Transmitter and power correction method

Abstract

Transmitter and power correction method. A transmitter includes a transmitter circuit, a correction circuit, and a transmitter signal strength indicator circuit. The transmitter circuit is coupled to a power supply node to receive a supply voltage and transmits an output signal via an antenna. The correction circuit senses a current of the power supply node to generate a first signal when the transmitter circuit operates in a first frequency band and to generate a second signal when the transmitter circuit operates in a second frequency band, and generates a correction signal based on the first signal and the second signal. The transmitter signal strength indicator circuit detects a power of the output signal to generate a first detection signal, and generates a second detection signal based on the correction signal and the first detection signal. The transmitter circuit adjusts the power of the output signal to a target power based on the second detection signal.

Description

Technical Field

[0001] This disclosure relates to transmitters, and more particularly to transmitters whose output power can be corrected using current sensing, and a power correction method. Background Technology

[0002] In most applications, the transmitter's output power must meet a target power so that the receiver can correctly identify the signal emitted by the transmitter. However, in practical applications, when the load at the transmitter's antenna changes, the transmitter's output power will also change, making the transmitter's output power inaccurate. Summary of the Invention

[0003] In some embodiments, one of the objectives of this disclosure is (but not limited to) to provide a transmitter and power correction method that can automatically correct output power through current sensing, thereby improving the shortcomings of the prior art.

[0004] In some embodiments, the transmitter includes transmitter circuitry, a calibration circuit, and a transmitter signal strength indicator circuit. The transmitter circuitry is coupled to a power node to receive a supply voltage and transmits an output signal via an antenna. The calibration circuitry is configured to sense a current in the power node when the transmitter circuitry operates in a first frequency band to generate a first signal having a first value, and to sense the current when the transmitter circuitry operates in a second frequency band to generate the first signal having a second value, and to generate a calibration signal based on the first signal having the first value and the first signal having the second value. The transmitter signal strength indicator circuitry is configured to detect the power of the output signal to generate a first detection signal, and to generate a second detection signal based on the calibration signal and the first detection signal. The transmitter circuitry is further configured to adjust the power of the output signal to a target power based on the second detection signal.

[0005] In some embodiments, the power correction method includes the following operations: sensing a current at a power node to generate a first signal having a first value when a transmitter circuit operates in a first frequency band, wherein the transmitter circuit is coupled to the power node to receive a supply voltage, and the transmitter circuit transmits an output signal via an antenna; sensing the current to generate the first signal having a second value when the transmitter circuit operates in a second frequency band; generating a correction signal based on the first signal having the first value and the first signal having the second value; detecting the power of the output signal to generate a first detection signal, and generating a second detection signal based on the correction signal and the first detection signal; and adjusting the power of the output signal to a target power based on the second detection signal.

[0006] The features, implementation, and technical effects of this disclosure are described in detail below with reference to the accompanying drawings. Attached Figure Description

[0007] Figure 1 This is a schematic diagram of a transmitter drawn according to some embodiments of the present disclosure; Figure 2 Drawings based on some embodiments of this disclosure Figure 1 A schematic diagram showing the power change of the output signal when the antenna return loss is 6 dB. Figure 3A The indication output signal is plotted according to some embodiments of this disclosure when Figure 1 The antenna's return loss is approximately 6 dB and the Smith chart shows the power when the transmitter circuit operates in the high-frequency band. Figure 3B The indicator current plotted according to some embodiments of this disclosure is when Figure 1 The Smith chart shows the return loss of the antenna is approximately 6 dB and the transmitter circuit operates in the high-frequency band. Figure 3C The indicator current plotted according to some embodiments of this disclosure is when Figure 1 Smith chart of the antenna return loss of approximately 6 dB and the transmitter circuit operating in the low-frequency band. Figure 4 Drawings based on some embodiments of this disclosure Figure 1 A diagram illustrating the lookup table; and Figure 5 This is a flowchart illustrating a power correction method according to some embodiments of the present disclosure.

[0008] Symbol Explanation

[0009] 100: Transmitter

[0010] 101: Antenna

[0011] 120: Transmitter circuit

[0012] 140: Correction circuit

[0013] 141: Current sensor circuit

[0014] 142, 143: Memory circuits

[0015] 145: Lookup Table

[0016] 160: Transmitter signal strength indicator circuit

[0017] 161: Power Detector Circuit

[0018] 162: Analog-to-digital conversion circuit

[0019] 163: Adder Circuit

[0020] 164: Subtractor Circuit

[0021] 201~204: Line Segments

[0022] 301, 302, 303: Circle

[0023] 500: Power Correction Method

[0024] D1, D2: Detection signals

[0025] DC: Correction signal

[0026] DC': Signal

[0027] DT: Target signal

[0028] I1: Current

[0029] N1: Power Node

[0030] P1~P12: Points

[0031] S1, S2, S3: Signals

[0032] S510, S520, S530, S540, S550, S560: Operation

[0033] VDD: Supply voltage

[0034] VO: Output signal Detailed Implementation

[0035] All terms used herein have their ordinary meanings. The definitions of the terms above in commonly used dictionaries, and the examples of any term used in this disclosure, are merely illustrative and should not be construed as limiting the scope or meaning of this disclosure. Similarly, this disclosure is not limited to the various embodiments shown in this specification.

[0036] As used herein, “coupled” or “connected” can refer to two or more components making direct physical or electrical contact with each other, or indirectly making direct physical or electrical contact with each other, or to two or more components operating or acting on each other. As used herein, the term “circuit system” can be a single system formed by at least one circuit, and the term “circuit” can be a device that connects at least one transistor and / or at least one active or passive component in a certain manner to process signals.

[0037] As used herein, the term "and / or" includes any combination of one or more of the listed related items. The terms first, second, third, etc., are used herein to describe and identify individual elements. Therefore, a first element herein may also be referred to as a second element without departing from the intent of this disclosure. For ease of understanding, similar elements in the figures will be designated with the same reference numerals.

[0038] Figure 1 This is a schematic diagram of a transmitter 100 according to some embodiments of the present disclosure. In some embodiments, the transmitter 100 has an output power adjustment mechanism that can adjust the output power according to the return loss of the antenna so that the actual output power of the transmitter 100 can reach the target power.

[0039] Transmitter 100 includes transmitter circuitry 120, correction circuitry 140, and transmitter signal strength indicator circuitry 160. Transmitter circuitry 120 can transmit an output signal VO via antenna 101. For example, transmitter circuitry 120 may include a baseband circuit (not shown), a digital-to-analog converter circuit (not shown), and an amplifier circuit (not shown) with adjustable gain. The baseband circuit generates an input signal, the digital-to-analog converter circuit converts the input signal to generate an analog signal, and the amplifier circuit amplifies the analog signal to generate the output signal VO. Transmitter circuitry 120 can adjust the amplification gain of the amplifier circuit according to a detection signal D2 to adjust the power of the output signal VO. In some embodiments, transmitter circuitry 120 is coupled to power node N1 to receive and drive a supply voltage VDD (e.g., 3.3 volts). For example, the aforementioned amplifier circuit can be coupled to power node N1 to receive and drive a supply voltage VDD. The above-described configuration of the transmitter circuit 120 is for illustrative purposes only, and this disclosure is not limited thereto.

[0040] In some embodiments, transmitter circuitry 120 may operate on one of a plurality of frequency bands. For example, these frequency bands may include (but are not limited to) a first frequency band (e.g., a low-frequency band), a second frequency band (e.g., a mid-frequency band), and a third frequency band (e.g., a high-frequency band), wherein the frequency ranges of each of the first, second, and third frequency bands are different from each other; for example, the frequency range of the third frequency band is higher than that of the second frequency band, and the frequency range of the second frequency band is higher than that of the first frequency band. In some embodiments, in 5G applications, the first frequency band may be the frequency band corresponding to channels 36 to 64, the second frequency band may be the frequency band corresponding to channels 100 to 144, and the third frequency band may be the frequency band corresponding to channels 149 to 177.

[0041] The correction circuit 140 senses the current I1 flowing into the transmitter circuit 120 from the power node N1 to generate a signal S1 with a first value when the transmitter circuit 120 operates in a first frequency band, and senses the current I1 to generate a signal S1 with a second value when the transmitter circuit 120 operates in another frequency band (e.g., one of the second and third frequency bands), and generates a correction signal DC based on the signal S1 with the first value and the signal S1 with the second value. In some embodiments, if the resolution of the second value is not high enough, the correction circuit 140 also senses the current I1 to generate a signal S1 with a third value when the transmitter circuit 120 operates in other frequency bands (e.g., the remainder of the second and third frequency bands), and generates a correction signal DC based on the signal S1 with the first value, the signal S1 with the second value, and the signal S1 with the third value.

[0042] In some embodiments, the correction circuit 140 can determine the impedance shift of the antenna 101 and a power compensation amount based on a signal S1 having a first value, a signal S1 having a second value, and / or a signal S1 having a third value, to generate a correction signal DC. In practical applications, the impedance of the antenna 101 may shift due to environmental conditions, the load effect of the receiving device, etc., thus causing the power of the output signal VO to fail to reach the target power. The impedance shift of the antenna 101 can be monitored by observing the return loss of the antenna 101. Further details will be provided in reference to... Figure 2 illustrate.

[0043] In some embodiments, the correction circuit 140 includes a current sensor circuit 141, a memory circuit 142, and a memory circuit 143. The current sensor circuit 141 is used to sense the current I1 when the transmitter circuit 120 operates in a specific frequency band to generate a signal S1 with a corresponding value. For example, the current sensor circuit 141 may sense the current I1 to generate a signal S1 with a first value when the transmitter circuit 120 operates in a first frequency band, sense the current I1 to generate a signal S1 with a second value when the transmitter circuit 120 operates in a second frequency band, and sense the current I1 to generate a signal S1 with a third value when the transmitter circuit 120 operates in a third frequency band. In some embodiments, the signal S1 may be (but is not limited to) a digital signal.

[0044] The memory circuit 142 stores a lookup table 145 and searches the lookup table 145 based on the signals S1 with different values ​​to generate the signal S2. In some embodiments, the memory circuit 142 may search the lookup table 145 based on signals S1 with different values ​​(e.g., signals S1 with a first value and signals S1 with a second value) to determine the impedance offset and power compensation amount of the antenna 101 to generate the signal S2. The configuration of the lookup table 145 will be described later. Figure 4 Note: In some embodiments, memory circuitry 142 may be implemented using (but is not limited to) dynamic random access memory.

[0045] Memory circuit 143 generates a correction signal DC based on signal S2. In some embodiments, memory circuit 143 stores multiple code words for compensating the transmitter signal strength index, which can be used to correct the output power detected by transmitter signal strength index circuit 160 (which may have errors due to output impedance offset of transmitter circuit 120). In some embodiments, memory circuit 143 may select one of the aforementioned codes based on signal S2 and output the selected code as correction signal DC. Alternatively, in other embodiments, memory circuit 143 may adjust the selected code based on signal S2 and output the adjusted code as correction signal DC. In some embodiments, memory circuit 143 may be a register circuit. In some embodiments, memory circuit 143 may be implemented by (but is not limited to) an electronically programmable fuse circuit.

[0046] The transmitter signal strength index circuit 160 detects the power of the output signal VO and generates a detection signal D1 (equivalent to the transmitter signal strength index of the output signal VO), and generates a detection signal D2 based on the correction signal DC and the detection signal D1. Thus, the transmitter circuit 120 can adjust the amplification gain according to the detection signal D2 to adjust the power of the output signal VO to the target power, compensating for power changes caused by the impedance shift of the antenna 101. For example, the transmitter signal strength index circuit 160 includes an automatic gain control mechanism, allowing the transmitter circuit 120 to adjust the amplification gain of its amplifier circuit according to the detection signal D2, thereby adjusting the power of the output signal VO.

[0047] In some embodiments, the transmitter signal strength indicator circuit 160 includes a power detector circuit 161, an analog-to-digital converter circuit 162, an adder circuit 163, and a subtractor circuit 164. The power detector circuit 161 detects the power of the output signal VO to generate a signal S3. The analog-to-digital converter circuit 162 converts the signal S3 into a detection signal D1. The adder circuit 163 sums the detection signal D1 with a correction signal DC to generate a signal DC'. The subtractor circuit 164 subtracts the signal DC' from the target signal DT to generate a detection signal D2, where the target signal DT indicates the target power of the output signal VO. In some embodiments, the detection signal D1, the correction signal DC, the signal DC', the detection signal D2, and / or the target signal DT may be digital signals. In some embodiments, the aforementioned signals may be analog signals, and the transmitter signal strength indicator circuit 160 may process these signals without using the analog-to-digital converter circuit 162. In other embodiments, these signals may be implemented as a combination of mixed analog and digital signals. The above-described configuration of the transmitter signal strength indicator circuit 160 is for illustrative purposes only, and this disclosure is not limited thereto.

[0048] Figure 2 Drawings based on some embodiments of this disclosure Figure 1 This diagram illustrates the power variation of the output signal VO when the return loss of antenna 101 is 6 dB. As mentioned earlier, in practical applications, the impedance of antenna 101 may shift, causing unexpected changes in the power of the output signal VO. Experiments show that the higher the absolute value of the return loss of antenna 101 (representing lower reflected energy received by antenna 101), the lower the power variation of the output signal VO; conversely, the lower the absolute value of the return loss of antenna 101 (representing higher reflected energy received by antenna 101), the greater the power variation of the output signal VO. For example, if the return loss of antenna 101 is approximately 10 dB, the power variation of the output signal VO is within approximately 1 dB. Conversely, if the return loss of antenna 101 is approximately 3–6 dB, the power variation of the output signal VO is approximately 2–3 dB. For example, as... Figure 2 As shown, line segment 201 represents the power change of the output signal VO when the impedance of antenna 101 does not shift. When the target power is set to 16 dBm, the output power VO is also 16 dBm. In other words, the power of the output signal VO can be linearly controlled when the impedance of antenna 101 does not shift.

[0049] Line segment 202 represents the power change of the output signal VO when the return loss of antenna 101 is approximately 6 dB (i.e., the impedance of antenna 101 shifts) and its phase is approximately 60 degrees. Line segment 203 represents the power change of the output signal VO when the return loss of antenna 101 is approximately 6 dB and its phase is approximately 240 degrees. Line segment 204 represents the power change of the output signal VO when the return loss of antenna 101 is approximately 6 dB and its phase is approximately 330 degrees. By comparing line segment 201 with the other lines 202-204, it can be understood that when the impedance of antenna 101 shifts, the power of the output signal VO will change differently based on the different phases of the output signal VO. For example, when the target power is set to 14 dBmW, the power change of the output signal VO is approximately 1.78 dB. Or, when the target power is set to 22 dBmW, the power change of the output signal VO is approximately 2.2 dB. The above power differences indicate that the output power of transmitter circuit 120 may be too low. Therefore, the correction circuit 140 can be used to determine the impedance offset of the antenna 101 and adjust the output power of the transmitter circuit 120 to improve the overall output power accuracy of the transmitter 100.

[0050] Figure 3A The indication output signal VO, plotted according to some embodiments of this disclosure, is in the case of... Figure 1 The antenna 101 has a return loss of approximately 6 dB, and the transmitter circuit 120 operates in a high-frequency band (i.e., the third frequency band) using a Smith chart of power. In some embodiments, a target power and a target return loss can be set to measure... Figure 1 The impedance of antenna 101 to generate Figure 3A The Smith chart was used to confirm the impedance shift of antenna 101. For example, in Figure 3A In this example, the target power is set to 16 dB, meaning that ideally the output signal VO has a power of 16 dB in all phases. The return loss of antenna 101 is set to 6 dB. Through S-parameter analysis, a circle 301 corresponding to a reflection coefficient S11 (which can be used to indicate return loss) of -6 dB can be plotted on the Smith chart.

[0051] Circle 301 contains multiple points P1 to P10, each representing the power of the output signal VO at different phases. For example, point P1 indicates that the power of the output signal VO with a phase of 0 degrees is 14.32 dB when the return loss of antenna 101 is 6 dB; point P10 indicates that the power of the output signal VO with a phase of 270 degrees is 15.81 dB when the return loss of antenna 101 is 6 dB; and point P12 indicates that the power of the output signal VO with a phase of 330 degrees is 14.84 dB when the return loss of antenna 101 is 6 dB.

[0052] Figure 3BThe indicator current I1 is plotted according to some embodiments of this disclosure when... Figure 1 The Smith chart shows the return loss of antenna 101 as approximately 6 dB and the value of transmitter circuit 120 operating in the high-frequency band (i.e., the third frequency band). Corresponding to... Figure 3A By sensing Figure 1 The values ​​of the current I1 at different phases can be obtained, and circle 302 can be plotted on the Smith chart. Corresponding to circle 301, circle 302 also contains multiple points P1 to P10, among which... Figure 3A The positions of multiple points P1 to P10 are the same as Figure 3B The positions of multiple points P1 to P10. Figure 3B In the diagram, each point represents the value of current I1 at different phases. For example, point P1 indicates that the value of current I1 is 356.42 mA when the phase of the output signal VO is 0 degrees and the return loss of antenna 101 is 6 dB; point P10 indicates that the value of current I1 is 368.32 mA when the phase of the output signal VO is 270 degrees and the return loss of antenna 101 is 6 dB; and point P12 indicates that the value of current I1 is 366.21 mA when the phase of the output signal VO is 330 degrees and the return loss of antenna 101 is 6 dB.

[0053] Figure 3C The indicator current I1 is plotted according to some embodiments of this disclosure when... Figure 1 The Smith chart shows the return loss of antenna 101 as approximately 6 dB and the value of transmitter circuit 120 operating in the low-frequency band (i.e., the first frequency band). Similar... Figure 3B Under the given measurement conditions, in this example, the return loss of antenna 101 is still set to 6 dB, while transmitter circuit 120 is changed to operate in the low-frequency band (i.e., the first frequency band). Thus, using the same measurement method, the values ​​of this current I1 at different phases can be plotted on a Smith chart to generate circle 303. Corresponding to circles 301 and 302, circle 303 also contains multiple points P1 to P10, among which... Figure 3C The positions of multiple points P1 to P10 are the same as Figure 3A and Figure 3B The positions of multiple points P1 to P10.

[0054] Similarly, in Figure 3C In the diagram, each point represents the value of current I1 at different phases. For example, point P10 indicates that the value of current I1 is 357.9 milliamperes when the phase of the output signal VO is 270 degrees and the return loss of antenna 101 is 6 dB, and point P12 indicates that the value of current I1 is 334.43 milliamperes when the phase of the output signal VO is 330 degrees and the return loss of antenna 101 is 6 dB.

[0055] Depend on Figure 3A It can be seen that the power corresponding to point P10 is quite close to the target power (e.g., 16 dB), while the power corresponding to point P12 differs significantly from the target power. Therefore, the correction circuit 140 will compensate for the impedance shift corresponding to point P12. However, in Figure 3B It can be seen that the value of the current I1 corresponding to point P10 is quite close to the value of the current I1 corresponding to point P12. The difference between the two current values ​​may be lower than the resolution of the current sensor circuit 141, causing the correction circuit 140 to be unable to accurately determine whether the impedance shift of the antenna 101 corresponds to point P10 or point P12 based on the current I1 measured in a single frequency band. In this case, the transmitter circuit 120 can be controlled to operate in another frequency band (e.g., the first frequency band) and the values ​​of the current I1 corresponding to points P10 and P12 can be sensed again. Figure 3C As shown, there is a significant difference between the current I1 value corresponding to point P10 and the current I1 value corresponding to point P12. Therefore, by mapping multiple points in different frequency bands, the correction circuit 140 can more accurately determine whether the impedance shift of the antenna 101 corresponds to point P10 or point P12.

[0056] On the other hand, such as Figure 3B As shown, the current I1 value corresponding to point P5 (i.e., 315.52 mA) is quite close to the current I1 value corresponding to point P6 (i.e., 314.91 mA). The difference in current between these two values ​​may be below the resolution of the current sensing circuit 141. Accordingly, as... Figure 3C As shown, there is a significant difference between the current I1 value corresponding to point P5 (i.e., 300.79 mA) and the current I1 value corresponding to point P6 (i.e., 307.74 mA). This allows the correction circuit 140 to more accurately determine whether the impedance shift of the antenna 101 corresponds to point P5 or point P6. Accordingly, it should be understood that if the measured value of the transmitter circuit 120 operating in the low-frequency band (i.e., the first frequency band) is still lower than the resolution of the current sensor circuit 141, the transmitter circuit 120 can be controlled to operate in another frequency band (e.g., the second frequency band) and the value of the current I1 can be sensed. In this way, points P1 to P10 can be equivalently mapped from the first frequency band to the second frequency band, and the impedance shift of the antenna 101 can be determined based on the current I1 corresponding to points P1 to P12 in the second frequency band.

[0057] Figure 4 Drawings based on some embodiments of this disclosure Figure 1 A schematic diagram of lookup table 145. Based on Figures 3A to 3C As shown in the Smith chart, it should be understood that in some embodiments, Figure 1 The lookup table 145 can be accessed through Figures 3A to 3CThe measurement method shown is established in advance.

[0058] For example, Figure 4 The lookup table 145 corresponds to the case where the target power is 16 dBmW. Lookup table 145 indicates the correspondence between multiple impedance information, multiple first current values, multiple second current values, and multiple third current values. The multiple impedance information indicates multiple reflection coefficients (in this example, 0.5, corresponding to a return loss of 6 dB) measured by antenna 101 based on output signals VO with different phases. The multiple first current values ​​are the values ​​of current I1 corresponding to output signals VO with different phases when transmitter circuit 120 operates in the first frequency band. The multiple second current values ​​are the values ​​of current I1 corresponding to output signals VO with different phases when transmitter circuit 120 operates in the second frequency band. The multiple third current values ​​are the values ​​of current I1 corresponding to output signals VO with different phases when transmitter circuit 120 operates in the third frequency band. Furthermore, lookup table 145 can also indicate the correspondence between these impedance information, multiple first power compensation amounts in the first frequency band, multiple second power compensation amounts in the second frequency band, and multiple third power compensation amounts in the third frequency band. The first power compensation amount, the second power compensation amount, and the third power compensation amount represent the difference between the power of the output signal VO and the target power in the corresponding frequency band.

[0059] In detail, Figure 3A and Figure 3B In the third frequency band, the power of the output signal VO corresponding to point P10 is 15.81 dB, and the difference between this power and the target power is 0.19 dB (i.e., the third power compensation amount). The value of the current I1 corresponding to point P10 is 368.32 mA (i.e., the third current value). Correspondingly, in Figure 3C In the first frequency band, the power of the output signal VO corresponding to point P10 is 16.48 dB, and the difference between this power and the target power is -0.48 dB (i.e., the first power compensation amount). The value of the current I1 corresponding to point P10 is 357.9 mA (i.e., the first current value). Therefore, by searching the lookup table 145, it can be determined that the impedance information corresponding to point P10 is a reflection coefficient of 0.5 and the phase of the output signal VO is 270 degrees. In this way, the correction circuit 140 can confirm the impedance offset of the antenna 101 based on this impedance information (marked with a thick box), and can generate the corresponding signal S2 in different frequency bands according to the first power compensation amount, the second power compensation amount, and the third power compensation amount corresponding to this impedance information.

[0060] Figure 5This is a flowchart illustrating a power correction method 500 according to some embodiments of the present disclosure. In some embodiments, the power correction method 500 may be (but is not limited to) [methods described in the original text]. Figure 1 The transmitter 100 is executing.

[0061] In operation S510, the transmitter circuit is controlled to operate in one of multiple frequency bands, and the target power of the transmitter circuit is set, wherein the transmitter circuit receives the supply voltage via a power node and transmits the output signal via an antenna. For example, the transmitter circuit 120 can be controlled to operate in a first frequency band and the target power of the transmitter circuit 120 can be set (e.g., the aforementioned 16 dB) via software or a control circuit (not shown) in the system.

[0062] In operation S520, the value of the current at the power node is sensed to generate a signal having a first value. For example, the current sensor circuit 141 can sense the current I1 to generate a signal S1 having a first value.

[0063] In operation S530, the transmitter circuit is controlled to operate in one of the remaining frequency bands, and the current value of the power supply node is sensed to generate a signal with other values. For example, the transmitter circuit 120 can be controlled by software to operate in the second frequency band. Under this condition, the current sensing circuit 141 can sense the current I1 to generate a signal S1 with a second value. Similarly, the transmitter circuit 120 is again controlled to operate in the third frequency band. Under this condition, the current sensing circuit 141 can sense the current I1 to generate a signal S1 with a third value.

[0064] In operation S540, a correction signal is generated by searching a lookup table based on a signal having a first value and signals having other values. For example, as described above, the memory circuit 142 can search the lookup table 145 based on a signal S1 having a third value to confirm relevant information for a third frequency band, and search the lookup table 145 based on a signal S1 having a first value to confirm relevant information for a first frequency band, thereby confirming the impedance shift of the antenna 101. Next, the memory circuit 142 can generate corresponding correction signals DC in different frequency bands based on multiple power compensation amounts corresponding to this impedance shift. In some embodiments, if the impedance shift cannot be effectively determined based on the relevant information for both the first and third frequency bands, the memory circuit 142 can also search the lookup table 145 for information about the second frequency band based on a signal S1 having a second value to confirm the impedance shift of the antenna 101.

[0065] In operation S550, the power of the output signal is detected to generate a first detection signal, and a second detection signal is generated based on the first detection signal and a correction signal. In operation S560, the power of the output signal is adjusted to a target power based on the second detection signal. For example, the transmitter signal strength indicator circuit 160 can detect the power of the output signal VO to generate a detection signal D1, and sum the detection signal D1 and the correction signal DC to generate a detection signal D2. In this way, the transmitter circuit 120 can adjust the amplification gain based on the detection signal D2, thereby adjusting the power of the output signal VO.

[0066] The descriptions of the various operations of the power correction method 500 described above can be found in the foregoing embodiments, and therefore will not be repeated here. The aforementioned operations are merely examples and are not limited to being performed in the order shown in these examples. Without departing from the operational mode and scope of the embodiments of this disclosure, various operations in the power correction method 500 may be appropriately added, replaced, omitted, or performed in a different order. Alternatively, one or more operations in the power correction method 500 may be performed simultaneously or partially simultaneously.

[0067] It should be understood that the above embodiments are illustrated using three frequency bands as an example. In different embodiments, the above-described circuit configurations, lookup table 145, and power correction method 500 can also be applied to applications with only two frequency bands. Therefore, the above embodiments are applicable to applications with two or more frequency bands. Furthermore, the above embodiments are illustrated with a return loss of 6 dB, but this disclosure is not limited thereto.

[0068] In summary, the transmitter and power correction method provided in some embodiments of this disclosure can effectively determine the impedance shift of the antenna by sensing the current in different frequency bands, and determine the corresponding power compensation amount, thereby correcting the power of the transmitter back to the target power.

[0069] Although the embodiments of this disclosure are described above, they are not intended to limit this disclosure. Those skilled in the art can make changes to the technical features of this disclosure based on its express or implied content. All such changes may fall within the scope of patent protection sought by this disclosure. In other words, the scope of patent protection of this disclosure shall be determined by the claims of this specification.

Claims

1. A transmitter comprising: A transmitter circuit is coupled to a power node to receive a supply voltage and transmits an output signal via an antenna; A calibration circuit is configured to sense a current at a power node to generate a first signal having a first value when the transmitter circuit operates in a first frequency band, and to sense the current to generate the first signal having a second value when the transmitter circuit operates in a second frequency band, and to generate a calibration signal based on the first signal having the first value and the first signal having the second value; and A transmitter signal strength indicator circuit is used to detect the power of the output signal to generate a first detection signal, and to generate a second detection signal based on the correction signal and the first detection signal. The transmitter circuit is also used to adjust the power of the output signal to a target power based on the second detection signal.

2. The transmitter of claim 1, wherein the correction circuit is configured to determine the impedance offset of the antenna and a power compensation amount based on the first value and the second value, so as to generate the correction signal.

3. The transmitter of claim 1, wherein the correction circuit comprises: A current sensor circuit is used to sense the current to generate the first signal having the first value when the transmitter circuit operates in the first frequency band, and to sense the current to generate the first signal having the second value when the transmitter circuit operates in the second frequency band. A first memory circuit is configured to store a lookup table and search the lookup table based on a first signal having a first value and a first signal having a second value to generate a second signal. as well as A second memory circuit is used to generate the correction signal based on the second signal.

4. The transmitter of claim 3, wherein the lookup table indicates a correspondence between a plurality of impedance information, a plurality of first current values, and a plurality of second current values, the plurality of impedance information indicating a plurality of reflection coefficients measured by the antenna based on the output signal having a different phase, the plurality of first current values ​​being values ​​corresponding to the output signal having a different phase when the transmitter circuit operates in the first frequency band, and the plurality of second current values ​​being values ​​corresponding to the output signal having a different phase when the transmitter circuit operates in the second frequency band.

5. The transmitter of claim 4, wherein the lookup table is further used to indicate the correspondence between the plurality of impedance information, the plurality of first power compensation amounts in the first frequency band, and the plurality of second power compensation amounts in the second frequency band.

6. The transmitter of claim 4, wherein each of the plurality of reflection coefficients is -6 dB.

7. The transmitter of claim 1, wherein the frequency ranges of the first frequency band and the second frequency band are different from each other.

8. The transmitter of claim 1, wherein the correction circuit is further configured to sense the current to generate the first signal having a third value when the transmitter circuit operates in a third frequency band, and to generate the correction signal based on the first signal having the first value, the first signal having the second value, and the first signal having the third value, wherein the frequency ranges of the first frequency band, the second frequency band, and the third frequency band are different from each other.

9. The transmitter of claim 1, wherein the transmitter circuitry is configured to adjust an amplification gain based on the second detection signal to adjust the power of the output signal.

10. A power correction method, comprising: When a transmitter circuit operates in a first frequency band, it senses a current in a power node to generate a first signal having a first value, wherein the transmitter circuit is coupled to the power node to receive a supply voltage, and the transmitter circuit transmits an output signal via an antenna. The current is sensed when the transmitter circuit operates in a second frequency band to generate the first signal having a second value; A correction signal is generated based on the first signal having the first value and the first signal having the second value; The power of the output signal is detected to generate a first detection signal, and a second detection signal is generated based on the correction signal and the first detection signal; and The power of the output signal is adjusted to a target power based on the second detection signal.

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