CN219372394U

CN219372394U - Radio frequency energy transmission device based on multistage power amplifier

Info

Publication number: CN219372394U
Application number: CN202320818131.5U
Authority: CN
Inventors: 徐天睿; 刘艳伟
Original assignee: Beijing Lingchuang Yigu Technology Development Co ltd
Current assignee: Beijing Lingchuang Yigu Technology Development Co ltd
Priority date: 2023-04-13
Filing date: 2023-04-13
Publication date: 2023-07-18
Anticipated expiration: 2033-04-13

Abstract

The utility model discloses a radio frequency energy transmission device based on a multi-stage power amplifier, which comprises: the power supply, the voltage conversion circuit and the radio frequency circuit, wherein the voltage conversion circuit is used for converting the power supply voltage into different working voltages required by the radio frequency circuit; the radio frequency circuit comprises a main control chip, a signal generator, a balun, a driving stage power amplifier, a final stage power amplifier, a transmitting coupler, a receiving coupler, an antenna and a carrier cancellation circuit connected with the receiving coupler, wherein the signal generator, the balun, the driving stage power amplifier, the final stage power amplifier, the transmitting coupler, the receiving coupler and the antenna are sequentially connected; the signal generator is used for generating a radio frequency differential modulation signal under the control of the main control chip; the drive stage power amplifier and the final stage power amplifier are used for amplifying the single-ended modulation signal output by the balun and transmitting the single-ended modulation signal to the transmitting coupler; the carrier cancellation circuit is used for adjusting the load impedance of the receiving coupler. The device can improve the stability and sensitivity of high-power radio frequency energy transmission and reduce the interference to a receiving channel.

Description

Radio frequency energy transmission device based on multistage power amplifier

Technical Field

The utility model relates to the technical field of radio frequency energy transmission, in particular to a radio frequency energy transmission device based on a multistage power amplifier.

Background

Currently, implantable spinal cord nerve stimulators, peripheral nerve or muscle electrical stimulators may be used for diagnosis of chronic diseases by functional electrical stimulation. In order to reduce the size of the device, a wireless energy transmission mode is generally adopted, an energy source is arranged outside the body, and electromagnetic induction of radio frequency is coupled with a magnetic field to supply power to the in-vivo electric stimulation device.

The external energy transmission and communication device of the existing electric stimulator is basically based on the radio frequency identification technology of an RFID integrated chip, and cannot meet the requirement of high-power private protocol communication. In a high-power application scene, the coupling degree between the transmitting end and the receiving end is higher, the impedance change of the antenna is larger, and the stability and the sensitivity of the transmission of radio frequency energy can be affected by carrier signal interference.

Therefore, there is a need for a multi-stage power amplifier-based rf energy transmission device that can provide stable multi-stage power amplification, reduce carrier signal interference, and improve stability and sensitivity of the rf receive path, so as to solve the above problems in the prior art.

Disclosure of Invention

In view of the above problems, the present utility model proposes a multi-stage power amplifier-based rf energy transmission device that overcomes or at least partially solves the above problems, and can achieve a power output of 5W-10W by adjusting the types of the driving stage power amplifier and the final stage power amplifier and the peripheral matching circuit, so as to meet the high-power rf energy transmission requirement. And by designing the carrier cancellation circuit, the interference signal on the energy transmission path can be eliminated, so that the stability and the sensitivity of the radio frequency receiving path are improved.

In particular, the utility model provides a multi-stage power amplifier-based radio frequency energy transmission device for transmitting electrical energy to and in radio frequency communication with an in vivo nerve electrical stimulator. The apparatus may include: power supply, voltage conversion circuit and radio frequency circuit.

The voltage conversion circuit is used for converting the power supply voltage into different working voltages required by the radio frequency circuit and the carrier cancellation circuit. The radio frequency circuit comprises a main control chip, a signal generator, a balun, a driving stage power amplifier, a final stage power amplifier, a transmitting coupler, a receiving coupler, an antenna and a carrier cancellation circuit which are sequentially connected; the signal generator is used for generating a radio frequency differential modulation signal with controllable level under the control of the main control chip; the balun is used for converting the radio frequency differential modulation signal generated by the signal generator into a single-ended modulation signal; the drive stage power amplifier and the final stage power amplifier are used for amplifying the single-ended modulation signal and transmitting the single-ended modulation signal to the transmitting coupler; the carrier cancellation circuit is used for adjusting the load impedance of the receiving coupler so as to reduce the interference of the reflected signal on the transmission of radio frequency energy.

Optionally, in the above device, the radio frequency circuit further includes a receiving demodulator, connected to the receiving coupler, for demodulating the radio frequency signal received by the receiving coupler into a digital modulation signal.

Alternatively, in the above apparatus, the signal generator employs MAX2900, the driving stage power amplifier employs MMZ09312B, the final stage power amplifier employs AFT09MS007NT1, and the receiving demodulator employs MAX41470.

Optionally, in the above device, the carrier cancellation circuit includes a first adjustable capacitor, a second adjustable capacitor, and a third adjustable capacitor, and the main control chip is configured to adjust capacitance values of the first adjustable capacitor, the second adjustable capacitor, and the third adjustable capacitor through the SPI, so as to control a load impedance of the receiving coupling end.

Optionally, in the above device, the carrier cancellation circuit further includes a first inductor, a second inductor, a third inductor, a first capacitor and a first resistor, where the first inductor is connected in parallel with the first adjustable capacitor, the second inductor is connected in series with the first capacitor and then connected in parallel with the second adjustable capacitor, and the third inductor and the first resistor are connected in parallel with the third adjustable capacitor respectively.

Optionally, in the above device, the main control chip is configured to generate the magnitude of the radio frequency differential modulation signal by using the SPI control signal generator, and is further configured to provide a first switching level for the driver stage power amplifier by using the GPIO, provide a second switching level for the final stage power amplifier, and provide a gate voltage for the final stage power amplifier by using the DAC.

Optionally, in the above device, the device further includes a signal detector connected to the transmitting coupler, and configured to detect a magnitude of a transmitting signal of the transmitting coupler and convert the radio frequency transmitting signal into an analog level signal and transmit the analog level signal to the main control chip.

Optionally, in the above apparatus, the voltage conversion circuit includes a DCDC module for converting the power supply voltage into an operating voltage of the final stage power amplifier, a first LDO module for converting the power supply voltage into an operating voltage of the driving stage power amplifier, and a second LDO module for converting the power supply voltage into an operating voltage required by the signal generator, the signal detector, the carrier cancellation circuit, and the receiving demodulator.

Optionally, in the above device, the DCDC module uses TPS61089RN as the DCDC chip, and the first LDO module and the second LDO module use TPS7a8001DRBR as the LDO chip.

According to the scheme provided by the utility model, the power output of 5W-10W can be realized by adjusting the types of the driving stage power amplifier and the final stage power amplifier and the peripheral matching circuit, and the high-power radio frequency energy transmission requirement can be met. And by designing the carrier cancellation circuit, the interference signal on the energy transmission path can be eliminated, so that the stability and the sensitivity of the radio frequency receiving path are improved.

The foregoing description is only an overview of the present utility model, and is intended to be implemented in accordance with the teachings of the present utility model in order that the same may be more clearly understood and to make the same and other objects, features and advantages of the present utility model more readily apparent.

Drawings

Various other advantages and benefits will become apparent to those of ordinary skill in the art upon reading the following detailed description of the preferred embodiments. The drawings are only for purposes of illustrating the preferred embodiments and are not to be construed as limiting the utility model. Also, like reference numerals are used to designate like parts throughout the figures. In the drawings:

fig. 1 shows a block diagram of a circuit configuration of a multi-stage power amplifier-based radio frequency energy transmission device according to an embodiment of the present utility model;

FIG. 2 shows a schematic diagram of the structure of a logic control circuit according to one embodiment of the utility model;

fig. 3 shows a signal flow diagram of a carrier cancellation circuit according to one embodiment of the utility model;

fig. 4 shows a schematic diagram of a carrier cancellation circuit according to an embodiment of the utility model.

Detailed Description

Exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be embodied in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.

The nerve electric stimulation system based on the transmission and control of the radio frequency energy provides the radio frequency energy for the implanted electric stimulator in real time through the external energy controller, so that the reliability of radio frequency communication and higher energy transmission efficiency are required to be ensured.

In order to meet the high-power radio frequency energy transmission requirement, a secondary or tertiary amplifying circuit is required to be arranged between a signal generator and a signal transmitting end in the external energy controller. However, under the condition of high-power radio frequency transmission, the coupling degree of the signal transmitting end and the receiving end is high, and great interference can be generated on energy transmission.

In order to improve the high-power radio frequency energy transmission efficiency, the scheme provides a radio frequency energy transmission device based on a multi-stage power amplifier, which can eliminate carrier interference of a signal coupling end, improve the radio frequency energy transmission efficiency, realize power output of 5W-10W and meet the requirement of high-power radio frequency energy transmission by adjusting a peripheral circuit of the type of the multi-stage amplifier.

Fig. 1 shows a block diagram of a multi-stage power amplifier based radio frequency energy transmission device according to one embodiment of the present utility model. The device can be used to deliver electrical energy to an implantable neurostimulator in vivo and to communicate at radio frequencies.

As shown in fig. 1, the apparatus may include a power supply, a voltage conversion circuit, and a radio frequency circuit. The voltage conversion circuit is used for converting the power supply voltage into different working voltages required by the radio frequency circuit and the carrier cancellation circuit; the radio frequency circuit comprises a main control chip MCU, a signal generator, a balun, a driving stage power amplifier, a final stage power amplifier, a transmitting coupler, a receiving coupler, an antenna, a carrier cancellation circuit and a receiving demodulator which are connected with the receiving coupler in sequence.

The signal generator can generate 920MHz radio frequency differential modulation signals, and the balun can convert the radio frequency differential modulation signals generated by the signal generator into radio frequency single-ended modulation signals. The differential signal is converted into a single-ended signal, so that electromagnetic interference can be reduced, and the anti-interference performance of the system is improved.

The main control chip MCU can control the magnitude of a radio frequency differential signal generated by the signal generator through the SPI, can also provide a first switching level for the driving stage power amplifier through the GPIO, can provide a second switching level for the final stage power amplifier, and can provide grid voltage for the final stage power amplifier through the DAC.

The main control chip MCU can respectively control a first switch level of the driving stage power amplifier and a second switch level of the final stage power amplifier through an externally arranged logic control circuit, and the first switch level and the second switch level can be in time sequence synchronization.

Fig. 2 shows a schematic diagram of the structure of a logic control circuit according to an embodiment of the present utility model. As shown in fig. 2, the logic control circuit includes switching devices SI2301 and SI2302, a start pin of the driving stage power amplifier is connected to a gate of SI2301 through a resistor R2332, and a start pin of the final stage power amplifier is connected to a source of SI 2301. A resistor R2334 is connected between the gate and the source of SI 2301. The drain of SI2301 is connected to the gate of SI2302 through resistor R2331. The gate of SI2302 is grounded through parallel R2333 and capacitor C2332, and the gate of SI2301 is grounded through parallel R2330 and capacitor C2330.

In one embodiment of the utility model, the signal generator uses MAX2900, the driver stage power amplifier uses MMZ09312B, and the final stage power amplifier uses AFT09MS007NT1. The main control chip MCU can generate an on-off keying radio frequency CW differential signal through the SPI and the GPIO control signal generator MAX2900 and adjust the size of the radio frequency differential signal. Under the high-power radio frequency transmission condition, the same-frequency transmission of OOK and ASK can be realized.

The 920MHz radio frequency single ended modulation signal was amplified by a driver stage power amplifier by about 15dB to the desired power by a final stage power amplifier (AFT 09MS007NT 1).

As shown in fig. 1, the device further comprises a signal detector, wherein the signal detector is connected with the transmitting coupler and is used for detecting the magnitude of a transmitting signal of the transmitting coupler, converting the transmitting signal into an analog level signal and transmitting the analog level signal to the main control chip. The receiving demodulator is used for demodulating the radio frequency signal received by the receiving coupler into a digital modulation signal.

In one embodiment of the utility model, the supply voltage is 3.8V-4.2V, and the voltage conversion circuit includes a DCDC module, a first LDO module, and a second LDO module, where the DCDC module is configured to convert the supply voltage to an operating voltage required by the final stage power amplifier, for example, a 4.2V supply voltage may be converted to 7.5V.

The first LDO module is used to convert the supply voltage to an operating voltage required by the driver stage power amplifier, for example, a 4.2V supply voltage may be converted to 3.6V. The second LDO module is configured to convert the power supply voltage into an operating voltage required by a signal generator, a signal detector, a carrier cancellation circuit, and a receiving demodulator in the radio frequency energy control device, for example, the power supply voltage of 4.2V may be converted into 3.3V.

The voltage regulation range is 7.5V-16V depending on the type of power amplifier. The DCDC module adopts TPS61089RN as a DCDC chip, and the first LDO module and the second LDO module adopt TPS7A8001DRBR as LDO chips.

Amplified by a driving stage power amplifier and a final stage power amplifier, and transmitted to an antenna end. The transmitting coupler and the signal detector can detect the transmitting signal and monitor the size of the transmitting signal in real time. Because the coupling degree between the transmitting end and the receiving end is higher in the high-power signal transmission process, a carrier cancellation circuit is required to be arranged, and the coupling end generates mismatch and reflection by changing the load impedance of the coupling end. The carrier cancellation circuit is used for adjusting the load impedance of the receiving coupler.

Fig. 3 shows a signal flow diagram of a carrier cancellation circuit according to one embodiment of the utility model. As shown in fig. 3, the radio frequency signal is transmitted from the input end to the output end, the output end performs radio frequency identification with the tag end through the antenna, and the tag end generates certain reflection due to the influence of the human body on the load impedance.

The carrier cancellation circuit adjusts the load of the coupling end to enable the coupling end to generate impedance mismatch and generate signal reflection, so that the signal reflected by the coupling end is equal to the interference signal, namely the interference signal, of the path 3 and the path 4 received by the isolation end, and the phase difference is 180 degrees, thereby canceling the interference signal on the path 3 and the path 4 and reducing the noise bottom of the receiving end.

By adjusting the load of the coupling end, the coupling end generates mismatch, so that the power of the path 1 is reflected to the path 2 and output to the isolation end. The signals Px and Pr+ (Pin-CL-D) on the path 2 have equal amplitude and 180 degrees phase difference, so that the signals are counteracted.

The receiving demodulation end only demodulates the tag reflected signal on the path 5 through the adjustment of the load impedance of the carrier cancellation circuit.

Fig. 4 shows a schematic diagram of a carrier cancellation circuit according to an embodiment of the utility model. As shown in fig. 4, the capacitance values of the first tunable capacitor CX1, the second tunable capacitor CX2, and the third tunable capacitor CX3 can be adjusted within a range between 0.8 pF to 4.5 pF.

The first inductor L1 is connected in parallel with the first adjustable capacitor CX1, the second inductor L2 is connected in series with the first capacitor C1 and then connected in parallel with the second adjustable capacitor CX2, and the third inductor L3 and the first resistor R1 are respectively connected in parallel with the third adjustable capacitor CX 3. The first inductor L1, the first capacitor C1, the second inductor L2, the third inductor L3 and the first resistor R1 are used for eliminating parasitic of the adjustable capacitor and parasitic parameters brought by the adjustable capacitor and the board under the passive condition.

The SPI is used for carrying out algorithm control, and the capacitance value of the adjustable capacitor is selected according to the sensitivity of the receiving end, so that the load impedance of the whole carrier cancellation circuit is controlled. And other resistors, capacitors and inductors are subjected to passive debugging, the matching is performed to 50 omega, and the debugging values of different circuit boards are slightly different.

The signal communication uses the private protocol communication of OOK signals. The radio frequency signal is back scattered to the Rx port of the Rx coupler, and is received and demodulated into a digital modulation signal through the receiving demodulator MAX41470, thereby completing the transceiving state of the whole communication.

Through the scheme, 5W-10W power output can be realized by adjusting the types of the driving stage power amplifier and the final stage power amplifier and the peripheral matching circuit, and the high-power radio frequency energy transmission requirement can be met. And by designing the carrier cancellation circuit, the interference signal on the energy transmission path can be eliminated, so that the stability and the sensitivity of the radio frequency receiving path are improved.

In the description provided herein, numerous specific details are set forth. However, it is understood that embodiments of the utility model may be practiced without these specific details. In some instances, well-known methods, structures and techniques have not been shown in detail in order not to obscure an understanding of this description.

Similarly, it should be appreciated that in the foregoing description of exemplary embodiments of the utility model, various features of the utility model are sometimes grouped together in a single embodiment, figure, or description thereof for the purpose of streamlining the disclosure and aiding in the understanding of one or more of the various inventive aspects. However, the disclosed method should not be construed as reflecting the intention that: i.e., the claimed utility model requires more features than are expressly recited in each claim. Rather, as the following claims reflect, inventive aspects lie in less than all features of a single foregoing disclosed embodiment. Thus, the claims following the detailed description are hereby expressly incorporated into this detailed description, with each claim standing on its own as a separate embodiment of this utility model.

Those skilled in the art will appreciate that the modules or units or components of the devices in the examples disclosed herein may be arranged in a device as described in this embodiment, or alternatively may be located in one or more devices different from the devices in this example. The modules in the foregoing examples may be combined into one module or may be further divided into a plurality of sub-modules.

Those skilled in the art will appreciate that the modules in the apparatus of the embodiments may be adaptively changed and disposed in one or more apparatuses different from the embodiments. The modules or units or components of the embodiments may be combined into one module or unit or component and, furthermore, they may be divided into a plurality of sub-modules or sub-units or sub-components. Any combination of all features disclosed in this specification (including any accompanying claims, abstract and drawings), and all of the processes or units of any method or apparatus so disclosed, may be used in combination, except insofar as at least some of such features and/or processes or units are mutually exclusive. Each feature disclosed in this specification (including any accompanying claims, abstract and drawings), may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise.

Furthermore, those skilled in the art will appreciate that while some embodiments described herein include some features but not others included in other embodiments, combinations of features of different embodiments are meant to be within the scope of the utility model and form different embodiments. For example, in the following claims, any of the claimed embodiments can be used in any combination.

Furthermore, some of the embodiments are described herein as methods or combinations of method elements that may be implemented by a processor of a computer system or by other means for performing the functions. Thus, a processor with the necessary instructions for implementing a method or a method element forms a means for implementing the method or the method element. Furthermore, the elements of the apparatus embodiments described herein are examples of the following apparatus: the apparatus is for carrying out the functions performed by the elements for carrying out the objects of the utility model.

As used herein, unless otherwise specified the use of the ordinal terms "first," "second," "third," etc., to describe a general object merely denote different instances of like objects, and are not intended to imply that the objects so described must have a given order, either temporally, spatially, in ranking, or in any other manner.

While the utility model has been described with respect to a limited number of embodiments, those skilled in the art, having benefit of the above description, will appreciate that other embodiments are contemplated within the scope of the utility model as described herein. Furthermore, it should be noted that the language used in the specification has been principally selected for readability and instructional purposes, and may not have been selected to delineate or circumscribe the inventive subject matter. Accordingly, many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the appended claims. The disclosure of the present utility model is intended to be illustrative, but not limiting, of the scope of the utility model, which is defined by the appended claims.

Claims

1. A multi-stage power amplifier-based radio frequency energy delivery device for delivering electrical energy to and in radio frequency communication with an in vivo nerve electrical stimulator, comprising: the power supply, the voltage conversion circuit and the radio frequency circuit are used for converting the power supply voltage into different working voltages required by the radio frequency circuit;

the radio frequency circuit comprises a main control chip, a signal generator, a balun, a driving-stage power amplifier, a final-stage power amplifier, a transmitting coupler, a receiving coupler, an antenna and a carrier cancellation circuit connected with the receiving coupler, wherein the signal generator, the balun, the driving-stage power amplifier, the final-stage power amplifier, the transmitting coupler, the receiving coupler and the antenna are sequentially connected;

the signal generator is used for generating a radio frequency differential modulation signal with a controllable level under the control of the main control chip; the balun is used for converting the radio frequency differential modulation signal generated by the signal generator into a single-ended modulation signal; the driving stage power amplifier and the final stage power amplifier are used for amplifying the single-ended modulation signal and transmitting the single-ended modulation signal to the transmitting coupler, and the single-ended modulation signal is received by the receiving coupler and radiated by an antenna; the carrier cancellation circuit is used for adjusting the load impedance of the receiving coupler.

2. The rf energy transmission device of claim 1, wherein the rf circuit further comprises a receive demodulator coupled to the receive coupler for demodulating the rf signal received by the receive coupler into a digital modulated signal.

3. The rf energy transmission device of claim 2, wherein the signal generator employs MAX2900, the driver stage power amplifier employs MMZ09312B, the final stage power amplifier employs AFT09MS007NT1, and the receive demodulator employs MAX41470.

4. The apparatus of claim 1, wherein the carrier cancellation circuit comprises a first adjustable capacitor, a second adjustable capacitor and a third adjustable capacitor, and the main control chip is configured to adjust capacitance values of the first adjustable capacitor, the second adjustable capacitor and the third adjustable capacitor through SPI to control the load impedance of the receiving coupling end.

5. The apparatus of claim 4, wherein the carrier cancellation circuit further comprises a first inductor, a second inductor, a third inductor, a first capacitor, and a first resistor, the first inductor being connected in parallel with the first adjustable capacitor, the second inductor being connected in series with the first capacitor and being connected in parallel with the second adjustable capacitor, the third inductor and the first resistor being connected in parallel with the third adjustable capacitor, respectively.

6. The rf energy transmission device of claim 1, wherein the master control chip is configured to control the magnitude of the rf differential modulation signal generated by the signal generator via the SPI, and further configured to provide a first switching level for the driver stage power amplifier via the GPIO, a second switching level for the final stage power amplifier, and a gate voltage for the final stage power amplifier via the DAC.

7. The rf energy transmission device of claim 2, further comprising a signal detector coupled to the transmit coupler for detecting a magnitude of a transmit signal of the transmit coupler and converting the rf transmit signal to an analog level signal for transmission to the host chip.

8. The rf energy transfer apparatus of claim 7, wherein the voltage conversion circuit comprises a DCDC module to convert a supply voltage to an operating voltage of the final stage power amplifier, a first LDO module to convert a supply voltage to an operating voltage of the driver stage power amplifier, and a second LDO module to convert a supply voltage to an operating voltage required by the signal generator, signal detector, carrier cancellation circuit, and receiver demodulator.

9. The apparatus of claim 8, wherein the DCDC module uses TPS61089RN as a DCDC chip, and the first and second LDO modules use TPS7a8001DRBR as LDO chips.