Apparatus and method for determining impedance and / or admittance in a wireless device

Abstract

In certain aspects, an apparatus includes a power detector coupled between a power amplifier and an antenna and a voltage detector coupled between the power amplifier and the antenna. The apparatus also includes a phase shifter coupled to the power detector and a load measurement circuit coupled to the power detector, the voltage detector, and the phase shifter.

Description

[0001] Cross-references to related applications

[0002] This application claims priority and benefit to Pending Non-Provisional Application Serial No. 17 / 039827, filed September 30, 2020, with the United States Patent and Trademark Office, the entire contents of which are incorporated herein by reference, as if their entire contents were fully set forth and used for all applicable purposes. Technical Field

[0003] Various aspects of this disclosure generally relate to wireless communication, and more specifically, to determining impedance and / or admittance in wireless devices. Background Technology

[0004] Wireless devices may include transmitters, receivers, and antennas for transmitting and receiving radio frequency (RF) signals. The characteristics of the transmitters and receivers are sensitive to the impedance seen at the transmitters and receivers. Impedance can be a function of antenna impedance, environmental conditions (e.g., reflections), and module circuitry. Summary of the Invention

[0005] The following is a simplified overview of one or more implementations to provide a basic understanding of these implementations. This overview is not a comprehensive summary of all anticipated implementations, nor is it intended to identify key or essential elements of all implementations, nor to depict the scope of any or all implementations. Its sole purpose is to present some concepts of one or more implementations in a simplified form as a prelude to the more detailed descriptions that follow.

[0006] The first aspect relates to an apparatus. The apparatus includes a power detector coupled between a power amplifier and an antenna, and a voltage detector coupled between the power amplifier and the antenna. The apparatus also includes a phase shifter coupled to the power detector, and a load measurement circuit coupled to the power detector, the voltage detector, and the phase shifter.

[0007] The second aspect relates to a method for measuring a load. The method includes: measuring the power supplied to the load to obtain a power measurement value; measuring the power supplied to the load with a phase shift to obtain a phase-shifted power measurement value; and determining the phase angle of the load based on the power measurement value, the phase-shifted power measurement value, and the phase shift.

[0008] The third aspect relates to an apparatus for measuring a load. The apparatus includes: components for measuring the power delivered to the load to obtain a power measurement value; components for measuring the power delivered to the load with a phase shift to obtain a phase-shifted power measurement value; and components for determining the phase angle of the load based on the power measurement value, the phase-shifted power measurement value, and the phase shift. Attached Figure Description

[0009] Figure 1 Examples of wireless devices including a transmitter, receiver, and antenna are shown in accordance with certain aspects of this disclosure.

[0010] Figure 2 An example of a circuit for determining impedance and / or admittance according to certain aspects of this disclosure is shown.

[0011] Figure 3 Exemplary implementations of a power detector and a phase shifter according to certain aspects of this disclosure are shown.

[0012] Figure 4 Another exemplary implementation of a phase shifter according to certain aspects of this disclosure is shown.

[0013] Figure 5 Another exemplary implementation of a power detector according to certain aspects of this disclosure is shown.

[0014] Figure 6 Exemplary implementations of the first square circuit, the second square circuit, and the difference circuit according to certain aspects of this disclosure are shown.

[0015] Figure 7 An exemplary implementation of a bias circuit according to certain aspects of this disclosure is shown.

[0016] Figure 8 An exemplary implementation of a voltage detector according to certain aspects of this disclosure is shown.

[0017] Figure 9 An exemplary implementation of a square circuit in a voltage detector according to certain aspects of this disclosure is shown.

[0018] Figure 10 An example of a transceiver according to certain aspects of this disclosure is shown.

[0019] Figure 11 An example of a resistive element for measuring power according to certain aspects of this disclosure is shown, wherein the resistive element is implemented using a switch.

[0020] Figure 12 An example of an amplifier control circuit for controlling the output voltage swing of a power amplifier, according to certain aspects of this disclosure, is shown.

[0021] Figure 13 An example of a tunable impedance matching network coupled between a power amplifier and an antenna according to certain aspects of this disclosure is shown.

[0022] Figure 14 An example of a phased antenna array according to certain aspects of this disclosure is shown, which can be used with aspects of this disclosure.

[0023] Figure 15 It is a diagram of an environment including an electronic device, which includes a transceiver according to certain aspects of this disclosure.

[0024] Figure 16 This is a flowchart illustrating an example of a method for measuring load according to certain aspects of this disclosure. Detailed Implementation

[0025] The detailed description set forth below, taken in conjunction with the accompanying drawings, is intended as a description of various configurations and not as representing only configurations in which the concepts described herein can be practiced. The detailed description includes specific details for the purpose of providing a thorough understanding of the various concepts. However, it will be apparent to those skilled in the art that these concepts can be practiced without these specific details. In some cases, to avoid obscuring these concepts, well-known structures and components are shown in block diagram form.

[0026] Figure 1 An example of a wireless device 105 is shown, including a power amplifier (PA) 110, a low-noise amplifier (LNA) 120, a switch 125, a bump 130, and an antenna 115. PA 110 is part of the transmitter of wireless device 105, while LNA 120 is part of the receiver of wireless device 105. Switch 125 is coupled between bump 130 and the output 114 of PA 110. Switch 125 is also coupled between bump 130 and the input 122 of LNA 120. As discussed further below, switch 125 is configured to selectively couple either PA 110 or LNA 120 to bump 130. In some respects, PA 110, LNA 120 and switch 125 are integrated on the chip, and bumps 130 (e.g. solder bumps) couple the chip to antenna 115 via lines 135 (e.g. metal traces on a printed circuit board, PCB).

[0027] In transmit mode, switch 125 couples the output 114 of PA 110 to antenna 115. In this mode, PA 110 receives an RF signal at its input 112 (e.g., from an up-converter), amplifies the received RF signal, and outputs the amplified RF signal at its output 114 for transmission via antenna 115. In receive mode, switch 125 couples the antenna 115 to input 122 of LNA 120. In this mode, LNA 120 receives an RF signal from antenna 115 at its input 122, amplifies the received RF signal, and outputs the amplified RF signal at its output 124 (e.g., to a down-converter).

[0028] The characteristics of the transmitter (including PA 110) and receiver (including LNA 120) are sensitive to the impedance seen at the transmitter and receiver. Impedance can be a function of the impedance of antenna 115, environmental conditions (e.g., reflections), the impedance of bump 130, and the line 135 between antenna 115 and bump 130. Typically, impedance is a complex impedance that includes resistive and reactive components.

[0029] Knowledge of impedance can be used to improve the performance of the transmitter and / or receiver. For example, the transmitter may include a tunable impedance matching network located between the output 114 of PA 110 and switch 125. Figure 1 (Not shown in the image). In this example, the impedance matching network can be tuned based on knowledge of impedance to provide the desired internal impedance at the output of PA 110. In another example, knowledge of impedance can be used to verify that an antenna module including antenna 115 meets impedance specifications.

[0030] Determining the impedance observed at the transmitter and receiver is challenging. Currently, test structures and probe systems are used to measure impedance. The drawback of this approach is that it requires an external system to measure the impedance and cannot determine impedance variations in the field, such as those caused by changes in environmental conditions (e.g., reflections). Accordingly, a built-in circuitry within the wireless device capable of measuring impedance is desired. It is also desirable that this built-in circuitry does not interfere with the operation of the transmitter and receiver.

[0031] Figure 2 An example of circuit 205 for determining the impedance and / or admittance of load 215 according to various aspects of this disclosure is shown. Circuit 205 may be integrated with PA 110. Circuit 205 includes a power detector 210, a phase shifter 220, a voltage detector 230, and load measurement circuitry 250. Power detector 210 is coupled between PA 110 and load 215. Load 215 may include Figure 1The loads shown are antenna 115, line 135, and bump 130, and may be sensitive to reflections. As discussed further below, power detector 210 is configured to measure the average power delivered to load 215 and output the average power measurement value to load measurement circuit 250.

[0032] Phase shifter 220 is coupled to power detector 210. Phase shifter 220 is configured to shift the phase of the average power measurement value of power detector 210 by a known phase shift, as discussed further below. Phase shifter 220 is controlled by load measurement circuitry 250.

[0033] Voltage detector 230 is coupled between output terminal 114 of PA 110 and power detector 210. Voltage detector 230 is configured to measure the voltage at power detector 210 and output the voltage measurement value to load measurement circuit 250.

[0034] Exemplary operations for measuring the impedance and / or admittance of load 215 will now be discussed in some respects.

[0035] During the first time period, power detector 210 measures the average power delivered to load 215 without any phase shift from phase shifter 220. In this case, load measurement circuit 250 can disable phase shifter 220 during the first time period, so that phase shifter 220 does not shift the phase of the average power measurement value of power detector 210 during the first time period, as discussed further below.

[0036] In some respects, power detector 210 measures the instantaneous power supplied to load 215, which is given by the product of the voltage and current of load 215, as follows:

[0037] p(t)=v(t)·i(t) (1)

[0038] Where p(t) is the power supplied to load 215, v(t) is the voltage across load 215, and i(t) is the current through load 215. In one example, the voltage v(t) across load 215 is a sinusoidal signal given by the following equation:

[0039] v(t)=Vcos(ω RF t) (2)

[0040] Where V is the amplitude of the voltage v(t), and ω RF This is the angular frequency of the voltage v(t). For wireless devices operating in the millimeter-wave (mmWave) band, the angular frequency can be in the GHz range. In this example, the load current i(t) is given by the following equation:

[0041] i(t)=Icos(ωRF t+θ) (3)

[0042] Where I is the amplitude of the current i(t), and θ is the phase angle between the voltage v(t) and the current i(t). The phase angle θ comes from the fact that the impedance of the load 215 is complex. For a purely resistive load, the phase angle θ is zero. In this example, the instantaneous power is given by substituting the expressions for voltage v(t) and current i(t) given in equations (2) and (3) into equation (1), respectively, with the following results:

[0043]

[0044] As shown in equation (4), the instantaneous power includes a first term and a second term, wherein the first term is composed of... Given, and the second item is by The second harmonic term is given. The first term provides the average power delivered to load 215. Therefore, power detector 210 can measure the average power delivered to load 215 by using a low-pass filter to filter out the second harmonic term in equation (4), thus obtaining the following average power:

[0045]

[0046] Where P L It is the average power. The power detector 210 outputs the average power P to the load measurement circuit 250. L The average power measurement is proportional. In this example, power detector 210 measures the power delivered to load 215 during a first time period to obtain the average power measurement.

[0047] During the second time period, power detector 210 measures the average power delivered to load 215 with a phase shift from phase shifter 220. In this case, load measurement circuit 250 can enable phase shifter 220 during the second time period to shift the phase of the average power measurement value of power detector 210 during the second time period. The average power measurement value with phase shift is proportional to the following formula:

[0048]

[0049] Where P xThe average power is the phase-shifted power, and γ is the phase shift. The phase shift γ is a known phase shift provided by phase shifter 220. Therefore, phase shifter 220 adds the phase shift γ to the phase angle θ in the average power measurement. Power detector 210 outputs the average power measurement with phase shift to load measurement circuit 250. Therefore, in this example, power detector 210 measures the power delivered to load 215 during the second time period when phase shifter 220 is enabled to obtain the power measurement with phase shift (i.e., the phase-shifted average power measurement).

[0050] Therefore, the load measurement circuit 250 receives both the average power measurement value without phase shift and the average power measurement value with phase shift from the power detector 210. Using the knowledge of the average power measurement value without phase shift, the average power measurement value with phase shift, and the phase shift γ, the load measurement circuit 250 is able to determine the phase angle θ of the load 215, as discussed further below.

[0051] As used herein, the term "proportional" encompasses the possibility that the scaling factor is less than 1, equal to 1, or greater than 1. Therefore, the average power measurement from the power detector 210 without phase shift output can be proportional to the average power P delivered to the load 215 with a scaling factor less than 1, greater than 1, or equal to 1. L Proportional. Similarly, the average power measurement with phase shift output from power detector 210 can be proportional to the average power P with phase shift by a scaling factor less than 1, greater than 1, or equal to 1. X Proportional.

[0052] The ratio of the average power measurement with phase shift to the average power measurement without phase shift is taken, and the results are as follows:

[0053]

[0054] Solving for the phase angle θ in equation (7), the result is as follows:

[0055]

[0056] Since the average power measurement without phase shift, the average power measurement with phase shift, and the phase shift γ are known, the load measurement circuit 250 can calculate the phase angle θ of the load 215 based on equation (8). In other words, the load measurement circuit 250 can calculate the phase angle θ between the load voltage v(t) and the load current i(t). Note that the ratio of the average power measurement with phase shift to the average power measurement without phase shift is approximately equal to the power ratio. This assumes that the scaling factors of the two power measurements are the same, so that the scaling factors cancel each other out in the ratio.

[0057] Voltage detector 230 measures the amplitude of the voltage V at power detector 210 and outputs a voltage measurement value proportional to the amplitude of voltage V to load measurement circuit 250. Load measurement circuit 250 can then determine the magnitude of the load admittance based on the following formula:

[0058]

[0059] Where |Y| is the magnitude of the admittance of load 215. Equation (9) can be derived from equation (5) and the fact that the load current equals the load voltage multiplied by the load admittance. Since the phase angle θ is known from the previous calculations, and the average power P L The measured values ​​of the load and the amplitude of the voltage V are provided by the power detector 210 and the voltage detector 230, respectively. Therefore, the load measurement circuit 250 can calculate the load admittance value proportional to the amplitude of the load admittance based on equation (9). The load measurement circuit 250 can determine the load impedance value proportional to the amplitude of the load impedance by calculating the reciprocal of the load admittance value.

[0060] As described above, the term "proportional" encompasses the possibility that the scaling factor is less than 1, equal to 1, or greater than 1. Therefore, the load admittance value calculated by the load measurement circuit 250 can be proportional to the magnitude of the load admittance with a scaling factor less than 1, greater than 1, or equal to 1. The load admittance value conveys information about the magnitude of the load admittance, where a larger admittance value indicates a larger magnitude of the load admittance. Similarly, the load impedance value calculated by the load measurement circuit 250 can be proportional to the magnitude of the load impedance with a scaling factor less than 1, greater than 1, or equal to 1. The load impedance value conveys information about the magnitude of the load impedance, where a larger impedance value represents a larger magnitude of the load impedance.

[0061] It should be understood that in some implementations, the load measurement circuit 250 may calculate the load admittance value instead of the load impedance value, because the load admittance provides similar information to the load impedance (i.e., low load admittance indicates high load impedance, and vice versa). Therefore, the load measurement circuit 250 may calculate the load admittance value, the load impedance value, or both.

[0062] In equation (9) given above, the load admittance is based on the square of the magnitude of the voltage V (i.e., |V|). 2The square of the voltage amplitude is calculated using the voltage detector 230. In one example, the voltage detector 230 measures the amplitude of the voltage V and outputs a voltage measurement value proportional to the amplitude of the voltage V to the load measurement circuit 250. In this example, the load measurement circuit 250 can calculate the square of the voltage amplitude by squaring the voltage measurement value from the voltage detector 230. In another example, the voltage detector 230 measures the square of the amplitude of the voltage V and outputs a voltage measurement value proportional to the square of the amplitude of the voltage V to the load measurement circuit 250. In this example, the load measurement circuit 250 does not need to calculate the square of the voltage amplitude because the measured value of the square of the voltage amplitude has already been provided by the voltage detector 230. In this example, the voltage squaring operation is performed at the voltage detector 230.

[0063] Therefore, circuit 205 measures the admittance and / or impedance of load 215, wherein the measured impedance may include calculated phase angle and / or load impedance values, and the measured admittance may include calculated phase angle and / or load admittance values. The measured admittance and / or impedance can be used to improve the performance of the transmitter and / or receiver.

[0064] For example, the transmitter may include a tunable impedance matching network located between the output 114 of PA 110 and the load 215. Figure 1 (Not shown in the diagram), where the impedance matching network is configured to transform the impedance of the load into a desired internal impedance at the output 114 of PA 110. In this example, the impedance transformation of the impedance matching network can be tuned based on a measured impedance of the load 215 to provide the desired impedance at the output 114 of PA 110. In some implementations, the measured admittance can be used to tune the impedance matching network by transforming the desired impedance into an equivalent desired admittance and tuning the impedance matching network based on the measured admittance to achieve the desired admittance at the output 114 of PA 110.

[0065] In another example, the measured impedance can be used to protect PA 110 from excessive voltage swings at output 114. For example, a significant increase in voltage swings at output 114 of PA 110 may occur due to a large increase in load impedance. This large increase in load impedance could be due to an open circuit or other fault. In this example, a large increase in load impedance can be detected by detecting a large increase in the measured impedance (e.g., the impedance value exceeds a threshold). When a large increase in load impedance is detected, the gain of PA 110 can be reduced to prevent excessive voltage swings at output 114 of PA 110, which could potentially damage PA 110. A large increase in load impedance can also be detected by detecting a large increase in the voltage measurement from voltage detector 230 and the accompanying smaller average power measurement from power detector 210 (indicating high impedance). In some implementations, a large increase in load impedance can be detected by detecting a large decrease in the measured admittance (e.g., the admittance value drops below a threshold).

[0066] In another example, the measured impedance can be used to verify that the antenna module, including antenna 115, meets the impedance specification. In this example, failure to meet the impedance specification may indicate a problem with line 135 or antenna 115. The measured admittance can also be used to verify compliance with the impedance specification. For example, the impedance specification can be given as an equivalent admittance specification. In this example, the measured admittance can be compared with the admittance specification to determine whether the antenna module meets the admittance specification and therefore the impedance specification.

[0067] Figure 3 An exemplary implementation of a power detector 210 and a phase shifter 220 according to certain aspects is shown. In this example, the power detector 210 includes a resistive element 310 coupled between a power amplifier (PA) 110 and a load 215. The resistive element 310 has a first terminal 312 coupled to the PA 110 and a second terminal 314 coupled to the load 215.

[0068] Resistive element 310 is coupled in series with load 215 such that the current flowing through load 215 also flows through resistive element 310. In some respects, resistive element 310 has a very low resistance (e.g., a few ohms), resulting in very low power loss from resistive element 310. Resistive element 310 can be implemented using a low-resistance resistor (e.g., a wire resistor). The very small power loss from resistive element 310 allows circuit 205 to measure the admittance and / or impedance of load 215, while having a very small effect on the power supplied from PA 110 to the load.

[0069] In some implementations, the resistive element 310 can be implemented using a switch (e.g., switch 125), where the on-resistance of the switch provides the resistance of the resistive element 310. The advantage of using a switch for the resistive element 310 is that the switch may already exist in the transmission path to switch between transmit and receive modes. In this case, using an existing switch as the resistive element 310 allows the power detector 210 to measure the power delivered to the load 215 without incurring additional power losses in the transmission path. The following discusses… Figure 11 An example of implementing the resistive element 310 using a switch is shown.

[0070] In this example, the power detector 210 also includes a transformer 320, a first square circuit 350, a second square circuit 360, a differential circuit 370, and a low-pass filter 380. The transformer 320 includes a first inductor 330 (e.g., a primary inductor) and a second inductor 335 (e.g., a secondary inductor), wherein the second inductor 335 is magnetically coupled to the first inductor 330.

[0071] In this example, the first inductor 330 of the transformer 320 is coupled in parallel with the resistive element 310. More specifically, the first terminal 332 of the first inductor 330 is coupled to the first terminal 312 of the resistive element 310, and the second terminal 334 of the first inductor 330 is coupled to the second terminal 314 of the resistive element 310.

[0072] The second inductor 335 is coupled between the input terminals of the square circuits 350 and 360. More specifically, the first terminal 336 of the second inductor 335 is coupled to the input terminal 352 of the first square circuit 350, and the second terminal 338 of the second inductor 335 is coupled to the input terminal 362 of the second square circuit 360.

[0073] The first square circuit 350 is configured to generate a first square signal at its output terminal 354, the first square signal being proportional to the square of the voltage at its input terminal 352. The second square circuit 360 is configured to generate a second square signal at its output terminal 364, the second square signal being proportional to the square of the voltage at its input terminal 362.

[0074] The differential circuit 370 has a first input terminal 372 coupled to the output terminal 354 of the first square circuit 350, a second input terminal 374 coupled to the output terminal 364 of the second square circuit 360, and an output terminal 376. The differential circuit 370 generates a differential signal proportional to the difference between the first square signal from the first square circuit 350 and the second square signal from the second square circuit 360.

[0075] A low-pass filter 380 is coupled between the output 376 of the differential circuit 370 and the load measurement circuit 250. The low-pass filter 380 is configured to low-pass filter the difference signal from the differential circuit 370 to generate an average power measurement of the load 215, which is output to the load measurement circuit 250. In some aspects, the load measurement circuit 250 may include an analog-to-digital converter (ADC) configured to convert the difference signal into a digital signal. In these aspects, the load measurement circuit 250 can calculate the phase angle in the digital domain and calculate the admittance and / or impedance values ​​in the digital domain.

[0076] As described above, the first square circuit 350, the second square circuit 360, the differential circuit 370, and the low-pass filter 380 generate an average power measurement of the load 215. This can be demonstrated in some respects by the following discussion.

[0077] Assuming the current through resistor 310 is equal to or sufficiently close to the current through load 215, and assuming the voltage at the second terminal 314 of resistor 310 is equal to the voltage across load 215, the current through load 215 can be given by the following formula:

[0078]

[0079] Where R is the resistance of resistor element 310, v A v(t) is the voltage at the first terminal 312 of the resistive element, and v(t) is the voltage at the second terminal 314 of the resistive element 310 (assuming it is equal to the voltage across the load 215). Equation (10) also gives the current through the resistive element 310, since the resistive element 310 is in series with the load 215. In this example, the voltage at the first terminal 312 of the resistive element 310 is related to the current through the load 215 and the voltage across the load 215, as follows:

[0080] v A (t)=i(t)·R+v(t) (11)

[0081] Where i(t).R is the voltage drop across resistor 310 caused by the current flowing through it. The square of the voltage at the first terminal 312 of resistor 310 is given by the following formula:

[0082] v A 2 (t)=i 2 (t)·R 2 +2v(t)i(t)R+v 2 (t) (12)

[0083] This is obtained through the square equation (11).

[0084] Assuming the voltage at the second terminal 314 of the resistive element 310 is equal to the voltage across the load 215, the difference between the square of the voltage at the first terminal 312 and the square of the voltage at the second terminal 314 is given by the following formula:

[0085] v A 2 (t)-v 2 (t)=i 2 (t)·R 2 +2v(t)i(t)R (13)

[0086] Because the resistance of resistor 310 is very low, the square term of resistance in equation (13) is very small and therefore can be ignored, as follows:

[0087] v A 2 (t)-v B 2 (t)=2v(t)i(t)R (14)

[0088] As shown in equation (14), the difference between the square of the voltage at the first terminal 312 and the square of the voltage at the second terminal 314 is proportional to the power supplied to the load 215 by a scaling factor of 2R. Therefore, the difference signal output by the difference circuit 370 (which is proportional to the difference between the first square signal from the first square circuit 350 and the second square signal from the second square circuit 360) is proportional to the power supplied to the load 215.

[0089] The low-pass filter 380 can then filter out the second harmonic component in the difference signal to produce an average power measurement proportional to the average power delivered to the load 215. As discussed above with reference to equation (4), the average power can be obtained by filtering out the second harmonic component (i.e., the second harmonic term in equation (4)) in the power delivered to the load 215. In this example, the low-pass filter 380 has a cutoff frequency below the second harmonic frequency in order to filter out the second harmonic component. For an example where the transmitter is used for transmission in the millimeter-wave (mmWave) band, the second harmonic frequency may be in the GHz range.

[0090] It should be understood that this disclosure is not limited to performing low-pass filtering on the difference signal to generate an average power measurement. In other implementations, low-pass filtering may be performed on the first squared signal and the second squared signal before the difference circuit 370, as referenced below. Figure 5 Further discussion is needed.

[0091] exist Figure 3In the example shown, phase shifter 220 is coupled to the center tap of a second inductor 335 (e.g., a secondary inductor) of transformer 320. In this example, phase shifter 220 includes a switchable RC circuit 345 coupled between the center tap of the second inductor 335 and ground. The switchable RC circuit 345 includes a resistor 342, a switch 344, and a capacitor 346 coupled in series between the center tap of the second inductor 335 and ground. In this example, the center tap of the second inductor is biased by bias circuit 340. Switch 344 can be implemented using one or more transistors, transmission gates, or another type of switch.

[0092] During operation, switch 344 is controlled by load measurement circuit 250 to selectively shift the average power measurement value of power detector 210. To measure the average power without phase shift, load measurement circuit 250 opens switch 344, which disables phase shifter 220. To measure the average power with phase shift, load measurement circuit 250 closes switch 344, which enables phase shifter 220. The closing of switch 344 causes resistor 342 and capacitor 346 to form a series RC circuit coupled to the center tap of second inductor 335. The series RC circuit shifts the phase of the average power measurement value according to the phase shift depending on the resistance of resistor 342 and the capacitance of capacitor 346. Because the resistance of resistor 342 and the capacitance of capacitor 346 are known, the phase shift caused by the series RC circuit is known.

[0093] Despite Figure 3 In the example shown, the switchable RC circuit 345 is coupled between the center tap of the second inductor 335 and ground; however, it should be understood that this disclosure is not limited to this example. In another example, the switchable RC circuit 345 may be coupled between the first terminal 336 and the second terminal 338 of the second inductor 335.

[0094] It should be understood that the phase shifter 220 is not limited to Figure 3 The exemplary switchable RC circuit 345 is shown. In this respect, Figure 4 Another exemplary implementation of phase shifter 220 is shown, wherein phase shifter 220 includes a switchable RL circuit 445 coupled between the center tap of second inductor 335 and ground. Switchable RL circuit 445 includes a resistor 442, a switch 444, and an inductor 446 coupled in series between the center tap of second inductor 335 and ground. Switch 444 can be implemented using one or more transistors, transmission gates, or another type of switch.

[0095] During operation, switch 444 is controlled by load measurement circuit 250 to selectively shift the average power measurement value of power detector 210. To measure the average power without phase shift, load measurement circuit 250 opens switch 444, which disables phase shifter 220. To measure the average power with phase shift, load measurement circuit 250 closes switch 444, which enables phase shifter 220. The closing of switch 444 causes resistor 442 and inductor 446 to form a series RL circuit coupled to the center tap of second inductor 335. The series RL circuit shifts the phase of the average power measurement value according to the phase shift depending on the resistance of resistor 442 and the inductance of inductor 446. Because the resistance of resistor 442 and the inductance of inductor 446 are known, the phase shift caused by the series RL circuit is known.

[0096] Despite Figure 4 In the example shown, the switchable RL circuit 445 is coupled between the center tap of the second inductor 335 and ground; however, it should be understood that this disclosure is not limited to this example. In another example, the switchable RL circuit 445 may be coupled between the first terminal 336 and the second terminal 338 of the second inductor 335.

[0097] It should be understood that the phase shifter 220 is not limited to the example given above. The phase shifter 220 can be implemented using other combinations of one or more resistive elements and one or more reactive elements (e.g., capacitors and / or inductors), such combinations causing a phase shift in the average power measurement of the power detector 210 to a known phase shift. One or more switches can be coupled to one or more resistive elements and one or more reactive elements to selectively enable and disable the phase shifter 220 by controlling one or more switches.

[0098] As mentioned above, the low-pass filtering can be performed before the differential circuit 370. At this point, Figure 5 An example is shown in which the power detector 210 includes a first low-pass filter 520 coupled between the output 354 of the first square circuit 350 and the first input 372 of the difference circuit 370, and a second low-pass filter 525 coupled between the output 364 of the second square circuit 360 and the second input 374 of the difference circuit 370.

[0099] During operation, the first low-pass filter 520 filters out the second harmonic component generated by the squaring operation of the first squaring circuit 350 from the first squared signal, and outputs the filtered first squared signal to the first input terminal 372 of the difference circuit 370. The second low-pass filter 525 filters out the second harmonic component generated by the squaring operation of the second squaring circuit 360 from the second squared signal, and outputs the filtered second squared signal to the second input terminal 374 of the difference circuit 370.

[0100] The difference circuit 370 then generates a difference signal proportional to the difference between the filtered first squared signal and the filtered second squared signal. Because the second harmonic components in the first and second squared signals are filtered out by the first low-pass filter 520 and the second low-pass filter 525, respectively, before being input to the difference circuit 370, the difference signal output from the difference circuit 370 does not include the aforementioned second harmonic components and is therefore proportional to the average power supplied to the load 215. Thus, in this example, the difference signal output from the difference circuit 370 provides an average power measurement for the load 215.

[0101] Figure 6 Exemplary implementations of the first square circuit 350, the second square circuit 360, the first low-pass filter 520, the second low-pass filter 525, and the difference circuit 370 are shown according to certain aspects. Note that, for ease of illustration, Figure 6 The load measurement circuit 250, PA 110 and load 215 are not shown.

[0102] exist Figure 6 In the example shown, the first square circuit 350 includes a first transistor 610, wherein the gate of the first transistor 610 is coupled to a first terminal 336 of the second inductor 335, and the source of the first transistor 610 is grounded. In this example, the power detector 210 includes a first current source 630 coupled between the power supply rail and the drain of the first transistor 610 to provide a bias current to the first transistor 610. The bias circuit 340 biases the gate of the first transistor 610 with a bias voltage (labeled "Vb") via the second inductor 335, which acts as a direct current (DC) short circuit. In this example, the input terminal 352 of the first square circuit 350 is located at the gate of the first transistor 610, and the output terminal 354 of the first square circuit 350 is located at the drain of the first transistor 610.

[0103] During operation, the first transistor 610 generates a drain current proportional to the square of the voltage at its gate, based on the square-law relationship between its drain current and gate voltage. Therefore, in this example, the first square signal of the first square circuit 350 is provided by the drain current of the first transistor 610, which is proportional to the square of the voltage at its gate (i.e., the input terminal 352 of the first square circuit 350).

[0104] The second square circuit 360 includes a second transistor 620, wherein the gate of the second transistor 620 is coupled to a second terminal 338 of a second inductor 335, and the source of the second transistor 620 is coupled to ground. In this example, the power detector 210 includes a second current source 635 coupled between a power supply rail and the drain of the second transistor 620 to provide a bias current to the second transistor 620. The bias circuit 340 biases the gate of the second transistor 620 with a bias voltage Vb via the second inductor 335, which acts as a DC short circuit. In this example, the input terminal 362 of the second square circuit 360 is located at the gate of the second transistor 620, and the output terminal 364 of the second square circuit 360 is located at the drain of the second transistor 620.

[0105] During operation, the second transistor 620 generates a drain current proportional to the square of the voltage at its gate, based on the square-law relationship between its drain current and gate voltage. Therefore, in this example, the second square signal of the second square circuit 360 is provided by the drain current of the second transistor 620, which is proportional to the square of the voltage at its gate (i.e., the input terminal 362 of the second square circuit 360).

[0106] exist Figure 6 In the example shown, each of the first transistor 610 and the second transistor 620 is implemented using an n-type field-effect transistor (NFET). However, it should be understood that the first transistor 610 and the second transistor 620 can be implemented using other types of transistors.

[0107] exist Figure 6 In the example shown, the first low-pass filter 520 includes a first capacitor C1 coupled between the output 354 of the first square circuit 350 and ground. The first capacitor C1 filters out the second harmonic component of the first square signal by acting as a short circuit to ground at the second harmonic frequency. The first capacitor C1 may include a metal capacitor, a metal-oxide-semiconductor (MOS) capacitor, and / or another type of capacitor. In some implementations, the first capacitor C1 may be implemented using the parasitic capacitance of the first transistor 610 and / or the first current source 630. Parasitic capacitance in electronic devices is inherent to the device structure and may be undesirable in some applications because it limits the frequency response of the device. In this example, the parasitic capacitance of the first transistor 610 and / or the first current source 630 can be used to filter out the second harmonic frequency without adding a separate capacitor for low-pass filtering.

[0108] exist Figure 6 In the example shown, the second low-pass filter 525 includes a second capacitor C2 coupled between the output terminal 364 of the second square circuit 360 and ground. The second capacitor C2 filters out the second harmonic component of the second square signal by acting as a short circuit to ground at the second harmonic frequency. The second capacitor C2 may include a metal capacitor, a MOS capacitor, and / or another type of capacitor. In some implementations, the second capacitor C2 may be implemented using the parasitic capacitance of the second transistor 620 and / or the second current source 635.

[0109] Figure 6 An example is shown where the differential circuit 370 includes a transimpedance amplifier 640 configured to generate a differential signal proportional to the difference between a filtered first squared signal and a filtered second squared signal multiplied by the gain of amplifier 640. In this example, the output 376 of the differential circuit 370 is a differential output including a first output 376-1 and a second output 376-2. In this example, the filtered first squared signal and the filtered second squared signal are currents, and the differential signal is a differential voltage.

[0110] In this example, the transimpedance amplifier 640 includes a differential amplifier 650, which has a first input terminal 652 coupled to a first input terminal 372 of the differential circuit 370, a second input terminal 654 coupled to a second input terminal 374 of the differential circuit 370, a first output terminal 656 coupled to a first output terminal 376-1 of the differential circuit 370, and a second output terminal 658 coupled to a second output terminal 376-2 of the differential circuit 370. The transimpedance amplifier 640 also includes a first feedback resistor 660 coupled between the first output terminal 656 and the first input terminal 652 of the amplifier 650, and a second feedback resistor 665 coupled between the second output terminal 658 and the second input terminal 654 of the amplifier 650. In this example, the gain of the transimpedance amplifier 640 is set by the resistance of the feedback resistors 660 and 665.

[0111] It should be understood that the differential circuit 370 is not limited to Figure 6 The exemplary implementation is shown. Generally, the differential circuit 370 can be implemented using any differential amplifier configured to generate a differential signal at the output of the differential amplifier that is proportional to the difference between the filtered first squared signal and the filtered second squared signal. The output of the differential amplifier can be differential or single-ended, and the differential signal can be either differential or single-ended.

[0112] In some aspects, the load measurement circuit 250 may include one or more ADCs configured to convert the difference signal into one or more digital signals (i.e., digital values). In these aspects, the load measurement circuit 250 may calculate the phase angle in the digital domain and calculate the admittance and / or impedance values ​​in the digital domain.

[0113] In some implementations, the filtered first squared signal and the filtered second squared signal can be converted into digital signals by one or more ADCs (not shown), and the difference circuit 370 can generate a difference signal in the digital domain. In this example, the difference signal is a digital difference signal.

[0114] Figure 7 An exemplary implementation of a bias circuit 340 according to certain aspects of this disclosure is shown. In this example, the bias circuit 340 includes a third transistor 710, a third current source 720, a resistor 730, and a capacitor C0. In this example, the third current source 720 is coupled between a power supply rail and the drain of the third transistor 710, and the source of the third transistor 710 is coupled to ground. The drain of the third transistor 710 is coupled to the gate of the third transistor 710 to generate a bias voltage at the gate of the third transistor 710. Figure 7 In the example shown, resistor 730 is coupled between the gate of third transistor 710 and the center tap of second inductor 335, and capacitor C0 is coupled between resistor 730 and ground. In this example, resistor 730 and capacitor C0 form a low-pass RC filter that removes noise from the bias voltage.

[0115] Figure 8 An exemplary implementation of a voltage detector 230 according to certain aspects is shown. In this example, the voltage detector 230 includes a squaring circuit 810 and a low-pass filter 820. The squaring circuit 810 has an input terminal 812 and an output terminal 814. The input terminal 812 of the squaring circuit 810 is coupled between the output terminal 114 of PA 110 and the power detector 210. For an example in which the power detector 210 includes a resistive element 310, the input terminal 812 of the squaring circuit 810 may be coupled to a first terminal 312 of the resistive element 310. The low-pass filter 820 is coupled between the output terminal 814 of the squaring circuit 810 and the load measurement circuit 250.

[0116] During operation, the squaring circuit 810 is configured to generate a squared signal at its output terminal 814 that is proportional to the square of the voltage at its input terminal 812. The squared signal includes a component proportional to the square of the voltage amplitude at input terminal 812 and a second harmonic component. A low-pass filter 820 filters out the second harmonic component, leaving the component proportional to the square of the voltage amplitude in the resulting filtered squared signal. Therefore, the filtered squared signal provides a measured value of the square of the voltage amplitude to the load measurement circuit 250, which can use this measured value to calculate the load admittance value (e.g., based on equation (9)).

[0117] Figure 9 An exemplary implementation of a square circuit 810 and a low-pass filter 820 according to certain aspects is provided. In this example, the square circuit 810 includes a transistor 910, wherein the source of the transistor 910 is coupled to ground. The input terminal 812 of the square circuit 810 is located at the gate of the transistor 910, and the output terminal 814 of the square circuit 810 is located at the drain of the transistor 910. In this example, the voltage detector 230 includes a current source 920 coupled between the power supply rail and the drain of the transistor 910 to provide a bias current to the transistor 910. The gate of the transistor 910 can be biased by a bias circuit 340 ( Figure 9 The voltage detector 230 is biased by a bias voltage generated by a resistor 310 (not shown in the image). In this example, the voltage detector 230 also includes a resistor coupled to the gate of the transistor 910 and a resistor 310 (not shown in the image). Figure 9 AC coupling capacitor 930 between the first terminal 312 (not shown in the image).

[0118] During operation, transistor 910 generates a drain current proportional to the square of the voltage at the gate of transistor 910, based on the square law relationship between the drain current of transistor 910 and the gate voltage of transistor 910. The drain current includes a component proportional to the square of the voltage amplitude at input terminal 812 and a second harmonic component, wherein the second harmonic component is filtered out by low-pass filter 820.

[0119] exist Figure 9 In the example, the low-pass filter 820 includes a capacitor Cf coupled between the output terminal 814 of the square circuit 810 and ground. The capacitor Cf filters out the second harmonic component of the first square signal by acting as a short circuit to ground at the second harmonic frequency. The capacitor Cf may include a metal capacitor, a MOS capacitor, and / or another type of capacitor. In some implementations, the capacitor Cf may be implemented using the parasitic capacitance of the transistor 910 and / or the current source 920.

[0120] exist Figure 9In the example, voltage detector 230 includes a transimpedance amplifier 940 having an input 942 coupled to the drain of transistor 910 and an output 944 coupled to load measurement circuit 250. Transimpedance amplifier 940 is configured to convert the filtered drain current of transistor 910 at input 942 into an output voltage at output 944 that is proportional to the square of the voltage magnitude at input 812 of square circuit 810. The output voltage provides a measured value of the square of the voltage magnitude to load measurement circuit 250, which can use this measurement to calculate a load admittance value (e.g., based on equation (9)).

[0121] exist Figure 9 In the example, the transimpedance amplifier 940 includes an amplifier 950 having a first input terminal 952 coupled to the drain of a transistor 910, a second input terminal 954 coupled to a reference voltage Vr, and an output terminal 956 coupled to a load measurement circuit 250. The transimpedance amplifier 940 also includes a feedback resistor 960 coupled between the output terminal 956 and the first input terminal 952 of the amplifier 950, wherein the gain of the transimpedance amplifier 940 is set by the resistance of the feedback resistor 960.

[0122] Figure 10 An exemplary transceiver 1010, in which circuitry 205 may be used, is shown according to various aspects of this disclosure. In this example, transceiver 1010 includes a PA 110 and an LNA 120 sharing an antenna 115. In this example, PA 110, LNA 120, and circuitry 205 are integrated on a chip 1005. Chip 1005 includes pads 1020 for coupling chip 1005 to antenna 115. In this example, pads 1020 may be connected via bumps (e.g., Figure 1 The bump 130 and line 135 (e.g., transmission line, metal trace, cable, etc.) shown are coupled to the antenna 115. In one example, the chip 1005 and the antenna 115 may be mounted on a substrate (e.g., a printed circuit board), wherein the line 135 includes one or more metal traces on the substrate coupled between the pad 1020 and the antenna 115.

[0123] In this example, power detector 210 is coupled between output 114 of PA 110 and pad 1020. The load measured by circuit 205 may include pad 1020, antenna 115, line 135, and bump 130 (e.g., Figure 1 The load is shown in the figure. Note that in Figures 2-5In this example, the load is represented by load 215. For an example where the power detector 210 uses a resistive element 310 to measure power, the resistive element 310 is coupled between the output 114 of PA 110 and pad 1020. In this example, the input 122 of LNA 120 is coupled to pad 1020.

[0124] Transceiver 1010 can operate in either transmit or receive mode. In transmit mode, PA 110 receives an RF signal at input 112 (e.g., from an up-converter), amplifies the received RF signal, and outputs the amplified RF signal at output 114 for transmission via antenna 115. In receive mode, LNA 120 receives an RF signal from antenna 115 at input 122, amplifies the received RF signal, and outputs the amplified RF signal at output 124 (e.g., to a down-converter).

[0125] In this example, circuit 205 can be used to measure the admittance and / or impedance of the load seen at output 114 of PA 110. Circuit 205 can also be used to measure the admittance and / or impedance of the load seen at input 122 of LNA 120, since input 122 of LNA 120 is also coupled to pad 1020.

[0126] Figure 11 An example of transceiver 1010 is shown, in which the resistive element 310 in power detector 210 is implemented using power switch 1110. In this example, power detector 210 can be used... Figures 3-7 This is implemented in any of the exemplary implementations of the power detector 210 shown. For ease of illustration, in Figure 11 Only the resistive element 310 and transformer 320 of the power detector 210 are shown. Figure 11 In the example, power switch 1110 is implemented using an NFET. However, it should be understood that power switch 1110 can be implemented using different types of transistors (e.g., PFETs).

[0127] In this example, power switch 1110 is controlled by controller 1120. In an example where power switch 1110 is implemented using an NFET, controller 1120 is coupled to the gate of the NFET. In this example, controller 1120 turns on power switch 1110 by applying a high voltage to the gate of the NFET and turns off power switch 1110 by applying a low voltage to the gate of the NFET.

[0128] In transmit mode, controller 1120 turns on (i.e., closes) power switch 1110. In this mode, power switch 1110 couples output 114 of PA 110 to pad 1020, which in turn couples to antenna 115. In receive mode, controller 1120 turns off (i.e., disconnects) power switch 1110. In this mode, power switch 1110 decouples output 114 of PA 110 from pad 1020. For example, this can be done to prevent output 114 of PA 110 from loading input 122 of LNA 120 in receive mode.

[0129] To measure the admittance and / or impedance of the load using circuit 205, controller 1120 turns on power switch 1110. In this example, the on-resistance of power switch 1110 provides the resistance of resistive element 310 to measure the power delivered to the load. The on-resistance is the resistance of power switch 1110 when it is turned on.

[0130] It should be understood that transceiver 1010 may include in the transmission path between output terminal 114 of PA 110 and pad 1020. Figure 11 One or more additional components are not shown. For example, transceiver 1010 may also include a transformer (not shown) that couples the output 114 of PA 110 to a resistive element 310 (e.g., power switch 1110). In this example, the transformer may be used to provide impedance matching between the output 114 of PA 110 and the load. It should also be understood that transceiver 1010 may include... Figure 11 One or more additional components (e.g., inductors) are not shown in the receive path between pad 1020 and input terminal 122 of LNA 120.

[0131] As described above, the load measurement circuit 250 can use the impedance or admittance value of the load 215 to protect PA 110 from excessive output voltage swings caused by a significant increase in load impedance. In this respect, Figure 12 An example is shown where the transmitter includes an amplifier control circuit 1210 coupled to a load measurement circuit 250 and a PA 110. The amplifier control circuit 1210 is configured to control the voltage swing at the output terminal 114 of the PA 110 (i.e., the output voltage swing) under the control of the load measurement circuit 250. For example, the amplifier control circuit 1210 can control the output voltage swing by controlling the gain of the PA 110. In this example, the amplifier control circuit 1210 can reduce the output voltage swing by decreasing the gain of the PA 110.

[0132] In this example, the load measurement circuit 250 can detect a significant increase in load impedance when the impedance value exceeds the impedance threshold or the admittance value drops below the admittance threshold (indicating high impedance). This significant increase in load impedance may be due to an open circuit or other fault. In response to detecting this significant increase in load impedance, the load measurement circuit 250 can instruct (i.e., instruct) the amplifier control circuit 1210 to reduce the output voltage swing of PA 110 (e.g., by reducing the gain of PA 110).

[0133] Figure 13 An example is shown where the transmitter includes a tunable impedance matching network 1310 coupled between the output 114 of PA 110 and a load 215. The impedance matching network 1310 is configured to transform the impedance of the load 215 to a desired impedance at the output of PA 110. In this example, a load measurement circuit 250 is coupled to a control input 1320 of the impedance matching network 1310 to control the impedance transformation of the impedance matching network 1310. In operation, the load measurement circuit 250 can tune the impedance transformation of the impedance matching network 1310 based on the impedance or admittance value of the load 215 to provide the desired impedance at the output 114 of PA 110.

[0134] Despite Figure 10 and Figure 11 An antenna 115 is shown, but it should be understood that a wireless device may include multiple antennas. For example, Figure 14 An example is shown in which a wireless device includes a phased antenna array 1450 containing multiple antennas 115-1 to 115-n for transmitting and / or receiving RF signals in a desired direction. In this example, the wireless device includes a frequency divider 1420, multiple transmit chains 1405-1 to 1405-n, and a beamformer 1460. The frequency divider 1420 has an input 1422 and multiple outputs 1424-1 to 1424-n. The frequency divider 1420 is configured to receive an RF signal at input 1422 (e.g., from an upconverter or another device), divide the RF signal into multiple RF signals, and output each of the multiple RF signals at a corresponding output of the multiple outputs 1424-1 to 1424-n.

[0135] Each transmit chain 1405-1 to 1405-n is coupled between a corresponding output of the frequency divider 1420 (outputs 1424-1 to 1424-n) and a corresponding antenna of the antenna array 1450 (antennas 115-1 to 115-n). Each of the transmit chains 1405-1 to 1405-n includes a corresponding phase shifter 1410-1 to 1410-n, a corresponding PA 110-1 to 110-n, and a corresponding circuit 205-1 to 205-n for measuring the impedance and / or admittance of the corresponding load (including the load of the corresponding antenna 115-1 to 115-n). Each of the circuits 205-1 to 205-n can be used... Figures 2-13 Implemented in any of the exemplary ways shown in the circuit 205.

[0136] Each of the phase shifters 1410-1 to 1410-n is configured to shift the phase of the signal in the corresponding transmit chain 1405-1 to 1405-n under the control of the beamformer 1460. For ease of illustration, in Figure 14 The specific connections between beamformer 1460 and phase shifters 1410-1 to 1410-n are not explicitly shown. In operation, beamformer 1460 uses phase shifters 1410-1 to 1410-n to shift the phase of the signals in transmit chains 1405-1 to 1405-n according to corresponding phase shifts to achieve the desired transmit beam direction of antenna array 1450.

[0137] exist Figure 14 In the example shown, each of circuits 205-1 to 205-n can be a separate instance of circuit 205 for measuring the corresponding load admittance and / or load impedance. Each instance of circuits 205-1 to 205-m may include a corresponding power detector 210, a corresponding phase shifter 220, a corresponding voltage detector 230, and a corresponding load measurement circuit 250 (e.g., ...) coupled between the corresponding PA 110-1 to 110-n and the corresponding antenna 115-1 to 115-n. Figure 2 (As shown). In some implementations, circuits 205-1 to 205-n may share load measurement circuit 250. In this example, the power detector 210, phase shifter 220, and voltage detector 230 in each of circuits 205-1 to 205-n may be coupled to the shared load measurement circuit 250, which may calculate the load impedance and / or load admittance of each of antennas 115-1 to 115-n.

[0138] Figure 15This is a schematic diagram of an environment 1500 including an electronic device 1502 containing a wireless transceiver 1596. According to various aspects of this disclosure, the transceiver 1596 may include a transceiver 1010, circuitry 205, a power amplifier (PA) 110, an energy level sensor (LNA) 120, a power detector 210, a load measurement circuitry 250, a phase shifter 220, and / or a voltage detector 230. In environment 1500, the electronic device 1502 communicates with a base station 1502 via a wireless link 1506. As shown, the electronic device 1502 is depicted as a smartphone. However, the electronic device 1502 can be implemented as any suitable computing device or other electronic device, such as a cellular base station, broadband router, access point, cellular or mobile phone, gaming device, navigation device, media device, laptop computer, desktop computer, tablet computer, server computer, network-attached storage (NAS) device, smart appliance, vehicle-based communication system, Internet of Things (IoT) device, sensor or security device, asset tracker, etc.

[0139] Base station 1502 communicates with electronic device 1502 via wireless link 1506, which can be implemented as any suitable type of wireless link. Although depicted as a base station tower of a cellular radio network, base station 1502 can represent or be implemented as another device, such as a satellite, terrestrial broadcast tower, access point, peer-to-peer device, mesh network node, fiber optic cable, or another electronic device as described above. Therefore, electronic device 1502 can communicate with base station 1502 or another device via a wired connection, a wireless connection, or a combination thereof. Wireless link 1506 can include a downlink for transmitting data or control information from base station 1502 to electronic device 1502, and an uplink for transmitting other data or control information from electronic device 1502 to base station 1502. Wireless link 1506 can be implemented using any suitable communication protocol or standard, such as 3GPP LTE, 3GPP NR 5G, IEEE 802.11, IEEE 802.16, Bluetooth, etc. TM etc.

[0140] Electronic device 1502 includes processor 1580 and memory 1582. Memory 1582 may be or form part of a computer-readable storage medium. Processor 1580 may include any type of processor, such as an application processor or a multi-core processor, configured to execute processor-executable instructions (e.g., code) stored in memory 1582. Memory 1582 may include any suitable type of data storage medium, such as volatile memory (e.g., random access memory (RAM)), non-volatile memory (e.g., flash memory), optical media, magnetic media (e.g., magnetic disk or magnetic tape), etc. In the context of this disclosure, memory 1582 is implemented to store instructions 1584, data 1586, and other information of electronic device 1502, and therefore, when configured as a computer-readable storage medium or part thereof, memory 1582 does not include transiently propagated signals or carrier waves.

[0141] Electronic device 1502 may also include input / output port 1590. I / O port 1590 enables data exchange or interaction with other devices, networks, or users, or data exchange or interaction between components of the device.

[0142] Electronic device 1502 may also include a signal processor (SP) 1592 (e.g., a digital signal processor (DSP)). The signal processor 1592 may operate similarly to a processor and is capable of executing instructions and / or processing information in conjunction with memory 1582.

[0143] For communication purposes, electronic device 1502 also includes a modem 1594, a wireless transceiver 1596, and an antenna (e.g., antenna 115). The wireless transceiver 1596 provides connectivity to a suitable network and other electronic devices connected to it using RF wireless signals. The wireless transceiver 1596 can facilitate communication over any suitable type of wireless network, such as a wireless local area network (LAN) (WLAN), a peer-to-peer (P2P) network, a mesh network, a cellular network, a wireless wide area network (WWAN), a navigation network (e.g., the Global Positioning System (GPS) of North America or another Global Navigation Satellite System (GNSS)), and / or a wireless personal area network (WPAN).

[0144] Figure 16 A method 1600 for measuring a load (e.g., load 215) is shown according to certain aspects. The load may have complex impedance and may include an antenna (e.g., antenna 115). Method 1600 may be performed by a power detector 210, a phase shifter 220, and a load measurement circuit 250.

[0145] In box 1610, the power delivered to the load is measured to obtain a power measurement value. The power measurement can be performed by power detector 210. In one example, the power measurement value can be proportional to the average power delivered to the load.

[0146] In box 1620, the power delivered to the load with phase shift is measured to obtain a phase-shifted power measurement. The power measurement with phase shift can be performed by power detector 210 and phase shifter 220.

[0147] In block 1630, the phase angle of the load is determined based on the power measurement, the phase-shifted power measurement, and the phase shift. For example, the phase angle can be determined by the load measurement circuit 250 (e.g., based on equation (8)). The phase shift can be a known phase shift of the phase shifter 220.

[0148] In some aspects, method 1600 may include: measuring the voltage on a path coupled to the load to obtain a voltage measurement, and determining the admittance or impedance value of the load based on the voltage measurement and a determined phase angle. For example, the path may be between a PA (e.g., PA 110) and a load (e.g., load 215). The voltage may be measured by a voltage detector 230, and the admittance or impedance value may be determined by a load measurement circuit 250. The admittance value may be proportional to the magnitude of the load's admittance, and the impedance value may be proportional to the magnitude of the load's impedance.

[0149] In some respects, measuring voltage may include: squaring the voltage to generate a squared signal proportional to the square of the voltage, and low-pass filtering the squared signal to obtain a voltage measurement. Squaring may be performed by squaring circuit 810, and low-pass filtering may be performed by low-pass filter 820.

[0150] In some respects, determining the phase angle of the load involves: determining the ratio of the power measurement to the phase-shifted power measurement, and determining the phase angle based on the determined ratio and the phase shift.

[0151] In some aspects, measuring the power delivered to a load with a phase shift includes: enabling a phase shifter coupled to a power detector, the phase shifter including resistive and reactive elements, and measuring the power delivered to the load using the power detector while the phase shifter is enabled. The phase shifter may correspond to phase shifter 220, and the power detector may correspond to power detector 210. The phase shifter may be enabled by load measurement circuitry 250. The resistive element may include a resistor (e.g., resistor 342 or 442), and the reactive element may include a capacitor (e.g., capacitor 346) or an inductor (e.g., inductor 446).

[0152] In some respects, measuring the power delivered to a load to obtain a power measurement includes: disabling the phase shifter, and using a power detector to measure the power delivered to the load while the phase shifter is disabled.

[0153] In some respects, a phase shifter includes a switch (e.g., switch 344 or 444). In these respects, disabling the phase shifter includes opening the switch, and enabling the phase shifter includes closing the switch.

[0154] In some aspects, a resistive element (e.g., resistive element 310) is coupled between a power amplifier (e.g., PA 110) and a load (e.g., load 215). In one example, the resistive element includes a switch (e.g., switch 1110). In these aspects, measuring the power supplied to the load to obtain a power measurement may include: squaring the voltage from a first terminal of the resistive element to obtain a first squared signal, squaring the voltage from a second terminal of the resistive element to obtain a second squared signal, and generating a difference signal based on the difference between the first squared signal and the second squared signal. The voltage from the first terminal (e.g., first terminal 312) may be squared by a first squared circuit 350, the voltage from the second terminal (e.g., terminal 314) may be squared by a second squared circuit 360, and the difference signal may be generated by a difference circuit 370. The difference circuit 370 may include a differential amplifier (e.g., differential amplifier 650), and the difference signal may be differential or single-ended.

[0155] In some aspects, method 1600 may include: low-pass filtering a first squared signal to obtain a filtered first squared signal, and low-pass filtering a second squared signal to obtain a filtered second squared signal, wherein generating a difference signal based on the difference between the first squared signal and the second squared signal includes generating a difference signal based on the difference between the filtered first squared signal and the filtered second squared signal. For example, the first squared signal may be low-pass filtered by a first low-pass filter 520, and the second squared signal may be low-pass filtered by a second low-pass filter 525. In these aspects, the difference signal provides a power measurement, and the difference signal may be proportional to the average power delivered to the load.

[0156] In some aspects, method 1600 may include low-pass filtering of the difference signal. For example, the filtered difference signal provides a power measurement and may be proportional to the average power delivered to the load. The difference signal may be low-pass filtered by low-pass filter 380.

[0157] The load measurement circuit 250 can be implemented using a general-purpose processor, a digital signal processor (DSP), a state machine, an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA) or other programmable logic device, discrete hardware components (e.g., logic gates), or any combination thereof designed to perform the functions described herein. The processor can perform the functions described herein by executing software that includes code for performing the functions. The software can be stored on a computer-readable storage medium such as RAM, ROM, EEPROM, optical disk, and / or magnetic disk.

[0158] Any reference to elements in this document using names such as "first," "second," etc., generally does not restrict the number or order of these elements. Rather, these names serve as a convenient way to distinguish two or more elements or instances of elements. Therefore, a reference to a first element and a second element does not imply that only two elements can be used or that the first element must precede the second element.

[0159] Within this disclosure, the term "exemplary" is used to mean "serving as an example, instance, or illustration." Any implementation or aspect described herein as "exemplary" is not necessarily to be construed as being more preferred or advantageous than other aspects of this disclosure. Similarly, the term "aspect" does not require that all aspects of this disclosure include the features, advantages, or modes of operation discussed.

[0160] The foregoing description provided in this disclosure is intended to enable any person skilled in the art to make or use this disclosure. Various modifications to this disclosure will be apparent to those skilled in the art, and the general principles defined herein may be applied to other variations without departing from the spirit or scope of this disclosure. Therefore, this disclosure is not intended to be limited to the examples described herein, but is accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. An apparatus comprising: A power detector, wherein the power detector comprises: A resistive element is coupled between the power amplifier and the antenna; A transformer, comprising a first inductor and a second inductor, wherein the first inductor is coupled in parallel with the resistive element, and the second inductor is magnetically coupled to the first inductor; A first square circuit including an input terminal and an output terminal, wherein the input terminal of the first square circuit is coupled to a first terminal of the second inductor; A second square circuit including an input terminal and an output terminal, wherein the input terminal of the second square circuit is coupled to a second terminal of the second inductor; and The differential circuit is coupled to the output terminal of the first square circuit, the output terminal of the second square circuit, and the load measurement circuit. A voltage detector is coupled between the power amplifier and the antenna; Phase shifter, coupled to the second inductor; and The load measurement circuit is coupled to the power detector, the voltage detector, and the phase shifter.

2. The apparatus of claim 1, wherein the phase shifter comprises: Second resistive element; Reactor components; as well as A switch is coupled to the second resistive element and the reactive element.

3. The apparatus of claim 1 further includes a low-pass filter coupled between the differential circuit and the load measurement circuit.

4. The apparatus according to claim 1, further comprising: A first low-pass filter is coupled between the output terminal of the first square circuit and the difference circuit; as well as A second low-pass filter is coupled between the output of the second square circuit and the difference circuit.

5. The apparatus of claim 1, wherein the phase shifter is coupled to the second inductor, and the phase shifter comprises: Second resistive element; Reactor components; as well as A switch is coupled to the second resistive element and the reactive element.

6. The apparatus according to claim 1, wherein: The first square circuit includes a first transistor; The gate of the first transistor is coupled to the first terminal of the second inductor; The drain of the first transistor is coupled to the differential circuit; The second square circuit includes a second transistor; The gate of the second transistor is coupled to the second terminal of the second inductor; and The drain of the second transistor is coupled to the differential circuit.

7. The apparatus of claim 1, wherein the voltage detector comprises: A square circuit having an input terminal and an output terminal, wherein the input terminal of the square circuit is coupled between the power amplifier and the antenna; as well as A low-pass filter is coupled between the output terminal of the square circuit and the load measurement circuit.

8. The apparatus according to claim 1, wherein: The load measurement circuit is configured to disable the phase shifter during a first time period; The power detector is configured to measure the power delivered to the load during the first time period to obtain a power measurement value, and output the power measurement value to the load measurement circuit, the load including the load of the antenna; The load measurement circuit is configured to enable the phase shifter during the second time period; The power detector is configured to measure the power delivered to the load during the second time period to obtain a phase-shift power measurement value, and to output the phase-shift power measurement value to the load measurement circuit. and The load measurement circuit is configured to determine the phase angle based on the power measurement value, the phase-shifted power measurement value, and the phase shift of the phase shifter.

9. The apparatus according to claim 8, wherein: The voltage detector is configured to measure the voltage between the power amplifier and the antenna to obtain a voltage measurement value, and output the voltage measurement value to the load measurement circuit; and The load measurement circuit is configured to determine the admittance or impedance value based on the voltage measurement and the determined phase angle.

10. The apparatus of claim 9, wherein the voltage measurement is proportional to the square of the voltage amplitude between the power amplifier and the antenna.

11. The apparatus according to claim 9, further comprising: An impedance matching network is coupled between the power amplifier and the antenna, wherein the load measurement circuit is configured to tune the impedance transformation of the impedance matching network based on the admittance value or the impedance value.

12. The apparatus according to claim 9, further comprising: An amplifier control circuit is configured to control the output voltage swing of the power amplifier, wherein the load measurement circuit is configured to instruct the amplifier control circuit to adjust the output voltage swing based on the admittance value or the impedance value.

13. The apparatus of claim 1, wherein the antenna is one of a plurality of antennas in an antenna array.

14. A method for measuring load, comprising: The power supplied to the load using a resistive element is measured to obtain a power measurement value, wherein the resistive element is coupled between the power amplifier and the load; Measuring the power delivered to the load using the resistive element with a phase shift to obtain a phase-shifted power measurement value, wherein measuring the power delivered to the load using the resistive element with the phase shift to obtain the phase-shifted power measurement value includes: The phase shift is caused at the transformer coupled to the resistive element; The voltage from the first terminal of the resistive element is squared to obtain a first squared signal; The voltage from the second terminal of the resistive element is squared to obtain a second squared signal; and A difference signal is generated based on the difference between the first squared signal and the second squared signal; and The phase angle of the load is determined based on the power measurement, the phase shift power measurement, and the phase shift.

15. The method of claim 14, further comprising: Measure the voltage along the path coupled to the load to obtain a voltage measurement value; as well as The admittance or impedance value of the load is determined based on the voltage measurement and the determined phase angle.

16. The method of claim 15, wherein measuring the voltage comprises: The voltage is squared to generate a squared signal that is proportional to the square of the voltage. as well as The squared signal is low-pass filtered to obtain the voltage measurement value.

17. The method of claim 15, wherein the admittance value is proportional to the magnitude of the admittance of the load.

18. The method of claim 15, wherein the impedance value is proportional to the magnitude of the impedance of the load.

19. The method of claim 14, wherein the load comprises the load of the antenna.

20. The method of claim 14, wherein determining the phase angle of the load comprises: Determine the ratio of the power measurement value to the phase shift power measurement value; as well as The phase angle is determined based on the determined ratio and the phase shift.

21. The method of claim 14, wherein causing the phase shift at the transformer coupled to the resistive element comprises: A phase shifter coupled to the transformer is activated, the phase shifter including a second resistive element and a reactive element.

22. The method of claim 21, wherein measuring the power supplied to the load to obtain the power measurement value comprises: Disable the phase shifter; as well as The power supplied to the load is measured using the resistive element with the phase shifter disabled.

23. The method according to claim 22, wherein: The phase shifter includes a switch; Disabling the phase shifter includes disconnecting the switch; and Enabling the phase shifter includes closing the switch.

24. The method of claim 14, further comprising: The first square signal is low-pass filtered to obtain the filtered first square signal; as well as The second squared signal is low-pass filtered to obtain the filtered second squared signal; Generating the difference signal based on the difference between the first squared signal and the second squared signal includes generating the difference signal based on the difference between the filtered first squared signal and the filtered second squared signal.

25. The method of claim 14, further comprising low-pass filtering the difference signal.

26. An apparatus for measuring load, comprising: A component for measuring the power supplied to the load using a resistive element to obtain a power measurement value, wherein the resistive element is coupled between the power amplifier and the load; A component for measuring the power delivered to the load using the resistive element with a phase shift to obtain a phase-shifted power measurement value, wherein the component for measuring the power delivered to the load using the resistive element with the phase shift to obtain the phase-shifted power measurement value includes: Components used to induce the phase shift at the transformer coupled to the resistive element; A component for squaring the voltage from the first terminal of the resistive element to obtain a first squared signal; A component for squaring the voltage from the second terminal of the resistive element to obtain a second squared signal; and A component for generating a difference signal based on the difference between the first squared signal and the second squared signal; and A component for determining the phase angle of the load based on the power measurement, the phase shift power measurement, and the phase shift.

27. The apparatus of claim 26, further comprising: A component used to measure the voltage along the path coupled to the load to obtain a voltage measurement value; as well as A component for determining the admittance or impedance value of the load based on the voltage measurement and the determined phase angle.

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