Radio frequency power amplifier and radio frequency chip

Abstract

A radio frequency power amplifier and a radio frequency chip. The radio frequency power amplifier comprises an amplifier (1), a first adjustable attenuation circuit (2), a second adjustable attenuation circuit (3), and a first capacitor (C1). Compared with the prior art, by adding the first adjustable attenuation circuit (2) and the second adjustable attenuation circuit (3) at an input terminal of the amplifier (1) and adopting a simple circuit structure, input attenuation protection is achieved; and fewer devices are used, so that the chip area cost can be effectively saved. Moreover, the input attenuation amounts of the first adjustable attenuation circuit (2) and the second adjustable attenuation circuit (3) can be flexibly adjusted by means of a digital control bit and an analog control voltage, thereby achieving free adjustment of different attenuation amounts at different temperatures. In addition, the input terminal of the amplifier (1) has a simple structure, so that complex feedback loop control is avoided, the response speed is faster, and the radio frequency performance of an amplifier path is less deteriorated.

Description

A radio frequency power amplifier and radio frequency chip Technical Field

[0001] This utility model relates to the field of wireless communication technology, and in particular to a radio frequency power amplifier and a radio frequency chip. Background Technology

[0002] In today's complex wireless communication systems, to ensure compatibility with multiple communication bands and the coexistence of various modes and frequency bands, the number of RF low-noise amplifiers (LNOAMAs) and antennas on mobile phones has increased. The LNOAMA input must be able to withstand higher power inputs without any damage to the amplifier components. The amplifier must not damage subsequent filters, RF switches, or other components even with a certain level of input power over-push. Traditional input protection circuits sometimes use simple diode limiting, which only provides a fixed attenuation and cannot be dynamically adjusted. Alternatively, more complex power detection is used for amplifier gain feedback control, which cannot achieve a fast response speed, and the complex circuitry increases the difficulty of circuit design and chip cost.

[0003] With the increasing integration of RF front-end modules, higher demands are placed on the reliability and cost of individual components. As shown in Figure 1, the protection circuit in related technologies consists of stacked diodes. Since diodes have fixed threshold voltages, the power threshold of the protection circuit is relatively fixed, failing to provide attenuation and limiting effects under different input powers. Furthermore, the threshold voltage is also fixed due to temperature variations, making it impossible to achieve controllable attenuation at high and low temperatures. In other technologies, a power detection circuit is designed to detect and judge the RF input power. Once a certain threshold is reached, the bias current or gain of the RF power amplifier is adjusted to achieve automatic gain control or output power control. However, its detection accuracy is significantly affected by the manufacturing process, and the circuit structure is more complex, increasing chip area and cost.

[0004] Therefore, there is an urgent need for a new RF power amplifier and RF chip to solve the above-mentioned technical problems.

[0005] Utility Model Content

[0006] This invention provides an RF power amplifier and an RF chip, aiming to provide an RF power amplifier that can adjust the input attenuation value according to the actual environment, realize adjustable attenuation at the amplifier input end, and thus protect the amplifier itself and subsequent circuit devices.

[0007] In a first aspect, the present invention provides a radio frequency power amplifier, including an amplifier, a first adjustable attenuation circuit, a second adjustable attenuation circuit, and a first capacitor;

[0008] The input terminal of the amplifier serves as the input terminal of the radio frequency power amplifier for receiving radio frequency signals, and the output terminal of the amplifier serves as the output terminal of the radio frequency power amplifier for outputting radio frequency signals.

[0009] The input terminal of the first adjustable attenuation circuit is used to connect to an external control circuit, and the output terminal of the first adjustable attenuation circuit is connected to the input terminal of the amplifier; the first adjustable attenuation circuit is used to attenuate and limit the radio frequency signal received at the input terminal of the amplifier.

[0010] The input terminal of the second adjustable attenuation circuit is used to receive an external control voltage, and the output terminal of the second adjustable attenuation circuit is connected to the input terminal of the amplifier; the second adjustable attenuation circuit is used to attenuate and limit the radio frequency signal received at the input terminal of the amplifier.

[0011] The output terminal of the first adjustable attenuation circuit is connected to the output terminal of the second adjustable attenuation circuit, and then connected to the input terminal of the amplifier via the first capacitor in series.

[0012] Preferably, the first adjustable attenuation circuit includes a plurality of first resistors, a plurality of first switches, and a control unit; the first ends of the plurality of first resistors are interconnected and serve as the output terminals of the first adjustable attenuation circuit, the second ends of the plurality of first resistors are respectively connected to the control terminals of the plurality of first switches, the output terminals of the plurality of first switches are respectively connected to the output terminals of the control unit, and the input terminal of the control unit serves as the input terminal of the first adjustable attenuation circuit.

[0013] Preferably, the control unit includes a plurality of comparators; the input terminals of the plurality of comparators serve as the input terminals of the control unit, the first input terminals of the plurality of comparators are respectively used to receive different external voltage levels, the second input terminals of the plurality of comparators are used to receive control signals output by an external control circuit, the input terminals of the plurality of comparators are connected one-to-one with the output terminals of the plurality of first switches, and the output terminals of the comparators serve as the output terminals of the control circuit.

[0014] Preferably, the first resistor comprises three, the first switch comprises three, and the second terminals of the three first resistors are respectively connected to the control terminals of the three first switches in a one-to-one correspondence.

[0015] Preferably, the comparator comprises three, and the output terminals of the three comparators are respectively connected to the output terminals of the three first switches in a one-to-one correspondence.

[0016] Preferably, the second adjustable attenuation circuit includes a first diode unit and a second diode unit connected in series with the first diode unit; the first diode unit includes a plurality of first diodes connected in series, the second diode unit includes a plurality of second diodes connected in series, the negative terminal of the first diode unit is used to connect to an external control circuit, the positive terminal of the first diode unit is connected to the negative terminal of the second diode unit and together serve as the output terminal of the second adjustable attenuation circuit, and the negative terminal of the second diode unit serves as the input terminal of the second adjustable attenuation circuit; wherein, the number of first diodes in the first diode unit is the same as the number of second diodes in the second diode unit.

[0017] Preferably, the second adjustable attenuation circuit further includes a second resistor and a third resistor; the negative terminal of the first diode unit is connected to an external control circuit via the second resistor in series, and the positive terminal of the second diode unit is connected to an external control voltage via the third resistor in series; wherein, the second resistor and the third resistor are both adjustable resistors.

[0018] Preferably, the first diode unit includes two first diodes connected in series, and the second diode unit includes two second diodes connected in series.

[0019] Secondly, this utility model also provides a radio frequency chip, which includes a radio frequency power amplifier as described in any of the above embodiments.

[0020] Compared with existing technologies, this invention achieves input attenuation protection by adding a first adjustable attenuation circuit and a second adjustable attenuation circuit at the input of the amplifier, and by using a simple circuit structure. It uses fewer components, effectively saving chip area costs. Simultaneously, the input attenuation of the first and second adjustable attenuation circuits can be flexibly adjusted via digital control bits and analog control voltages, allowing for free adjustment of different attenuation levels at different temperatures. Furthermore, due to the simple input structure of the amplifier, complex feedback loop control is avoided, resulting in faster response speed and less degradation of the amplifier's RF performance. Attached Figure Description

[0021] The present invention will now be described in detail with reference to the accompanying drawings. The above and other aspects of the present invention will become clearer and easier to understand through the detailed description in conjunction with the following drawings. In the drawings:

[0022] Figure 1 is a schematic diagram of the circuit structure of a radio frequency power amplifier in the related technology;

[0023] Figure 2 is a schematic diagram of the circuit structure of the radio frequency power amplifier provided in an embodiment of the present invention;

[0024] Figure 3 is a schematic diagram of the circuit structure of the control unit in the radio frequency power amplifier provided in this embodiment of the present invention. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present utility model and are not intended to limit the present utility model.

[0026] Example 1

[0027] Please refer to Figures 2-3. This utility model provides an RF power amplifier 100, including an amplifier 1, a first adjustable attenuation circuit 2, a second adjustable attenuation circuit 3, and a first capacitor C1.

[0028] The input terminal of the amplifier 1 serves as the input terminal of the radio frequency power amplifier 100 for receiving radio frequency signals, and the output terminal of the amplifier 1 serves as the output terminal of the radio frequency power amplifier 100 for outputting radio frequency signals; specifically, the amplifier 1 is an operational amplifier.

[0029] The input terminal of the first adjustable attenuation circuit 2 is used to connect to an external control circuit, and the output terminal of the first adjustable attenuation circuit 2 is connected to the input terminal of the amplifier 1; the first adjustable attenuation circuit 2 is used to attenuate and limit the radio frequency signal received at the input terminal of the amplifier 1.

[0030] The input terminal of the second adjustable attenuation circuit 3 is used to receive the external control voltage VCtrl1, and the output terminal of the second adjustable attenuation circuit 3 is connected to the input terminal of the amplifier 1; the second adjustable attenuation circuit 3 is used to attenuate and limit the radio frequency signal received at the input terminal of the amplifier 1.

[0031] The output terminal of the first adjustable attenuation circuit 2 is connected to the output terminal of the second adjustable attenuation circuit 3, and then connected to the input terminal of the amplifier 1 via the first capacitor C1 in series. The first capacitor C1 is a DC blocking capacitor shared by the first adjustable attenuation circuit 2 and the second adjustable attenuation circuit 3. The second adjustable attenuation circuit 3 and the external control voltage VCtrl1 will generate a fixed DC capacitor through voltage division. Due to the addition of the first capacitor C1, the RF power amplifier does not require an external additional DC blocking capacitor.

[0032] Specifically, when a high-power radio frequency signal is received at the input terminal of amplifier 1 through the first adjustable attenuation circuit 2 and the second adjustable attenuation circuit 3, attenuation limiting can be achieved, reducing the input power entering amplifier 1, thereby protecting the amplifier and subsequent circuits from damage.

[0033] In this embodiment, the first adjustable attenuation circuit 2 includes a plurality of first resistors R1, a plurality of first switches S1, and a control unit 21. The first ends of the plurality of first resistors R1 are interconnected and serve as the output terminals of the first adjustable attenuation circuit 2. The second ends of the plurality of first resistors R1 are respectively connected to the control terminals of the plurality of first switches S1. The output terminals of the plurality of first switches S1 are respectively connected to the output terminals of the control unit 21. The input terminal of the control unit 21 serves as the input terminal of the first adjustable attenuation circuit 2. It should be noted that the plurality of first switches S1 can also be independently designed as registers for control, thereby achieving adjustable attenuation configuration.

[0034] Specifically, the conduction of multiple first switches S1 is controlled by the logic of control unit 21, and the resistance values ​​of multiple first resistors R1 are different, thereby achieving adjustable attenuation at different levels.

[0035] In this embodiment, the control unit 21 includes a plurality of comparators com; the input terminals of the plurality of comparators com serve as the input terminals of the control unit 21, the first input terminals of the plurality of comparators com are respectively used to receive different external levels, the second input terminals of the plurality of comparators com are used to receive control signals output by an external control circuit, the input terminals of the plurality of comparators com are connected one-to-one with the output terminals of the plurality of first switches S1, and the output terminals of the comparators com serve as the output terminals of the control circuit.

[0036] Specifically, the second input terminal of the comparator com receives the control signal output by the external control circuit as the control voltage VCtrl2. The control voltage VCtrl2 is set to a voltage with a certain temperature coefficient. Different reference levels with the same zero temperature coefficient are set at the first input terminal of the comparator com, thereby realizing adjustable attenuation at different levels.

[0037] In this embodiment, the first resistor R1 includes three resistors, the first switch S1 includes three switches, and the second terminals of the three first resistors R1 are respectively connected to the control terminals of the three first switches S1.

[0038] In this embodiment, the comparator com includes three, and the output terminals of the three comparators com are respectively connected to the output terminals of the three first switches S1 one by one.

[0039] For example, please refer to Figure 2. Taking three comparators com as an example, the first input terminals of the three comparators com respectively receive external levels Vref1, Vref2 and Vref3. By comparing the three levels with zero temperature coefficient, the attenuation of three different levels can be adjusted.

[0040] In this embodiment, the second adjustable attenuation circuit 3 includes a first diode unit 31 and a second diode unit 32 connected in series with the first diode unit 31. The first diode unit 31 includes a plurality of first diodes D1 connected in series, and the second diode unit 32 includes a plurality of second diodes D2 connected in series. The cathode of the first diode unit 31 is used to connect to an external control circuit, and the anode of the first diode unit 31 is connected to the cathode of the second diode unit 32 and together serve as the output terminal of the second adjustable attenuation circuit 3. The cathode of the second diode unit 32 serves as the input terminal of the second adjustable attenuation circuit 3. The number of first diodes D1 in the first diode unit 31 is the same as the number of second diodes D2 in the second diode unit 32. It should be noted that the number of first diodes D1 and second diodes D2 is not limited; one or more are feasible and can be set according to actual conditions.

[0041] Specifically, by adjusting the voltage value, multiple first diodes D1 and multiple second diodes D2 are biased into a slightly conductive state. When the RF input swing amplitude increases, these diodes conduct during certain periods, achieving a limiting attenuation effect. Furthermore, the number and area of ​​the multiple first diodes D1 and multiple second diodes D2 can be adjusted according to different power level application scenarios. By adjusting the temperature coefficient of the external control voltage VCtrl1, different attenuation levels can be achieved at room temperature and high / low temperatures, enabling flexible temperature control.

[0042] The second adjustable attenuation circuit 3 further includes a second resistor R2 and a third resistor R3; the negative terminal of the first diode unit 31 is connected to an external control circuit via the second resistor R2 in series, and the positive terminal of the second diode unit 32 is connected to an external control voltage via the third resistor R3 in series. Both the second resistor R2 and the third resistor R3 are adjustable resistors, and their resistance values ​​are relatively small, serving to fine-tune the attenuation amplitude.

[0043] In this embodiment, the first diode unit 31 includes two first diodes D1 connected in series, and the second diode unit 32 includes two second diodes D2 connected in series.

[0044] Compared with existing technologies, this invention achieves input attenuation protection by adding a first adjustable attenuation circuit and a second adjustable attenuation circuit at the input of the amplifier, and by using a simple circuit structure. It uses fewer components, effectively saving chip area costs. Simultaneously, the input attenuation of the first and second adjustable attenuation circuits can be flexibly adjusted via digital control bits and analog control voltages, allowing for free adjustment of different attenuation levels at different temperatures. Furthermore, due to the simple input structure of the amplifier, complex feedback loop control is avoided, resulting in faster response speed and less degradation of the amplifier's RF performance.

[0045] Example 2

[0046] This utility model embodiment also provides a radio frequency chip, which includes the radio frequency power amplifier 100 as described in the above embodiment and can achieve the same technical effect. Refer to the description in the above embodiment, and it will not be repeated here.

[0047] It should be noted that, in this document, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0048] The embodiments of the present utility model have been described above with reference to the accompanying drawings. The disclosed embodiments are merely preferred embodiments of the present utility model. However, the present utility model is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many equivalent changes under the guidance of the present utility model without departing from the spirit and scope of the claims. All such changes are within the protection scope of the present utility model.

Claims

1. A radio frequency power amplifier, characterized in that, It includes an amplifier, a first adjustable attenuation circuit, a second adjustable attenuation circuit, and a first capacitor; The input terminal of the amplifier serves as the input terminal of the radio frequency power amplifier for receiving radio frequency signals, and the output terminal of the amplifier serves as the output terminal of the radio frequency power amplifier for outputting radio frequency signals. The input terminal of the first adjustable attenuation circuit is used to connect to an external control circuit, and the output terminal of the first adjustable attenuation circuit is connected to the input terminal of the amplifier; the first adjustable attenuation circuit is used to attenuate and limit the radio frequency signal received at the input terminal of the amplifier. The input terminal of the second adjustable attenuation circuit is used to receive an external control voltage, and the output terminal of the second adjustable attenuation circuit is connected to the input terminal of the amplifier; the second adjustable attenuation circuit is used to attenuate and limit the radio frequency signal received at the input terminal of the amplifier. The output terminal of the first adjustable attenuation circuit is connected to the output terminal of the second adjustable attenuation circuit, and then connected to the input terminal of the amplifier via the first capacitor in series.

2. The radio frequency power amplifier as described in claim 1, characterized in that, The first adjustable attenuation circuit includes a plurality of first resistors, a plurality of first switches, and a control unit; the first ends of the plurality of first resistors are interconnected and serve as the output terminals of the first adjustable attenuation circuit; the second ends of the plurality of first resistors are respectively connected to the control terminals of the plurality of first switches; the output terminals of the plurality of first switches are respectively connected to the output terminals of the control unit; and the input terminal of the control unit serves as the input terminal of the first adjustable attenuation circuit.

3. The radio frequency power amplifier as described in claim 2, characterized in that, The control unit includes multiple comparators; the input terminals of the multiple comparators serve as the input terminals of the control unit, the first input terminals of the multiple comparators are respectively used to receive different external voltage levels, the second input terminals of the multiple comparators are used to receive control signals output by an external control circuit, the input terminals of the multiple comparators are connected one-to-one with the output terminals of the multiple first switches, and the output terminals of the comparators serve as the output terminals of the control circuit.

4. The radio frequency power amplifier as described in claim 3, characterized in that, The first resistor comprises three, and the first switch comprises three, with the second ends of the three first resistors respectively connected to the control ends of the three first switches.

5. The radio frequency power amplifier as described in claim 4, characterized in that, The comparator comprises three, and the output terminals of the three comparators are respectively connected to the output terminals of the three first switches.

6. The radio frequency power amplifier as described in claim 1, characterized in that, The second adjustable attenuation circuit includes a first diode unit and a second diode unit connected in series with the first diode unit; the first diode unit includes a plurality of first diodes connected in series, and the second diode unit includes a plurality of second diodes connected in series; the cathode of the first diode unit is used to connect to an external control circuit, the anode of the first diode unit is connected to the cathode of the second diode unit and together serve as the output terminal of the second adjustable attenuation circuit, and the cathode of the second diode unit serves as the input terminal of the second adjustable attenuation circuit; wherein, the number of first diodes in the first diode unit is the same as the number of second diodes in the second diode unit.

7. The radio frequency power amplifier as described in claim 6, characterized in that, The second adjustable attenuation circuit further includes a second resistor and a third resistor; the negative terminal of the first diode unit is connected to an external control circuit via the second resistor in series, and the positive terminal of the second diode unit is connected to an external control voltage via the third resistor in series; wherein, both the second resistor and the third resistor are adjustable resistors.

8. The radio frequency power amplifier as described in claim 6, characterized in that, The first diode unit includes two first diodes connected in series, and the second diode unit includes two second diodes connected in series.

9. A radio frequency chip, characterized in that, The radio frequency chip includes the radio frequency power amplifier as described in any one of claims 1-8.

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