Power amplifier and wireless transmitter

Abstract

The present invention relates to a power amplifier and a wireless transmitter, wherein the power amplifier comprises a power device and a matching network. One output end of the power device is connected to one input end of the matching network. The input end of the matching network comprises two input ports, and the power amplifier further comprises a matching capacitor. The matching capacitor is connected in series with the matching network, such that the impedance difference between the two input ports of the matching network is within a predefined range, and the two input ports of the input end of the matching network can achieve a coherent impedance, thus maximizing the output power of the power amplifier and achieving true impedance matching between the power amplifier and the antenna. Figure to be published for the abstract: Figure 3

Description

Title of invention: Power amplifier and wireless transmitter Technical field

[0001] The present invention relates to the field of amplifiers, and more particularly to a power amplifier and a wireless transmitter. Technical background

[0002] The existing radio frequency power amplifier generally has a differential structure, and the antenna generally has an asymmetric structure, thus, a matching network must be connected between the RF power amplifier and the antenna to realize the matching between the two, so that the RF power amplifier in the differential structure can provide maximum power to the antenna.

[0003] However, since there are two ports on the output side of the matching network, one of which is connected to the antenna and the other is grounded, there is an undesirable effect at the ground end, which affects the output power of the RF power amplifier to the antenna, and does not maximize the output power of the RF power amplifier. Disclosure of the invention

[0004] The technical problems to be solved by the present invention are as follows: a power amplifier and a wireless transmitter capable of improving the output power of the power amplifier are provided.

[0005] For this, the present invention adopts the following technical solution:

[0006] a power amplifier, comprising a power device and a matching network, an output end of the power device being connected to an input end of the matching network, the input end of the matching network comprising two input ports, and the power amplifier further comprising a matching capacitor;

[0007] the matching capacitor is connected in series to the matching network, so that the impedance difference between the two input ports of the matching network is within a predefined range.

[0008] For this, the present invention adopts another following technical solution:

[0009] a wireless transmitter comprising the above power amplifier.

[0010] The beneficial effects of the present invention are as follows: the matching network is connected in series with the matching capacitor, so that the impedance difference between the two input ports of the matching network is within a predefined range, and the two input ports of the input end of the matching network can obtain consistent impedance, thereby maximizing the output power of the power amplifier and realizing real matching between the power amplifier and the antenna; by innovatively discovering that the non-ideal effect exists at the ground end of the matching network, the two input ports of the input end of the matching network may have non-coherent impedance, so that the power amplifier cannot output the maximum power, and the matching network is connected in series with the matching capacitor, so that the two input ports of the input end of the matching network can have coherent impedance, and the output power of the power amplifier is greatly improved. Description of figures

[0011] [Fig. 1] shows a circuit structure diagram of a power amplifier according to an embodiment of the present invention;

[0012] [Fig.2] shows a circuit structure diagram of a wireless transmitter according to an embodiment of the present invention;

[0013] [Fig.3] shows a circuit structure diagram illustrating an implementation of a matching network in a power amplifier according to an embodiment of the present invention;

[0014] [Fig.4] represents an equivalent circuit diagram illustrating an implementation of a power amplifier according to an embodiment of the present invention;

[0015] [Fig.5] shows a circuit structure diagram illustrating another implementation of a power amplifier according to an embodiment of the present invention;

[0016] [Fig.6] shows an equivalent circuit diagram illustrating another implementation of a power amplifier according to an embodiment of the present invention;

[0017] [Fig.7] shows a circuit structure diagram illustrating another implementation of a power amplifier according to an embodiment of the present invention;

[0018] [Fig.8] shows a circuit structure diagram illustrating another implementation of a power amplifier according to an embodiment of the present invention;

[0019] [Fig.9] shows a circuit structure diagram illustrating another implementation of a power amplifier according to an embodiment of the present invention;

[0020] [Fig. 10] shows a circuit structure diagram illustrating an implementation of a matching capacitor of a power amplifier according to an embodiment of the present invention;

[0021] [Fig. 11] represents a graph of the simulation results of the impedance observed on the primary side of a transformer in a prior art power amplifier;

[0022] [Fig. 12] shows a graph of the simulation results of the observed impedance of the primary side of a transformer in a power amplifier according to an embodiment of the present invention.

[0023] References 100: Power amplifier 110: Power device 120: Adaptation network 130: Matching capacitor 200: Wireless transmitter 210: Input adaptation network 220: Output adaptation network 230: Power amplifier 410: Ideal transformer 810: First inductor 910: Second inductor Clp: First capacitor Cln: Second capacitor Cpp: Third capacitor Cpn: Fourth capacitor Ci: Fifth capacitor Cp: ​​Parasitic capacitor Cs: Parasitic capacitor Cc: Parasitic capacitor Lp: Primary side leakage inductor Ls: Secondary side leakage inductor Lm: Excitation inductor Li: Third Inductor Rl: Equivalent impedance of the antenna P, N: Ends Detailed description of the implementation method

[0024] In order to describe in detail the technical content, the objectives achieved and the effects of the present invention, the following description will be made with reference to the embodiments in conjunction with the accompanying drawings.

[0025] A power amplifier, comprising a power device and a matching network, an output end of the power device being connected to a an input end of the matching network, the input end of the matching network comprising two input ports, and the power amplifier further comprising a matching capacitor;

[0026] the matching capacitor is connected in series to the matching network, so that the impedance difference between the two input ports of the matching network is within a predefined range.

[0027] According to the above description, the matching network is connected in series with the matching capacitor, so that the impedance difference between the two input ports of the matching network is within a predefined range, and the two input ports of the input end of the matching network can obtain a consistent impedance, thereby maximizing the output power of the power amplifier and realizing real matching between the power amplifier and the antenna;by innovatively discovering that the non-ideal effect exists at the ground end of the matching network, the two input ports of the input end of the matching network may have non-coherent impedance, so that the power amplifier cannot output the maximum power, and the matching network is connected in series with the matching capacitor, so that the two input ports of the input end of the matching network may have coherent impedance, and the output power of the power amplifier is greatly improved. ;

[0028] Further, the matching capacitor comprises a first capacitor and a second capacitor;

[0029] the first capacitor and the second capacitor are of different sizes;

[0030] an output end of the matching network comprises two output ports, the first capacitor and the second capacitor being connected in series to the two output ports respectively.

[0031] According to the above description, two capacitors of different sizes are respectively connected in series to the two output ports of the matching network, there is no need to increase the inductor, only two capacitors are needed at the output, and the two input ports of the input end of the matching network can conveniently and quickly see the same impedance under the condition that the area of ​​the matching network is not excessively increased, so that the two-stage voltage and phase of the power amplifier are the same, and the transmission power is effectively improved.

[0032] Further, the output end of the matching network comprises two output ports, one of said output ports being grounded and the other output port being connected in series to the matching capacitor.

[0033] According to the above description, since the capacitors of the network Matching capacitors are usually connected in series or parallel, the impedance of the input end of the matching network cannot be balanced, and the impedance of the input end of the matching network can be balanced to a certain extent by connecting the matching capacitor in series with the ungrounded end of the matching network.

[0034] Furthermore, the power amplifier further comprises a third capacitor and a fourth capacitor;

[0035] the third capacitor and the fourth capacitor are of different sizes;

[0036] the third capacitor and the fourth capacitor are connected in parallel to the two input ports respectively.

[0037] According to the above description, based on the series connection of the matching capacitors at the ungrounded end of the matching network, two capacitors of different sizes are connected in series on each of the two input ports of the matching network, thereby better solving the problem of impedance mismatch at the input end of the matching network.

[0038] Furthermore, the power amplifier further comprises a first inductor;

[0039] the first inductor is connected in series to the matching capacitor.

[0040] According to the above description, based on the series connection of the capacitors matching network at the ungrounded end of the matching network, an inductor is connected in series at the ungrounded end of the matching network, which can better solve the problem of impedance mismatch at the input end of the matching network.

[0041] Furthermore, the power amplifier further comprises a second inductor;

[0042] one end of the second inductor is connected to one end of the matching capacitor close to the matching network, and the other end is grounded.

[0043] According to the above description, the ungrounded end of the matching network being connected in series with the matching capacitor, an inductor is connected in parallel between two output ports of the matching network, in order to better solve the problem of the inconsistent impedance of the input end of the matching network.

[0044] Furthermore, the matching network is a balun.

[0045] Further, the balun comprises a transformer;

[0046] the output end of the power device is connected to a primary side of the transformer;

[0047] the matching capacitor is connected in series to a secondary side of the transformer so that the impedance difference between a P end and an N end of the primary side of the transformer is within a predefined range.

[0048] Furthermore, the matching capacitor is a resonant capacitor.

[0049] Further, the resonant capacitor comprises a fifth capacitor and a third inductor;

[0050] the fifth capacitor and the third inductor are connected in parallel.

[0051] According to the above description, it is known that the matching capacitor can be implemented by using a resonant capacitor (LC resonator) with a capacitor connected in parallel to an inductor, that is, the matching capacitor is implemented by using a capacitive resonator, so that the implementation flexibility of the matching capacitor is improved, and the application range of the matching capacitor is expanded.

[0052] A wireless transmitter comprising the above power amplifier.

[0053] The power amplifier and the wireless transmitter can be applied to an application scene where the matching effect of the matching network is poor due to the non-ideal effect of the grounding end of the matching network, and the following description is given by the specific implementations:

[0054] in an optional implementation, as illustrated in [Fig.l], a power amplifier 100 comprises a power device 110 and a matching network 120, an output end of the power device 110 being connected to an input end of the matching network 120, the input end of the matching network 120 comprising two input ports, and the power amplifier 100 further comprising a matching capacitor 130;

[0055] the matching capacitor 130 is connected in series to the matching network 120, so that the impedance difference between the two input ports of the matching network 120 is within a predefined range;

[0056] wherein a predefined range can be flexibly set according to a specific application scene, for example, the predefined range can be set to 5 ohms, after a matching capacitor 130 is connected in series to a matching network 120, the impedance values ​​seen by two ports at the input end of the matching network 120 can be calculated, the value of the matching capacitor 130 in series is adjusted by comparing the difference between the impedance values ​​seen by the two ports, and if the difference is less than 5 ohms, it is indicated that the impedance values ​​seen by the two ports at the input end of the matching network 120 are consistent;

[0057] In another optional implementation, the respective predefined ranges of the reactance and the resistance may be set separately, and then the size of the series matching capacitor 130 is adjusted until the difference between the resistances and the difference between the reactance are within the predefined ranges.

[0058] As illustrated in [Fig.2], the circuit structure diagram of the wireless transmitter 200 shows an input matching network 210, a power device 110, a output matching network 220 and an antenna which are sequentially connected, the input matching network 210, the power device 110 and the output matching network 220 forming a power amplifier 230, the power device 110 may be a differential amplifier, and an output end of the power amplifier 230 is connected to the antenna in the wireless transmitter 200. The output matching network 220 acts to harmonize the impedance between the power amplifier 230 and the antenna to maximize the power output from the power amplifier 230 to the antenna.

[0059] Since the antenna has an asymmetric structure, the output matching network 220 must convert the differential signal emitted by the radio frequency power amplifier 230 into an asymmetric signal. The output matching network 220 therefore has two functions: one is to harmonize the impedance between the power amplifier 230 and the antenna, and the other is to convert the differential signal from the power amplifier 230 into an asymmetric signal.

[0060] In an optional implementation, a balun may be used as the matching network 120 to match the power amplifier 100 and the antenna;

[0061] more specifically, the matching network 120 may comprise a transformer, and the output end of the power device 110 is connected to a primary side of the transformer;

[0062] the matching capacitor 130 is connected in series to a secondary side of the transformer so that the impedance difference between a P end and an N end of the primary side of the transformer is within a predefined range.

[0063] The series connection of the matching capacitor 130 and the matching network 120 can be achieved in different ways:

[0064] in an optional embodiment, as illustrated in [Fig.3], the matching capacitor 130 comprises a first capacitor CLP and a second capacitor CLN;

[0065] the first capacitor CLP and the second capacitor CLN are of different sizes;

[0066] an output end of the matching network 120 comprises two output ports, the first capacitor CLP and the second capacitor CLN being connected in series to the two output ports respectively; more specifically, one of the output ports is connected to the second capacitor CLN and then grounded, and the other output port is connected to the first capacitor CLP and then connected to the antenna;

[0067] [Fig.4] is an equivalent diagram of the circuit shown in [Fig.3], in which the RF transformer can be equivalently an ideal transformer 410, a primary side leakage inductor Lp, a secondary side leakage inductor Ls, an excitation inductor Lm and a parasitic capacitor Cp, Cs and Cc. As shown in [Fig.4], Rl represents the equivalent impedance of the antenna. The non-ideal effect of the grounding end is equivalent to an LGND inductor; grounding one end of the secondary side of the transformer causes the P end and the N end of the primary side to have inconsistent impedance, which makes the differential power amplifier unable to deliver the maximum power.

[0068] In the present implementation, two capacitors CLP and CLN of different magnitude are connected in series to the secondary side of the transformer, and the P end and the N end of the primary side of the transformer can have the same impedance, so that the two-stage voltage and phase of the differential power amplifier are the same, and the efficient transmission of power is realized.

[0069] In another optional implementation, as illustrated in [Fig. 5], the output end of the matching network 120 includes two output ports, one of which is grounded and the other of which is connected in series to the matching capacitor 130, i.e., the matching capacitor 130 is connected in series to [Fig. 6] is an equivalent diagram of the circuit illustrated in [Fig. 5].

[0070] Based on the circuit structure shown in [Fig.5], in order to further improve the matching degree between the power amplifier and the antenna and better solve the problem of inconsistent impedance at the P end and the N end of the primary side of the transformer, the following improvements can be made:

[0071] in a first implementation, as illustrated in [Fig.7], the power amplifier further comprises a third capacitor Cpp and a fourth capacitor Cpn;

[0072] the third capacitor Cpp and the fourth capacitor Cpn are of different sizes;

[0073] the third capacitor Cpp and the fourth capacitor Cpn are respectively connected in parallel to the two input ports, that is, one end of the third capacitor Cpp is connected to the P port of the primary side of the transformer and the other end is grounded, and one end of the fourth capacitor Cpn is connected to the N port of the primary side of the transformer and the other end is grounded.

[0074] In a second implementation, as illustrated in [Fig.8], the inductor further comprises a first inductor 810, wherein the inductor is a series-connected inductor;

[0075] the first inductor 810 is connected in series with the matching capacitor 130, that is, the ungrounded end of the secondary side of the transformer is connected to one end of the first inductor 810, and the other end of the first inductor 810 is connected to one end of the nearby matching capacitor 130 of the transformer.

[0076] In a third implementation, as illustrated in [Fig.9], the inductor further comprises a second inductor 910, wherein the inductor is a parallel-connected inductor;

[0077] one end of the second inductor 910 is connected to one end of the matching capacitor 130 close to the matching network 120, and the other end is grounded.

[0078] In another optional implementation, as illustrated in [Fig.10], the matching capacitor 130 may be a resonant capacitor;

[0079] more precisely, the resonant capacitor comprises a fifth capacitor Ci and a third inductor Li;

[0080] the fifth capacitor Ci and the third inductor Li are connected in parallel, in which:

[0081] CLN or CLP = (co2LiCi - l) / co2Li

[0082] in other words, in the present implementation, an LC resonator is connected in parallel to an inductor via a capacitor, and the LC resonator is made capacitive in order to realize a matching capacitor 130.

[0083] [Fig. 11] and 12 represent the graphs of the simulation results of a power amplifier without a connected matching capacitor of the prior art and a power amplifier with a connected matching capacitor according to the present invention, respectively:

[0084] [Fig.l 1] shows the simulation results of the input impedance observed at the P end and the N end of the transformer when the matching capacitor is not connected (the left graph is the real part, the right graph is the imaginary part).In the left graph, the upper curve represents the resistance value measured at the P end, the input resistance at the P end being 364.5 ohms, a lower curve represents the resistance value measured at the N end, and the input resistance at the N end being 233.4 ohms; in the right graph, the upper curve represents the reactance value measured at the P end, the input reactance at the P end being 26.3 ohms, the lower curve represents the reactance value measured at the N end, and the input reactance at the N end being 18.4 ohms; thus, the input differential mode resistance difference is 131.1 ohms and the input differential mode reactance difference is 7.9 ohms; .

[0085] [Fig. 12] shows the simulation results of the input impedance observed at the P end and the N end of the transformer when the matching capacitor is connected (the left graph is the real part, the left graph is the right is the imaginary part). In the left graph, the upper curve represents the resistance value measured at the P end, the input resistance at the P end being 302.3 ohms, a lower curve represents the resistance value measured at the N end, and the input resistance at the N end being 299.3 ohms; in the right graph, the upper curve represents the reactance value measured at the P end, the input reactance at the P end being 19 ohms, the lower curve represents the reactance value measured at the N end, and the input reactance at the N end being 17.4 ohms; thus, the input differential mode resistance difference is 3 ohms and the input differential mode reactance difference is 1.6 ohms;

[0086] According to the simulation comparison, the consistency of the impedance observed at the P end and the N end of the primary side of the transformer is ensured by adding the matching capacitor, so that the influence of the non-ideal effect at the ground end of the matching network on the power matching of the matching network is resolved, and the output power of the power amplifier is greatly improved.

[0087] In another optional implementation, a wireless transmitter comprising a power amplifier according to any of the above implementations.

[0088] In summary, for the power amplifier and the wireless transmitter according to the present invention, the matching network is connected in series with the matching capacitor, so that the impedance difference between the two input ports of the matching network is within a predefined range, and the two input ports of the input end of the matching network can obtain consistent impedance, thereby maximizing the output power of the power amplifier and realizing real matching between the power amplifier and the antenna; the matching capacitor can be connected in series with the matching network in different modes, the series connection modes are various and flexible;by innovatively discovering that the non-ideal effect exists at the ground end of the matching network, the two input ports of the input end of the matching network may have non-coherent impedance, so that the power amplifier cannot output the maximum power, and the matching network is connected in series with the matching capacitor, so that the two input ports of the input end of the matching network may have coherent impedance, and the output power of the power amplifier is greatly improved. ;

[0089] The foregoing description is only illustrative of the present invention and is not intended to limit the scope of the present invention, and all equivalent modifications made by the description and drawings of the present invention, or direct or indirect application in the relevant art, are included within the scope of the present invention.

Claims

Claims

1. A power amplifier (100, 230), comprising a power device (110) and a matching network (120), an output end of said power device (110) being connected to an input end of said matching network (120), the input end of the matching network (120) comprising two input ports, wherein said power amplifier (100, 230) further comprises a matching capacitor (130); said matching capacitor (130) is connected in series with the matching network (120), so that the impedance difference between the two input ports of the matching network (120) is within a predefined range.

2. A power amplifier (100, 230) according to claim 1, wherein said matching capacitor (130) comprises a first capacitor (CLP) and a second capacitor (CLN); said first capacitor (CLP) and said second capacitor (CLN) are of different sizes; an output end of said matching network (120) comprises two output ports, said first capacitor (CLP) and said second capacitor (CLN) being connected in series to the two output ports respectively.

3. The power amplifier (100, 230) of claim 1, wherein the output end of said matching network (120) comprises two output ports, one of said output ports being grounded and the other output port being connected in series to the matching capacitor (130).

4. A power amplifier (100, 230) according to claim 3, wherein it further comprises a third capacitor (Cpp) and a fourth capacitor (Cpn); said third capacitor (Cpp) and the fourth capacitor (Cpn) are of different sizes; said third capacitor (Cpp) and the fourth capacitor (Cpn) are connected in parallel to the two input ports respectively.

5. A power amplifier (100, 230) according to claim 3, wherein it further comprises a first inductor (810); said first inductor (810) is connected in series with the matching capacitor (130).

6. A power amplifier (100, 230) according to claim 3, in which it further comprises a second inductor (910); one end of said second inductor (910) is connected to one end of the matching capacitor (130) close to the matching network (120), and the other end is grounded.

7. A power amplifier (100, 230) according to any one of claims 1 to 6, wherein the matching network (120) is a balun.

8. A power amplifier (100, 230) according to claim 7, wherein said balun comprises a transformer; the output end of said power device (110) is connected to a primary side of the transformer; said matching capacitor (130) is connected in series to a secondary side of the transformer so that the impedance difference between a P end and an N end of the primary side of the transformer is within a predefined range.

9. A power amplifier (100, 230) according to any one of claims 1 to 6, wherein the matching capacitor (130) is a resonant capacitor.

10. A power amplifier (100, 230) according to claim 9, wherein said resonant capacitor comprises a fifth capacitor (Ci) and a third inductor (Li); said fifth capacitor (Ci) and the third inductor (Li) are connected in parallel.

11. A wireless transmitter (200), wherein it comprises a power amplifier (100, 230) according to any one of claims 1 to 10.

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