Radio frequency power amplifier and radio frequency chip

Abstract

The utility model provides a radio frequency power amplifier and a radio frequency chip. The radio frequency power amplifier comprises an amplifier, a first adjustable attenuation circuit, a second adjustable attenuation circuit and a first capacitor. Compared with the prior art, the first adjustable attenuation circuit and the second adjustable attenuation circuit are additionally arranged at the input end of the amplifier, input attenuation protection is achieved by adopting a simple circuit structure, the number of used devices is small, and the chip area cost can be effectively saved. Meanwhile, the input attenuation amount of the first adjustable attenuation circuit and the second adjustable attenuation circuit can be flexibly adjusted through a digital control bit and an analog control voltage, and free adjustment of different attenuation amounts at different temperatures is achieved; meanwhile, the input end of the amplifier is simple in structure, complex feedback loop control is avoided, the response speed is higher, and deterioration of the radio frequency performance of an amplifier channel is smaller.

Description

TECHNICAL FIELD

[0001] The utility model relates to wireless communication technical field, especially involve a kind of radio frequency power amplifier and radio frequency chip. BACKGROUND

[0002] In current complex wireless communication system, in order to be compatible with multiple simultaneous communication frequency band increases, multiple mode multiple band communication coexistence, mobile phone end radio frequency low noise amplifier and amplifier quantity increase, antenna quantity increases, low noise amplifier input end requires can withstand higher power input, amplifier device cannot have any damage. Amplifier requires under input over-push certain power, without damaging later-stage filter, radio frequency switch and other devices. In traditional input protection circuit, some adopt simple diode limiting, which can only provide fixed attenuation, and cannot be dynamically adjusted. Or use more complex power detection to carry out the feedback control of amplifier gain, which cannot realize faster response speed, and the complex circuit increases the difficulty of circuit design and chip cost.

[0003] With higher integration of radio frequency front-end module, higher reliability and cost of single device are required. Figure 1 As shown in the figure, the protection circuit in the related art circuit is composed of diodes stacked in positive and negative directions. Since the diodes have fixed threshold voltage, the opening power point of the protection circuit is relatively fixed, and cannot meet the attenuation and limiting effect under different input powers. At the same time, the threshold voltage is also fixed due to the influence of temperature, and cannot realize controllable attenuation at high and low temperatures. In some other technical means, a power detection circuit is designed to detect and judge the radio frequency input power, and after reaching a certain threshold, the bias current or gain of the radio frequency power amplifier is adjusted to realize automatic gain or output power control. However, the detection accuracy is greatly affected by the process, and the circuit structure is relatively complex, increasing the chip area and cost.

[0004] Therefore, a new radio frequency power amplifier and radio frequency chip are needed to solve the above technical problems. UTILITY MODEL CONTENTS

[0005] The utility model provides a kind of radio frequency power amplifier and radio frequency chip, to provide a kind of input attenuation value can be adjusted to actual environment, realize adjustable attenuation in amplifier input end, and then protect the radio frequency power amplifier of amplifier itself and later-stage circuit device.

[0006] In the first aspect, the utility model provides a kind of radio frequency power amplifier, including amplifier, first adjustable attenuation circuit, second adjustable attenuation circuit and first capacitor;

[0007] The input end of the amplifier serves as the input end of the radio frequency power amplifier and is configured to receive a radio frequency signal, and the output end of the amplifier serves as the output end of the radio frequency power amplifier and is configured to output the radio frequency signal.

[0008] The input end of the first adjustable attenuation circuit is configured to be connected to an external control circuit, and the output end of the first adjustable attenuation circuit is connected to the input end of the amplifier.

[0009] The input end of the second adjustable attenuation circuit is configured to receive an external control voltage, and the output end of the second adjustable attenuation circuit is connected to the input end of the amplifier.

[0010] The output end of the first adjustable attenuation circuit is connected to the output end of the second adjustable attenuation circuit via the first capacitor.

[0011] Preferably, the first adjustable attenuation circuit comprises a plurality of first resistors, a plurality of first switches, and a control unit; the first ends of the plurality of first resistors are connected to each other and serve as the output end of the first adjustable attenuation circuit, the second ends of the plurality of first resistors are respectively connected to the control ends of the plurality of first switches in one-to-one correspondence, the output ends of the plurality of first switches are respectively connected to the output ends of the control unit, and the input end of the control unit serves as the input end of the first adjustable attenuation circuit.

[0012] Preferably, the control unit comprises a plurality of comparators; the input ends of the plurality of comparators serve as the input end of the control unit, the first input ends of the plurality of comparators are respectively configured to receive different external levels, the second input ends of the plurality of comparators are configured to receive a control signal output by an external control circuit, the input ends of the plurality of comparators are respectively connected to the output ends of the plurality of first switches in one-to-one correspondence, and the output ends of the comparators serve as the output end of the control circuit.

[0013] Preferably, the first resistor comprises three, the first switch comprises three, and the second ends of the three first resistors are respectively connected to the control ends of the three first switches in one-to-one correspondence.

[0014] Preferably, the comparator comprises three, and the output ends of the three comparators are respectively connected to the output ends of the three first switches in one-to-one correspondence.

[0015] Preferably, the second adjustable attenuation circuit comprises a first diode unit and a second diode unit connected in series with the first diode unit; the first diode unit comprises a plurality of first diodes connected in series, the second diode unit comprises a plurality of second diodes connected in series, the negative pole of the first diode unit is used for connecting an external control circuit, the positive pole of the first diode unit is connected with the negative pole of the second diode unit and serves as an output terminal of the second adjustable attenuation circuit together, and the negative pole of the second diode unit serves as an input terminal of the second adjustable attenuation circuit; wherein the number of the first diodes in the first diode unit is the same as the number of the second diodes in the second diode unit.

[0016] Preferably, the second adjustable attenuation circuit further comprises a second resistance and a third resistance; the negative pole of the first diode unit is connected with the external control circuit through the second resistance in series, and the positive pole of the second diode unit is connected with the external control voltage through the third resistance in series; wherein the second resistance and the third resistance are adjustable resistances.

[0017] Preferably, the first diode unit comprises two first diodes connected in series with each other, and the second diode unit comprises two second diodes connected in series with each other.

[0018] In the second aspect, the utility model also provides a radio frequency chip, the radio frequency chip includes the radio frequency power amplifier of any one of above-mentioned embodiments.

[0019] Compared with the prior art, the utility model adds the first adjustable attenuation circuit and the second adjustable attenuation circuit at the input terminal of the amplifier, and realizes input attenuation protection by using a simple circuit structure, which uses few devices and can effectively save the chip area cost. At the same time, the input attenuation of the first adjustable attenuation circuit and the second adjustable attenuation circuit can be flexibly adjusted by digital control bits and analog control voltage to realize free adjustment of different attenuation amounts at different temperatures. At the same time, since the input terminal structure of the amplifier is simple, complex feedback loop control is avoided, the response speed is faster, and the deterioration of the radio frequency performance of the amplifier path is smaller. BRIEF DESCRIPTION OF DRAWINGS

[0020] The above and other aspects of the utility model will become more apparent and more easily understood by the following detailed description in conjunction with the accompanying drawings. In the drawings:

[0021] Figure 1 is the circuit structure schematic diagram of the radio frequency power amplifier of the related art;

[0022] Figure 2It is the circuit structure schematic view of the radio frequency power amplifier provided by the embodiment of the utility model.

[0023] Figure 3 It is the circuit structure schematic view of the control unit in the radio frequency power amplifier provided by the embodiment of the utility model. DETAILED DESCRIPTION

[0024] In order to make the purpose, technical scheme and advantage of the utility model more clearly, the following is in combination with the embodiment, and the utility model is further detailedly explained.It should be understood that the specific embodiment described here is only used to explain the utility model, and is not used to limit the utility model.

[0025] Embodiment one

[0026] Please refer to Figures 2-3 The utility model provides a kind of radio frequency power amplifier 100, including amplifier 1, first adjustable attenuation circuit 2, second adjustable attenuation circuit 3 and first capacitor C1;

[0027] The input end of the amplifier 1 is used as the input end of the radio frequency power amplifier 100, for receiving radio frequency signal, and the output end of the amplifier 1 is used as the output end of the radio frequency power amplifier 100, for outputting radio frequency signal;Specifically, the amplifier 1 is an operational amplifier.

[0028] The input end of the first adjustable attenuation circuit 2 is used to connect external control circuit, and the output end of the first adjustable attenuation circuit 2 is connected to the input end of the amplifier 1;The first adjustable attenuation circuit 2 is used to attenuate and limit the radio frequency signal received by the input end of the amplifier 1;

[0029] The input end of the second adjustable attenuation circuit 3 is used to receive external control voltage VCtrl1, and the output end of the second adjustable attenuation circuit 3 is connected to the input end of the amplifier 1;The second adjustable attenuation circuit 3 is used to attenuate and limit the radio frequency signal received by the input end of the amplifier 1;

[0030] The output end of the first adjustable attenuation circuit 2 is connected to the output end of the second adjustable attenuation circuit 3, and is connected to the input end of the amplifier 1 after being connected in series with the first capacitor C1;Wherein, the first capacitor C1 is a common dc blocking capacitor of the first adjustable attenuation circuit 2 and the second adjustable attenuation circuit 3, and the second adjustable attenuation circuit 3 and external control voltage VCtrl1 voltage division will produce fixed dc capacitor, because of the addition of the first capacitor C1, so that the radio frequency power amplifier does not need to use external additional additional dc blocking capacitor.

[0031] Specifically, when the input end of the amplifier 1 receives a radio frequency signal with large power, the first adjustable attenuation circuit 2 and the second adjustable attenuation circuit 3 can realize attenuation limiting, reduce the input power of the amplifier 1, and further protect the amplifier and the subsequent circuit from being damaged.

[0032] In the 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 connected to each other and serve as the output end of the first adjustable attenuation circuit 2. The second ends of the plurality of first resistors R1 are connected to the control ends of the plurality of first switches S1 in one-to-one correspondence. The output ends of the plurality of first switches S1 are connected to the output ends of the control unit 21. The input end of the control unit 21 serves as the input end of the first adjustable attenuation circuit 2. It should be noted that the plurality of first switches S1 can also be controlled by a register designed independently to realize adjustable attenuation configuration.

[0033] Specifically, whether the plurality of first switches S1 are turned on or not is controlled by the control unit 21. The resistances between the plurality of first resistors R1 are different, thereby realizing adjustable attenuation of different gears.

[0034] In the embodiment, the control unit 21 includes a plurality of comparators com. The input ends of the plurality of comparators com serve as the input end of the control unit 21. The first input ends of the plurality of comparators com are used to receive different external levels. The second input ends of the plurality of comparators com are used to receive control signals output by an external control circuit. The input ends of the plurality of comparators com are connected to the output ends of the plurality of first switches S1 in one-to-one correspondence. The output ends of the comparators com serve as the output end of the control circuit.

[0035] Specifically, the control signals output by the external control circuit received by the second input ends of the comparators com are control voltages VCtrl2. The control voltages VCtrl2 are set as voltages with a certain temperature coefficient. Different reference levels with zero temperature coefficient are set at the first input ends of the comparators com, thereby realizing adjustable attenuation of different gears.

[0036] In the embodiment, the first resistors R1 include three, and the first switches S1 include three. The second ends of the three first resistors R1 are connected to the control ends of the three first switches S1 in one-to-one correspondence.

[0037] In the embodiment, the comparators com include three. The output ends of the three comparators com are connected to the output ends of the three first switches S1 in one-to-one correspondence.

[0038] For example,Figure 2 Taking three comparators com as an example, the first input ends of the three comparators com receive external levels Vref1, Vref2 and Vref3 respectively, and by comparing the three levels with zero temperature coefficient, the attenuation of three different gears is realized.

[0039] In the embodiment, the second adjustable attenuation circuit 3 comprises 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 comprises a plurality of first diodes D1 connected in series, and the second diode unit 32 comprises a plurality of second diodes D2 connected in series; the negative electrode of the first diode unit 31 is used for connecting an external control circuit, the positive electrode of the first diode unit 31 is connected with the negative electrode of the second diode unit 32 and serves as an output end of the second adjustable attenuation circuit 3, and the negative electrode of the second diode unit 32 serves as an input end of the second adjustable attenuation circuit 3; wherein the number of the first diodes D1 in the first diode unit 31 is the same as the number of the second diodes D2 in the second diode unit 32. It should be noted that the number of the first diodes D1 and the second diodes D2 is not limited, and one or more is feasible, which can be set according to actual conditions.

[0040] Specifically, by adjusting the voltage value, the plurality of first diodes D1 and the plurality of second diodes D2 are biased in a micro-conduction state, and when the swing amplitude of the radio frequency input increases, the plurality of first diodes D1 and the plurality of second diodes D2 are turned on under part of the period, thereby realizing the effect of amplitude limiting attenuation. At the same time, according to different power level application scenarios, the number and area of the plurality of first diodes D1 and the plurality of second diodes D2 can be adjusted correspondingly. And by the voltage temperature coefficient of the external control voltage VCtrl1, different attenuation amounts at normal temperature and high and low temperatures can be realized, achieving flexible temperature control.

[0041] The second adjustable attenuation circuit 3 further comprises a second resistor R2 and a third resistor R3; the negative electrode of the first diode unit 31 is connected with the external control circuit after being connected with the second resistor R2 in series, and the positive electrode of the second diode unit 32 is connected with the external control voltage after being connected with the third resistor R3 in series. Wherein, the second resistor R2 and the third resistor R3 are adjustable resistors, and the resistance values of the second resistor R2 and the third resistor R3 are small, which functions to fine-tune the attenuation amount.

[0042] In the embodiment, the first diode unit 31 comprises two first diodes D1 connected in series with each other, and the second diode unit 32 comprises two second diodes D2 connected in series with each other.

[0043] Compared with the prior art, the utility model discloses a first adjustable attenuation circuit and a second adjustable attenuation circuit are additionally arranged at the input end of the amplifier, and input attenuation protection is realized by simple circuit structure, and the utility model discloses a few devices are used, and the chip area cost can be effectively saved.

[0044] Embodiment two

[0045] The utility model embodiment still provides a kind of radio frequency chip, the radio frequency chip includes the radio frequency power amplifier 100 as described in above-mentioned embodiment, and can realize same technical effect, refer to the description in above-mentioned embodiment, here no longer tediously repeat.

[0046] It should be noted that, in this document, the terms "comprising", "including" or any other variant thereof are intended to cover a non-exclusive inclusion, so that a process, method, article or apparatus that comprises a list of elements does not only include those elements but can also include other elements not expressly listed or inherent to such process, method, article or apparatus. Without more limitations, the element defined by the statement "comprising a" does not exclude the presence of additional identical elements in the process, method, article or apparatus that includes the element.

[0047] The embodiments of the utility model are described above in combination with the drawings, and the disclosed is only the preferred embodiment of the utility model, but the utility model is not limited to the above-mentioned specific implementation, and the above-mentioned specific implementation is only illustrative, not restrictive, and the person skilled in the art can make a lot of equivalent changes without departing from the purpose of the utility model and the scope of the claims, which all belong to the protection of the utility model.

Claims

1. A radio frequency power amplifier, characterized by, The amplifier, the first adjustable attenuation circuit, the second adjustable attenuation circuit and the first capacitor are included. An input end of the amplifier is used as an input end of the radio frequency power amplifier and is configured to receive a radio frequency signal, and an output end of the amplifier is used as an output end of the radio frequency power amplifier and is configured to output the radio frequency signal. An input end of the first adjustable attenuation circuit is configured to be connected to an external control circuit, and an output end of the first adjustable attenuation circuit is connected to the input end of the amplifier; the first adjustable attenuation circuit is configured to attenuate and limit the radio frequency signal received by the input end of the amplifier. An input end of the second adjustable attenuation circuit is configured to receive an external control voltage, and an output end of the second adjustable attenuation circuit is connected to the input end of the amplifier; the second adjustable attenuation circuit is configured to attenuate and limit the radio frequency signal received by the input end of the amplifier. The output end of the first adjustable attenuation circuit is connected to the output end of the second adjustable attenuation circuit and is connected to the input end of the amplifier through the first capacitor in series.

2. The radio frequency power amplifier of claim 1, wherein, The first adjustable attenuation circuit includes a plurality of first resistors, a plurality of first switches and a control unit; first ends of the plurality of first resistors are connected to each other and are used as an output end of the first adjustable attenuation circuit, second ends of the plurality of first resistors are connected to control ends of the plurality of first switches in one-to-one correspondence, output ends of the plurality of first switches are connected to output ends of the control unit, and an input end of the control unit is used as an input end of the first adjustable attenuation circuit.

3. The radio frequency power amplifier of claim 2, wherein, The control unit includes a plurality of comparators; input ends of the plurality of comparators are used as input ends of the control unit, first input ends of the plurality of comparators are configured to receive different external levels, a second input end of the plurality of comparators is configured to receive a control signal output by an external control circuit, input ends of the plurality of comparators are connected to output ends of the plurality of first switches in one-to-one correspondence, and output ends of the comparators are used as output ends of the control circuit.

4. The radio frequency power amplifier of claim 3, wherein, The first resistor includes three first resistors, and the first switch includes three first switches; the second ends of the three first resistors are connected to the control ends of the three first switches in one-to-one correspondence.

5. The radio frequency power amplifier of claim 4, wherein, The comparator includes three comparators; the output ends of the three comparators are connected to the output ends of the three first switches in one-to-one correspondence.

6. The radio frequency power amplifier of claim 1, wherein, 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, a negative electrode of the first diode unit is configured to be connected to an external control circuit, a positive electrode of the first diode unit and a negative electrode of the second diode unit are connected and are used as an output end of the second adjustable attenuation circuit, and the negative electrode of the second diode unit is used as an input end of the second adjustable attenuation circuit; wherein the number of the first diodes in the first diode unit is the same as the number of the second diodes in the second diode unit.

7. The radio frequency power amplifier of claim 6, wherein, The second adjustable attenuation circuit further comprises a second resistor and a third resistor; the negative pole of the first diode unit is connected to an external control circuit after being connected in series with the second resistor, and the positive pole of the second diode unit is connected to an external control voltage after being connected in series with the third resistor; wherein the second resistor and the third resistor are both adjustable resistors.

8. The radio frequency power amplifier of claim 6, wherein, The first diode unit comprises two first diodes connected in series with each other, and the second diode unit comprises two second diodes connected in series with each other.

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

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