Transformer output matching circuit, radio frequency front-end module and wireless communication module
By designing a transformer output matching circuit that integrates filters and RF transceiver switches, the problem of difficulty in miniaturizing the RF front-end module is solved, and the miniaturization and loss reduction of the RF front-end module is achieved.
Patent Information
- Application Number
- CN202420773996.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-04-15
- Publication Date
- 2025-03-11
- Estimated Expiration
- 2034-04-15
AI Technical Summary
Among existing wireless communication modules, it is difficult to miniaturize the RF front-end module because a single PA chip is difficult to meet the strict harmonic power indicators, resulting in the need of additional filter chips and RF switch chips, increasing circuit complexity and volume.
By designing a transformer output matching circuit that integrates filters and RF transceiver switches, combining control switches, filter circuits and transformers, an integrated circuit is formed, which simplifies the design of RF front-end modules and realizes the integration of RF switches and filters.
The RF front-end module is miniaturized, which reduces overall loss and increases bandwidth. On the basis of meeting the harmonic power requirements, the modules required for RF transmission are simplified.
Smart Images
Figure CN222602412U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the field of communication technology design, in particular to a transformer output matching circuit, a radio frequency front-end module and a wireless communication module. Background Art
[0002] With the advancement of wireless communication technology, the functions that wireless communication modules need to support are becoming more and more abundant. Therefore, in order to add enough functions to the electronic board with limited space while keeping the overall cost acceptable, the current wireless communication modules have an increasingly strong demand for miniaturized chips. As a key module in the wireless communication module, the RF front-end module chip also needs to be miniaturized as much as possible. However, small-sized RF front-end module chips generally cannot meet the harmonic power requirements during transmission, and it is necessary to add an additional RF filter chip (PA Chip) (built with discrete components such as inductors and capacitors or filter chips) to the RF front-end module to achieve this. The addition of the RF filter chip not only increases the chip cost, but also increases the complexity and volume of the circuit. In addition, the RF power amplifier chip (PA Chip) and the RF transceiver switch (Switch Chip) chip are often two independent chips, making the RF front-end chip unable to meet the demand for miniaturization.
[0003] Please refer to Figure 1 In order to reduce the size of the RF front-end module, the prior art integrates a single PA chip (PA Chip) in the RF front-end module, but it is difficult for a single PA chip to meet strict harmonic power indicators. In order to make the harmonic power meet the rated requirements, the RF front-end module also integrates an output matching filter network. The output matching filter network usually needs to be implemented using multiple discrete inductors, capacitors or additional filter chips. Although this design can effectively suppress harmonics and ensure that the load impedance is in the optimal power efficiency area, this method not only requires additional filter chips, but also additional RF switch chips, as well as multiple chip capacitors and inductors. As a result, the size of the overall RF front-end module is still large, and the miniaturization of the RF module is still difficult to achieve. In addition, the prior art often designs the output filter matching network and the transceiver switch separately as independent chips (such as Figure 1 The Filter chip and Switch chip shown in the figure above increase the loss of RF signals during transmission, including the loss of the output filter matching network and the loss of the RF switch. The accumulation of these losses will lead to a decrease in overall power output and poor efficiency. In order to compensate for the power loss, the RF single-chip PA needs to provide a higher output power, which in turn requires the single-chip PA to be larger in size, further hindering the miniaturization of the module. Utility Model Content
[0004] The purpose of the utility model is to provide a transformer output matching circuit, a radio frequency front-end module and a wireless communication module. Through a new architecture design, the radio frequency switch and the filter circuit are integrated into one, so as to realize the miniaturization of the radio frequency front-end module on the basis of meeting the harmonic power requirements of the radio frequency front-end module.
[0005] The utility model discloses a transformer output matching circuit, comprising: a radio frequency receiving path, a filtering circuit, a first transformer and an antenna;
[0006] The radio frequency receiving path, the filtering circuit and the first transformer are integrated into one;
[0007] When the transformer output matching circuit works in the transmission mode, the first transformer is electrically connected to the filter circuit, and the radio frequency transmission signal is sequentially input to the antenna after passing through the first transformer and the filter circuit for signal transmission;
[0008] When the transformer output matching circuit operates in a receiving mode, the RF receiving signal is received through any of the RF receiving paths and then input into the filter circuit, and the filter circuit transmits the RF receiving signal to the antenna for signal reception.
[0009] Furthermore, it also includes a control switch, the filter circuit includes a coupling capacitor, one end of the control switch is connected to the coupling capacitor and the RF receiving path, and the other end is grounded;
[0010] When the RF transmission signal is input to the transformer output matching circuit, the control switch is closed, and the RF receiving switch on the RF receiving path is opened;
[0011] When the RF receiving signal is input to the transformer output matching circuit, the control switch is opened, the RF receiving switch on the RF receiving path is closed, and the RF receiving signal is input to the filter circuit via the coupling capacitor.
[0012] Further, the filtering circuit includes: a first capacitor, a second capacitor, a first inductor and a second inductor;
[0013] One end of the first capacitor is connected to the control switch and one end of the control switch, the other end of the first capacitor is connected to the transformer and the first inductor, the first inductor is connected to the second inductor, and the second inductor is connected to the antenna; the second capacitor is connected in parallel at both ends of the first inductor.
[0014] Furthermore, the filtering circuit further includes: a third capacitor and a third inductor;
[0015] Therefore, one end of the third capacitor is connected between the first inductor and the second inductor, and the other end is grounded through the third inductor.
[0016] Furthermore, the filtering circuit further includes: a fourth capacitor and a fourth inductor;
[0017] One end of the fourth capacitor is connected between the second inductor and the antenna, and the other end is grounded through the fourth inductor.
[0018] Furthermore, a first output end of the secondary coil of the first transformer is connected to the filter circuit, the filter circuit is connected to the antenna, and a second output end of the secondary coil is grounded.
[0019] The utility model also provides a radio frequency front-end module, including the above-mentioned transformer output matching circuit and signal amplification and matching network, the signal amplification and matching network is connected to the transformer output matching circuit, and the signal amplification and matching network is integrated with the transformer output matching circuit.
[0020] Further, the signal amplification and matching network includes: an input matching network, a driver amplifier, a second transformer and a differential amplifier;
[0021] The RF transmission signal is input to the driving amplifier through the input matching network. The driving amplifier converts the RF transmission signal into a differential signal through the second transformer and inputs the differential signal to the differential amplifier. The differential amplifier inputs the differential signal to the first input terminal and the second input terminal of the primary coil of the first transformer respectively.
[0022] Furthermore, the second transformer is a balun.
[0023] The utility model also provides a wireless communication module, which adopts the above-mentioned radio frequency front-end module.
[0024] Compared with the prior art, the utility model has at least the following advantages:
[0025] The transformer output matching circuit disclosed in the utility model integrates a control switch, a filter circuit, a first transformer and an antenna, forming a transformer output matching circuit integrating a filter and a radio frequency transceiver switch. Independently designed radio frequency switches and filters are no longer used, and the overall loss of the transformer output matching circuit integrating the filter and the radio frequency transceiver switch is lower and the bandwidth is wider. On the basis of meeting the harmonic power requirements of the radio frequency front-end module, the modules required for radio frequency transmission are simplified, and the miniaturization of the radio frequency front-end module is realized.
[0026] Furthermore, the RF front-end module disclosed in the utility model includes an integrated signal amplification and matching network and a transformer output matching circuit, which further simplifies the modules required for RF transmission on the basis of meeting the harmonic power requirements of the RF front-end module, thereby realizing the miniaturization of the RF front-end module. BRIEF DESCRIPTION OF THE DRAWINGS
[0027] Figure 1 It is a schematic diagram of the surface packaging structure of the radio frequency front-end module in the background technology;
[0028] Figure 2 This is a schematic diagram of the structure of the radio frequency front-end module in the utility model;
[0029] Figure 3 It is a structural schematic diagram of a single-transmit-multiple-receive RF front-end module in the utility model;
[0030] Figure 4 It is another structural schematic diagram of the single-transmit-multiple-receive RF front-end module in the utility model;
[0031] Figure 5 It is a structural schematic diagram of the multi-transmit and multi-receive radio frequency front-end module in the utility model;
[0032] Figure 6 The present invention is a schematic diagram of the surface packaging structure of a power amplifier chip integrating a filter and a switch. DETAILED DESCRIPTION
[0033] The following is a description of a transformer output matching circuit, a radio frequency front-end module and a chip of the utility model in combination with a schematic diagram, which shows a preferred embodiment of the utility model. It should be understood that those skilled in the art can modify the utility model described herein and still achieve the beneficial effects of the utility model. Therefore, the following description should be understood as being widely known to those skilled in the art, and not as a limitation to the utility model.
[0034] The present invention is described in more detail in the following paragraphs by way of example with reference to the accompanying drawings. The advantages and features of the present invention will become more apparent from the following description. It should be noted that the accompanying drawings are in very simplified form and in non-precise proportions, and are only used to conveniently and clearly assist in explaining the purpose of the embodiments of the present invention.
[0035] Embodiment 1
[0036] This embodiment provides a transformer output matching circuit 4 (Integrated Harmonic Filter and RxSwitch), please refer to Figure 2-Figure 6 The transformer output matching circuit 4 includes: a radio frequency receiving path 3, a filter circuit 1, a first transformer 2 and an antenna ANT.
[0037] Specifically, the first output end a of the secondary coil of the first transformer is connected to the filter circuit 1, the filter circuit 1 is connected to the antenna ANT, and the second output end b of the secondary coil is grounded.
[0038] The RF receiving path 3, the filter circuit 1 and the first transformer 2 are integrated into one; when the transformer output matching circuit 4 works in the transmitting mode, the first transformer 2 is electrically connected to the filter circuit 1, and the RF receiving signal passes through the first transformer 2 and the filter circuit 1 in sequence and is then input into the antenna ANT for signal transmission; when the transformer output matching circuit 4 works in the receiving mode, the RF receiving signal is received through any of the RF receiving paths 3 and then input into the filter circuit 1, and the filter circuit 1 transmits the RF receiving signal to the antenna ANT for signal reception.
[0039] The transformer output matching circuit 4 disclosed in this embodiment integrates a radio frequency receiving path 3, a filter circuit 1 and a first transformer 2. A radio frequency receiving switch is provided on the radio frequency receiving path 3, thereby forming a transformer output matching circuit 4 integrating a filter and a radio frequency receiving switch. Independently designed radio frequency switches and filters are no longer used, which simplifies the modules required for radio frequency transmission and realizes the miniaturization of radio frequency front-end modules. In addition, due to the use of the transformer output matching circuit 4 integrating filters and radio frequency switches, the overall loss of the radio frequency path is only composed of the first transformer 2 and the radio frequency receiving switch, and the loss is relatively low.
[0040] Further, the RF receiving circuit 3 in this embodiment is connected between the control switch and the coupling capacitor. In a specific example, please refer to Figure 3 , the RF receiving circuit 3 is connected between the control switch and the first capacitor C1. In another specific example, please refer to Figure 4 The RF receiving circuit 3 is connected between the first control switch S1 and the first capacitor C1, and between the third capacitor C3 and the second control switch S2. It is understandable that the connection position of the RF receiving circuit 3 is not specifically limited here, and the RF receiving circuit 3 can be connected at an appropriate position according to the frequency response characteristics.
[0041] Furthermore, the specific number of RF receiving paths 3 is not limited, and can be 1, 2 or 3. Each RF receiving path 3 is provided with an RF receiving switch (S1-Sn switch as shown in the figure), and each RF receiving path 3 is independently provided in the transformer output matching circuit 4 and connected to the filter circuit 1.
[0042] When the RF transmission signal is input to the transformer output matching circuit 4, the filter circuit 1 and the first transformer 2 are powered on together to form a RF filter matching network, thereby filtering and impedance matching the RF transmission signal. At this time, the control switch pulled down to the ground is closed, and the RF receiving switches (S2-Sn) on the RF receiving path 3 are all disconnected, so that the RF transmission signal works at a preset impedance position. At the same time, the RF connection between the RF transmission path and the RF receiving path 3 is cut off to prevent the transmission power from being fed back to the RF receiving path 3, forming an RF loop and affecting the transmission performance. When the RF receiving signal is input to the transformer output matching circuit 4, the control switch pulled down to the ground is disconnected, and the RF receiving switch on the RF receiving path 3 is closed. The RF receiving signal enters the filter circuit 1 for filtering and is coupled to the antenna ANT for signal reception.
[0043] In a specific example, the filter circuit 1 may be configured to include: a first capacitor C1, a second capacitor C2, a first inductor L1, and a second inductor L2.
[0044] One end of the first capacitor C1 is connected to one end of the control switch and one end of the RF receiving path 3. When the RF receiving signal is input into the RF receiving path 3, it is coupled to the antenna ANT through the first capacitor C1; the other end of the first capacitor C1 is connected to the first transformer 2 and the first inductor L1, the first inductor L1 is connected to the second inductor L2, and the second inductor L2 is connected to the antenna ANT; the second capacitor C2 is connected in parallel to both ends of the first inductor L1.
[0045] In this example, the first capacitor C1, the second capacitor C2, the first inductor L1, the second inductor L2 and the first transformer 2 form a radio frequency filter matching network. Specifically, the first transformer 2 can be used to achieve impedance transformation and signal coupling. The first capacitor C1, the second capacitor C2, the first inductor L1, and the second inductor L2 form a filter circuit 1, which can be used to filter the radio frequency transmission signal.
[0046] In another specific example, when the RF receiving circuit 3 is only connected between the first capacitor C1 and the first switch S1, the filter circuit 1 further includes: a third capacitor C3, a fourth capacitor C4, a third inductor L3 and a fourth inductor L4.
[0047] Specifically, one end of the third capacitor C3 is connected between the first inductor L1 and the second inductor L2, and the other end is grounded through the third inductor L3. One end of the fourth capacitor C4 is connected between the second inductor L2 and the antenna ANT, and the other end is grounded through the fourth inductor L4.
[0048] In this example, the combination of the first inductor L1, the second inductor L2, the third capacitor C3 and the fourth capacitor C4 can be used as a bandpass filter to filter the RF signal in a specific frequency band; the third capacitor C3 and the third inductor L3 can form a high-pass filter for suppressing low-frequency interference; the first inductor L1, the second inductor L2 and the third inductor L3 can be combined to form a RF matching network for matching the output impedance of the RF amplifier with the input impedance of the subsequent circuit or the antenna ANT; the combination of the third capacitor C3, the second inductor L2 and the fourth capacitor C4 can suppress harmonic components.
[0049] It can be seen that the above-mentioned filter circuit 1 can suppress interference signals, improve signal quality, and can also achieve radio frequency matching, improve the transmission efficiency of radio frequency signals, thereby improving the performance of the radio frequency front end.
[0050] Those skilled in the art will appreciate that the structure of the filter circuit 1 is not limited to the above, and different filter circuits 1 can be selected according to actual needs.
[0051] Embodiment 2
[0052] This embodiment provides a radio frequency front-end module. Figure 2-Figure 5 The RF front-end module adopts the transformer output matching circuit 4 in the first embodiment, including: a signal amplification and matching network. The signal amplification and matching network is connected to the transformer output matching circuit 4, and the signal amplification and matching network is integrated with the transformer output matching circuit 4, that is, integrated on a chip.
[0053] In this embodiment, please refer to Figure 4 The number of the signal amplification and matching networks can be 1, 2, 3, etc., and any signal amplification and matching network is connected to any first transformer 2 in the transformer output matching circuit 4. Those skilled in the art can select the number of signal amplification and matching networks according to actual conditions, so as to realize the multiple transmission structure of the radio frequency signal.
[0054] The present embodiment proposes a transformer power synthesis miniaturized RF front-end module architecture with integrated filter and RF transceiver switch, which eliminates the need for additional filter chips and transceiver switch chips, realizes the miniaturization of the RF front-end module, and reduces the preparation cost of the RF front-end module.
[0055] Specifically, the signal amplification and matching network includes: an input matching network (InputMatch), a driver amplifier (PAD), a second transformer and a differential amplifier (PA+ and PA-).
[0056] When the transformer output matching circuit 4 works in the transmitting mode, the RF transmitting signal is input to the driving amplifier through the input matching network, and the driving amplifier converts the RF transmitting signal into a differential signal through the second transformer and inputs it to the differential amplifier, and the differential amplifier is powered on and the differential signal is respectively input to the first input terminal c and the second input terminal d of the primary coil of the first transformer 2. When the transformer output matching circuit 4 works in the receiving mode, the differential amplifier is powered off.
[0057] This embodiment abandons the traditional single-ended power amplifier and adopts a differential power amplifier and implements impedance matching and power synthesis through the first transformer 2, thereby improving the output efficiency and bandwidth of the power amplifier.
[0058] In a specific example, the second transformer is an interstage matching balun. The first input end e of the primary coil of the balun is connected to the output end of the driving amplifier, the second input end f is connected to the power supply voltage VBAT, and the first output end g and the second output end h of the secondary coil are respectively connected to the positive input end (PA+) and the negative input end (PA-) of the differential amplifier. The balun can achieve impedance matching to improve the transmission power between devices.
[0059] Since the above-mentioned RF front-end module adopts a transformer output matching network with integrated filter and RF switch, the overall loss of the RF path is only composed of the transformer and the RF receiving switch. In theory, since the loss of the transformer will not deteriorate with the increase of the impedance conversion ratio, and the bandwidth of the transformer is wider than that of the multi-stage LC filter matching network, the signal amplification and matching network integrated with the transformer output matching circuit 4 is more advantageous in efficiency and bandwidth than the traditional amplifier, so there is no need for the amplifier to output a larger power to compensate for the loss in the RF path, and the output power of the amplifier is related to the size of the amplifier. Therefore, under the condition of meeting the power output condition, a smaller differential power amplifier can be selected in this embodiment to reduce the overall size of the RF front-end module. On the other hand, unlike the independently designed RF switch and filter, the RF front-end module integrated with the transformer output matching circuit 4 and the signal amplification and matching network is smaller in size, which reduces the design cost and simplifies the modules required for RF transmission, and the RF receiving circuit can be implemented through CMOS innovative circuit design, further reducing the design cost of the RF front-end module.
[0060] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.
Claims
1. A transformer output matching circuit, characterized in that: include: A radio frequency receiving path, a filtering circuit, a first transformer and an antenna; The radio frequency receiving path, the filtering circuit and the first transformer are integrated into one; When the transformer output matching circuit works in the transmission mode, the first transformer is electrically connected to the filter circuit, and the radio frequency transmission signal is sequentially input to the antenna after passing through the first transformer and the filter circuit for signal transmission; When the transformer output matching circuit operates in a receiving mode, a radio frequency receiving signal is received through any of the radio frequency receiving paths and then input into the filter circuit, and the filter circuit transmits the radio frequency receiving signal to the antenna for signal reception.
2. The transformer output matching circuit according to claim 1, characterized in that: It also includes a control switch, the filter circuit includes a coupling capacitor, one end of the control switch is connected to the coupling capacitor and the radio frequency receiving path, and the other end is grounded; When the RF transmission signal is input to the transformer output matching circuit, the control switch is closed, and the RF receiving switch on the RF receiving path is opened; When the RF receiving signal is input to the transformer output matching circuit, the control switch is opened, the RF receiving switch on the RF receiving path is closed, and the RF receiving signal is input to the filter circuit via the coupling capacitor.
3. The transformer output matching circuit according to claim 2, characterized in that: The filter circuit comprises: a first capacitor, a second capacitor, a first inductor and a second inductor; One end of the first capacitor is connected to one end of the control switch and one end of the RF receiving path, the other end of the first capacitor is connected to the transformer and the first inductor, the first inductor is connected to the second inductor, and the second inductor is connected to the antenna; the second capacitor is connected in parallel to both ends of the first inductor.
4. The transformer output matching circuit according to claim 3, characterized in that: The filter circuit further includes: a third capacitor and a third inductor; Therefore, one end of the third capacitor is connected between the first inductor and the second inductor, and the other end is grounded through the third inductor.
5. The transformer output matching circuit according to claim 4, characterized in that: The filter circuit further includes: a fourth capacitor and a fourth inductor; One end of the fourth capacitor is connected between the second inductor and the antenna, and the other end is grounded through the fourth inductor.
6. The transformer output matching circuit according to claim 1, characterized in that: A first output end of the secondary coil of the first transformer is connected to the filter circuit, the filter circuit is connected to the antenna, and a second output end of the secondary coil is grounded.
7. A radio frequency front-end module, characterized in that: include: A signal amplification and matching network and a transformer output matching circuit as described in any one of claims 1 to 6; The signal amplification and matching network is connected to the transformer output matching circuit, and the signal amplification and matching network is integrated with the transformer output matching circuit.
8. The RF front-end module according to claim 7, characterized in that: The signal amplification and matching network includes: an input matching network, a driver amplifier, a second transformer and a differential amplifier; The RF transmission signal is input to the driving amplifier through the input matching network. The driving amplifier converts the RF transmission signal into a differential signal through the second transformer and inputs the differential signal to the differential amplifier. The differential amplifier inputs the differential signal to the first input terminal and the second input terminal of the primary coil of the first transformer respectively.
9. The RF front-end module according to claim 8, characterized in that: The second transformer is a balun.
10. A wireless communication module, characterized in that: Use the radio frequency front-end module as claimed in claim 9.