Power amplifier and radio frequency chip

Abstract

The present invention relates to the technical field of wireless communications. Disclosed in the present invention is a power amplifier. The power amplifier comprises a signal input end, a radio frequency amplifier and a signal output end which are electrically connected in sequence, and an average power tracking circuit. An input end of the average power tracking circuit is used for connecting a power supply and receiving an output signal of an external host computer, an output end of the average power tracking circuit is connected to an input end of a radio frequency amplifier, and the average power tracking circuit is used for converting, on the basis of a received target voltage value, a power supply voltage output by the power supply into a preset voltage to supply power to the radio frequency amplifier. The average power tracking circuit comprises a voltage conversion circuit, a comparator, a loop filter circuit, a PWM modulator, a voltage divider circuit, a pulse circuit, and a first inductor. By switching the characteristics of the loop filter, the present invention enables the power supply to achieve both fast establishment and high-precision output, thereby allowing a working voltage of the amplifier to be as low as possible, and further reducing power consumption of the power amplifier.

Description

Power amplifier and radio frequency chip TECHNICAL FIELD

[0001] The present application relates to the field of wireless communication technology, in particular to a power amplifier and a radio frequency chip. BACKGROUND

[0002] Power amplifiers have become more and more common in today's society for wireless communication. By using power amplifiers in radio frequency communication systems, the radio frequency signals are amplified and then transmitted through antennas. For portable terminals, managing the radio frequency signal transmission power to extend the battery life can greatly improve the competitiveness of the product in the market.

[0003] With the development of communication technology, in order to reduce the power consumption of the power amplifier, the APT circuit (average power tracking) technology has been more and more widely used. In LTE network, 5G NR and other systems, the transmission power of the terminal is constantly adjusted by the system control. The APT circuit tracks the output power of the power amplifier and changes the operating voltage of the power amplifier in real time. Especially in the TDD system, the transmit circuit is quickly turned on and off, and the APT circuit must respond quickly to the working state of the transmit circuit, quickly turn on in the starting stage, and maintain high-precision voltage output in the stable stage.

[0004] However, the APT circuit of the conventional power amplifier is difficult to balance between the lock-in time and the stability precision; while meeting the lock-in time, the stability precision is often sacrificed, thereby increasing the power supply noise and deteriorating the radio frequency indicators. SUMMARY

[0005] The purpose of the embodiment of the present application is to provide a power amplifier, and the average power tracking circuit converts the VCC voltage into a suitable voltage value according to the received target value to power the power amplifier; to solve the problem that the output voltage lock-in time and stability precision of the existing power amplifier are difficult to balance.

[0006] In order to solve the above technical problems, in a first aspect, the embodiment of the present application provides a power amplifier, the power amplifier comprises a signal input end, a radio frequency amplifier and a signal output end connected in sequence, and an average power tracking circuit, an input end of the average power tracking circuit is used to connect a power supply and receive an output signal of an external host computer, an output end of the average power tracking circuit is connected to an input end of the radio frequency amplifier, and the host computer is used to transmit a target voltage value to the average power tracking circuit according to a preset output power; the average power tracking circuit is used to convert a power supply voltage output by the power supply into a preset voltage to power the radio frequency amplifier according to the received target voltage value;

[0007] The average power tracking circuit comprises a voltage conversion circuit, a comparator, a loop filter circuit, a PWM modulator, a voltage dividing circuit, a pulse circuit and a first inductor;

[0008] The input end of the voltage conversion circuit is used as the input end of the average power tracking circuit, the output end of the voltage conversion circuit is connected with the first input end of the comparator and the input end of the pulse circuit respectively, the host computer is used for outputting a direct current signal according to a preset output power, the voltage conversion circuit is used for converting the direct current signal into an analog direct current signal and sending the analog direct current signal to the first input end of the comparator and the input end of the pulse circuit respectively.

[0009] The output end of the comparator is connected with the first end of the loop filter circuit, the output end of the pulse circuit is connected with the second end of the loop filter circuit, and the comparator is used for comparing and processing the analog direct current signal and a voltage dividing signal input by the voltage dividing circuit and outputting a corresponding comparison voltage.

[0010] The third end of the loop filter circuit is connected with the first end of the PWM modulator, the second end of the PWM modulator is connected with the power supply, the loop filter circuit is used for processing the comparison voltage and a pulse signal output by the pulse circuit and outputting a stable control signal to the PWM modulator.

[0011] The PWM modulator outputs a stable voltage after receiving and modulating the control signal, the third end of the PWM modulator is connected with the first end of the first inductor, the second end of the first inductor is used as the output end of the average power tracking circuit and is connected with the first end of the voltage dividing circuit, the second end of the voltage dividing circuit is grounded, and the third end of the voltage dividing circuit is connected with the second input end of the comparator.

[0012] Preferably, the pulse circuit comprises a first capacitor and a first resistor, the first end of the first capacitor is used as the input end of the pulse circuit, the second end of the first capacitor is used as the output end of the pulse circuit and is connected with the first end of the first resistor, and the second end of the first resistor is grounded.

[0013] Preferably, the average power tracking circuit further comprises a second capacitor, the first end of the second capacitor is connected with the second end of the first inductor, and the second end of the second capacitor is grounded.

[0014] Preferably, the loop filter circuit comprises a first transistor, a second transistor, a second resistor, a third resistor, a third capacitor, a fourth capacitor and a fifth capacitor.

[0015] The gate of the first transistor is used as the second end of the loop filter circuit, the source of the first transistor is grounded, the drain of the first transistor is connected with the first end of the third resistor and the gate of the second transistor respectively, the second end of the third resistor is used for connecting the power supply, the source of the second transistor is grounded, and the drain of the second transistor is connected with the first end of the third capacitor.

[0016] The second end of the third capacitor is connected with the first end of the fourth capacitor and the first end of the second resistor respectively, the first end of the second resistor is also used as the third end of the loop filter circuit, the second end of the second resistor is connected with the first end of the fifth capacitor, and the second end of the fourth capacitor is connected with the second end of the fifth capacitor and grounded.

[0017] Preferably, the first transistor is an NMOS transistor.

[0018] Preferably, the second transistor is an NMOS transistor.

[0019] Preferably, the voltage conversion circuit is a D / A converter.

[0020] In the second aspect, the present application provides a radio frequency chip, which comprises the power amplifier.

[0021] Compared with the prior art, the power amplifier in the present application has the following advantages: the input end of the average power tracking circuit is used for connecting the power supply and receiving the target voltage value of the external host computer, the average power tracking circuit is used for converting the power supply voltage output by the power supply into a preset voltage to supply power to the radio frequency amplifier according to the received target voltage value; the voltage conversion circuit of the average power tracking circuit converts the power supply into a suitable working voltage, the output is adjusted by the pulse circuit and the comparator and output to the loop filter circuit, and the working voltage is output to reach a stable state by the loop filter circuit; due to the longer loop response time and the improved loop stability, the output power supply ripple is reduced and the precision is improved; at the same time, by switching the loop filter characteristics, the power supply can be quickly established and high-precision output; under the condition of meeting the requirements of various indicators of the radio frequency output signal, the working voltage of the amplifier should be as low as possible, the compatibility of the output voltage lock time and the stable precision is strong, and the power consumption of the power amplifier is further reduced. BRIEF DESCRIPTION OF DRAWINGS

[0022] In order to make the technical solutions in the embodiments of the present application clearer, the accompanying drawings needed in the embodiments will be briefly introduced below. Obviously, the accompanying drawings in the following description only represent some of the embodiments of the present application, and all of the other embodiments obtained by a person of ordinary skill in the art without any creative effort based on the embodiments in the present application shall fall within the protection scope of the present application.

[0023] Fig. 1 is a whole circuit diagram of the power amplifier provided by the embodiment of the present application;

[0024] Fig. 2 is a circuit diagram of the average power tracking circuit provided by the embodiment of the present application;

[0025] Fig. 3 is a circuit diagram of the loop filter circuit provided by the embodiment of the present application.

[0026] In the drawings, 100 is a power amplifier, 1 is a signal input end, 2 is a radio frequency amplifier, 3 is a signal output end, 4 is a host computer, 5 is an average power tracking circuit, 51 is a voltage conversion circuit, 52 is a pulse circuit, 53 is a comparator, 54 is a loop filter circuit, 55 is a PWM modulator, and 56 is a voltage dividing circuit. DETAILED DESCRIPTION

[0027] The technical solutions in the embodiments of the present application will be described clearly and completely below. Obviously, the described embodiments only represent some of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all the other embodiments obtained by a person of ordinary skill in the art without any creative effort shall fall within the protection scope of the present application.

[0028] Embodiment one

[0029] Please refer to Figs. 1-3, the embodiment of the present application provides a power amplifier 100, which comprises a signal input end 1, a radio frequency amplifier 2 and a signal output end 3 connected in sequence, and an average power tracking circuit 5 (APT circuit). The input end of the average power tracking circuit 5 is used to connect a power supply VCC and receive the output signal of an external host computer 4. The output end of the average power tracking circuit 5 is connected to the input end of the radio frequency amplifier 2. The host computer 4 is used to transmit a target voltage value to the average power tracking circuit 5 according to a preset output power. The average power tracking circuit 5 is used to convert the power supply voltage output by the power supply VCC into a preset voltage to supply power to the radio frequency amplifier 2 according to the target voltage value. The host computer 4 transmits the target voltage value to the APT circuit through a digital or analog interface according to the required output power. The APT circuit converts the voltage of the power supply VCC into a suitable voltage value to supply power to the radio frequency amplifier 2 according to the received target value.

[0030] The average power tracking circuit 5 comprises a voltage conversion circuit 51, a comparator 53, a loop filter circuit 54, a PWM modulator 55, a voltage dividing circuit 56, a pulse circuit 52 and a first inductor L1.

[0031] The input end of the voltage conversion circuit 51 is the input end of the average power tracking circuit 5, the output end of the voltage conversion circuit 51 is connected to the first input end (1 pin) of the comparator 53 and the input end of the pulse circuit 52 respectively, the host computer 4 is used to output a direct current signal according to a preset output power, the voltage conversion circuit 51 is used to convert the direct current signal V1 into an analog direct current signal V2 and send the analog direct current signal V2 to the first input end of the comparator 53 and the input end of the pulse circuit 52 respectively; the output end (3 pin) of the comparator 53 is connected to the first end (1 pin) of the loop filter circuit 54, the output end of the pulse circuit 52 is connected to the second end (2 pin) of the loop filter circuit 54, the comparator 53 is used to compare and process the analog direct current signal V2 and the voltage dividing signal input by the voltage dividing circuit 56 and output a corresponding comparison voltage; the third end (3 pin) of the loop filter circuit 54 is connected to the first end (1 pin) of the PWM modulator 55, the second end (2 pin) of the PWM modulator 55 is connected to the power supply VCC, the loop filter circuit 54 is used to process the comparison voltage and the pulse signal output by the pulse circuit 52 and output a stable control signal to the PWM modulator 55. The PWM modulator 55 receives the control signal for modulation and outputs a stable voltage, the third end (3 pin) of the PWM modulator 55 is connected to the first end of the first inductor L1, the second end of the first inductor L1 is the output end of the average power tracking circuit 5 and is connected to the first end (1 pin) of the voltage dividing circuit 56, the second end (2 pin) of the voltage dividing circuit 56 is grounded, and the third end (3 pin) of the voltage dividing circuit 56 is connected to the second input end (2 pin) of the comparator 53.

[0032] The host computer 4 outputs a direct current signal V1 according to the time slot (Slot) radio frequency signal power value. The opening time of the direct current signal V1 is usually slightly ahead of the radio frequency signal to be transmitted; the time interval of the advance is called the time advance, which is usually about 1-2us. And the closing time is slightly lagging behind the radio frequency signal to be transmitted. The amplitude represented by the direct current signal V1 depends on the radio frequency signal transmission power.

[0033] The direct current signal V1 can be in digital form or in analog form. The direct current signal V1 in digital form is converted into an analog direct current signal V2 by the voltage conversion circuit 51. The analog direct current signal V2 reaches the first input end of the comparator 53, so that the output end of the comparator 53 outputs a high level. The loop filter circuit 54 integrates and filters the input signal and outputs a stable control signal to control the PWM modulator 55. When the PWM modulator 55 is the first end signal voltage, the greater the duty cycle of the output signal of the third end of the PWM modulator 55.

[0034] Specifically, the input end of the average power tracking circuit 5 is connected to the power supply VCC and the output signal of the host computer 4, and the average power tracking circuit 5 is used to convert the power supply voltage output by the power supply VCC into a preset voltage according to the target voltage value to supply power to the radio frequency amplifier 2; the voltage conversion circuit 51 of the average power tracking circuit 5 converts the power supply VCC into a suitable working voltage, which is adjusted by the pulse circuit 52 and the comparator 53 and output to the loop filter circuit 54. After the working voltage is output to a stable state by the loop filter circuit 54, the loop response time becomes longer and the loop stability is improved, so that the ripple of the output power supply VCC is reduced and the precision is improved; at the same time, by switching the loop filter characteristics, the power supply VCC can be quickly established and high-precision output; so that under the condition of meeting the requirements of various indicators of the radio frequency output signal, the working voltage of the amplifier should be as low as possible, the compatibility of the output voltage lock time and the stability precision is strong, and the power consumption of the power amplifier 100 is further reduced.

[0035] In this embodiment, the pulse circuit 52 includes a first capacitor C1 and a first resistor R1. The first end of the first capacitor C1 is used as the input end of the pulse circuit 52, the second end of the first capacitor C1 is connected to the first end of the first resistor R1, and the second end of the first resistor R1 is grounded. The analog direct current signal V2 generates a steep rising edge at the moment of starting, and a positive pulse voltage V3 is formed on the first resistor R1 through the first capacitor C1.

[0036] In this embodiment, the average power tracking circuit 5 further includes a second capacitor C2. The first end of the second capacitor C2 is connected to the second end of the first inductor L1, and the second end of the second capacitor C2 is grounded.

[0037] In this embodiment, the loop filter circuit 54 includes a first transistor Q1, a second transistor Q2, a second resistor R2, a third resistor R3, a third capacitor C3, a fourth capacitor C4 and a fifth capacitor C5.

[0038] The gate of the first transistor Q1 is the second end of the loop filter circuit 54, the source of the first transistor Q1 is grounded, the drain of the first transistor Q1 is connected to the first end of the third resistor R3 and the gate of the second transistor Q2 respectively, the second end of the third resistor R3 is connected to the power supply VCC, the source of the second transistor Q2 is grounded, and the drain of the second transistor Q2 is connected to the first end of the third capacitor C3, and the second end of the third capacitor C3 is the first end of the loop filter circuit 54.

[0039] The second end of the third capacitor C3 is connected to the first end of the fourth capacitor C4 and the first end of the second resistor R2 respectively, the first end of the second resistor R2 is also the third end of the loop filter circuit 54, the second end of the second resistor R2 is connected to the first end of the fifth capacitor C5, and the second end of the fourth capacitor C4 is connected to the second end of the fifth capacitor C5 and grounded.

[0040] In this embodiment, the first transistor Q1 is an NMOS transistor.

[0041] In this embodiment, the second transistor Q2 is an NMOS transistor.

[0042] In this embodiment, the voltage dividing circuit 56 can be a plurality of resistors connected in series or in parallel.

[0043] In this embodiment, the voltage conversion circuit 51 is a D / A converter. The direct current signal V1 can be in digital form or in analog form. The digital direct current signal V1 becomes an analog direct current signal V2 after passing through the D / A converter.

[0044] In this embodiment, the third end of the PWM modulator 55 outputs a signal which is integrated and filtered by the first inductor L1 and the second capacitor C2 to output a stable direct current signal VCC. The greater the duty cycle of the signal output from the third end of the PWM modulator 55, the higher the VCC voltage. Therefore, by adjusting the duty cycle of the signal output from the PWM modulator 55, the VCC voltage can be controlled. The VCC voltage is output to the radio frequency amplifier 2 for power supply.

[0045] At the same time, VCC is connected to the input end of the voltage dividing circuit 56, and after a certain proportional voltage division, it is sent to the second input end of the comparator 53 from the third end of the voltage dividing circuit 56. Through the closed-loop feedback circuit, the VCC voltage is stabilized.

[0046] The analog direct current signal V2 is also connected to the first capacitor C1.

[0047] The analog direct current signal V2 generates a steep rising edge at the start of the moment, and a positive pulse voltage V3 is formed on the first resistor R1 through the first capacitor C1.

[0048] The first capacitor C1 outputs is connected to the gate of the first transistor Q1 inside the loop filter. The first transistor Q1 and the second transistor Q2 are both NMOS tubes. When the positive pulse voltage V3 is high, the drain and source of the first transistor Q1 are turned on, and the drain is 0V; at the same time, the drain and source of the second transistor Q2 are turned off, and the third capacitor C3 is floating.

[0049] Since the third capacitor C3 is in a floating state, the loop filter circuit 54 is composed of the fourth capacitor C4, the fifth capacitor C5 and the second resistor R2 at this time. At this time, the loop response time t1.

[0050] When the direct current signal V1 reaches a stable state, the analog direct current signal V2 also stabilizes. Due to the direct current isolation characteristic of the first capacitor C1, the analog direct current signal V2 cannot pass through the first capacitor C1, so the positive pulse voltage V3 on the first resistor R1 is reduced to 0V, and the drain and source of the first transistor Q1 are turned off, the drain and source of the second transistor Q2 are turned on, and the third capacitor C3 is grounded.

[0051] At this time, the loop filter is composed of the third capacitor C3, the fourth capacitor C4, the fifth capacitor C5 and the second resistor R2, and the loop response time t2. Obviously, t2>t1.

[0052] Therefore, at the moment when the direct current signal V1 starts, the entire loop response time is short, so that the VCC output quickly reaches the required voltage.

[0053] When the direct current signal V1 reaches a stable state, the loop response time becomes longer, the loop stability is improved, and therefore the VCC ripple output is reduced and the precision is improved. In this way, by switching the loop filter characteristics, the VCC can be quickly established and also can be output with high precision.

[0054] Embodiment two

[0055] The embodiment of the present application provides a radio frequency chip, and the radio frequency chip comprises the power amplifier 100.

[0056] It should be noted that in this paper, the term "including", "containing" or any other variant thereof is intended to cover non-exclusive inclusion, so that the process, method, article or device including a series of elements not only includes those elements, but also includes other elements not explicitly listed or inherent to such process, method, article or device. Without more limitation, the element defined by the statement "including a" does not exclude the presence of another identical element in the process, method, article or device including the element.

[0057] The above merely illustrates the embodiments of the present application, and is not intended to limit the patent scope of the present application. Any equivalent structure or equivalent process conversion, or direct or indirect application in other related technical fields, which is made according to the content of the present application, shall be included in the patent protection scope of the present application.

Claims

1. A power amplifier, comprising a signal input end, a radio frequency amplifier and a signal output end connected in sequence, and an average power tracking circuit, an input end of the average power tracking circuit being used for connecting a power supply and receiving an output signal of an external host computer, an output end of the average power tracking circuit being connected to an input end of the radio frequency amplifier, the host computer being used for transmitting a target voltage value to the average power tracking circuit according to a preset output power, the average power tracking circuit being used for converting a power supply voltage output by the power supply into a preset voltage to supply power to the radio frequency amplifier according to the received target voltage value, characterized in that the average power tracking circuit comprises a voltage conversion circuit, a comparator, a loop filter circuit, a PWM modulator, a voltage dividing circuit, a pulse circuit and a first inductor. The input end of the voltage conversion circuit is used as the input end of the average power tracking circuit, the output end of the voltage conversion circuit is connected to the first input end of the comparator and the input end of the pulse circuit respectively, the host computer is used for outputting a direct current signal according to a preset output power, the voltage conversion circuit is used for converting the direct current signal into an analog direct current signal and sending the analog direct current signal to the first input end of the comparator and the input end of the pulse circuit respectively. The output end of the comparator is connected to the first end of the loop filter circuit, the output end of the pulse circuit is connected to the second end of the loop filter circuit, the comparator is used for comparing and processing the analog direct current signal and a voltage dividing signal input by the voltage dividing circuit, and outputting a corresponding comparison voltage. The third end of the loop filter circuit is connected to the first end of the PWM modulator, the second end of the PWM modulator is connected to the power supply, the loop filter circuit is used for processing the comparison voltage and a pulse signal output by the pulse circuit, and outputting a stable control signal to the PWM modulator. The PWM modulator receives the control signal for modulation and outputs a stable voltage, the third end of the PWM modulator is connected to the first end of the first inductor, the second end of the first inductor is used as the output end of the average power tracking circuit and is connected to the first end of the voltage dividing circuit, the second end of the voltage dividing circuit is grounded, and the third end of the voltage dividing circuit is connected to the second input end of the comparator. The pulse circuit comprises a first capacitor and a first resistor, the first end of the first capacitor is used as the input end of the pulse circuit, the second end of the first capacitor is used as the output end of the pulse circuit and is connected to the first end of the first resistor, and the second end of the first resistor is grounded.

2. The power amplifier of claim 1, wherein, The average power tracking circuit further comprises a second capacitor, the first end of the second capacitor is connected to the second end of the first inductor, and the second end of the second capacitor is grounded.

3. The power amplifier of claim 1, wherein, The loop filter circuit comprises a first transistor, a second transistor, a second resistor, a third resistor, a third capacitor, a fourth capacitor and a fifth capacitor.

4. The power amplifier of claim 1 or 2, wherein, ​ The gate of the first transistor is a second end of the loop filter circuit, the source of the first transistor is grounded, the drain of the first transistor is connected with the first end of the third resistor and the gate of the second transistor respectively, the second end of the third resistor is connected with the power supply, the source of the second transistor is grounded, and the drain of the second transistor is connected with the first end of the third capacitor, and the second end of the third capacitor is a first end of the loop filter circuit. The second end of the third capacitor is connected with the first end of the fourth capacitor and the first end of the second resistor respectively, the first end of the second resistor is also a third end of the loop filter circuit, the second end of the second resistor is connected with the first end of the fifth capacitor, and the second end of the fourth capacitor is connected with the second end of the fifth capacitor and grounded.

5. The power amplifier of claim 4, wherein, The first transistor is an NMOS transistor.

6. The power amplifier of claim 4, wherein, The second transistor is an NMOS transistor.

7. The power amplifier of claim 1, wherein, The voltage conversion circuit is a D / A converter.

8. A radio frequency chip, characterized by The radio frequency chip comprises the power amplifier according to any one of claims 1-7.

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