a circuit topology for adaptive impedance matching connected to one of the terminals of a non-50 ohm source FIG. 5C is a schematic diagram showing a Smith chart associated with one of the circuit topologies of FIG. 5B according to an embodiment of the present invention; FIG. 5D is a diagram illustrating the present invention according to the present invention One embodiment, a schematic diagram of a scatter parameter map associated with one of the states of the circuit topology of FIG. 5B; FIG. 5E is a diagram showing the circuit topology associated with FIG. 5B, in accordance with an embodiment of the present invention A schematic diagram of a tuning step; FIG. 5F is a schematic diagram showing various tuning values of a reactance component of FIG. 5E according to an embodiment of the present invention; FIG. 5G is a diagram illustrating an embodiment of the present invention a schematic diagram of a scatter parameter map associated with the tuning step of FIG. 5F; FIG. 5H is a diagram illustrating another tuning step associated with the circuit topology of FIG. 5B in accordance with an embodiment of the present invention Schematic; Figure 51 is a diagram showing A schematic diagram of various tuning values of the reactance component of FIG. 5H according to an embodiment of the present invention; FIG. 5J is a scatter parameter diagram associated with the tuning step of FIG. 5H according to an embodiment of the present invention; Figure 6A is a schematic diagram showing a circuit topology for adaptive impedance matching of a capacitive load in accordance with an embodiment of the present invention;

6B is a schematic diagram showing a Smith chart reflecting an adaptive tuning step performed by the circuit topology of FIG. 6A 201238243 according to an embodiment of the present invention; FIG. 6C is a diagram showing implementation according to the present invention For example, a schematic diagram of a scatter plot corresponding to the Smith chart of FIG. 6B; FIG. 6D is a diagram illustrating yet another adaptive tuning step performed by the circuit topology of FIG. 6A, in accordance with an embodiment of the present invention. A schematic diagram of a Smith chart; FIG. 6E is a schematic diagram showing a scatter diagram corresponding to the Smith chart of FIG. 6D according to an embodiment of the present invention; FIG. 7 is a diagram illustrating an embodiment of the present invention A schematic diagram of a general system component layout; and FIG. 8 is a flow chart showing an adaptive impedance tuning method in accordance with an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION The following examples further illustrate the invention, but should not be construed as limiting the scope in any way. Systems, methods, and associated circuit topologies for adaptively matching the impedance of a terminal by using voltage feedback to eliminate the need for phase information are provided. This results in simplified circuit topologies and reduced implementation costs due to production tolerances, increased reliability due to reduced component count, increased communication range, increased communication reliability, increased stability of transmitter load regulation, and other advantages. In various embodiments, an antenna matching circuit is provided that utilizes a plurality of dynamic tunable reactive components, and a voltage feedback circuit for adaptively matching the impedance of a 201238243 terminal, the terminal being coupled to an antenna, such as an action Near Field Communication (NFC) loop antenna in the device. In various embodiments, the matching circuit described herein relies on voltage feedback and uses a separate capacitor tuning network to adaptively match the impedance variations of the narrowband inductive antenna. Alternatively, the split inductor § 5 is networked for adaptive impedance matching of narrowband capacitive antennas. The matching circuit topology and related methods described herein can also be used to dynamically mate the impedance of various other power components associated with inductive or capacitive coupling, including but not limited to antennas (including due to user and/or environmental interactions). Easy-impedance mismatched mobile phone antenna), inductive power attenuator, radio frequency identification (RFID) converter (such as a key reader), fm transmitter (such as connecting a player to a vehicle radio) )). Preferably, a predetermined threshold of the feedback voltage Vfb triggers the initiation of an embodiment of the matching algorithm described below. Similarly, when the feedback voltage Vfb falls below another predetermined threshold, the variable reactance element returns to a predefined initial value. Referring to Figure 1A, an embodiment of a circuit topology for adaptively matching the impedance connected to one of the terminals of the inductive component is shown. In this embodiment, the inductive component is an inductive loop antenna, such as a mobile device, such as an NFC loop antenna for use in a mobile phone, smart phone, tablet device, laptop, or the like. In other embodiments, the antenna is a primary RF antenna that couples a mobile device to a base station, or a radio frequency identification (RFID) device antenna. In other embodiments, the inductive component forms an inductively coupled terminal payment terminal, an electronic key, an inductively coupled power supply, or other device that implements inductive coupling. Circuit topology 100 includes a signal generator 102 coupled to a feedback power 10 201238243 path 104. The signal generator i 〇 2 includes an input impedance R0, such as 50 ohms (e.g., representative of one of the mobile device transmitters, ohmic input impedance). One of the terminals of signal generator 102 is coupled to a first terminal of resistor 106 of a high impedance feedback circuit 104. Resistor 1〇6 has a value R 4 , such as 99 5 0 ohms. The second terminal of signal generator 丨〇 2 is coupled to ground 108. The second terminal of resistor 106 is coupled to an amplifier 1〇9, which is coupled to a second 50 ohm variable signal source 11A. Matching circuit 112 includes adaptive variable capacitors 114, 丨16 having respective tunable values C^C2. The variable capacitors 114, 116 are via a variable electrical k-element 118' such as a digital or analog micro-motor (or micro-electronic) system (MEMS) device, an electrical + varactor, a digital tunable capacitor circuit, a switched capacitor array, etc. And implemented. In the embodiment, each of the adaptive contact capacitors C1 and C2 is implemented by a dedicated variable reactance element. Alternatively, the -single-variable reactive component 118 is configured to be an adaptive contactable capacitor network cn, c2, wherein the C1AC2 share-switchable reactive component library. In the embodiment of the electric (four) group, the plurality of reactive elements are arranged in series as needed, and for example, the added capacitance is individually shorted. _ Multi-throw switch selects capacitor splitting. Alternatively or in addition to each of the 'capacitor banks': the work elements are digitally controlled by a processor of a microcontroller executing a computer readable instruction stored in the memory and including being configured to be based on - The feedback signal is used to select an algorithm for switching configurations. In the implementation of the second command, the feedback signal triggers different modes, such as standby, starting the tuning resonance, and performing an impedance tuning (split). 201238243 In a further embodiment, the tuning is implemented by a voltage controlled dielectric material (BST) for the capacitor (or in the case of an inductive tuning described below for a matched capacitive load, a ferromagnetic tuned inductor with a movable core) And a mechanically tuned capacitor having a moving conductive plate or dielectric, for example using a stepper motor actuator. Alternatively, relay switching, MOSFET or other transistor switching, or a PIN diode switch can be utilized. In the illustrated embodiment, the first terminal of the variable capacitor 114 is coupled to the first terminal of the resistor 106 of the feedback circuit 104, and the second terminal of the variable capacitor 114 is coupled to the first terminal of the variable capacitor 116. The variable capacitor 116 is further connected to ground. In this embodiment, the inductive antenna 120 is connected across the terminals of the variable capacitor 116 of the matching circuit 118. Inductor antenna 120 is represented by an inductor 122 having a value L1 and a resistor 124 having a value of R1 (e.g., 50 ohms). Resistor 124 represents radiation and heat loss. An embodiment of a tuning algorithm initially includes resonating by tuning the value C1 of the variable capacitor 114 to minimize the absolute value of the feedback voltage. Once the resonance is achieved, the values C1 and C2 of the variable capacitors 114, 116 are tuned such that the absolute value of the feedback voltage Vfb becomes % of the absolute value (a known value) of the generator voltage Vgeni, while the sum of the held values C1 + C2 is A constant. This is based on feedback voltage adaptive matching of antenna impedance changes without phase information. By eliminating the reactive component of the impedance, the load impedance is minimized - so the voltage is also maximized. In a consistent embodiment, an algorithmic control tuning is implemented via a microcontroller using an analog input to an analog-to-digital converter (adc) such as a feedback voltage. The microcontroller includes one or more digital output pins for controlling the reactor switches in a series or parallel configuration. If the varactor is used as an adjustable power 12 201238243 container, then control an external digit to the analog converter (D AC) or use an embedded DAC to convert back to the analog domain. One of the adaptive impedance matching associated with one of the circuit topologies of Figure 1A is described in more detail with reference to Figures 1B-1E. The initial value of the capacitor 114 (value C1) and the initial value of the capacitor 116 (value C2) are based on the following formula:

Ctune = —I— ω2Π

Cl = Ν * Ctune C2 - Ctune - Cl The first step of the adaptive tuning procedure needs to adjust the value of ^ until the |Vfb| of the feedback circuit 104 is minimized, which is the capacitance of the antenna coil by the capacitor C1+C2 The elimination of the resonance occurs as shown in the scatter parameter diagram corresponding to one of the Smith chart and the 1C chart in FIG. 1B. After this tuning step, sii approximates the real number at the desired frequency (Fig. 1 8), and vfb is minimized at the desired frequency (the ic diagram). In this example, the desired frequency is 13 56 MHz. Figures 1B and 1C show that C1 changes 2pF to achieve resonance, however, impedance matching is still not ideal. When Cdelta = 2pF, the value of |Vfb| or |S21| is minimized. The second step of the adaptive tuning procedure needs to adjust C1 & C2 while maintaining (: Shan 1 ^ = (: 1 + € 2 unchanged, as shown in Figure 11) and the figure shown in the diagram. Make the following settings. If 02' = €2-〇£16 as '(:1,=(:1+€(1611&. Adjustments are performed by using different Cdelta values until |汨 in the figure 丨vfb丨 or 丨S21丨达i So far this indication - ideal match. The first and first plots show that cddta = 4pF means - ideal match 'because the su seen from the generator is very close to the history 13 201238243 Miestu Center (ID map) and | Vfb| = l/2 * |Vgenerator| or S21 is very close to 1 (Fig. 1E). One of the matching methods of Figure 1A is a mathematical proof of the embodiment. As discussed above, the first step requires the use of C1. Resonate by minimizing the voltage Vfb across the generator terminal as follows: j〇)C2 j(〇C\ K\

V,N j〇)C2 jcoC2 + Rl) j(〇C\ j(〇C2 (jaLl + R\) Since Cl is the only variable and is set: J + = jcoCi j〇)C2 + (jwL\ + R\ The result is VFB =\VC2\ V, s jc〇Cl

A + jB

VIN jc〇C\

+ A + JB R〇 j(〇C\

+ A + jB j〇>c\

The + A + jB equation can be minimized only by setting. Resonance is not intended to be an ideal match because resonance can mean any real impedance and ideal match occurs only when A = R〇. The second matching step requires changing C1 and C2 while maintaining the resonance mode. The resonance occurs as follows: 14 201238243 ωΒ α = Β mC\ j(〇C2 jcoC2 *(jaLl + Rl) (j0Ll + R\) Since the Q value is high, we know 丨jcoLl| » |R1|, allowing one to ignore R1 Approximate value. Then we get

B ωΟΙ jcoC2 j(〇L\ jcoC2 + jcoL\ ωΠ coC2 ωΙΛ ®(C1 + C2); Definition = Cl + C2 ω2Π and keep it constant, the resonance is maintained - so if C2 changes AC, then C1 Also changes -AC. At resonance, the network impedance Zm (antenna and matching capacitor) is a real number as follows:

Zm j(〇C\ · + jcoCl < (/*^1+ 7?l)

Re jcoC2

Re jmL\ + R\ jcoCl + jcolA + Λ1 jwC2 + j〇)L\ + R] \-ω21\α + j^C2R\

Re 〇ωΠ + - ω2Πα - jcoC2R\) fy-a2L\C2f + {〇)C2R\)2 /?1-6j2Z1C2/?1 + ^2Z1C2/?1 i\-m2L\C2f +{aC2R\)2 ( ]-a2L\C2f +{〇)C2R\)2 1 + {ω2ηα} - 2m2L\C2 + (coC2R\)2 If the coil is high Q (0)L1»R1): 15 201238243 1 + {ωΟΙωη) 2 - 2iy2LlC2 + {〇}C2R\f \ + ^2L\Clf -2m2L\C2 Feedback voltage across the generator terminals: R\

yFB R] (\-M2L\C2f

vIN ίί and 〇 +- R\ -a2L\C2j R\ +R\ and then use constant (C1 + C2) we get:

VFB R\ R〇

X~^-2C2 +RX

vFB

V,N · _1_ ^ C2 1 \2 C1 + C2 + 1 Solve this equation and provide an ideal match when it equals % 16 201238243 __C2 R\{ C1 + C2 R0 (χ C2 R\{ CI + C2

C1 + C2 CI + C2 C2 Cl y R0 Ctune

C\ = N^ Ctune * Ctune = —-— = Cl + C2 ω2α C2 = Ctune-Cl This is equal to the approximation formula discussed above for the 1A-1E plot. Referring to Figure 2A, another embodiment of a circuit topology for adaptive matching being coupled to an inductive component, such as the impedance of a terminal of the antenna, is shown. The circuit topology 200 is similar to that described above with respect to FIG. 1A except that the first terminal of the resistor 106 of the high impedance feedback circuit 104' is coupled to the first terminal of the variable capacitor 116, and the variable capacitor 116 is further coupled to ground. 108. Inductor antenna 120 is coupled between the first terminal of resistor 106 and ground 108. The feedback voltage Vfb associated with this circuit topology is the voltage across the shunt capacitor C2. In this embodiment, the tuning algorithm is typically performed in two steps. First, resonance is achieved by tuning the value C1 of the variable capacitor 114 to maximize voltage feedback. Tuning C1 eliminates the reactive component seen by the generator and, as a result of 201232243, maximizes the current drawn from the generator. Then, the voltage across the antenna terminals is maximized. Therefore, the second step generally again includes maximizing the voltage feedback by adjusting the values of c 1 and C 2 while maintaining C1 + C2. Therefore, adaptively matching the antenna 120 does not require phase information. In the illustrated embodiment, the generator 102 has a 50 ohm impedance. One of the adaptive impedance matching associated with one of the circuit topologies of Figure 2A is described in more detail with reference to Figures 2B-2E. In this embodiment, the initial value of capacitor 114 (value C1) and the initial value of capacitor 116 (C2) are based on the following equation:

Ctune =-- ω2ΙΑ

Cl = * Ctune C2 = Ctune - Cl The first step of this embodiment of the spectrum modulation procedure needs to adaptively adjust the value of C1 until the feedback circuit 104, after 丨vfb| of 埠2 is maximized, this occurs in When the antenna coil reactance is canceled by the capacitance C1+C2 and resonated, as shown in the scatter parameter diagram corresponding to one of the Smith chart and the 2C chart of FIG. 2B. After this tuning step, S11 approximates the real number (Fig. 2B) and Vfb is maximized (Fig. 2C). Figures 2B and 2C show that C1 changes 2pF to achieve resonance, however, impedance matching is still not ideal. When Cdelta = 2 pF, the value of |Vfb| or |S21| is maximized. The second step of the illustrated embodiment of the adaptive tuning procedure requires adjustment of C1 and 02' while maintaining 〇11-like = (:1+€2 unchanged, as shown in Figures 20 and 2, as follows: 5 history. Right C2, = C2 - Cdelta, then C1, = Cl + Cdelta. 18 201238243 Adjustment is performed by using different Cdelta values until |Vfb| or |S21| in Figure 2E is maximized, this Indicates an ideal match. One of the matching methods of one of the methods of Figure 2A illustrates the use of C1 to generate resonance by maximizing the voltage Vfb across C2:

Ffi = \VCl\ Z

vIN A—)AW) j(〇C\ + 1 /. ,,

A + jB jcoCl *(]ωΣ\ + R\) jcoC2 + 〇ωΖ1 + Λΐ) This formula does not include Cl. The result is:

VfB=\VC2[

VIN

A + jB

Rn j(〇C\

+ A + jB R〇 1 j(〇C\

+ A + jB Changing only Cl results in a simple first-order equation. Vfb is maximized by making C1 = J- ω ,, thus eliminating the reactive part of the denominator. The impedance seen by the generator is Ζ = — — — + = , which is the consistent number of non-resonances. The resonance of jc〇C\ does not mean an ideal match, since resonance can refer to any real impedance and an ideal match occurs when A = R0 also holds. 19 201238243 The second matching step requires simultaneous changes in Cl and C2 while maintaining resonance. C1 ωΒ

B ωΟ\ jmC2 ja>C2 .+ (joLl + R\) Since the Q value is high, we know that jc〇Ll»Rl, which allows an approximation of R1 to be ignored. In this situation:

B ωΟΙ im j〇)C2 j〇)C2 )G)L\ ωΙ\ 〇)C2 ω (Cl + C2) = ωη Resonance is maintained by ω L\ by defining the concealment = and keeping it constant. Therefore, the value of C2 changes Δ (: the value of Cl needs to be changed - Δ (:. At resonance, the network impedance Zin is a real number: z

IN jwC2 j〇)C2 + jcoLX + R\ '(jwL\ + R\) '1 *{jwL\ + R\) jwC2 =Re jwL\-l· R\ 1 jcoC2 + Jd)lA + /U _\ -w2L\C2 + jwC2R\ {jaL\ + 7?l)(l - o2L\C2 - jcoC2R\) ^-m2L\Clf +{coC2R\y

Re R\-m2L\C2R\ + m2L\C2R\ {^-m2L\Clf +{f〇C2R\)2 R\ ^-m2L\Clf + {〇)C2R\y· 1 + (ω2Πα^ - 2a2L\ C2 + (〇)C2R\f 20 201238243 If the coil is high Q ((Ll»Rl): Z...=_ News_a_R\_ 川 l + (®C2iyZ,l)2-2ft)2Z , lC2 + (iyC2/?l)2 1 + (^1102^-2^1102 (\-a2L\C2f If we then look at the feedback voltage across C2: VFB ZlN jd V, N {\-w2L\C2f j Ritual 0 + (ΐ-ω2πα^

Rl + j .(\-a2L\C2f wC\ Κ0(\-ω2Π€2} +R\ Use constant Cftme = a + C2: ω2Π <=> ω2 L\ = (C1 + C2) We get: ii C2 丫Ri + j- ^ Ctune J yFa wC\ vIN f D 1 C2 V ni 1 + 7' Ctune C2, Ctune, R\wC\ ' C2 1

Ctune

^tuneA(zuC\R\f +C\A (cCm)2+f 1. C2 Ctune, wCl ( C2 + 1 Λ1 + Λ0 1—V Ctune \2

vFB

V, N

ctCI Ctune2 R\ + R0CV

VIN Ctune R\ + R0Cl This equation is differentiated from Cl and Cl is set equal to zero (0) to find the maximum and minimum values. We get: 21 201238243 d dCl

VFH 2 * Ctunia'RQCm2 - Ctuni02aRl+ 4ctu^ii〇2R\2 +C12 (ctunio^Rl2 ^IClunimC\2R\+ω^Ο2Cl4) C1 = 0 or

Vfb is minimized or maximized. select

Cl = Ctune , \R0~ w2L\ Since C1=0 gets the minimum and Cl must be positive, we use the restricted formula Cl + C2 = -^-〇C2 = one--C1 ω L\ ω L\ to determine the match Has occurred: Z, «S___Λ___ (ΐ~ω2πα}

Rl \λ· \-ω2η ω2Π ω2Π (Rl' R〇. R0 \ Refer to Figure 3A, another implementation of a circuit topology for adaptive matching of the impedance of a terminal connected to an inductive component such as an antenna The circuit topology 300 includes a signal generator 302 coupled to a high impedance envelope feedback circuit 〇4. One embodiment of the signal generator 302 has an input impedance R0, such as 50 ohms. The signal generator 302 One of the terminals is connected to a first terminal of one of the resistors 306 of the feedback circuit 〇 4. One embodiment of the resistor 306 has a value R4 'eg, 9950 ohms. The second terminal of the signal generator 3 〇 2 is connected to Ground 308. The second terminal of resistor 306 is coupled to an amplifier 309 that is multiplexed to a second 50 ohm variable signal source 31. Matching circuit 312 includes an adaptation 22 having respective tunable values C3 and C4 201238243 Variable capacitors 314, 316. As noted above, the variable capacitors 314, 316 are via at least one variable reactance element 318, such as a digital or analog micro-electromechanical (or microelectronic) system (MEMS) device, an electronic varactor, Digital tunable electricity The container circuit, the switched capacitor array, etc. are implemented. In the illustrated embodiment, the first terminal of the variable capacitor 316 is coupled to the first terminal of the resistor 3〇6 of the feedback circuit 〇4, and the variable capacitor 316 The second terminal is connected to ground 308. The first terminal of variable capacitor 316 is also coupled to the first terminal of variable capacitor 314. In this embodiment, inductor antenna 120 is coupled to second of variable capacitor 314. Between the terminal and ground 308. Inductor antenna 320 is represented by an inductor 322 having a value L2 and a resistor 324 having a value R2 (e.g., 50 ohms), and resistor 324 represents radiation and heat loss. In an embodiment of the algorithm, the resonance is approximated by tuning the value C4 of the variable capacitor 316 to maximize voltage feedback. Next, the values of the capacitor 316 (C4) and the value of 314 (C3) are tuned while maintaining the ratio 1/(1/C3+1/C4) is a constant until the feedback voltage is equal to one-half of the generator voltage (ie Vfb = MVgenerator). Therefore, phase information is not needed to achieve a match. More specifically, C3 and C4 The initial value is found according to the following formula C3- 1 is still Lanl ~ ^-\lRani C4 = -Tir δΤ L (-- C3 In this example, the modulation results in a C4 offset of 30% and a C3 increase of 20pF. First, the value of C4 is adjusted until feedback The |Vfb| of 埠4 (S42) of circuit 304 is maximized when it is very close to resonance, and the antenna coil reactance is eliminated by string 23 201238243 coupling capacitor: Figure 3 shows an initial match of one Smith chart, and 3C And the 3D graph 'will not C4 reduce the result of U〇pF, which occurs very close to resonance and maximizes falsehood. Subsequent 'C3 and C4 are both adjusted while maintaining the relationship 3 + H = CTl(10) unchanged, thus maintaining resonance until feedback S42 becomes 1 'corresponding to Vfb = l/2 * Vgen. Figure 3E depicts a Stella, Stu before this step. The 3F and 3G graphs respectively show a Smith chart and a scatter parameter map according to this step when C3 is reduced by 20 pF and C4 is adjusted while maintaining resonance. Figure 3F shows that when c:3 is reduced by 2〇pF, Vfb=1/2*Vgen (ie, 3 (S42=l in the scatter parameter diagram of Fig. 3) is very close to an ideal match. Figure 2 is another embodiment of a circuit topology for adaptive matching being connected to an inductive component, such as the impedance of a terminal of an antenna. Circuit topology 400 is similar to that described in relation to Figure 3A above. The first terminal of resistor 306 of high impedance feedback circuit 304' is coupled to the second terminal of variable capacitor 316. In this embodiment, the initial values of C3 and C4 are based on the following equation: C3 = ___1 0) 2L « m First, the value of C4 is adjusted until the 丨Vfb丨 of the antenna terminal is maximized 24 201238243, which occurs when the antenna coil reactance is cancelled by the capacitance 1/(1/C3+1/C4). 4B-4D illustrates the foregoing steps, wherein FIG. 4B depicts a Smith chart before the step, and FIG. 4C-4D shows a Smith chart and a corresponding scatter parameter graph where the resonance is caused by C4 is changed until |Vfb| is maximized (S11 approximates real number). Specifically, it shows that the resonance that is still not an ideal match is achieved by reducing C4 by 140 pF. In this embodiment, |Vfb| or |S42| is maximized when Cdelta = -140pF. Next, both C3 and C4 are adjusted while keeping ctune = 1/(1/C3+1/C4) unchanged. Specifically, different cdelta values are used until |Vfb| or |S42| in the 4F and 4G maps are maximized, respectively. This indicates an approximate ideal match. An inductive antenna matching non--50 ohm generator is used to match the 5A-5J diagram, using a non-50 nm generator for adaptively matching a circuit topology connected to the impedance of a terminal of an inductive antenna. An embodiment is shown. The signal level of the feedback point is calculated by loading a R 0 = 50 ohm antenna on the transmitter, where the generator power and impedance are known. Specifically, if the generator outputs Vg and the generator impedance is Rg instead of R0; then Vfb is Vg*R0/(R0+Rg). The tuning step then first changes C1 to minimize Vfb, which causes the antenna and matching to resonate. Second, the impedance is changed to keep C1 + C2 constant (C1 decreases AC and C2 increases AC, and vice versa) until Vfb is equal to Vg*R0/(R0+Rg). As shown in Figures 5-5-5, using the foregoing method, the match is nearly ideal for a 50 ohm load regardless of the generator impedance. In an adaptive design embodiment, Vfb is minimized by the 25 201238243 when the Cl delta is 56 pF (Fig. 5E-5G), and Cla = 8 〇 pF is obtained. With this value, the antenna and matching network enter resonance at 13.56 MHz. In the subsequent steps, both ci and C2 change while Cl + C2 == Cm. This means, for example, that c] increasing lpF means subtracting lpF from C2 (Fig. 5H-5J). In the illustrated embodiment, a 50 ohm load corresponds to a Vfb of 236.236 Vp in order to obtain a 50 ohm match of 〇dBm from a 10 ohm transmitter. Clb was reduced by 32 pF from 80 pF and the result was 48 pF, and similarly, C2b was increased by 32 pF, resulting in 287 pF and Vfb = 0.242 Vp. Capacitive Antenna Matching Using Inductors Referring to Figure 6A, an embodiment of a circuit topology for adaptive matching being coupled to a capacitive element, such as the impedance of a terminal of a capacitive antenna, is shown. A capacitor antenna is designed as a series resistor Ra representing radiation and loss, and a capacitor Ca representing a reactance. In the illustrated embodiment, the matching circuit includes two variable inductors. In one embodiment, a tunable inductor or a positive reactive impedance is implemented using an inductor component. For example, by moving a core into a coil, the reactance increases (or if a conductive surface, such as mechanically closer to an inductor, the reactance decreases due to an increase in parasitic capacitance). Alternatively, a parallel tunable capacitor can be added to a large inductor, in which case the parasitic capacitance from the capacitor can then be tuned to reduce the effective inductance. In an embodiment, the tunable inductors are connected in series. At higher frequencies, a tunable capacitor connected through a quarter-wavelength transmission line can be utilized as a positive reactive component, such as an inductor. The impedance seen by the generator circuit is: 26 201238243

Zin = (four) 2 + 7^) ; wi, 2+/wLl + Ra + j^ }ω12 ·

TwCa Ϊω12 + ]ωϋ + If the following relationship is satisfied, resonance is achieved: 1 Ra2 1

12 = ——--L1 + -τ~λ-r* ^ —----LI Dress 2Ca 〇_-ω2ΐ{^ ω2€α If at resonance Ra &lt;&lt; l/(c〇Ca) ' Then the Q value is high and we can simplify the relationship by ignoring the smaller component Ra. Once the resonance is achieved, the impedance is tuned and the resonance is maintained by keeping the relationship L1 + L2 = constant. Specifically, in order to tune the circuit, the shunt inductor L2 is successively adjusted to obtain resonance, and then the impedance is tuned while maintaining the above relationship - by increasing dL to L1 successively and adjusting L1 by subtracting dL from [2] And L2 to maintain resonance. The program is controlled by using feedback from the antenna terminals and maximizing the feedback amplitude. First, the circuit is resonated by using L2 and then the impedance is matched and maintained by simultaneously adjusting L1 and L2 while maintaining L1 + L2 = constant. During this two tuning steps, the feedback amplitude is maximized. Referring to Figures 6B-6E, the feedback voltage is maximized by bringing the network impedance as close as possible to the center of the Smith chart shown. For example, for L1 = 125uH, decreasing L2 causes the circuit to resonate and maximize the amplitude of the feedback circuit when L2 approaches 152nH (Fig. 6B-6C). Next, both L1 and L2 are adjusted while maintaining Ll+L2=l_25uH+ 152nH. As shown in Fig. 6E, the feedback amplitude is maximized by shifting 60 nH from L1 to L2. 27 201238243 Referring to Figure 7, a diagram showing the layout of the general system components of the foregoing inventive embodiment is shown. System 700 includes a source/generator 702, a load 706', and a match/feedback circuit 704 that couples the generator to the load and operates in accordance with an embodiment of the adaptive tunable circuit topology and associated tuning algorithms described above. Finally, Figure 8 is a flow chart showing an adaptive impedance tuning method in accordance with an embodiment of the present invention. In step 8A, a first adjustment is made to the value of one of the reactive components to minimize or maximize a feedback voltage in accordance with a corresponding embodiment of the circuit topology described above. In step 802, the adjustment continues until the circuit is at least nearly resonant. If so, in step 8〇2, a second adjustment is made to the values of the plurality of reactive components while maintaining a predetermined relationship between the plurality of reactive components is a constant to match the impedance, as described in detail above. . All references, including publications, patent applications, and patents, cited herein are hereby incorporated by reference in their entirety in their entirety in the entirety in The same degree is incorporated. The use of "a" and "an" and "the" and the like Interpreted as covering both singular and plural. Unless otherwise stated, the words "including", "having", "including" and "including" are intended to be interpreted as an open-ended term (meaning "including but not limited to"). Unless otherwise indicated herein, the <RTI ID=0.0> </ RTI> </ RTI> </ RTI> <RTI ID=0.0> </ RTI> </ RTI> </ RTI> </ RTI> </ RTI> Clearly contradictory to the context, as listed in this article. Execute in the order in which they are combined. Unless all methods of the second method can be used in any way, use any of the crimes or model language provided in this article (for example, "such as" is difficult to better understand and not to the scope of the present invention. Restrictions. The language in the specification is not to be construed as a non-required component that is indispensable for the practice of the invention. The preferred embodiments of the present invention are described herein as including the inventors' practice of the invention. Good mode ^When reading the above instructions, those who are better at the 1 (4) silk secrets can see the money. The inventor expects the hot training union to make such changes when appropriate, and the moon person intends to clearly describe this article. The invention is embodied in other ways, and thus, the invention includes all modifications and equivalents of the subject matter described herein. Any combination of all possible variations is included in the present invention. [Schematic Description] FIG. 1A illustrates an embodiment of the present invention for use in an inductor. Schematic diagram of a circuit topology for adaptive impedance matching; FIG. 1B is a schematic diagram showing a Smith chart of an adaptive tuning step performed by a circuit topology of the eighth drawing; FIG. 12 is a schematic diagram showing a scatter diagram corresponding to the Smith chart of FIG. 1B; 29 201238243 The ID diagram is a diagram illustrating a second map according to an embodiment of the present invention. A schematic diagram of a Smith chart of another adaptive tuning step performed by the circuit topology; FIG. 1 is a schematic diagram showing a scatter diagram corresponding to the Smith chart of the 1D map according to an embodiment of the present invention; FIG. 2 is a schematic diagram showing another circuit topology for adaptive impedance matching of an inductive load according to an embodiment of the present invention; FIG. 2 is a diagram illustrating a second embodiment according to an embodiment of the present invention 2A is a schematic diagram of a Smith chart of an adaptive tuning step performed by the circuit topology of the figure, and FIG. 2C is a diagram illustrating Smith corresponding to the second figure according to an embodiment of the present invention A schematic diagram of a scatter plot; FIG. 2D is a schematic diagram of a Smith chart reflecting another adaptive tuning step performed via the circuit topology of the second diagram, in accordance with an embodiment of the present invention; Is a schematic diagram showing a scatter diagram corresponding to the Smith chart of the 2D graph according to an embodiment of the present invention; FIG. 3 is a diagram showing the adaptability for an inductive load according to an embodiment of the present invention. A schematic diagram of another circuit topology of impedance matching; FIG. 3 is a schematic diagram showing a Smith chart associated with the circuit topology of FIG. 3 according to an embodiment of the present invention; FIG. 3C is a diagram showing One embodiment of the invention, a schematic diagram of another Smith chart associated with the circuit topology of FIG. 3; FIG. 3D is a diagram showing one of the harmonic circuits of 201238243 according to an embodiment of the present invention A schematic diagram of a scatter plot associated with a state; FIG. 3E is a schematic diagram showing a Smith chart associated with the circuit topology of FIG. 3A in accordance with an embodiment of the present invention; FIG. 3F is a graphical representation this A schematic diagram of another Smith chart associated with the circuit topology of FIG. 3A; FIG. 3G is a scatter associated with the tuning circuit of FIG. 3A, in accordance with an embodiment of the present invention FIG. 4A is a schematic diagram showing another circuit topology for adaptive impedance matching of an inductive load according to an embodiment of the present invention; FIGS. 4B and 4C are diagrams showing the present invention. An embodiment, a schematic diagram of a Smith chart associated with respective states of the circuit of FIG. 4A; FIG. 4D is a diagram of a scatter parameter map associated with FIG. 4C, in accordance with an embodiment of the present invention 4E and 4F are schematic diagrams showing a Smith chart associated with respective states of the circuit of FIG. 4A according to an embodiment of the present invention; FIG. 4G is a diagram illustrating an embodiment of the present invention, A schematic diagram of a scatter parameter map associated with FIG. 4F; FIGS. 5A and 5B are diagrams showing another implementation of a circuit topology for adaptive impedance matching connected to one of the terminals of a non-50 ohm source Schematic diagram of the example, Figure 5C is a diagram A schematic diagram of a Smith chart associated with one of the states of the circuit topology of FIG. 5B in accordance with an embodiment of the present invention; FIG. 5D is a circuit topology diagram of FIG. 5B in accordance with an embodiment of the present invention A schematic diagram of a scatter parameter map associated with a state; 31 201238243 Figure 5E is a schematic diagram showing a tuning step associated with the circuit topology of Figure 5B, in accordance with an embodiment of the present invention; Is a schematic diagram showing various tuning values of a reactive component of FIG. 5E according to an embodiment of the present invention; FIG. 5G is a diagram showing steps related to the fifth embodiment of FIG. 5 according to an embodiment of the present invention; A schematic diagram of a scatter parameter map, FIG. 5H is a schematic diagram showing another tuning step associated with the circuit topology of FIG. 5B in accordance with an embodiment of the present invention; A schematic diagram showing various tuning values of the reactance component of FIG. 5H according to an embodiment of the present invention; FIG. 5J is a scatter diagram associated with the tuning step of FIG. 5H according to an embodiment of the present invention; a schematic diagram of a parameter map; FIG. 6A is a schematic diagram showing a circuit topology for adaptive impedance matching of a capacitive load according to an embodiment of the present invention; FIG. 6B is a diagram illustrating a sixth embodiment according to an embodiment of the present invention. A schematic diagram of a Smith chart of an adaptive tuning step performed by the circuit topology; FIG. 6C is a schematic diagram showing a scatter diagram corresponding to the Smith chart of FIG. 6B according to an embodiment of the present invention; The figure is a schematic diagram showing a Smith chart reflecting another adaptive tuning step performed via the circuit topology of FIG. 6A according to an embodiment of the present invention; FIG. 6E is a diagram illustrating an embodiment of the present invention, A schematic diagram of a scatter plot corresponding to the Smith chart of FIG. 6D; 32 201238243 FIG. 7 is a schematic diagram showing the layout of a general system component of an embodiment of the present invention; and FIG. 8 is a diagram showing the layout of a general system component according to the present invention; A flow chart of an adaptive impedance tuning method of an embodiment. [Main component symbol description] 100, 200, 300, 400... Circuit topology 102.. Signal generator/generator 104.. Feedback circuit/high impedance feedback circuit 104'... High impedance feedback circuit/feedback Circuits 106, 124... Resistors 108.. Ground 109.. Amplifier 110...Second 50 Ohm Variable Signal Source 112.. Matching Circuits 114, 116...Adaptive Variable Capacitors/Variable Capacitors /capacitor 118.. Variable Reacting Component / Exclusive Variable Reactive Component / Matching Circuit 120.. Inductor Antenna / Antenna 122.. Inductor 302.. Signal Generator 304.. High Impedance Envelope Feedback Circuit/Feedback Circuit 304'... High Impedance Feedback Circuitry 306.. Resistor 308. • Ground 309.. Amplifier 33 201238243 310.. Second 50 Ohm Variable Signal Source 312.. Matching Circuit 314 316...Adaptive Variable Capacitor/Variable Capacitor 318.. Variable Reacting Element 320.. Inductor Antenna 322.. Inductance 324.. Resistor 700.. System 702.. Source / Generator 704.. Match/Feedback Circuit 706... Loads 800, 802, 804.. Steps

Cl, C2... Tunable Value / Adaptive Tunable Capacitance / Adaptive Tunable Capacitor Network / Value C2... Tunable Value / Adaptive Tunable Capacitance / Adaptive Tunable Capacitor Network / Value / Parallel Capacitor C3, C4... Tunable value/value Ra... Series resistor Ca... Capacitor U, L2... Values Rl, R2, R4... Value 34

Claims (1)

201238243 VII. Patent application scope: 1. A system for matching the impedance of a terminal, the system comprising: a signal generator; a matching circuit connected to the signal generator, the matching circuit comprising at least one adapted a variable reactance component that adjusts the value of the plurality of reactive components, the at least one variable reactance component configured to: (a) perform a first adjustment on one of the reactive components of the reactive components To minimize or maximize a feedback voltage at least near resonance, and (b) perform a second adjustment on the values of the plurality of reactive components while maintaining a predetermined relationship between the plurality of reactive components is a constant Matching the impedance; and a feedback circuit coupled to the matching circuit, the feedback circuit configured to vary the feedback voltage. 2. The system of claim 1, wherein the terminal is connected to a converter. 3. The system of claim 2, wherein the converter is an antenna. 4. The system of claim 3, wherein the antenna is an inductive antenna. 5. The system of claim 3, wherein the antenna is a capacitive antenna. 6. The system of claim 3, wherein the antenna is a Near Field Communication (NFC) antenna. 7. The system of claim 3, wherein the antenna is a loop antenna. The system of claim 1, wherein the plurality of reactive components are capacitors. 9. The pure reactive component of the towel is an inductor as claimed in the application for full-time (4). The system of claim 1, wherein the at least one variable reactance element adaptively adjusts the value of the plurality of reactive components in response to detecting an increase in the feedback voltage above a predetermined threshold. 11. The system of claim 2, wherein the at least one variable reactance component resets the value of the plurality of reactive components to a value that is detected to decrease the feedback voltage below a predetermined threshold The initial value is predetermined. 12. A matching circuit for matching the impedance of a terminal, the matching circuit comprising at least one variable reactance element for adaptively adjusting a value of a plurality of reactive components, the at least - variable reactance element being configured (4) performing a first adjustment on one of the -reactive components of the reactive components to minimize or maximize a feedback voltage at least near resonance, and performing a second adjustment on the values of the plurality of reactive components, Maintaining a predetermined relationship between the plurality of reactive components is a constant to match the impedance. 13. The matching circuit of claim 12, wherein the terminal is connected to a converter. 14. The matching circuit of claim 13, wherein the converter is an antenna. 5. The matching circuit of claim 14, wherein the antenna is an inductive antenna. 6. The matching circuit according to claim 14, wherein the antenna is 36 201238243 a capacitor antenna. 17. The matching circuit of claim 14, wherein the antenna is a near field communication (NFC) antenna. 18. The matching circuit of claim 14, wherein the antenna is a loop antenna. 19. The matching circuit of claim 12, wherein the plurality of reactive components are capacitors. 20. The matching circuit of claim 12, wherein the plurality of reactive components are inductors. 21. The matching circuit of claim 12, wherein the at least one variable reactance element adaptively adjusts the value of the plurality of reactive components in response to detecting an increase in the feedback voltage above a predetermined threshold . 22. The matching circuit of claim 12, wherein the at least one variable reactance element resets the value of the plurality of reactive components in response to detecting a decrease in the feedback voltage below a predetermined threshold Become a predetermined initial value. 23. A method of matching the impedance of a terminal by adaptively adjusting a value of a plurality of reactive components of a matching circuit, the method comprising the steps of: one of a reactive component of the reactive components Performing a first adjustment to minimize or maximize a feedback voltage at least near resonance; and performing a second adjustment on the values of the plurality of reactive components while maintaining a predetermined relationship between the plurality of reactive components is a constant To match the impedance. 24. The method of claim 23, wherein the terminal is connected to a converter. The method of claim 24, wherein the converter is an antenna. 26. The method of claim 25, wherein the antenna is a Near Field Communication (NFC) antenna. 27. The method of claim 23, wherein the plurality of reactive components are capacitors. 28. The method of claim 23, wherein the plurality of reactive components are inductors. 29. The method of claim 23, wherein the at least one variable reactance element adaptively adjusts the value of the plurality of reactive components in response to detecting an increase in the feedback voltage above a predetermined threshold. 30. The method of claim 23, wherein the at least one variable reactance element resets the value of the plurality of reactive components to a value that is detected to decrease the feedback voltage below a predetermined threshold The initial value is predetermined. 38