Power amplifier circuit for radio frequency front-end assembly

Abstract

The utility model relates to the technical field of radio frequency signals, in particular to a power amplifier circuit for a radio frequency front-end component, which is characterized in that the input end of an amplifier is connected with the transmitting end of a radio frequency transceiver, the output end of the amplifier is connected with one end of a first biasing circuit, and the other end of the first biasing circuit is connected with the input end of a power amplifier; the output end of the power amplifier is connected with one end of the second biasing circuit, the other end of the second biasing circuit is connected with the input end of the low-pass filter, the output end of the low-pass filter is connected with the feedback channel and the output end of the coupler, and the coupling input end of the coupler is connected with the input end of the power detector. According to the scheme, high-frequency signals and low-frequency signals are selectively fed back through the feedback channel, self-oscillation is avoided, the frequency response of the amplifier is improved, the high-frequency performance of the amplifier is better, high-frequency distortion is reduced, and meanwhile the gain instability of a low-frequency band is avoided.

Description

Technical Field

[0001] The utility model relates to the technical field of radio frequency signals, and in particular to a power amplifier circuit for a radio frequency front-end component. Background Art

[0002] One of the main tasks of the RF front end is to enhance the weak RF signal from the antenna or other sensors. The power amplifier circuit can provide sufficient gain to amplify the signal to a level that can be accurately processed by the subsequent circuit. This is especially important for long-distance communication or reception in weak signal environments.

[0003] The power amplifier circuit currently used in RF front-end components lacks an effective feedback mechanism, which results in unstable amplifier gain and prone to self-oscillation. At the same time, the existing power amplifier circuit lacks a real-time power monitoring mechanism and cannot timely understand the working status of the power amplifier. When the power amplifier is reflected or open-circuited, there is a lack of protection measures, which can easily cause damage to the front-end devices. Utility Model Content

[0004] The utility model aims to solve the problems that the prior art lacks an effective feedback mechanism, resulting in unstable amplifier gain and prone to self-oscillation, as well as lacks a real-time power monitoring mechanism, making it impossible to timely understand the working status of the power amplifier, which easily leads to damage to the front-end components.

[0005] The utility model is realized by the following technical solutions:

[0006] A power amplifier circuit for a radio frequency front-end component comprises an amplifier, a first bias circuit, a power amplifier, a second bias circuit, a low-pass filter, a feedback channel, a coupler, a power detector and a comparator, wherein the input end of the amplifier is connected to the transmitting end of a radio frequency transceiver, the output end of the amplifier is connected to one end of the first bias circuit, the other end of the first bias circuit is connected to the input end of the power amplifier, the output end of the power amplifier is connected to one end of the second bias circuit, the other end of the second bias circuit is connected to the input end of the low-pass filter, the output end of the low-pass filter is connected to the output ends of the feedback channel and the coupler respectively, the coupling input end of the coupler is connected to the input end of the power detector, and the voltage detection end of the power detector is connected to the input end of the comparator.

[0007] Furthermore, the first bias circuit includes three pins, wherein pin 1 is connected to the output end of the amplifier, pin 2 is connected to the input end of the power amplifier, and pin 3 is connected to the first decoupling circuit.

[0008] Furthermore, the first decoupling circuit includes a resistor and three capacitors, and the three pins of the first bias circuit are connected in series with the resistor and in parallel with the three capacitors respectively.

[0009] Furthermore, the second bias circuit includes 6 pins, wherein pin 1 is connected to the second decoupling circuit, pin 4 is connected to the output of the power amplifier, pin 3 is connected to the input of the low-pass filter, and pins 2, 5, and 6 are all grounded.

[0010] Furthermore, the second decoupling circuit includes three capacitors, and pin 1 of the second bias circuit is connected in parallel with the three capacitors respectively.

[0011] Furthermore, the feedback channel includes a capacitor and a resistor, the capacitor and the resistor are connected in series, and the feedback channel is connected in parallel between the low-pass filter and the coupler.

[0012] Furthermore, the output end of the low-pass filter is connected to the gate of the MOS tube, and the drain of the MOS tube is connected to the output end of the filter circuit and the coupler respectively.

[0013] Furthermore, the model of the amplifier is TQP3M9008; the model of the first bias circuit is TCBT-114+; the model of the power amplifier is PHA-202+; the model of the second bias circuit is RCBT-63+; the model of the low-pass filter is LFCN-400; the model of the coupler is SCBD-16-63HP+; the model of the power detector is ADL5903; and the model of the comparator is RS331XF.

[0014] Beneficial effects of the utility model:

[0015] (1) The utility model proposes a power amplifier circuit for a radio frequency front-end component, which selectively feeds back high-frequency and low-frequency signals through a feedback channel. The capacitor allows the high-frequency signal to pass through, and the resistor controls the amplitude of the feedback signal, stabilizes the gain of the amplifier, avoids self-oscillation, improves the frequency response of the amplifier, makes its high-frequency performance better, reduces high-frequency distortion, and avoids gain instability in the low-frequency band;

[0016] (2) The utility model proposes a power amplifier circuit for a radio frequency front-end component, which couples a portion of the signal from the main signal path through a coupler for power detection, ensuring that the system understands the working status of the power amplifier in real time, detects whether the power amplifier is transmitting normally (path state) or reflecting (open circuit state), and protects the front-end device from damage through feedback signals;

[0017] (3) The utility model proposes a power amplifier circuit for a radio frequency front-end component, which provides a stable bias voltage for the amplifier and the power amplifier through a first bias circuit to ensure their normal operation; removes noise and interference in different frequency bands through a first decoupling circuit to form a low-pass filter network, further filters out high-frequency noise, and provides a pure bias voltage;

[0018] (4) The utility model proposes a power amplifier circuit for a radio frequency front-end component, which provides the required bias for the output end of the power amplifier through a second bias circuit to ensure its normal operation; and removes noise and interference in different frequency bands through a second decoupling circuit to provide a smooth and stable power supply voltage and signal voltage. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0020] Figure 1 This is a system block diagram of a power amplifier circuit for a radio frequency front-end component proposed by the utility model;

[0021] Figure 2 A connection schematic diagram of an amplifier and a first bias circuit of a power amplifier circuit for a radio frequency front-end component proposed by the utility model;

[0022] Figure 3 A connection schematic diagram of a power amplifier, a second bias circuit, a low-pass filter and a feedback channel of a power amplifier circuit for a radio frequency front-end component proposed by the utility model;

[0023] Figure 4 A schematic diagram of a coupler connection for a power amplifier circuit of a radio frequency front-end component proposed by the utility model;

[0024] Figure 5 The utility model provides a connection principle diagram of a power detector and a comparator for a power amplifier circuit of a radio frequency front-end component. DETAILED DESCRIPTION

[0025] In order to make the purpose, technical solutions and advantages of the utility model more clearly understood, the utility model is further described in detail below in conjunction with embodiments and drawings. The schematic implementation manner of the utility model and its description are only used to explain the utility model and are not intended to limit the utility model.

[0026] Example 1

[0027] refer to Figure 1 , this embodiment proposes a power amplifier circuit for a radio frequency front-end component.

[0028] A power amplifier circuit for a radio frequency front-end component comprises an amplifier, a first bias circuit, a power amplifier, a second bias circuit, a low-pass filter, a feedback channel, a coupler, a power detector and a comparator. The input end of the amplifier is connected to the transmitting end of the radio frequency transceiver, the output end of the amplifier is connected to one end of the first bias circuit, the other end of the first bias circuit is connected to the input end of the power amplifier, the output end of the power amplifier is connected to one end of the second bias circuit, the other end of the second bias circuit is connected to the input end of the low-pass filter, the output end of the low-pass filter is connected to the output ends of the feedback channel and the coupler respectively, the coupling input end of the coupler is connected to the input end of the power detector, and the voltage detection end of the power detector is connected to the input end of the comparator.

[0029] The power amplifier circuit also includes a first decoupling circuit and a second decoupling circuit.

[0030] Specifically, the amplifier is used to receive and amplify the weak signal sent by the transmitter in the radio frequency transceiver module, the amplifier model is TQP3M9008, the output end of the amplifier is connected to the first bias circuit, and the amplified signal is transmitted to the power amplifier;

[0031] The first bias circuit is used to provide bias voltage and stability to ensure the normal operation of the amplifier and the power amplifier. The model of the first bias circuit is TCBT-114+. Pin 1 of the first bias circuit is connected to the output end of the amplifier, and pin 2 is connected to the input end of the power amplifier to provide the required bias for the input end of the power amplifier. Pin 3 is connected to the first decoupling circuit. The first decoupling circuit can cover a wider frequency range by connecting three capacitors in parallel, effectively removing noise and interference in different frequency bands, and ensuring the purity of the bias voltage. In addition, the combination of resistors and capacitors can form a low-pass filter network to further filter out high-frequency noise, while providing necessary damping to prevent oscillation.

[0032] The power amplifier is used to further amplify the amplitude of the signal to increase the strength of the signal. The model of the power amplifier is PHA-202+. The output end of the power amplifier is connected to the second bias circuit to ensure accurate processing of the signal.

[0033] The second bias circuit provides the required bias for the output end of the power amplifier to ensure its normal operation. The model of the second bias circuit is RCBT-63+. Pin 4 of the bias circuit is connected to the output end of the power amplifier, pin 3 is connected to the low-pass filter to provide an input signal for the low-pass filter, and pin 1 is connected to the second decoupling circuit. The second decoupling circuit can cover a wider frequency range by connecting three capacitors in parallel, effectively filtering out noise and interference in different frequency bands, ensuring the purity of the bias voltage. The filtering effect of the capacitor can absorb high-frequency noise and spike voltage, and provide a smooth and stable power supply voltage and signal voltage.

[0034] The low-pass filter is used to filter out high-frequency noise and interference and retain the basic part of the radio frequency signal. The model of the low-pass filter is LFCN-400. The output end of the low-pass filter is respectively connected to the feedback channel and the coupler.

[0035] The feedback channel includes a capacitor and a resistor, the capacitor and the resistor are connected in series, the feedback channel is connected in parallel between the low-pass filter and the coupler, the resistor can control the amplitude of the feedback signal in the feedback channel, thereby stabilizing the gain of the amplifier and avoiding self-oscillation caused by excessive amplifier gain; the capacitor makes the feedback channel selective for signals of different frequencies. The capacitor allows high-frequency signals to pass through, while generating a large impedance for low-frequency signals, thereby playing a role in frequency selection.

[0036] Specifically, since the capacitor has low impedance to high-frequency signals, the feedback channel mainly feeds back high-frequency signals to the input end. This can help the amplifier's frequency response to be flatter, reduce high-frequency distortion, and improve the amplifier's high-frequency performance. The capacitor has high impedance to low-frequency signals, thereby reducing the amount of feedback of low-frequency signals and avoiding unstable or excessive gain in the low-frequency band.

[0037] The connection from the output of the low-pass filter to the input of the feedback channel is used to ensure that the amplified signal can be received by the feedback channel for feedback processing. The feedback channel is connected in parallel between the low-pass filter and the coupler, and the feedback signal can directly affect the input of the amplifier to adjust the gain and frequency response of the amplifier;

[0038] The coupler monitors the output power of the power amplifier by coupling a part of the main signal, ensuring that the system can understand the working status of the power amplifier in real time. The coupler can detect whether the signal is transmitted normally (path state) or reflected (open circuit state), thereby judging the status of the power amplifier. When it is detected that the power amplifier is in an open circuit state, the system can shut down the power amplifier in time to prevent damage to the front-end device due to signal reflection. The coupler in this embodiment is designed as a bidirectional coupler, and the signal input pin and output pin can be swapped, which increases the flexibility and adaptability of the circuit design. Through the coupler, a part of the signal is guided to the power detector, and then the voltage is compared through the comparator to realize the monitoring and feedback of the power amplifier status. The model of the coupler is SCBD-16-63HP+, and the input end of the coupler is respectively connected to the feedback channel and the output end of the low-pass filter, and the coupling input end of the coupler is connected to the power detector;

[0039] The power detector detects the power level of the radio frequency signal introduced by the coupler, converts the power information into a corresponding direct current voltage, and inputs the direct current voltage into the comparator. The model of the power detector is ADL5903;

[0040] The comparator compares the voltage output by the power detector with a preset threshold value and outputs a corresponding control signal to dynamically control and adjust the power amplifier. If the comparator determines that the voltage is out of the normal range, the FPGA detects that the link is open and shuts down the power amplifier to avoid damaging the device. The model of the comparator is RS331XF.

[0041] Example 2

[0042] This embodiment, based on Embodiment 1, proposes a specific circuit structure of a power amplifier circuit for a radio frequency front-end component.

[0043] A power amplifier circuit for a radio frequency front-end component includes an amplifier, a first bias circuit, a power amplifier, a second bias circuit, a low-pass filter, a feedback channel, a coupler, a power detector and a comparator.

[0044] The input end of the amplifier U1 is connected to the capacitor C17, the other end of the capacitor C17 is connected to the transmitting end of the RF transceiver module, the output end of the amplifier U1 is connected to the 1st pin of the first bias circuit U2, the 3rd pin of the first bias circuit U2 is respectively connected to one end of the capacitor C11, one end of the capacitor C12, one end of the capacitor C13, and one end of the resistor R11, the other ends of the capacitors C11, C12, and C13 are all grounded, the 3rd pin of the first bias circuit U2 is respectively connected to one end of the resistor R12, the resistor R13 The other end of the resistor R12 is connected to one end of the resistor R14 and one end of the capacitor C18, the other end of the capacitor C18 is connected to the 2nd pin of the power amplifier U3, the 7th pin of the power amplifier U3 is connected to the second bias circuit U4, the 1st pin of the second bias circuit U4 is connected to one end of the capacitor C14, one end of the capacitor C15, and one end of the capacitor C16, the other ends of the capacitors C14, C15, and C16 are all grounded, the 3rd pin of the second bias circuit U4 is connected to the low-pass filter U5, the Pin 3 is connected to one end of resistor R4, the gate of MOS tube Q2, and one end of capacitor C6 respectively. The other end of resistor R4 is connected to one end of capacitor C5, and the other end of capacitor C5 is grounded. The other end of capacitor C6 is connected to one end of resistor R9. The other end of resistor R9 is connected to the drain of MOS tube Q2, one end of inductor L1, and one end of capacitor C7 respectively. The other end of inductor L1 is connected to one end of capacitor C2, one end of capacitor C3, and one end of capacitor C4 respectively. The other ends of capacitors C2, C3, and C4 are all grounded. The other end of C7 is connected to pin 2 of coupler U6, pin 4 of coupler U6 is respectively connected to one end of resistor R35 and one end of resistor R32, the other end of resistor R32 is respectively connected to one end of resistor R36 and pin 1 of power detector U7, pin 7 of power detector U7 is connected to pin 1 of comparator U8, pin 4 of comparator is respectively connected to one end of resistor R27 and power control circuit, the other end of resistor R27 is respectively connected to pin 5 of comparator and one end of capacitor C45, and the other end of capacitor C45 is grounded.

[0045] Example 3

[0046] This embodiment proposes a coupler implementation method for a power amplifier circuit of a radio frequency front-end component based on Embodiment 1.

[0047] The coupler U6 in this embodiment is a bidirectional coupler. The signal input pin and the signal output pin of the coupler U6 can be swapped, and the coupling input pin and the coupling output pin can also be swapped, as long as they are consistent with the signal input and output pins. The main function of the coupler U6 is to detect whether the power amplifier is open or closed, so as to protect the front-end devices from damage.

[0048] When the input signal is 40dBm, the frequency is 1700-1000MHz, and the link output is in path, since the main path loss of coupler U6 is 0.2dB, the input signal is about 38.8dBm and the coupling degree is 20.3dB. Therefore, the coupled input signal is 19.7dBm. According to the coupling direction loss of 25dB, the coupled output signal is -5.3 dBm.

[0049] At this time, the power detector U7 receives a -5.3 dBm signal. Based on this signal, the power detector U7 outputs a voltage of about 1.1V to the +IN pin of the comparator U8. The comparator U8 compares this voltage with -IN and finally sends the information to the power control circuit, i.e., FPGA. The FPGA detects that the link is available and there is no need to shut down the power amplifier.

[0050] On the contrary, when the link output is open, the 38.8 dBm signal will be fully reflected, and the reverse input pin of the coupler U6 will output a 13.8 dBm signal to the power detector U7. At this time, the power detector U7 outputs a voltage of about 1.8V to the +IN pin of the comparator U8. The comparator U8 uses this voltage to compare with -IN, and finally sends the information to the FPGA. The FPGA detects that the link is open and needs to shut down the power amplifier to avoid damage to the device.

[0051] The above shows and describes the basic principle and main features of the utility model and the advantages of the utility model. Those skilled in the art should understand that the utility model is not limited by the above embodiments. The above embodiments and the description only illustrate the principle of the utility model. Without departing from the spirit and scope of the utility model, the utility model may have various changes and improvements, which fall within the scope of the utility model to be protected. The scope of protection claimed by the utility model is defined by the attached claims and their equivalents.

Claims

1. A power amplifier circuit for a radio frequency front-end component, characterized in that: The invention comprises an amplifier, a first bias circuit, a power amplifier, a second bias circuit, a low-pass filter, a feedback channel, a coupler, a power detector and a comparator. The input end of the amplifier is connected to the transmitting end of the radio frequency transceiver, the output end of the amplifier is connected to one end of the first bias circuit, the other end of the first bias circuit is connected to the input end of the power amplifier, the output end of the power amplifier is connected to one end of the second bias circuit, the other end of the second bias circuit is connected to the input end of the low-pass filter, the output end of the low-pass filter is respectively connected to the output ends of the feedback channel and the coupler, the coupling input end of the coupler is connected to the input end of the power detector, and the voltage detection end of the power detector is connected to the input end of the comparator.

2. A power amplifier circuit for a radio frequency front-end component according to claim 1, characterized in that: The first bias circuit includes three pins, wherein pin 1 is connected to the output end of the amplifier, pin 2 is connected to the input end of the power amplifier, and pin 3 is connected to the first decoupling circuit.

3. A power amplifier circuit for a radio frequency front-end component according to claim 2, characterized in that: The first decoupling circuit includes a resistor and three capacitors. The three pins of the first bias circuit are connected in series with the resistor and are connected in parallel with the three capacitors respectively.

4. A power amplifier circuit for a radio frequency front-end component according to claim 1, characterized in that: The second bias circuit includes 6 pins, wherein pin 1 is connected to the second decoupling circuit, pin 4 is connected to the output end of the power amplifier, pin 3 is connected to the input end of the low-pass filter, and pins 2, 5, and 6 are all grounded.

5. A power amplifier circuit for a radio frequency front-end component according to claim 4, characterized in that: The second decoupling circuit includes three capacitors, and pin 1 of the second bias circuit is connected in parallel with the three capacitors respectively.

6. A power amplifier circuit for a radio frequency front-end component according to claim 1, characterized in that: The feedback channel includes a capacitor and a resistor, the capacitor and the resistor are connected in series, and the feedback channel is connected in parallel between the low-pass filter and the coupler.

7. A power amplifier circuit for a radio frequency front-end component according to claim 1, characterized in that: The output end of the low-pass filter is connected to the gate of the MOS tube, and the drain of the MOS tube is connected to the output end of the filter circuit and the coupler respectively.

8. The power amplifier circuit for a radio frequency front-end component according to claim 1, characterized in that: The model of the amplifier is TQP3M9008; the model of the first bias circuit is TCBT-114+; the model of the power amplifier is PHA-202+; the model of the second bias circuit is RCBT-63+; the model of the low-pass filter is LFCN-400; the model of the coupler is SCBD-16-63HP+; the model of the power detector is ADL5903; and the model of the comparator is RS331XF.

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