An envelope tracking method and apparatus

Abstract

The application provides an envelope tracking method and device, the method obtains a target envelope tracking input current signal through a boost circuit, and transmits the target envelope tracking input current signal to an amplification circuit through the boost circuit; the amplification circuit comprises an operational amplifier and a feedback network, and the operational amplifier works in a floating ground mode; the amplification circuit performs closed-loop conversion amplification on the target envelope tracking input current signal, and outputs an envelope tracking output voltage; the application also provides an envelope tracking device, and solves the problem that in the prior art, when the envelope tracking output voltage amplitude is high and the swing is large, the operational amplifier has high loss and low efficiency in the linear amplification process, so that the target envelope tracking input current signal is converted and amplified more efficiently, the conversion efficiency of the operational amplifier is improved, the amplification loss is reduced, and the user experience is improved.

Description

TECHNICAL FIELD

[0001] Embodiments of the present application relate to, but are not limited to, the technical field of electronic devices, in particular, relate to, but are not limited to, an envelope tracking method and device. BACKGROUND

[0002] The envelope tracking technology can be applied in various fields such as communication. The output of the envelope tracking power supply can change along with the required signal change, and the bandwidth is relatively high, generally in the order of megahertz to hundreds of megahertz. It is usually applied in envelope tracking power amplifier circuit, and is used to power the power amplifier, so that the power amplifier power supply voltage follows the change of the required amplified signal power, thereby improving the efficiency of the power amplifier.

[0003] The current technology generally refers to Figure 1 , through a one-stage operational amplifier, or refers to Figure 2 , through a two-stage operational amplifier to amplify and track the input envelope signal.

[0004] As shown in Figure 1 , the input end 101 of the operational amplifier 104 applies an envelope voltage signal Ui, and the input envelope signal is tracked and amplified by the feedback resistors R1 and R2. When the Ui signal amplitude is relatively small, the corresponding operational amplifier gain needs to be set relatively large, which affects the bandwidth of the operational amplifier. When the Ui signal amplitude is relatively large, the operational amplifier gain can be set smaller, and the bandwidth of the operational amplifier is correspondingly higher. Although the use of a one-stage amplifier has a simple circuit and low power consumption, when the output voltage amplitude is large, in order to improve the bandwidth of the tracked envelope signal, the operational amplifier gain cannot be too large, so the amplitude of the input envelope signal Ui needs to be large, which is generally difficult to achieve.

[0005] Figure 2 In the prior art, the envelope signal tracking amplification is realized by two-stage operational amplifiers 106 and 107. The use of two-stage operational amplifiers can make the input envelope signal Ui amplitude smaller. The feedback resistors R3 and R4 of the first-stage operational amplifier 106 are used for signal amplification. The amplified envelope signal is applied to the input signal of the second-stage operational amplifier 108, and the feedback resistor R5 of the second-stage operational amplifier 107 forms a voltage follower to output a large current to power the power amplifier. The use of a two-stage amplifier has the advantage of small input envelope signal amplitude and easy implementation. However, due to the addition of one-stage operational amplifier, the device is increased, the power consumption is relatively large, and the signal time delay is increased, which has a certain impact on the efficiency.

[0006] When the envelope tracking power amplifier requires a wide power supply envelope voltage range, such as 10-30V, the output voltage range of the envelope tracking power supply also needs to be relatively wide, within the 10-30V range. If the existing circuit described above is used for amplification and tracking, due to the wide output voltage range of the op-amp, the supply voltage must also be above 30V, and the output voltage swing, amplitude, and frequency must be large. Figure 1 The circuit requires a very large input envelope signal Ui, which is difficult to achieve. Figure 2 The circuitry is complex, with numerous components, and the operational amplifiers suffer significant losses, impacting efficiency. Although the power amplifier's efficiency has improved, the efficiency of the envelope tracking power supply in the power supply section has decreased, affecting overall efficiency. Current technology has the following shortcomings:

[0007] 1. When the envelope tracking output voltage range is wide and the amplitude is high, the amplitude of the input signal cannot be too small when directly amplifying the envelope signal for output. Otherwise, it will have a certain impact on the bandwidth of the operational amplifier, indirectly affecting the size of the envelope bandwidth of the input signal. It is generally difficult to achieve a large input signal amplitude.

[0008] 2. When the envelope tracking output voltage range is relatively wide and the amplitude is relatively high, although the input signal amplitude can be smaller during multi-stage amplification, the number of components increases, the loss also increases, and the efficiency is affected.

[0009] 3. When the envelope tracking output voltage range is relatively wide and the amplitude is relatively high, the efficiency is low when the op-amp is directly grounded. In addition, the required op-amp operating voltage is also relatively high, and the bandwidth requirement is also very high. There are few op-amps that can meet the requirements of high bandwidth, high voltage, and high current output. Summary of the Invention

[0010] The envelope tracking method and apparatus provided in this invention mainly solve the technical problem that in the prior art, when the output voltage amplitude of envelope tracking is large, the operational amplifier suffers large losses and low efficiency during linear amplification.

[0011] To solve the above technical problems, embodiments of the present invention provide an envelope tracking device, including: an amplification circuit and a boost circuit, wherein: the amplification circuit includes an operational amplifier and a feedback network;

[0012] The operational amplifier comprises a non-inverting input end, a negative power supply end, a positive power supply end, an output end of the operational amplifier, and an inverting input end, the non-inverting input end is applied with a reference voltage VREF, the negative power supply end is connected with a first voltage source VEE, the positive power supply end is connected with a second voltage source VCC, the voltage value of the reference voltage VREF is greater than the voltage value of the first voltage source VEE, and the voltage value of the reference voltage VREF is less than the second voltage source VCC, and the voltage value of the first voltage source VEE is greater than zero;

[0013] The first end of the boost circuit receives a target envelope tracking input current signal, and the second end of the boost circuit is connected with the inverting input end, so as to transmit the target envelope tracking input current signal to the inverting input end through the boost circuit, and then transmit the target envelope tracking input current signal to the operational amplifier;

[0014] The first end of the feedback network is connected with the inverting input end, and the second end of the feedback network is connected with the output end of the operational amplifier, so as to transmit the output voltage signal of the output end of the operational amplifier to the inverting input end;

[0015] The amplification circuit is used for closed-loop conversion amplification of the target envelope tracking input current signal, and the output end of the operational amplifier outputs an envelope tracking output voltage.

[0016] The embodiment of the present application further provides an envelope tracking method, comprising:

[0017] The boost circuit obtains a target envelope tracking input current signal, and transmits the target envelope tracking input current signal to an amplification circuit, the amplification circuit comprises an operational amplifier and a feedback network, and the operational amplifier works in floating ground mode;

[0018] The amplification circuit performs closed-loop conversion amplification on the target envelope tracking input current signal, and outputs an envelope tracking output voltage.

[0019] The present application has the following advantages:

[0020] The application provides an envelope tracking method and device, the envelope tracking method obtains a target envelope tracking input current signal through a boosting circuit, and transmits the target envelope tracking input current signal to an amplification circuit, the amplification circuit comprises an operational amplifier and a feedback network, and the operational amplifier works in floating ground mode; the amplification circuit performs closed-loop conversion amplification on the target envelope tracking input current signal, and outputs an envelope tracking output voltage. The problem that the operational amplifier has large loss and low efficiency in linear amplification when the envelope tracking output voltage has high amplitude and large swing is solved, the target envelope tracking input current signal is amplified more efficiently, the conversion efficiency of the operational amplifier is improved, the amplification loss is reduced, and the user experience is improved.

[0021] Other features and corresponding advantages of the application will be set forth in part in the description that follows, and in part will be apparent from the description or can be learned by practice of the application. It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the application, as claimed. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 A circuit for envelope signal tracking amplification in the prior art background of the application;

[0023] Figure 2 Another circuit for envelope signal tracking amplification in the prior art background of the application;

[0024] Figure 3 A circuit schematic diagram of an envelope tracking device according to the first embodiment of the application;

[0025] Figure 4 A circuit schematic diagram of another envelope tracking device according to the first embodiment of the application;

[0026] Figure 5 A circuit schematic diagram of another envelope tracking device according to the first embodiment of the application;

[0027] Figure 6-1 A circuit schematic diagram of another envelope tracking device according to the first embodiment of the application;

[0028] Figure 6-2 A circuit schematic diagram of another envelope tracking device according to the first embodiment of the application;

[0029] Figure 6-3 A circuit schematic diagram of another envelope tracking device according to the first embodiment of the application;

[0030] Figure 7 A circuit schematic diagram of another envelope tracking device according to the first embodiment of the application;

[0031] Figure 8 A circuit schematic diagram of another envelope tracking device according to the first embodiment of the application;

[0032] Figure 9 Circuit schematic diagram of another envelope tracking device of the embodiment one of the present application;

[0033] Figure 10 Circuit schematic diagram of another envelope tracking device of the embodiment one of the present application;

[0034] Figure 11 Circuit schematic diagram of another envelope tracking device of the embodiment one of the present application;

[0035] Figure 12 Circuit schematic diagram of another envelope tracking device of the embodiment one of the present application;

[0036] Figure 13 Circuit schematic diagram of another envelope tracking device of the embodiment one of the present application;

[0037] Figure 14 Circuit schematic diagram of another envelope tracking device of the embodiment one of the present application;

[0038] Figure 15-1 Envelope tracking output voltage waveform schematic diagram of the circuit principle of the envelope tracking device of the embodiment one of the present application;

[0039] Figure 15-2 Target envelope tracking input current signal waveform schematic diagram of the circuit principle of the envelope tracking device of the embodiment one of the present application;

[0040] Figure 16 Flowchart schematic diagram of the envelope tracking method of the embodiment two of the present application;

[0041] Figure 17 Flowchart schematic diagram of the envelope tracking method of the embodiment three of the present application. DETAILED DESCRIPTION

[0042] In order to make the objects, technical solutions and advantages of the present application clearer, the embodiments of the present application are further described in detail below with reference to the drawings. It should be understood that the specific embodiments described herein are only used to explain the present application and should not be used to limit the present application.

[0043] Embodiment one:

[0044] Please refer to Figure 3 The envelope tracking device provided in the embodiment includes an amplification circuit and a boost circuit 303, the amplification circuit includes an operational amplifier 301 and a feedback network 302.

[0045] The operational amplifier 301 comprises a non-inverting input terminal 3011, a power negative terminal V-, a power positive terminal V+, an output terminal 3012 of the operational amplifier, and an inverting input terminal 3013. The non-inverting input terminal 3011 is applied with a reference voltage VREF. The power negative terminal V- is connected to a first voltage source VEE, which has the ability to output and input current. The power positive terminal V+ is connected to a second voltage source VCC. The voltage value of the reference voltage VREF is greater than the voltage value of the first voltage source VEE, and the voltage value of the reference voltage VREF is less than the second voltage source VCC. The voltage value of the first voltage source VEE is greater than zero.

[0046] The first end of the boost circuit 303 receives a target envelope tracking input current signal IA. The second end of the boost circuit 303 is connected to the inverting input terminal 3013, for transmitting the target envelope tracking input current signal to the inverting input terminal 3013 through the boost circuit 303, and then to the operational amplifier 301.

[0047] The first end of the feedback network 302 is connected to the inverting input terminal 3013. The second end of the feedback network 302 is connected to the output terminal 3012 of the operational amplifier, for transmitting the output voltage signal of the output terminal 3012 of the operational amplifier to the inverting input terminal 3013.

[0048] The amplification circuit is used for closed-loop conversion amplification of the target envelope tracking input current signal. The output terminal 3012 of the operational amplifier outputs an envelope tracking output voltage VOUT.

[0049] In some embodiments, the boost circuit transmits the target envelope tracking input current signal. Since the transmitted is a current signal, the current signal size will not change after passing through the boost circuit, that is, the current signal size between the target envelope tracking input current signal flowing into the boost circuit and the target envelope tracking input current signal flowing out of the boost circuit is consistent.

[0050] In some embodiments, the size of the reference voltage VREF applied to the non-inverting input terminal of the operational amplifier can be set according to the needs of those skilled in the art.

[0051] It should be noted that, according to the principle of the operational amplifier, the voltage levels of the non-inverting input terminal 3011 and the inverting input terminal 3013 are the same.

[0052] In some embodiments, the first voltage source VEE connected to the power negative terminal V- is less than the second voltage source VCC connected to the power positive terminal V+. The first voltage source VEE is not directly connected to the ground. Thus, the actual power voltage of the operational amplifier is the voltage difference between the power positive terminal V+ and the power negative terminal V-. This reduces the actual working power voltage range of the operational amplifier, which is equivalent to floating ground operation of the operational amplifier, reduces the power consumption of the operational amplifier, and improves the amplification efficiency.

[0053] It should be noted that the voltage between the first voltage source VEE connected to the negative power supply terminal V-, the second voltage source VCC connected to the positive power supply terminal V+ and the reference voltage VREF satisfies VCC > VREF > VEE > 0V.

[0054] In some embodiments, the first voltage source has an output and an input current capability.

[0055] In some embodiments, referring to Figure 4 , the feedback network is composed of a feedback resistor R6 connected between the inverting input terminal 3013 of the operational amplifier and the output terminal 3012 of the operational amplifier. According to the circuit principle, in an ideal case, the current flowing through the feedback resistor R6 is consistent with the size of the target envelope tracking input current signal IA. The target envelope tracking input current signal IA is applied to the inverting input terminal 3013 of the operational amplifier after passing through the boost circuit, and after conversion through the operational amplifier 301 and the feedback resistor R6, the amplified output envelope tracking output voltage VOUT is obtained. In some embodiments, the conversion formula of the target envelope tracking input current signal IA and the output envelope tracking output voltage VOUT satisfies: VOUT = VREF + R6*IA. Wherein, the VOUT output voltage amplitude is between VREF and VCC. Through this circuit, the target envelope tracking input current signal IA is amplified into the output envelope tracking output voltage VOUT, and the actual working voltage of the operational amplifier OP4 itself is VCC-VEE, and the actual output swing is between VREF-VEE and VCC-VEE, so that the operational amplifier can work in floating ground, reducing the loss of the operational amplifier OP4 itself and improving the efficiency.

[0056] In some embodiments, as shown in Figure 5 , the envelope tracking device further comprises a constant current source signal circuit 304 connected with the first end of the boost circuit 303, for converting the envelope tracking input current signal IA1 into the target envelope tracking input current signal IA. It should be noted that the target envelope tracking input current signal is a negative current signal that meets the requirements of the boost circuit, that is, the signal direction is from the second end of the boost circuit to the first end of the boost circuit. It should be noted that the constant current source signal circuit 304 provides an output constant size direct current constant current source signal IA2, wherein the direction and size of the constant current source signal IA2 can be set by the person skilled in the art as needed.

[0057] In some embodiments, as shown in Figure 6-1As shown, if the envelope tracking input current signal IA1 is negative and the constant current source signal IA2 is positive, the target envelope tracking input current signal IA can be obtained by subtracting the constant current source signal IA2 from the constant current source signal circuit 304 from the envelope tracking input current signal IA1, i.e., IA = IA1 - IA2. It should be noted that IA2 ≤ IA1. It should also be noted that if the envelope tracking input current signal IA1 is negative, whether or not the constant current source signal circuit 304 needs to be set can be determined as needed.

[0058] In some embodiments, such as Figure 6-2 As shown, if the envelope tracking input current signal IA1 is a negative current and the constant current source signal IA2 is also a negative current, then the target envelope tracking input current signal IA can be obtained by adding the constant current source signal IA2 of the constant current source signal circuit 304 to the envelope tracking input current signal IA1, that is, IA = IA1 + IA2. At this time, the relationship between the magnitudes of IA1 and IA2 is not limited.

[0059] It should be noted that for the constant current source signal circuit 304, the current signal flowing into the constant current source signal circuit 304 is a negative current, and the current signal flowing out of the constant current source signal circuit 304 is a positive current.

[0060] In some embodiments, such as Figure 6-3 As shown, if the envelope tracking input current signal IA1 is a negative current, then a constant current source signal circuit is not required.

[0061] It should be noted that if the envelope tracking input current signal IA1 is negative, the current direction of the constant current source signal IA2 can be either positive or negative. If the envelope tracking input current signal IA1 is positive, then the current direction of the constant current source signal IA2 can only be negative.

[0062] In some embodiments, such as Figure 7 As shown, if the envelope tracking input current signal IA1 is a positive current, the target envelope tracking input current signal IA can be obtained by subtracting the envelope tracking input current signal IA1 from the constant current source current signal IA2 of the constant current source signal circuit 304, i.e., IA = IA2 - IA1. It should be noted that IA1 ≤ IA2. It should also be noted that if the envelope tracking input current signal IA1 is a positive current, a constant current source signal circuit must be provided. This circuit generates a constant-magnitude DC current signal IA2 to process the envelope tracking input current signal IA1, ensuring that the target envelope tracking input current signal IA meets the requirements.

[0063] In some embodiments, such as Figure 8As shown, the envelope tracking device also includes a switching circuit 305, which is connected to the output terminal 3012 of the operational amplifier and to the load 306. The switching circuit 305 is used to reduce the output current of the operational amplifier 301 by providing a portion of the current to the load 306 through the switching circuit 305.

[0064] In some embodiments, a parallel switching circuit is used to provide a portion of the current required by the load, thereby reducing the operational amplifier's output current and improving its efficiency. It should be noted that in some embodiments, the load can be a power amplifier.

[0065] In some embodiments, such as Figure 9 As shown, the envelope tracking device also includes a digital-to-analog converter (DAC) 307. The negative power supply terminal of the DAC 307 is grounded, and the output terminal of the DAC 307 is connected to the first terminal of the boost circuit 303, used to convert and output the envelope tracking input current signal IA1. It should be noted that when no constant current source signal circuit is provided between the DAC and the boost circuit, the envelope tracking input current signal IA1 is the same as the target envelope tracking input current signal IA. It should also be noted that when the envelope tracking input current signal IA1 is a negative current, the current flows from the output terminal of the DAC into the DAC's internal components.

[0066] In some embodiments, such as Figure 10 As shown, the envelope tracking device also includes a bias resistor R7; the bias resistor R7 is connected between the output terminal of the digital-to-analog converter 307 and the first terminal of the boost circuit 303, and is used to provide the bias voltage required for the normal operation of the digital-to-analog converter 307. In some embodiments, the magnitude of this bias voltage is: VREF - voltage drop of the boost circuit itself - voltage drop of R7.

[0067] In some embodiments, the first end of the bias resistor is connected to the output of the digital-to-analog converter, and the second end of the bias resistor is connected to the first end of the boost circuit.

[0068] In some embodiments, the boost circuit includes a Zener diode and a capacitor, with the Zener diode and capacitor connected in parallel, and the anode of the Zener diode connected in parallel with the capacitor serving as the first terminal of the boost circuit.

[0069] like Figure 11As shown, the boost circuit can be composed of a Zener diode VD1 and a capacitor C1 connected in parallel. In this case, the target envelope tracking input current signal IA is connected from one end of the parallel connection between the Zener diode VD1 and capacitor C1 to the second end of the bias resistor R7, which provides the bias voltage required for the output port of the digital-to-analog converter 307 to operate. This voltage is calculated as: VREF - VD1 voltage drop - R7 voltage drop. One end of the cathode of the Zener diode VD1 and one end of the capacitor C1 are connected in parallel to the inverting input terminal 3013 of the operational amplifier 301. After the voltage is boosted by the Zener diode VD1, the target envelope tracking input current signal IA is transmitted to the inverting input terminal 3013 of the operational amplifier 301. The target envelope tracking input current signal IA flows through both capacitor C1 and the Zener diode VD1, with most of the current flowing through capacitor C1, resulting in better voltage regulation by the Zener diode VD1.

[0070] It should be noted that the value of the bias resistor can be chosen according to the actual application requirements, and can be as low as 0Ω. The bias resistor provides the bias voltage required for the DAC output.

[0071] In some embodiments, the boost circuit includes a voltage regulator.

[0072] like Figure 12 As shown, the boost circuit can be composed of a voltage regulator 308. The positive terminal of the voltage regulator 308 is connected to the inverting input terminal 3013, and the negative terminal of the voltage regulator 308 is connected to the second terminal of the bias resistor R7. The voltage regulator 308 is used to provide a suitable regulated voltage, transmitting the target envelope tracking input current signal IA to the inverting input terminal 3013 of the operational amplifier 301. After being amplified by the operational amplifier 301, the envelope tracking output voltage VOUT is obtained. At this time, the bias voltage required for the output port of the digital-to-analog converter 307 to operate is supplied. The magnitude of this voltage is: VREF - voltage regulator voltage - voltage drop across R7.

[0073] In some embodiments, the switching circuit consists of a BUCK circuit, including: an inductor, a first MOSFET, and a second MOSFET, wherein:

[0074] The first terminal of the inductor is connected to the output terminal of the operational amplifier;

[0075] The source of the first MOSFET is grounded, and the drain of the first MOSFET is connected to the second terminal of the inductor.

[0076] The drain of the second MOSFET is connected to the power supply, and the source of the second MOSFET is connected to the second terminal of the inductor.

[0077] like Figure 13As shown, the switching circuit includes an inductor L1, a first MOSFET Q1, and a second MOSFET Q2. The first terminal of inductor L1 is connected to the output terminal 3012 of the operational amplifier. The source of the first MOSFET Q1 is grounded, and its drain is connected to the second terminal of inductor L1. The drain of the second MOSFET Q2 is connected to the power supply VCC, and its source is connected to the second terminal of inductor L2. In some embodiments, the switching circuit is also connected to a load. Through a BUCK circuit, it provides the load with the required current, reducing the output current of the operational amplifier, thereby reducing the power consumption of the operational amplifier and improving its efficiency.

[0078] To facilitate understanding, a specific embodiment will be used to further illustrate the envelope tracking device provided by the present invention.

[0079] like Figure 14 As shown, the envelope tracking device includes: a digital-to-analog converter 307, a bias resistor R7, a constant current source signal circuit 304, a boost circuit composed of a capacitor C1 and a Zener diode VD1, an amplifier circuit, and a BUCK switch circuit composed of an inductor L11, a first MOSFET Q1, and a second MOSFET Q2. The amplifier circuit includes an operational amplifier 301 and a feedback network composed of a feedback resistor R6. The connection relationships between the various parts are shown in [reference needed]. Figure 14The negative power supply terminal of the digital-to-analog converter DAC 307 is grounded. A bias resistor R7 is connected in series with the output terminal of DAC 307. The other end of the bias resistor R7 is connected to the parallel connection between the anode of Zener diode VD1 and capacitor C1. Simultaneously, the anode of Zener diode VD1 is also connected to a constant current source signal circuit 304. One end of the cathode of Zener diode VD1 is connected to the inverting input terminal 3013 of operational amplifier 301. Operational amplifier 301 operates in floating mode. Operational amplifier 301 includes a non-inverting input terminal 3011, a negative power supply terminal V-, a positive power supply terminal V+, an output terminal 3012, and an inverting input terminal 3013. A reference voltage VREF is applied to the non-inverting input terminal 3011. The negative power supply terminal V- is connected to a first voltage source VEE, which has the capability to output and input current. The positive power supply terminal V+ is connected to a second voltage source VCC. The voltage value of the reference voltage VREF is greater than the voltage value of the first voltage source VEE, and the voltage value of the reference voltage VREF is less than the voltage value of the second voltage source VCC. The voltage value of the first voltage source VEE is greater than zero. The first end of the feedback resistor R6 is connected to the inverting input terminal 3013, and the second end of the feedback resistor R6 is connected to the output terminal 3012 of the operational amplifier, used to transmit the output voltage signal of the output terminal 3012 to the inverting input terminal 3013. The first terminal of inductor L1 is connected to the output terminal of the operational amplifier; the source of the first MOSFET Q1 is grounded, and the drain of the first MOSFET Q1 is connected to the second terminal of inductor L1; the drain of the second MOSFET Q2 is connected to the power supply, and the source of the second MOSFET Q2 is connected to the second terminal of inductor L1.

[0080] After the digital-to-analog converter DAC 307 outputs the envelope tracking input current signal IA1, it is superimposed with the constant current source signal IA2 from the constant current source signal circuit to generate the target envelope tracking input current signal IA. This target envelope tracking input current signal IA is then transmitted to the inverting input terminal 3013 of operational amplifier 301 via a boost circuit composed of capacitor C1 and Zener diode VD1. The amplifier circuit performs closed-loop conversion and amplification of the target envelope tracking input current signal, and the output terminal 3012 of the operational amplifier outputs the envelope tracking output voltage VOUT. The feedback resistor R6 of the amplifier circuit transmits the output voltage signal from the output terminal 3012 of the operational amplifier to the inverting input terminal 3013, thus forming a closed-loop conversion and amplification.

[0081] It should be noted that, depending on the DAC model, the output envelope tracking input current signal can be either a positive current (current flowing out of the DAC output) or a negative current (current flowing into the DAC output). When the output envelope tracking input current signal is a positive current, a constant current source signal circuit is required to convert it into the target envelope tracking input current signal that meets subsequent requirements.

[0082] It should be noted that, according to circuit principles, under ideal conditions, the magnitude of the current flowing through resistor R6 is the same as the magnitude of the input envelope tracking input current signal.

[0083] It should be noted that since a current signal is transmitted, the magnitude of the target envelope tracking input current signal will not be changed after passing through the boost circuit. That is, if a constant current source circuit exists, the magnitude of the target envelope tracking input current signal obtained by superimposing the envelope tracking input current signal and the constant current source current signal is the same as the magnitude of the target envelope tracking input current signal flowing out of the boost circuit. If a constant current source circuit does not exist, the magnitudes of the envelope tracking input current signal and the target envelope tracking input current signal are the same.

[0084] In some embodiments, a bias voltage required for normal operation of the DAC is provided by a bias resistor. The magnitude of this bias voltage is: VREF - voltage drop of the boost circuit itself - voltage drop of the feedback resistor.

[0085] In some embodiments, the conversion formula between the target envelope tracking input current signal and the output envelope tracking output voltage VOUT satisfies: Output envelope tracking output voltage VOUT = Reference voltage VREF + Resistance of feedback resistor * Target envelope tracking input current signal IA. It should be noted that since the boost current transmits a current signal, when there is no constant current source circuit in the circuit, the magnitudes of the target envelope tracking input current signal IA and the envelope tracking input current signal IA1 are the same.

[0086] It should be noted that the output voltage amplitude of the output envelope tracking output voltage VOUT is between VREF and VCC.

[0087] Through the above circuit, the envelope tracking input current signal IA1 is amplified into the output envelope tracking output voltage VOUT. Furthermore, the actual operating voltage of operational amplifier 301 is VCC-VEE, and the actual output swing is between VREF-VEE and VCC-VEE, allowing the op-amp to operate on floating ground. This reduces the losses of operational amplifier 301 itself and improves efficiency. For example, when VCC = 30V, VREF = 10V, and VEE = 8V, the operational amplifier's supply voltage is 22V. For the operational amplifier itself, the output voltage is in the range of 2-20V. Compared to when the operational amplifier is directly grounded, for the same amplification result, a 30V supply is required, resulting in an output voltage range of 12-30V, thus reducing amplification losses and improving efficiency.

[0088] like Figure 15-1 and Figure 15-2The diagram illustrates the signal waveforms at different positions of the envelope tracking device in this embodiment of the invention during operation. IA represents the target envelope tracking input current signal, which is a high-frequency changing signal. VOUT is the amplified output envelope tracking voltage, with an amplitude between VREF and VCC. The input current signal IA and the output voltage VOUT exhibit a linear amplification relationship. The positive power supply voltage of the operational amplifier is VCC, and the negative power supply voltage is VEE. A reference voltage VREF is applied to the non-inverting input of the operational amplifier, where VREF > VEE > 0.

[0089] The envelope tracking device provided in this invention includes an amplification circuit composed of an operational amplifier and a feedback network, as well as a boost circuit. The target envelope tracking input current signal is transmitted through the boost circuit and then converted by the amplification circuit to obtain the envelope tracking output voltage. This solves the problem in existing related technologies where the operational amplifier suffers significant losses and low efficiency during linear amplification when the envelope tracking output voltage amplitude and swing are large. It achieves more efficient conversion of the target envelope tracking input current signal, improves the conversion efficiency of the operational amplifier, reduces amplification losses, and enhances the user experience.

[0090] Furthermore, the negative terminal of the DAC power supply is grounded to the ground plane, while the negative terminal of the operational amplifier is not directly grounded. The envelope of the DAC output tracks the input current signal. After passing through the boost circuit, the current signal is unaffected. The current signal is applied to the inverting input of the operational amplifier, linearly amplified, and then output to the subsequent power amplifier load. This solves the problem of signal transmission when the DAC and operational amplifier are not on the same ground.

[0091] Furthermore, the negative power supply terminal V- of the operational amplifier is connected to a relatively high voltage source (the power supply voltage V+ is higher than that of the V- terminal), and is not directly grounded. In this way, the actual power supply voltage of the operational amplifier is the voltage difference between the positive power supply terminal V+ and the negative power supply terminal V-, so as to reduce the actual operating voltage range of the operational amplifier, which is equivalent to the operational amplifier operating on a floating ground, reducing the power consumption of the operational amplifier and improving the amplification efficiency.

[0092] Furthermore, when the DAC output envelope tracking input current signal is positive, a constant current source circuit is added, and the target envelope tracking input current signal is obtained by subtracting the two current signals.

[0093] Furthermore, when the DAC output envelope tracking input current signal is negative, a constant current source circuit can be added if necessary. The target envelope tracking input current signal is obtained by subtracting the two current signals.

[0094] Furthermore, the output parallel switching circuit provides part of the current required by the power amplifier load, reduces the output current of the operational amplifier, and improves the efficiency of the operational amplifier.

[0095] Example 2:

[0096] This embodiment also provides an envelope tracking method, such as Figure 16 As shown, the method includes:

[0097] S1601: The boost circuit acquires the target envelope tracking input current signal;

[0098] S1602: Transmits the target envelope tracking input current signal to the amplifier circuit;

[0099] S1603: The amplifier circuit performs closed-loop conversion and amplification on the target envelope tracking input current signal, and outputs the envelope tracking output voltage.

[0100] In some embodiments, the envelope tracking method described above can be applied to the envelope tracking device described in any of the above embodiments.

[0101] In some embodiments, the target envelope tracking input current signal may be a current signal directly output by a digital-to-analog converter (DAC), or it may be a current signal after further processing of the envelope current signal output by the DAC.

[0102] In some embodiments, the amplifier circuit includes an operational amplifier and a feedback network, wherein the operational amplifier operates on floating ground.

[0103] In some embodiments, the negative power supply terminal of the operational amplifier is connected to a relatively high first voltage source VEE, which is lower than the second voltage source VCC connected to the positive power supply terminal of the operational amplifier. A reference voltage VREF is applied to the non-inverting input terminal of the operational amplifier, and the relationship between the three voltage sources is: VCC > VREF > VEE > 0V. This configuration enables the operational amplifier to operate on a floating ground.

[0104] It should be noted that since a current signal is transmitted, the magnitude of the target envelope tracking input current signal will not be changed after passing through the boost circuit. That is, if a constant current source circuit exists, the magnitude of the target envelope tracking input current signal obtained by superimposing the envelope tracking input current signal and the constant current source current signal is the same as the magnitude of the target envelope tracking input current signal flowing out of the boost circuit. If a constant current source circuit does not exist, the magnitudes of the envelope tracking input current signal and the target envelope tracking input current signal are the same.

[0105] In some embodiments, the magnitude of the reference voltage VREF applied to the non-inverting input of the operational amplifier can be set according to the needs of those skilled in the art.

[0106] It should be noted that, according to the operational amplifier principle, the voltage levels of the non-inverting input terminal 3011 and the inverting input terminal 3013 are the same.

[0107] In some embodiments, the negative power supply terminal V- is connected to a first voltage source VEE, which is smaller than the second voltage source VCC connected to the positive power supply terminal V+. This first voltage source is not directly grounded. In this way, the actual power supply voltage of the operational amplifier is the voltage difference between the positive power supply terminal V+ and the negative power supply terminal V-, thereby reducing the actual operating voltage range of the operational amplifier. This is equivalent to the operational amplifier operating on a floating ground, reducing the power consumption of the operational amplifier and improving the amplification efficiency.

[0108] In some embodiments, the first voltage source has both output and input current capabilities.

[0109] In some embodiments, the feedback network in the amplifier circuit consists of a feedback resistor R connected between the inverting input and the output of the operational amplifier. Ideally, according to circuit principles, the current flowing through the feedback resistor should be the same as the current of the target envelope tracking input current signal IA. The target envelope tracking input current signal IA is boosted and applied to the inverting input of the operational amplifier. After conversion by the operational amplifier and the feedback resistor R, the amplified output envelope tracking voltage VOUT is obtained. In some embodiments, the conversion formula between the target envelope tracking input current signal IA and the output envelope tracking voltage VOUT satisfies: VOUT = VREF + R6 * IA. The amplitude of the VOUT output voltage is between VREF and VCC. Through this circuit, the target envelope tracking input current signal IA is amplified into the output envelope tracking voltage VOUT, and the actual operating voltage absolute value of the operational amplifier OP4 is VCC-VEE, with an actual output swing between VREF-VEE and VCC-VEE. This allows the operational amplifier to operate on a floating ground, reducing the losses of the operational amplifier OP4 itself and improving efficiency.

[0110] In some embodiments, the amplifier circuit transmits the output voltage signal of the operational amplifier back to the negative terminal of the operational amplifier through a feedback network.

[0111] In some embodiments, before acquiring the target envelope tracking input current signal, the method further includes: converting the envelope tracking input current signal into a target envelope tracking input current signal through a constant current source signal circuit.

[0112] It should be noted that the target envelope tracking input current signal is a current signal that meets the requirements of the boost circuit, and its signal direction is negative current, that is, its signal direction is from the second terminal of the boost circuit to the first terminal of the boost circuit. It should also be noted that the constant current source signal circuit provides a DC constant current source signal with a constant output magnitude, and the direction and magnitude of the constant current source signal can be set by those skilled in the art as needed.

[0113] In some embodiments, if the envelope tracking input current signal is a negative current and the constant current source current signal is a positive current, the target envelope tracking input current signal is obtained by subtracting the constant current source current signal of the constant current source signal circuit from the envelope tracking input current signal, and the envelope tracking input current signal is greater than or equal to the constant current source current signal of the constant current source signal circuit.

[0114] In some embodiments, if the envelope tracking input current signal is negative and the constant current source current signal is negative, the target envelope tracking input current signal is obtained by adding the constant current source current signal of the constant current source signal circuit to the envelope tracking input current signal.

[0115] It should be noted that for the constant current source signal circuit 304, the current signal flowing into the constant current source signal circuit 304 is a negative current, and the current signal flowing out of the constant current source signal circuit 304 is a positive current.

[0116] It should be noted that if the envelope tracking input current signal is a negative current, it can be decided whether or not a constant current source signal circuit needs to be set up.

[0117] In some embodiments, if the envelope tracking input current signal is a positive current, the target envelope tracking input current signal is obtained by subtracting the envelope tracking input current signal from the constant current source current signal of the constant current source signal circuit, and the envelope tracking input current signal is less than or equal to the constant current source current signal of the constant current source signal circuit.

[0118] It should be noted that if the envelope tracking input current signal is a positive current, a constant current source signal circuit must be set up. The constant current source signal, which generates a constant DC current signal, processes the envelope tracking input current signal so that the target envelope tracking input current signal meets the requirements.

[0119] It should be noted that the constant current source signal can be either a positive or negative current. The magnitude and direction of the constant current source signal can be set by those skilled in the art according to the magnitude and direction of the corresponding envelope tracking input current signal, so as to achieve the processing of the envelope tracking input current signal by a constant DC current signal generated by the constant current source signal circuit, so that the target envelope tracking input current signal meets the requirements.

[0120] It should be noted that if the envelope tracking input current signal IA1 is negative, the current direction of the constant current source signal IA2 can be either positive or negative. If the envelope tracking input current signal IA1 is positive, then the current direction of the constant current source signal IA2 can only be negative.

[0121] In some embodiments, the envelope tracking method further includes reducing the output current of the operational amplifier by providing a portion of the load current through a switching circuit.

[0122] In some embodiments, a parallel switching circuit is used to provide a portion of the current required by the load, thereby reducing the operational amplifier's output current and improving its efficiency. It should be noted that the load can be a power amplifier.

[0123] In some embodiments, the envelope tracking method further includes:

[0124] The input current signal is tracked by the output envelope of the digital-to-analog converter.

[0125] It should be noted that the negative power supply terminal of the digital-to-analog converter (DAC) is grounded, and the output terminal of the DAC is connected to the first terminal of the boost circuit to track the input current signal by converting the output envelope.

[0126] It should be noted that when there is no constant current source signal circuit between the digital-to-analog converter (DAC) and the boost circuit, the envelope tracking input current signal is the same as the target envelope tracking input current signal. It should also be noted that when the envelope tracking input current signal is negative, the current flows from the output of the DAC into the DAC's internal components.

[0127] In some embodiments, the envelope tracking method further includes:

[0128] A bias resistor provides the bias voltage required for the digital-to-analog converter to operate normally.

[0129] In some embodiments, the magnitude of the bias voltage is: VREF - voltage drop of the boost circuit itself - voltage drop of R7.

[0130] In some embodiments, the boost circuit includes a Zener diode and a capacitor, with the Zener diode and capacitor connected in parallel, and the end of the Zener diode connected in parallel with the capacitor serving as the first terminal of the boost circuit.

[0131] In some embodiments, the boost circuit can consist of a Zener diode and a capacitor connected in parallel. In this case, the target envelope tracking input current signal is connected from one end of the Zener diode and capacitor in parallel to the second end of the bias resistor, which provides the bias voltage required for the output port of the digital-to-analog converter to operate. This voltage is calculated as: VREF - Zener diode voltage drop - bias resistor voltage drop. One end of the Zener diode cathode and one end of the capacitor are connected in parallel to the inverting input of the operational amplifier. After the voltage is boosted by the Zener diode, the target envelope tracking input current signal is transmitted to the inverting input of the operational amplifier. The target envelope tracking input current signal flows through both the capacitor and the Zener diode, with most of the current flowing through the capacitor, resulting in better voltage regulation by the Zener diode.

[0132] In some embodiments, the boost circuit includes a voltage regulator.

[0133] In some embodiments, a voltage regulator is used to provide a suitable regulated voltage to transmit the target envelope tracking input current signal to the inverting input of an operational amplifier. After amplification by the operational amplifier, the envelope tracking output voltage VOUT is obtained. This voltage then supplies the bias voltage required for the output port of the digital-to-analog converter to operate. The magnitude of this voltage is: VREF - voltage regulator voltage - bias resistor voltage drop.

[0134] In some embodiments, the switching circuit includes: an inductor, a first MOSFET, and a second MOSFET;

[0135] The first terminal of the inductor is connected to the output terminal of the operational amplifier;

[0136] The source of the first MOSFET is grounded, and the drain of the first MOSFET is connected to the second terminal of the inductor.

[0137] The drain of the second MOSFET is connected to the power supply, and the source of the second MOSFET is connected to the second terminal of the inductor.

[0138] In some embodiments, the switching circuit is also connected to the load, and the BUCK circuit reduces the output current of the operational amplifier, thereby reducing the power consumption of the operational amplifier and improving efficiency.

[0139] Example 3:

[0140] The envelope tracking method described above will be further illustrated below with a specific embodiment. (See [link to relevant documentation]). Figure 17 ,like Figure 17 As shown, a specific envelope tracking method includes:

[0141] S1701: Digital-to-analog converter output envelope tracks input current signal;

[0142] S1702: Converts the envelope tracking input current signal into the target envelope tracking input current signal through a constant current source signal circuit;

[0143] S1703: Boost circuit acquires target envelope tracking input current signal;

[0144] S1704: Transmits the target envelope tracking input current signal to the amplifier circuit;

[0145] S1705: The amplifier circuit performs closed-loop conversion and amplification on the target envelope tracking input current signal, and outputs the envelope tracking output voltage.

[0146] S1706: Reduces the output current of the operational amplifier by providing a portion of the load current through a switching circuit.

[0147] It should be noted that the amplifier circuit includes an operational amplifier and a feedback network. The feedback network is used to transmit the output voltage signal from the operational amplifier's output terminal to its inverting input terminal, thereby forming a closed-loop conversion amplification.

[0148] It should be noted that, depending on the DAC model, the output envelope tracking input current signal can be either a positive current (current flowing out of the DAC output) or a negative current (current flowing into the DAC output). When the output envelope tracking input current signal is a positive current, a constant current source signal circuit is required to convert it into the target envelope tracking input current signal that meets subsequent requirements.

[0149] It should be noted that, according to circuit principles, under ideal conditions, the magnitude of the current flowing through resistor R6 is the same as the magnitude of the input envelope tracking input current signal.

[0150] It should be noted that since a current signal is transmitted, the magnitude of the target envelope tracking input current signal will not be changed after passing through the boost circuit. That is, if a constant current source circuit exists, the magnitude of the target envelope tracking input current signal obtained by superimposing the envelope tracking input current signal and the constant current source current signal is the same as the magnitude of the target envelope tracking input current signal flowing out of the boost circuit. If a constant current source circuit does not exist, the magnitudes of the envelope tracking input current signal and the target envelope tracking input current signal are the same.

[0151] In some embodiments, a bias voltage required for normal operation of the DAC is provided by a bias resistor. The magnitude of this bias voltage is: VREF - voltage drop of the boost circuit itself - voltage drop of the feedback resistor.

[0152] In some embodiments, the conversion formula between the target envelope tracking input current signal and the output envelope tracking output voltage VOUT satisfies: Output envelope tracking output voltage VOUT = Reference voltage VREF + Resistance of feedback resistor * Target envelope tracking input current signal IA. It should be noted that since the boost current transmits a current signal, when there is no constant current source circuit in the circuit, the magnitudes of the target envelope tracking input current signal IA and the envelope tracking input current signal IA1 are the same.

[0153] It should be noted that the output voltage amplitude of the output envelope tracking output voltage VOUT is between VREF and VCC.

[0154] Through the above circuit, the envelope tracking input current signal IA1 is amplified into the output envelope tracking output voltage VOUT. The actual operating voltage of the operational amplifier itself is VCC-VEE, and the actual output swing is between VREF-VEE and VCC-VEE, allowing the operational amplifier to operate floating, reducing its own losses and improving efficiency. For example, when VCC=30V, VREF=10V, and VEE=8V, the operational amplifier's supply voltage is 22V. For the operational amplifier itself, the output voltage is in the range of 2-20V. Compared to when the operational amplifier is directly grounded, for the same amplification result, a 30V supply is required, resulting in an output voltage range of 12-30V, thus reducing amplification losses and improving efficiency.

[0155] This invention provides an envelope tracking method that acquires a target envelope tracking input current signal through a boost circuit and transmits it to an amplifier circuit via the same circuit. The amplifier circuit includes an operational amplifier and a feedback network, with the operational amplifier operating on floating ground. The amplifier circuit performs closed-loop conversion amplification on the target envelope tracking input current signal, outputting an envelope tracking output voltage. This method solves the problem in existing related technologies where the operational amplifier suffers significant losses and low efficiency during linear amplification when the envelope tracking output voltage amplitude and swing are large. It achieves more efficient amplification of the target envelope tracking input current signal, improves the operational amplifier's conversion efficiency, reduces amplification losses, and enhances the user experience.

[0156] It should be understood that, in some cases, at least one step shown or described may be performed in a different order than that described in the above embodiments.

[0157] The above description, in conjunction with specific implementation methods, provides a further detailed explanation of the embodiments of the present invention. It should not be construed that the specific implementation of the present invention is limited to these descriptions. For those skilled in the art, various simple deductions or substitutions can be made without departing from the concept of the present invention, and all such modifications and substitutions should be considered within the scope of protection of the present invention.

Claims

1. An envelope tracking device, characterized in that, The envelope tracking device includes: an amplifier circuit and a boost circuit, wherein: the amplifier circuit includes an operational amplifier and a feedback network; The operational amplifier includes a non-inverting input terminal, a negative power supply terminal, a positive power supply terminal, an output terminal of the operational amplifier, and an inverting input terminal. A reference voltage VREF is applied to the non-inverting input terminal. The negative power supply terminal is connected to a first voltage source VEE, and the positive power supply terminal is connected to a second voltage source VCC. The voltage value of the reference voltage VREF is greater than the voltage value of the first voltage source VEE, and the voltage value of the reference voltage VREF is less than the voltage value of the second voltage source VCC. The voltage value of the first voltage source VEE is greater than zero. The first terminal of the boost circuit receives the target envelope tracking input current signal, and the second terminal of the boost circuit is connected to the inverting input terminal. The boost circuit is used to transmit the target envelope tracking input current signal to the inverting input terminal and then to the operational amplifier. The boost circuit boosts or provides a regulated voltage without changing the magnitude of the target envelope tracking input current signal passing through the boost circuit. The first end of the feedback network is connected to the inverting input terminal, and the second end of the feedback network is connected to the output terminal of the operational amplifier, for transmitting the output voltage signal of the operational amplifier to the inverting input terminal; The amplifier circuit is used to perform closed-loop conversion and amplification of the target envelope tracking input current signal, and the output terminal of the operational amplifier outputs the envelope tracking output voltage.

2. The envelope tracking device as described in claim 1, characterized in that, The envelope tracking device also includes a constant current source signal circuit. The constant current source signal circuit is connected to the first terminal of the boost circuit and is used to convert the envelope tracking input current signal into a target envelope tracking input current signal.

3. The envelope tracking device as described in claim 1, characterized in that, The envelope tracking device further includes a switching circuit connected to the output terminal of the operational amplifier and connected to a load, used to reduce the output current of the operational amplifier.

4. The envelope tracking device according to any one of claims 1-3, characterized in that, The envelope tracking device also includes a digital-to-analog converter. The negative power supply terminal of the digital-to-analog converter is grounded, and the output terminal of the digital-to-analog converter is connected to the first terminal of the boost circuit, which is used to track the input current signal by converting the output envelope.

5. The envelope tracking device as described in claim 4, characterized in that, The envelope tracking device also includes a bias resistor; The bias resistor is connected between the output terminal of the digital-to-analog converter and the first terminal of the boost circuit to provide the bias voltage required for the digital-to-analog converter to operate normally.

6. The envelope tracking device according to any one of claims 1-3, characterized in that, The boost circuit includes a Zener diode and a capacitor. The Zener diode and the capacitor are connected in parallel. The end of the Zener diode connected in parallel with the capacitor serves as the first terminal of the boost circuit.

7. The envelope tracking device according to any one of claims 1-3, characterized in that, The boost circuit includes a voltage regulator.

8. An envelope tracking method, characterized in that, The envelope tracking method includes: A boost circuit acquires a target envelope tracking input current signal and transmits the target envelope tracking input current signal to an amplifier circuit. The boost circuit boosts or provides a regulated voltage without changing the magnitude of the target envelope tracking input current signal passing through the boost circuit. The amplifier circuit includes an operational amplifier and a feedback network, and the operational amplifier operates in a floating state. The amplifier circuit performs closed-loop conversion and amplification on the target envelope tracking input current signal, and outputs an envelope tracking output voltage.

9. The envelope tracking method as described in claim 8, characterized in that, Before acquiring the target envelope tracking input current signal, the following steps are also included: The envelope tracking input current signal is converted into the target envelope tracking input current signal through a constant current source signal circuit.

10. The envelope tracking method as described in claim 9, characterized in that, The envelope tracking method further includes: The output current of the operational amplifier is reduced by using a switching circuit.

11. The envelope tracking method according to any one of claims 8-10, characterized in that, The envelope tracking method further includes: The envelope tracking input current signal is output through a digital-to-analog converter.

12. The envelope tracking method as described in claim 11, characterized in that, The envelope tracking method further includes: The bias voltage required for normal operation of the digital-to-analog converter is provided by a bias resistor.

13. The envelope tracking method according to any one of claims 8-10, characterized in that, The boost circuit includes a Zener diode and a capacitor. The Zener diode and the capacitor are connected in parallel. The end of the Zener diode connected in parallel with the capacitor serves as the first terminal of the boost circuit.

14. The envelope tracking method according to any one of claims 8-10, characterized in that, The boost circuit includes a voltage regulator.

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