An envelope tracking power amplifier switching power supply control method and a switching power supply

Abstract

The present invention discloses a control method and a switching power supply for an envelope tracking power amplifier. The method includes: performing at least one ripple adjustment process on a first switching signal to output a ripple injection signal without a DC voltage; obtaining a first DC voltage with ripple injection based on superimposing the ripple injection signal on the first DC voltage; outputting the comparison result between the second DC voltage and the first DC voltage with ripple injection to the switching power supply, so that the switching power supply obtains a second switching signal, and the second switching signal is a switching signal with a switching frequency; receiving the second switching signal and outputting it to the switching power supply, so that the switching power supply obtains a DC current, thereby realizing the stable operation of the switching power supply through a ripple injection circuit while minimizing the ripple of the switching power supply, improving its efficiency and anti-interference ability, and reducing noise.

Description

Technical Field

[0001] The present application relates to the field of wireless communication technologies, and more particularly, to a method for controlling a switching power supply of an envelope tracking power amplifier and a switching power supply. Background Art

[0002] Output ripple refers to the remaining AC component in the DC voltage output by the power supply due to incomplete filtering. When powered by a battery, ripples will be generated due to load fluctuations. These ripples are likely to generate undesirable harmonics in the equipment in use, and the harmonics will cause many harms, reducing the efficiency of the power supply; strong ripples will cause the generation of surge voltage or current, resulting in the burning out of electrical equipment; they will even interfere with the logical relationship of digital circuits, affecting their normal operation and bringing noise interference, making image equipment and audio equipment unable to work properly. Therefore, the new generation of wireless communication pays more attention to the output ripple while putting forward higher requirements for the efficiency, linearity, and stability of the power supplies of signal output devices and signal receiving devices.

[0003] Existing switching power supplies for envelope tracking power amplifiers adopt a linear amplifier-switching power supply structure, where the switching power supply circuit provides voltage and current to the power amplifier through the same control circuit; at the same time, to ensure the stability of the switching power supply, the ripple of the power supply cannot be minimized during the circuit design process. That is to say, a certain amount of ripple is included in the circuit output voltage to ensure the stability of the power supply.

[0004] However, the inventors found during the implementation of the present invention that if one wants to further improve the efficiency, anti-interference ability, and reduce the noise of the switching power supply of the envelope tracking power amplifier, the output ripple of the power supply can only be further reduced. Summary of the Invention

[0005] The present invention provides a method for controlling a switching power supply of an envelope tracking power amplifier to solve the technical problems in the prior art that the power supply for wireless communication devices has low efficiency and the output ripple cannot be minimized. The method includes:

[0006] Performing at least one ripple adjustment process on a first switching signal to output a ripple injection signal that does not include a DC voltage, where the first switching signal is obtained based on the comparison result between a second DC voltage and a first DC voltage;

[0007] Obtaining a first DC voltage with ripple injection by superimposing the ripple injection signal on the first DC voltage;

[0008] Outputting the comparison result between the second DC voltage and the first DC voltage with ripple injection to the switching power supply so that the switching power supply obtains a second switching signal, where the second switching signal is a switching signal with a switching frequency;

[0009] Receive the second switching signal and output it to the switching power supply so that the switching power supply obtains a DC current.

[0010] Preferably, to obtain the second DC voltage, the specific steps include:

[0011] Obtain a third DC voltage according to the DC component signal in the obtained envelope signal;

[0012] Obtain the first DC voltage by sensing the DC voltage required for the output of the switching power supply;

[0013] Receive and superimpose the third DC voltage and the difference voltage to obtain the second DC voltage, where the difference voltage is obtained by comparing the first DC voltage and the third DC voltage.

[0014] Preferably, to obtain the first switching signal according to the comparison result between the second DC voltage and the first DC voltage, the specific steps include:

[0015] When the second DC voltage is greater than or equal to the first DC voltage, and when the switching power supply is output in a constant-time conduction mode, obtain a high-level signal of the switching signal;

[0016] When the second DC voltage is lower than the first DC voltage, and / or when the second DC voltage is greater than or equal to the first DC voltage and the switching power supply is output in a cut-off state, obtain a low-level signal of the switching signal.

[0017] Preferably, perform at least one ripple adjustment process on the first switching signal and output a ripple injection signal without DC voltage, and the specific steps include:

[0018] Receive the first switching signal and perform signal filtering to obtain a first adjusted ripple;

[0019] Receive the first adjusted ripple and perform signal filtering to obtain a second adjusted ripple;

[0020] Perform an operation on the first adjusted ripple and the second adjusted ripple and output the ripple injection signal.

[0021] Preferably, compare the second DC voltage and the ripple injection first DC voltage, output to make the switching power supply work in a conduction or cut-off state, and obtain the second switching signal. The specific steps include:

[0022] When the second DC voltage is greater than or equal to the ripple injection first DC voltage, and when the switching power supply is output in a constant-time conduction mode, obtain a high-level signal with a switching frequency;

[0023] When the second DC voltage is lower than the first DC voltage with ripple injection, and / or when the second DC voltage is greater than or equal to the first DC voltage with ripple injection and the output makes the switching power supply in the cut-off state, a low-level signal with a switching frequency is obtained.

[0024] Preferably, it further includes obtaining the AC voltage and AC current of the switching power supply. The specific steps include:

[0025] Obtaining a second envelope signal according to the first envelope signal, wherein the second envelope signal is linearly amplified and includes a DC component and an AC component;

[0026] Outputting the AC voltage and the AC current according to the AC component signal in the obtained second envelope signal.

[0027] Correspondingly, the present invention also proposes a switching power supply for an envelope tracking power amplifier, including a ripple injection circuit with a subtraction unit, a first ripple adjustment unit, and a second ripple adjustment unit.

[0028] The first ripple adjustment unit is used to perform ripple adjustment processing on the received signal and output a first adjusted ripple to the second ripple adjustment unit and the subtraction unit;

[0029] The second ripple adjustment unit is used to perform ripple adjustment processing on the first adjusted ripple and output a second adjusted ripple to the subtraction unit;

[0030] The subtraction unit is used to perform an operation on the first adjusted ripple and the second adjusted ripple and output a ripple injection signal without a DC voltage.

[0031] Preferably, it further includes a switch control circuit.

[0032] The switch control circuit includes a logic control unit, a switch control unit, a switch unit, and an inductor connected in sequence, and is configured to superimpose and compare the ripple injection signal with the DC voltage sensed by the switching power supply demand through the logic control unit, and output a switch control signal to obtain a switch signal and a DC current with a switching frequency required by the switching power supply.

[0033] Preferably, it further includes a voltage adjustment circuit.

[0034] The voltage adjustment circuit includes a filtering unit, an adder, a voltage detector, a voltage follower, and a resistor;

[0035] The filtering unit and the voltage detector are both connected to the voltage follower and the resistor in sequence through the adder, and perform tracking detection and superposition on the DC voltage required by the switching power supply to obtain the DC drive voltage of the switching power supply.

[0036] Preferably,

[0037] The first ripple adjustment unit and the second ripple adjustment unit are composed of any one or any combination of capacitors, reactances, and resistors.

[0038] Compared with the prior art, the present invention has the following beneficial effects:

[0039] The present invention discloses an envelope tracking power amplifier switching power supply control method and a switching power supply. The method includes: performing at least one ripple adjustment process on a first switching signal to output a ripple injection signal without a DC voltage; obtaining a ripple-injected first DC voltage based on superimposing the ripple injection signal on the first DC voltage; outputting a comparison result of the second DC voltage and the ripple-injected first DC voltage to the switching power supply so that the switching power supply obtains a second switching signal, where the second switching signal is a switching signal with a switching frequency; receiving the second switching signal and outputting it to the switching power supply so that the switching power supply obtains a DC current, thereby realizing stable operation of the switching power supply through a ripple injection circuit while minimizing the ripple of the switching power supply, improving its efficiency and anti-interference ability, and reducing noise. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the following drawings are only some embodiments of the present application. For those skilled in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0041] Figure 1 It is a schematic flowchart of a novel envelope tracking power amplifier switching power supply control method proposed in an embodiment of the present invention;

[0042] Figure 2 It is a schematic structural diagram of a switching power supply in an embodiment of the present invention;

[0043] Figure 3 It is a schematic diagram of the control principle of an envelope tracking power amplifier switching power supply in an embodiment of the present invention;

[0044] Figure 4 It is a schematic structural diagram of a ripple injection circuit in an embodiment of the present invention;

[0045] Figure 5 It is a schematic structural diagram of a switch control circuit in an embodiment of the present invention;

[0046] Figure 6 It is a schematic structural diagram of a voltage adjustment circuit in an embodiment of the present invention;

[0047] Figure 7Schematic diagram of the linear circuit structure in the embodiments of the present invention. Detailed implementation manners

[0048] Next, the technical solutions in the embodiments of the present application will be clearly and completely described with reference to the accompanying drawings in the embodiments of the present application. Apparently, the described embodiments are only a part rather than all of the embodiments of the present application. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present application without creative efforts shall fall within the protection scope of the present application.

[0049] As described in the background art, in the existing envelope tracking power amplifier switching power supply, if you want to further improve the efficiency and anti-interference of the envelope tracking power amplifier switching power supply, it is necessary to further reduce the power supply output ripple. When the output ripple is reduced to the limit that the switching power supply can handle, the stability of the switching power supply will be affected.

[0050] To solve the above problems, the embodiments of the present application propose a control method for an envelope tracking power amplifier switching power supply, which provides an injection ripple signal to the switching power supply based on a ripple injection circuit, and ensures the stability and reliability of its operation while reducing the ripple of the switching power supply itself; different circuits are used to separately provide a DC voltage and a DC current to the load, further improving the efficiency of the switching power supply.

[0051] As Figure 1 shown in the flowchart of the above control method for the envelope tracking power amplifier switching power supply, the method includes the following steps:

[0052] Step S101, perform at least one ripple adjustment process on the first switching signal, and output a ripple injection signal that does not include a DC voltage, where the first switching signal is obtained according to the comparison result between the second DC voltage and the first DC voltage.

[0053] Specifically, in the specific application scenario of the present application, as Figure 3 shown, the first switching signal is generated by the switch control circuit 32, and the ripple injection circuit 31 performs at least one ripple adjustment process on the first switching signal and outputs a ripple injection signal that does not include a DC voltage. The first switching signal is obtained according to the comparison result between the second DC voltage Vdc2 and the first DC voltage Vdc1.

[0054] To obtain an accurate second DC voltage, in the preferred embodiment of the present application, to obtain the second DC voltage, the specific steps include:

[0055] Obtain a third DC voltage according to the DC component signal in the obtained envelope signal;

[0056] Obtain the first DC voltage by sensing the DC voltage required for the output of the switching power supply;

[0057] Receive and superimpose the third DC voltage and the difference voltage to obtain the second DC voltage, where the difference voltage is obtained by comparing the first DC voltage and the third DC voltage.

[0058] Specifically, as Figure 3 shown, determine the third DC voltage according to the DC shunt in the envelope signal S2, obtain the first DC voltage by sensing the DC voltage required for the output of the switching power supply, and superimpose the difference between the first DC voltage and the third DC voltage as the difference voltage and the third DC voltage to obtain the second DC voltage.

[0059] It should be noted that the solutions of the above preferred embodiments are only a specific implementation solution proposed by this application. The above DC shunt signal and the difference voltage can be obtained by measurement or calculation, and different obtaining methods do not affect the protection scope of this application.

[0060] To obtain an accurate first switching signal, in the preferred embodiment of this application, obtain the first switching signal according to the comparison result of the second DC voltage and the first DC voltage. The specific steps include:

[0061] When the second DC voltage is greater than or equal to the first DC voltage, output a high-level signal of the switching signal when the switching power supply is in the constant-time conduction mode;

[0062] When the second DC voltage is lower than the first DC voltage, and / or when the second DC voltage is greater than or equal to the first DC voltage, output a low-level signal of the switching signal when the switching power supply is in the cut-off state.

[0063] As described above, in the specific application scenario of this application, as Figure 5 shown, the switch control unit 322 adopts any COT control module that can implement COT control. For COT, there are two types: constant on-time, that is, Constant OnTime; and constant off-time, that is, Constant Off Time. By comparing the second DC voltage and the first DC voltage, output a high-level signal of the switching signal when the switching power supply is in the constant-time conduction mode, or output a low-level signal when the switching power supply is in the cut-off state.

[0064] It should be noted that the solutions of the above preferred embodiments are only specific implementation solutions proposed by the present application, and various COT control units in the prior art can be referred to, including timers or timers that may be involved in COT control, or other circuits or functional units cooperating with the timers or timers. The main purpose is to calculate and determine the corresponding constant on-time or constant off-time. Other ways of obtaining the first switching signal according to the comparison result of the second DC voltage and the first DC voltage all fall within the protection scope of the present application.

[0065] As Figure 2 shown, when the DC voltage is included in the ripple signal, during the process of superimposing it on the third DC voltage Vdc3, the value of the third DC voltage Vdc3 will be changed, so that the power supply output voltage is inconsistent with the actually required voltage, affecting the power supply stability and efficiency. And when the frequencies are different, it will cause the injected ripple signal to fail. To avoid the above problems, in the preferred embodiment of the present application, at least one ripple adjustment process is performed on the first switching signal to output a ripple injection signal without DC voltage. The specific steps include:

[0066] Receiving the first switching signal and performing signal filtering processing to obtain a first adjusted ripple;

[0067] Receiving the first adjusted ripple and performing signal filtering processing to obtain a second adjusted ripple;

[0068] Performing an operation on the first adjusted ripple and the second adjusted ripple to output the ripple injection signal.

[0069] Specifically, a first adjusted ripple is obtained by performing signal filtering processing on the first switching signal, and a second adjusted ripple is obtained by performing signal filtering processing on the first adjusted ripple again. Finally, a ripple injection signal is output according to the operation result of the first adjusted ripple and the second adjusted ripple. In the specific application scenario of the present application, the operation result can be generated by a subtraction unit. As Figure 4 shown, the subtraction unit 313 performs an operation on the SW1 and SW2 ripple signals to remove the DC voltage part and outputs an injected ripple signal SW3. The injected ripple signal SW3 is superimposed on the first DC voltage Vdc1 only to increase the ripple without changing the voltage value of the first DC voltage Vdc1. And, by performing two filtering processes on the switching signal SW4 with a switching frequency, the obtained first adjusted ripple SW1 and second adjusted ripple SW2 have different signal amplitudes, but their frequencies are the same as those of the switching signal SW4. The frequency of the injected ripple signal SW3 obtained from the first adjusted ripple SW1 and the second adjusted ripple SW2 is the same as the frequency of the DC voltage to which the ripple needs to be injected. Therefore, injecting the ripple signal SW3 into the DC voltage will not affect the DC voltage frequency and other characteristics.

[0070] It should be noted that the solutions of the above preferred embodiments are only a specific implementation solution proposed by this application. Those skilled in the art can set different numbers of ripple adjustment processes according to actual needs, which does not affect the protection scope of this application.

[0071] Step S102: Based on superimposing the ripple injection signal onto the first DC voltage, obtain the ripple-injected first DC voltage.

[0072] Specifically, in the specific application scenario of this application, as Figure 2 shown, the ripple injection circuit 31 superimposes the ripple injection signal onto the first DC voltage to obtain the ripple-injected first DC voltage.

[0073] Step S103: Output the comparison result between the second DC voltage and the ripple-injected first DC voltage to the switching power supply, so that the switching power supply obtains a second switching signal, and the second switching signal is a switching signal with a switching frequency.

[0074] As described above, by comparing the ripple-injected first DC voltage with the second DC voltage, a second switching signal with a switching frequency is output according to the comparison result.

[0075] To obtain an accurate second switching signal, in the preferred embodiment of this application, compare the second DC voltage with the ripple-injected first DC voltage, and output to make the switching power supply operate in a conducting or cutoff state to obtain the second switching signal. The specific steps include:

[0076] When the second DC voltage is greater than or equal to the ripple-injected first DC voltage, output to make the switching power supply in a constant-time conduction mode to obtain a high-level signal with a switching frequency;

[0077] When the second DC voltage is lower than the ripple-injected first DC voltage, and / or when the second DC voltage is greater than or equal to the ripple-injected first DC voltage, output to make the switching power supply in a cutoff state to obtain a low-level signal with a switching frequency.

[0078] Specifically, in the specific application scenario of this application, as Figure 5 shown, the switch control unit 322 adopts any COT control module that can implement COT control. For COT, there are two types: constant conduction time and constant cutoff time. By comparing the second DC voltage with the ripple-injected first DC voltage, output a high-level signal with a switching frequency when the switching power supply is in a constant-time conduction mode, or output a low-level signal with a switching frequency when the switching power supply is in a cutoff state.

[0079] It should be noted that the solutions of the above preferred embodiments are only a specific implementation solution proposed by this application. Various COT control units in the prior art can be used for reference, including timers or counters involved in COT control, or other circuits or functional units cooperating with timers or counters. Their main purpose is to calculate and determine the corresponding constant on-time or constant off-time. Other methods of obtaining the second switching signal all fall within the protection scope of this application.

[0080] Step S104: Receive the second switching signal and output it to the switching power supply so that the switching power supply obtains a direct current.

[0081] As described above, by outputting the second switching signal to the switching power supply, the switching power supply obtains a direct current.

[0082] In a preferred embodiment of this application, in order to provide an alternating voltage and an alternating current to a load, the specific steps for obtaining the alternating voltage and the alternating current of the switching power supply include:

[0083] Obtain a second envelope signal according to the first envelope signal, where the second envelope signal is linearly amplified and includes a direct current component and an alternating current component;

[0084] Output the alternating voltage and the alternating current according to the alternating current component signal in the obtained second envelope signal.

[0085] Specifically, in a specific application scenario of this application, as Figure 3 shown, an alternating voltage Vac and an alternating current Iac are provided to the load according to the alternating current component signal in the obtained second envelope signal S2.

[0086] By applying the above technical solutions, the first switching signal is subjected to at least one ripple adjustment process to output a ripple injection signal without a direct current voltage; based on superimposing the ripple injection signal on the first direct current voltage to obtain a ripple injection first direct current voltage; outputting the comparison result of the second direct current voltage and the ripple injection first direct current voltage to the switching power supply so that the switching power supply obtains a second switching signal, where the second switching signal is a switching signal with a switching frequency; receiving the second switching signal and outputting it to the switching power supply so that the switching power supply obtains a direct current, thereby achieving stable operation of the switching power supply through the ripple injection circuit while minimizing the ripple of the switching power supply, improving its efficiency and anti-interference ability, and reducing noise.

[0087] In order to further elaborate on the technical idea of the present invention, the technical solutions of the present invention will be described below in combination with specific application scenarios.

[0088] It is necessary to inject a ripple signal into the circuit to improve the stability and reliability of the switching power supply. This is because when the ripple in the circuit is too high, the efficiency of the power supply will be reduced. A strong ripple will cause the generation of surge voltage or current, resulting in the burnout of electrical equipment. It will even interfere with the logical relationship of digital circuits, affect their normal operation and bring noise interference, making image equipment and audio equipment unable to work properly. Therefore, during the power supply design process, in order to reduce circuit losses and improve efficiency, circuit designers minimize the ripple to the greatest extent through reasonable parameter selection, making the linearity between the circuit and the processed signal better. However, when the circuit ripple is reduced to a certain extent, that is, when the circuit ripple exceeds the limit that the circuit can handle, the stability of the circuit will be reduced. That is to say, the circuit switch or other components will get out of control, seriously affecting the use of the circuit and even resulting in system crashes.

[0089] By introducing a ripple injection signal, that is, circuit designers can minimize the circuit ripple to the greatest extent through the design of component parameters. That is, when the circuit ripple exceeds the limit that the system can handle, at this time, the power supply provides a ripple injection signal to the circuit through the control method of the above embodiment. Without increasing the circuit ripple, the circuit ripple meets the requirements of circuit stability and reliability, thus ensuring the stability of the power supply.

[0090] Such as Figure 2 shown is the schematic diagram of the switching power supply structure in the embodiment of the present invention. As Figure 3 shown is the schematic diagram of the switching power supply control principle of the envelope tracking power amplifier in the embodiment of the present invention. The third DC voltage Vdc3 does not include the ripple in the switching power supply. If the DC voltage is directly provided to the load through the third DC voltage Vdc3, distortion will occur. Therefore, according to the DC component signal in the obtained envelope signal S2, the third DC voltage Vdc3 is obtained. The first DC voltage Vdc1 is obtained by sensing the DC voltage required for the output of the switching power supply. The difference voltage is obtained by comparing the first DC voltage Vdc1 and the third DC voltage Vdc3. The first DC voltage Vdc1 and the difference voltage are superimposed to obtain the second DC voltage Vdc2. This second DC voltage Vdc2 is the DC voltage actually required for the operation of the switching power supply.

[0091] The linear circuit 1 realizes the linear amplification of the envelope signal S1 and provides the AC voltage Vac and the AC current Iac to the RF power amplifier through the voltage detector 21; the voltage adjustment circuit 2 realizes the adjustment of the second DC voltage Vdc2 by detecting and comparing the third DC voltage Vdc3, so as to output the DC voltage to the RF power amplifier; the ripple injection circuit 31 and the switch control circuit 32 reduce the ripple of the switching power supply system by injecting the ripple injection signal while improving the stability and efficiency of the switching power supply, and provide the DC current Idc to the RF power amplifier, thus not only reducing the ripple of the switching power supply, but also further improving the efficiency of the switching power supply through the sub-circuit supply of the DC voltage and the DC current.

[0092] In order to provide the AC voltage Vac and the AC current Iac to the load, according to the AC component signal in the obtained second envelope signal S2, the AC voltage Vac and the AC current Iac are provided to the load.

[0093] The specific structure of the ripple injection circuit 31 is as Figure 4 shown, including a ripple injection circuit with a subtraction unit 313, a first ripple adjustment unit 311, and a second ripple adjustment unit 312. The switching control signal SW4 or the switching control signal SW5 with the switching frequency passes through the first ripple adjustment unit 311, and outputs the first adjusted ripple SW1 to the second ripple adjustment unit 312 and the subtraction unit 313. After the second ripple adjustment unit adjusts and processes the first ripple signal SW1, it outputs the second ripple signal SW2 to the subtraction unit 313. The subtraction unit 313 performs a subtraction operation on the received first ripple signal SW1 and the second ripple signal SW2 and then outputs the injection ripple signal SW3 that does not contain the DC voltage.

[0094] When a DC voltage is included in the ripple signal, during the process of its superposition onto the first DC voltage Vdc1, the value of the first DC voltage Vdc1 will be changed, thereby making the power supply output voltage inconsistent with the actually required voltage, and affecting the stability and efficiency of the power supply. The embodiments of the present application design a two-stage same-frequency ripple adjustment unit and a subtraction unit, which helps to solve the above problems. This is because the first ripple signal SW1 generated after the signal SW4 or SW5 is filtered by the first ripple adjustment unit 311 contains the ripple signal of the DC voltage; the second ripple signal SW2 generated after the first ripple signal SW1 is filtered by the second ripple adjustment unit 312 is a ripple signal close to the DC voltage. The subtraction unit 313 performs an operation on the ripple signals SW1 and SW2 to remove the DC voltage part and outputs an injected ripple signal SW3. The superposition of the injected ripple signal SW3 and the first DC voltage Vdc1 only increases the ripple without changing the voltage value of the first DC voltage Vdc1. The ripple injection signal SW3 is not a fixed value, but a dynamic ripple injection signal that changes with the change of the internal ripple of the switching power supply, which can accurately adjust the circuit ripple and further ensure the stability of the power supply.

[0095] At the same time, it also avoids the problem that the injected ripple signal fails due to different frequencies. This is because the above embodiment performs two filtering processes on the switching signal SW4 with a switching frequency. The obtained first adjustment ripple SW1 and the second adjustment ripple SW2 have different signal amplitudes, but their frequencies are the same as that of the switching signal SW4. The frequency of the switching signal SW4 is the same as the DC voltage signal that needs to inject ripple. Therefore, the frequency of the injected ripple signal SW3 obtained through the first adjustment ripple SW1 and the second adjustment ripple SW2 is the same as the frequency of the DC voltage that needs to inject ripple. Therefore, after injecting the ripple signal SW3 into the DC voltage, it will not affect the DC voltage frequency and other characteristics, and only realizes the change of the ripple, ensuring that the power supply ripple superposition can achieve the expected purpose.

[0096] The above embodiments improve the stability of the switching power supply, improve the efficiency, and reduce the switching power supply ripple without increasing the circuit ripple. This is because when the ripple in the circuit is lower than the limit that the switching power supply can recognize, the efficiency of the switching power supply is improved, the anti-interference ability is enhanced, and the noise is low, but it will cause poor stability of the switching power supply, unable to recognize the switching power supply ripple, and distortion occurs. In the above embodiments, the power supply ripple is reduced below the limit that the switching power supply can recognize, the efficiency of the switching power supply is improved, and at the same time, a ripple signal is injected into the switching power supply. Without increasing the ripple of the switching power supply itself, the ripple is superimposed, so that the switching power supply ripple reaches the recognizable situation and improves the stability of the switching power supply.

[0097] For the first ripple adjustment unit and the second ripple adjustment unit, which are mainly used for filtering the signals SW4 and SW5, any circuit or module that can achieve filtering can be used. Therefore, it can include any one or any combination of capacitors, reactances, and resistors.

[0098] The specific structure of the switch control circuit 32 is as Figure 5 shown, including a logic control unit 321, a switch control unit 322, a switch unit 323, and an inductor L connected in sequence, configured to superimpose and compare the ripple injection signal SW3 and the first DC voltage Vdc1 of the DC voltage sensing the switch power supply demand through the logic control unit 321, and output a switch control signal to obtain a switch signal SW4 and a DC current Iac with a switching frequency required by the switch power supply.

[0099] The logic control unit 321 compares and judges the DC voltage containing the ripple signal required by the radio frequency power amplifier PA with the DC voltage without the ripple, and outputs a logic control signal to the switch control unit 322; the switch control unit 322 receives the logic control signal output by the logic control unit 321 and outputs a working mode signal of constant on-time or constant off-time; the switch unit 323 conducts or cuts off according to the working mode signal output by the switch control unit and outputs a switch signal with a switching frequency; the inductor L is used to provide a DC current Idc to the radio frequency power amplifier under the action of the switch signal with the switching frequency.

[0100] The above switch control unit 322 adopts any COT control module that can achieve COT control. For COT, there are two types: constant on-time, that is, Constant On Time; and constant off-time, that is, Constant Off Time. It should be noted that the present disclosure does not focus on the innovative implementation of the COT control unit. Therefore, various COT control units in the prior art can be borrowed, including timers or timers that may be involved in COT control, or other circuits or functional units cooperating with the timers or timers, and their main purpose is to calculate and determine the corresponding constant on-time or constant off-time.

[0101] The switch control unit 322 adopts COT control, so that the working frequency of the switch unit 323 is not limited by the equivalent load, hysteresis, loop delay, input signal, etc. It not only has a simple scheme, high efficiency, can eliminate control signal jitter, but also can reduce noise; moreover, the COT control has a high response speed and is very suitable for application scenarios such as envelope tracking that require a large input signal bandwidth and are convenient for expansion.

[0102] The switch control circuit 32 has at least two functions. One is to provide a ripple injection signal to the ripple injection circuit 31. The other is to provide a DC operating current Iac to the RF power amplifier. The control signal output by the switch unit 323 generates an induced current Iac after passing through the inductor L, and this induced current Iac is the DC operating current required by the RF power amplifier. This switch control circuit 32 only provides current to the RF power amplifier and does not provide voltage, and its principle is the same as that described in the previous embodiment, improving the power supply operating efficiency.

[0103] The specific structure of the voltage adjustment circuit 2 is as Figure 6 shown, and it includes a filtering unit 23, an adder 24, a voltage detector 21, a voltage follower 22, and a resistor R. The filtering unit 23 and the voltage detector 21 are both connected to the voltage follower 22 and the resistor R in sequence through the adder 24, and perform tracking detection and superposition on the first DC voltage Vdc1 required by the switching power supply to obtain the second DC voltage Vdc2, which is the DC drive voltage of the switching power supply.

[0104] The input end of the filtering unit 23 is connected to the output end of the linear circuit 1, and the output end is connected to the input end of the adder 23. The voltage detector 21 includes a first input end connected to the output end of the linear circuit 1, and also includes a second input end for connecting to the output end of the RF power amplifier to sense the DC voltage required by the load, and its output end is connected to the adder 24. The input end of the voltage follower 21 is connected to the output end of the adder, and the output end is connected to one end of the resistor R to output the second DC voltage Vdc2.

[0105] The voltage adjustment circuit 2 is used to provide a DC voltage to the RF power amplifier. Therefore, a filtering unit 23 is provided in the power supply adjustment circuit 2 to allow the third DC voltage Vdc3 in the envelope signal S2 except for the AC voltage Vac part to pass through.

[0106] The above technical solution not only improves the efficiency of the switching power supply, but also helps to solve the problem of signal distortion caused by insufficient supply voltage of the switching power supply. This is because one end of the voltage detector 21 in the voltage adjustment circuit 2 senses the third DC voltage Vdc3 in the envelope signal S2, and the other end senses the DC voltage required by the switching power supply, that is, the first DC voltage Vdc1 including the ripple voltage. By comparing Vdc1 and Vdc3 to output a difference voltage ΔV, and superimposing the third DC voltage Vdc3 and the difference voltage ΔV, and outputting it to the voltage follower 22, the tracking of the first DC voltage Vdc1 is realized, so that the output second voltage Vdc2 tends to be the same as the first DC voltage Vdc1, meeting the requirement of the switching power supply for the DC voltage. By continuously adjusting the second DC voltage Vdc2 with the first DC voltage Vdc1, the problem of signal distortion or increased system loss caused by the ripple voltage is solved.

[0107] The specific structure of the linear circuit 1 is as follows Figure 7 As shown, the purpose of the linear circuit 1 is to linearly amplify or attenuate the envelope signal, that is, to amplify the input small signal to the required power level, or to attenuate the large signal to the required power level.

[0108] Specifically, taking the signal amplification process as an example. The linear circuit 1 uses a linear amplifier 11. The forward input terminal of the linear amplifier 11 receives the envelope signal S1, and outputs the linearly amplified envelope signal S. The reverse input terminal is connected to the output terminal. For the linear circuit, the output power can be adjusted by selecting linear amplifiers with different parameters, and the power supply processing bandwidth ability can be expanded.

[0109] By applying the above technical solutions, the ripple injection circuit provides a ripple injection signal to the switching power supply, ensuring the stability and reliability of its operation while reducing the ripple of the switching power supply itself; by separately providing DC voltage and DC current to the load through different circuits, the efficiency of the switching power supply is further improved.

[0110] To achieve the above technical objectives, an embodiment of the present application also proposes an envelope tracking power amplifier switching power supply, including a ripple injection circuit including a subtraction unit, a first ripple adjustment unit, and a second ripple adjustment unit.

[0111] The first ripple adjustment unit is used to perform ripple adjustment processing on the received signal and output the first adjusted ripple to the second ripple adjustment unit and the subtraction unit;

[0112] The second ripple adjustment unit is used to perform ripple adjustment processing on the first adjusted ripple and output the second adjusted ripple to the subtraction unit;

[0113] The subtraction unit is used to perform an operation on the first adjusted ripple and the second adjusted ripple, and output a ripple injection signal that does not include DC voltage.

[0114] In a specific application scenario, it also includes a switch control circuit.

[0115] The switch control circuit includes a logic control unit, a switch control unit, a switch unit, and an inductor connected in sequence, and is configured to superimpose and compare the ripple injection signal with the DC voltage sensed by the switching power supply through the logic control unit, and output a switch control signal to obtain a switching signal and a DC current with a switching frequency required by the switching power supply.

[0116] In a specific application scenario, it also includes a voltage adjustment circuit.

[0117] The voltage adjustment circuit includes a filtering unit, an adder, a voltage detector, a voltage follower, and a resistor;

[0118] The filtering unit and the voltage detector are both connected to the voltage follower and the resistor through the adder in sequence to track, detect and superimpose the DC voltage required by the switching power supply, so as to obtain the DC drive voltage of the switching power supply.

[0119] In a specific application scenario, the first ripple adjustment unit and the second ripple adjustment unit are composed of any one or any combination of a capacitor, a reactance, and a resistor.

[0120] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application and are not intended to limit them. Although the present application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some of the technical features. And these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A switching power supply control method for an envelope tracking power amplifier, characterized in that The method includes: Performing at least one ripple adjustment process on a first switching signal to output a ripple injection signal without a DC voltage, where the first switching signal is obtained based on a comparison result between a second DC voltage and a first DC voltage; Obtaining a first DC voltage with ripple injection by superimposing the ripple injection signal on the first DC voltage; Outputting a comparison result between the second DC voltage and the first DC voltage with ripple injection to the switching power supply, so that the switching power supply obtains a second switching signal, where the second switching signal is a switching signal with a switching frequency; Receiving the second switching signal and outputting it to the switching power supply, so that the switching power supply obtains a DC current; Obtaining the first switching signal based on the comparison result between the second DC voltage and the first DC voltage, and the specific steps include: When the second DC voltage is greater than or equal to the first DC voltage, outputting a high-level signal of the switching signal when the switching power supply is in a constant-time conduction mode; When the second DC voltage is lower than the first DC voltage, and / or when the second DC voltage is greater than or equal to the first DC voltage and the switching power supply is in a cut-off state, outputting a low-level signal of the switching signal; Comparing the second DC voltage and the first DC voltage with ripple injection, and outputting a signal to make the switching power supply work in a conduction or cut-off state to obtain the second switching signal, and the specific steps include: When the second DC voltage is greater than or equal to the first DC voltage with ripple injection, outputting a high-level signal with a switching frequency when the switching power supply is in a constant-time conduction mode; When the second DC voltage is lower than the first DC voltage with ripple injection, and / or when the second DC voltage is greater than or equal to the first DC voltage with ripple injection and the switching power supply is in a cut-off state, outputting a low-level signal with a switching frequency.

2. The method according to claim 1, characterized in that, Obtaining the second DC voltage, and the specific steps include: obtaining a third DC voltage according to the DC component signal in the obtained envelope signal; Obtaining the first DC voltage by sensing the DC voltage required for the output of the switching power supply; Receiving and superimposing the third DC voltage and a difference voltage, where the difference voltage is obtained by comparing the first DC voltage and the third DC voltage, to obtain the second DC voltage.

3. The method according to claim 2, wherein Performing at least one ripple adjustment process on the first switching signal to output a ripple injection signal without a DC voltage, and the specific steps include: Receiving the first switching signal, performing signal filtering processing to obtain a first adjusted ripple; receiving the first adjusted ripple, performing signal filtering processing to obtain a second adjusted ripple; Performing an operation on the first adjusted ripple and the second adjusted ripple to generate the ripple injection signal.

4. The method according to claim 1, characterized in that, It further includes obtaining the AC voltage and AC current of the switching power supply, and the specific steps include: Obtaining a second envelope signal according to a first envelope signal, where the second envelope signal is linearly amplified and includes a DC component and an AC component; Outputting the AC voltage and the AC current according to the AC component signal in the obtained second envelope signal.

5. An envelope tracking power amplifier switching power supply, characterized in that Using the envelope tracking power amplifier switching power supply control method according to any one of claims 1 to 4, the envelope tracking power amplifier switching power supply includes a ripple injection circuit of a subtraction unit, a first ripple adjustment unit, and a second ripple adjustment unit. The first ripple adjustment unit is configured to perform ripple adjustment processing on the received signal and output a first adjusted ripple to the second ripple adjustment unit and the subtraction unit. The second ripple adjustment unit is configured to perform ripple adjustment processing on the first adjusted ripple and output a second adjusted ripple to the subtraction unit. The subtraction unit is configured to perform an operation on the first adjusted ripple and the second adjusted ripple, and output a ripple injection signal without a DC voltage.

6. The envelope tracking power amplifier switching power supply according to claim 5, characterized in that, It further includes a switch control circuit. The switch control circuit includes a logic control unit, a switch control unit, a switch unit, and an inductor connected in sequence, and is configured to superimpose and compare the ripple injection signal with the DC voltage sensed by the switching power supply demand through the logic control unit, and output a switch control signal to obtain a switching signal and a DC current with a switching frequency required by the switching power supply.

7. The envelope tracking power amplifier switching power supply according to claim 5, characterized in that It further includes a voltage adjustment circuit. The voltage adjustment circuit includes a filtering unit, an adder, a voltage detector, a voltage follower, and a resistor. Both the filtering unit and the voltage detector are sequentially connected to the voltage follower and the resistor through the adder, and perform tracking detection and superposition on the DC voltage required by the switching power supply to obtain the DC drive voltage of the switching power supply.

8. The envelope tracking power amplifier switching power supply according to claim 5, wherein The first ripple adjustment unit and the second ripple adjustment unit are composed of any one or any combination of a capacitor, a reactance, and a resistor.

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