MEMS switch high-voltage driving control circuit based on RS485 communication

Abstract

The invention discloses an MEMS switch high-voltage driving control circuit based on RS485 communication, and belongs to the technical field of micro electro mechanical system driving control. The circuit comprises a power supply unit which is used for converting externally input VCC1 and VCC2 voltages into multipath working voltages; the communication unit adopts an RS485 transceiver chip U13 and is used for receiving an external instruction through an RS485 bus; the control core unit adopts a microcontroller U6 and is used for analyzing the instruction and generating an SPI (Serial Peripheral Interface) driving signal; the high-voltage driving module adopts at least one high-voltage driving chip capable of being cascaded and is used for converting the SPI signals into multiple paths of high-voltage driving signals; and the MEMS switch interface module is used for connecting an external MEMS switch array. Through the integrated design, remote control, large-scale channel expansion and reliable protection of the high-voltage driving circuit are achieved, the problems that in the prior art, a system is complex, the reliability is poor and centralized control is difficult are solved, and the high-voltage driving circuit is particularly suitable for driving a large-scale MEMS switch array.

Description

Technical Field

[0001] This invention belongs to the field of microelectromechanical system drive control technology, and specifically relates to a high-voltage drive control circuit for MEMS switches based on RS485 communication. Background Technology

[0002] MEMS switches, with their advantages of low insertion loss, high isolation, low power consumption, and high linearity, have shown great application potential in the radio frequency (RF) and terahertz (THz) fields, especially in reconfigurable smart metasurfaces (RIS) and high-speed communication systems. However, driving MEMS switches typically requires relatively high voltages (e.g., 20V to 50V) to generate sufficient electrostatic force to achieve switching action.

[0003] Existing MEMS switch control solutions typically suffer from the following problems: (1) High driving voltage: It requires an independent high voltage power supply or a complex high voltage generation circuit, which increases the system complexity and cost.

[0004] (2) Complex control interface: It lacks a unified and reliable remote communication and control interface, which is not convenient for centralized management and control in large arrays or distributed systems.

[0005] (3) Lack of protection: When working in high voltage or complex electromagnetic environment, there is no effective protection against external transient voltage and surge, which can easily lead to damage to control chip and MEMS switch.

[0006] Therefore, designing a MEMS switch control circuit with high integration, reliable communication, effective protection functions, and stable high-voltage drive is a problem that urgently needs to be solved in current technology. Summary of the Invention

[0007] The purpose of this invention is to provide a high-voltage drive control circuit for MEMS switches based on RS485 communication, so as to solve the problems of complexity, reliability and insufficient protection in the existing MEMS switch drive control.

[0008] To achieve the above objectives, the present invention adopts the following technical solution: A MEMS switch high-voltage drive control circuit based on RS485 communication includes: The power supply unit is used to convert the externally input first voltage VCC1 and second voltage VCC2 into multiple operating voltages required by the circuit. The communication unit is used to receive external control commands via an RS485 bus. The control core unit has its power input terminal connected to the logic operating voltage output by the power supply unit, and its serial communication port connected to the communication unit, used to parse the control commands and generate corresponding serial drive signals; The high-voltage drive unit has its logic power supply terminal connected to the logic operating voltage output by the power supply unit, its high-voltage power supply terminal connected to the second voltage VCC2, and its control signal input terminal connected to the serial communication port of the control core unit. It is used to convert the received serial drive signal into the high-voltage signal required for the multi-channel drive MEMS switch. The MEMS switch interface unit has its input terminal connected to the high-voltage output terminal of the high-voltage drive unit, and is used to output the high-voltage signal to an external MEMS switch array.

[0009] Furthermore, the power supply unit includes a reverse connection protection and buffer protection circuit module and a multi-stage step-down circuit module; The topology of the reverse connection protection and buffer protection circuit module is as follows: the externally input first voltage VCC1 is connected in series with the first ferrite bead L6 and the second ferrite bead L7; the node between the first ferrite bead L6 and the second ferrite bead L7 is connected to one end of the first filter capacitor C25 and the second filter capacitor C26, as well as the cathode of the first transient voltage suppression diode D8; the anodes of the first filter capacitor C25, the second filter capacitor C26, and the first transient voltage suppression diode D8 are all grounded; the output terminal of the second ferrite bead L7 is connected to the anode of the first diode D7 and one end of the third filter capacitor C24; the cathode of the first diode D7 is connected to the input terminal of the subsequent DC-DC step-down circuit; the other end of the third filter capacitor C24 is grounded. The topology of the multi-stage buck circuit module is as follows: the input terminal VIN of the DC-DC buck chip U4 is connected to the output terminal of the reverse connection protection and buffer protection circuit, and its ground pin GND and enable pin ON / OFF are both grounded; the output terminal OUTPUT of the DC-DC buck chip U4 is connected to one end of the power inductor L5 and the cathode of the freewheeling diode D6; the anode of the freewheeling diode D6 is grounded; the other end of the power inductor L5 serves as the first-stage buck output, outputting a 5V intermediate voltage, and is connected to one end of the fourth filter capacitor C23 and the fifth filter capacitor C22; the fourth filter capacitor C23 and the fifth filter capacitor C22... The other end of capacitor C22 is grounded; the 5V intermediate voltage is connected to the anode of the second diode D9; the cathode of the second diode D9 is connected to the input terminal IN of the linear regulator chip U5, one end of the sixth filter capacitor C21 and the seventh filter capacitor C19; the other ends of the sixth filter capacitor C21 and the seventh filter capacitor C19 are grounded; the ground pin GND of the linear regulator chip U5 is grounded, its output terminal OUT outputs a 3.3V logic voltage, and is connected to one end of the eighth filter capacitor C18 and the ninth filter capacitor C20; the other ends of the eighth filter capacitor C18 and the ninth filter capacitor C20 are grounded.

[0010] Furthermore, the communication unit is implemented using an RS485 transceiver chip U13, and its topology is as follows: The data input pin DI of the RS485 transceiver chip U13 is connected to the serial transmit pin TX of the control core unit through a first resistor R29; the data output pin RO of the RS485 transceiver chip U13 is connected to the serial receive pin RX of the control core unit through a second resistor R28; the driver enable pin DE and the receiver enable pin RE# of the RS485 transceiver chip U13 are interconnected and connected to the 3.3V voltage provided by the power supply unit through a pull-up resistor R30, so that the RS485 transceiver chip U13 is always in the drive and receive enable state; the non-inverting output pin A and the inverting output pin B of the RS485 transceiver chip U13 are directly connected to the A line and B line of the external RS485 bus, respectively.

[0011] Furthermore, the control core unit adopts a microcontroller U6, and its topology is as follows: In the microcontroller U6, all power supply pins are connected to the 3.3V logic operating voltage provided by the power supply unit, and all ground pins are grounded. Multiple type I filter capacitors are connected in parallel between the 3.3V power supply and ground to form a ground filtering module. The first high-speed external clock pin PD0-OSC-IN and the second high-speed external clock pin PD0-OSC-OUT of the microcontroller U6 are connected to the two ends of the external crystal oscillator X2, the nominal frequency of which is 8MHz; and the two ends of the crystal oscillator X2 are grounded through the first load capacitor C13 and the second load capacitor C11, respectively. The serial debug clock pin PA14 and the serial debug data input / output pin PA13 of the microcontroller U6 are respectively connected to the corresponding pins of the debug interface. The first serial communication transmit pin PA9 and the first serial communication receive pin PA10 of the microcontroller U6 are connected to the RS485 transceiver chip U13 of the communication unit to form an RS485 communication interface. The general-purpose input / output pins of the microcontroller U6 are configured as serial peripheral interfaces, specifically including: master output slave input pin PA7, which is connected to the data input pin of the first-level high-voltage drive unit; serial clock pin PA5, which is connected to the clock pin of all high-voltage drive units; output enable pin PA3, which is connected to the output enable pin of all high-voltage drive units; and latch enable pin PA4, which is connected to the latch enable pin of all high-voltage drive units.

[0012] Furthermore, the high-voltage drive unit includes at least one high-voltage drive chip, with the following topological relationship: Each of the high-voltage driver chips has a logic power supply pin connected to a 3.3V logic operating voltage provided by the power supply unit; each of the high-voltage driver chips has a high-voltage power supply pin connected to an externally input second voltage, which is the high voltage required to drive the MEMS switch; and a high-voltage filter capacitor is connected in parallel between the high-voltage power supply pin of each of the high-voltage driver chips and ground. The ground pin of each of the high-voltage drive chips is grounded; The clock pins of all high-voltage drive chips are connected to the serial clock pin of the control core unit; the latch enable pins of all high-voltage drive chips are connected to the latch enable pin of the control core unit; and the output enable pins of all high-voltage drive chips are connected to the output enable pin of the control core unit. The data input pin of the first-stage high-voltage driver chip is connected to the main device data output pin of the control core unit; the data output pin of the first-stage high-voltage driver chip is connected to the data input pin of the next-stage high-voltage driver chip; and subsequent high-voltage driver chips are cascaded in this manner. Each of the high-voltage drive chips has multiple high-voltage output pins connected to corresponding pins of the MEMS switch interface unit.

[0013] Compared with the prior art, the advantages of the present invention are: By highly integrating multiple functional modules such as power management, communication, core control, and high-voltage drive into a single circuit, this invention eliminates the need for separate and complex high-voltage power supplies and control systems found in traditional solutions. This not only significantly reduces the physical size of the circuit board and lowers material costs, but also simplifies the power supply and control links of the entire MEMS switch array, facilitating the miniaturization and modular deployment of the system.

[0014] Employing the industry-standard RS485 communication protocol, this invention boasts excellent common-mode interference immunity and long-distance transmission capabilities (up to kilometer or more). Combined with the intelligent processing capabilities of a microcontroller, it enables the stable reception and execution of complex instructions from a host computer, making it ideal for the centralized control and remote management of large, distributed MEMS switch arrays (such as terahertz metasurfaces). This solves the problems of complex control interfaces, short transmission distances, and weak anti-interference capabilities found in traditional solutions.

[0015] The high-voltage drive unit employs a dedicated high-voltage drive chip (HV9308PJ-G) and is cascaded via a simple "data output to data input" method. This unique serial cascading architecture allows the microcontroller to control dozens or even hundreds of high-voltage drive channels by sending a long string of shifted data, requiring only one set of SPI interface resources. This design significantly saves microcontroller I / O pins, enabling low-cost and high-efficiency expansion of the number of drive channels, perfectly meeting the needs of large-scale MEMS switch arrays.

[0016] The power input terminal is equipped with a reverse connection protection and buffer circuit including TVS diodes and ferrite beads, which can effectively suppress surge voltages, instantaneous high voltages, and electromagnetic interference in the power grid, preventing damage to downstream precision chips (such as MCUs and driver chips) due to power fluctuations or misoperation. Simultaneously, the communication interface is also adequately protected. This multi-layered protection mechanism significantly improves the operational stability and lifespan of the entire control circuit in complex electromagnetic environments.

[0017] Powered by a high-performance microcontroller (STM32), it generates precise and stable SPI communication timing and control signals. Through independent control of the output enable signal and latch enable signal, it enables synchronous refreshing or sequential switching of the states of all MEMS switching channels, avoiding the risk of signal crosstalk or momentary short circuits caused by asynchronous switching actions. This meets the stringent requirements for switching timing in high-end applications.

[0018] This invention provides a complete solution from power input to high-voltage output. Application manufacturers no longer need to design complex high-voltage generation circuits, level conversion circuits, and communication isolation circuits separately; they can directly use this circuit as a standard functional module, significantly shortening product development cycles and lowering the application threshold for MEMS switching technology. Attached Figure Description

[0019] Figure 1 This is a circuit schematic diagram of the power supply unit and the communication unit according to an embodiment of the present invention.

[0020] Figure 2 This is a circuit diagram of the control core unit in an embodiment of the present invention.

[0021] Figure 3 This is a circuit diagram of the high-voltage drive unit according to an embodiment of the present invention.

[0022] Figure 4 This is a schematic diagram of the chip circuit of the MEMS switch interface unit according to an embodiment of the present invention. Detailed Implementation

[0023] The present invention will now be described in further detail with reference to the accompanying drawings.

[0024] This invention discloses a high-voltage drive control circuit for MEMS switches based on RS485 communication. Focusing on providing stable and controllable high-voltage drive for MEMS switch arrays, the circuit is divided into several main parts: a power supply unit, a communication unit, a control core unit, a high-voltage drive unit, and a MEMS switch interface unit. These modules collaborate to complete the entire process from command reception to high-voltage output through explicit electrical connections and signal interactions. The externally input first voltage VCC1 and second voltage VCC2 are processed by the power supply unit to provide stable operating voltages for the remaining units; the communication unit is responsible for RS485 communication with the host computer; the control core unit parses commands and generates control timing sequences; the high-voltage drive unit converts logic signals into high-voltage drive signals; and finally, the signals are output to the MEMS switch array through the MEMS switch interface unit.

[0025] The power supply unit is the energy supply and protection unit for the entire circuit. It includes reverse connection protection and buffer protection circuit modules and multi-stage step-down circuit modules.

[0026] Refer to the specific circuit relationship of the reverse connection protection and buffer protection circuit module. Figure 1 The externally input voltage VCC1 is connected in series with the first ferrite bead L6 and the second ferrite bead L7. At the node between the first ferrite bead L6 and the second ferrite bead L7, one end of the first filter capacitor C25 and the second filter capacitor C26, as well as the cathode of the first transient voltage suppression diode D8 (TVS diode D8), are connected; the anodes of the first filter capacitor C25, the second filter capacitor C26, and the first transient voltage suppression diode D8 are all grounded.

[0027] The output terminal of the second ferrite bead L7 is connected to the anode of the first diode D7 and one end of the third filter capacitor C24. The cathode of the first diode D7 is connected to the input terminal of the subsequent DC-DC buck circuit. The other end of the third filter capacitor C24 is grounded.

[0028] This part of the circuit suppresses high-frequency noise through the first ferrite bead L6 and the second ferrite bead L7, absorbs surge voltage through the TVS diode D8, and implements reverse connection protection through the first diode D7.

[0029] Reference Figure 1 The specific circuit relationships of the multi-stage buck converter module are as follows: The protected voltage is input to the input terminal VIN of the DC-DC buck chip U4 (model XL2594-5.0). The ground pin GND and the enable pin ON / OFF of the DC-DC buck chip U4 are both grounded. The output terminal OUTPUT of the DC-DC buck chip U4 is connected to one end of the power inductor L5 and the cathode of the freewheeling diode D6; the anode of the freewheeling diode D6 is grounded.

[0030] The other end of the power inductor L5 serves as the first-stage step-down output, providing a 5V intermediate voltage, and is connected to one end of the fourth filter capacitor C23 and the fifth filter capacitor C22; the other ends of the fourth filter capacitor C23 and the fifth filter capacitor C22 are both grounded.

[0031] A 5V intermediate voltage is connected to the anode of the second diode D9. The cathode of the second diode D9 is connected to the input terminal IN of the linear regulator chip U5 (LDO chip, model AMS1117-3.3), one end of the sixth filter capacitor C21, and one end of the seventh filter capacitor C19; the other ends of the sixth filter capacitor C21 and the seventh filter capacitor C19 are both grounded.

[0032] The ground pin GND of the linear regulator chip U5 is grounded, and its output terminal OUT outputs a 3.3V logic voltage, which is connected to one end of the eighth filter capacitor C18 and the ninth filter capacitor C20; the other ends of the eighth filter capacitor C18 and the ninth filter capacitor C20 are both grounded.

[0033] The 3.3V logic voltage powers the logic sections of the control core unit and the communication unit, while the 5V intermediate voltage primarily powers the interface section of the communication unit.

[0034] Reference Figure 1 The communication unit enables reliable reception of remote commands. Its core is the RS485 transceiver chip U13 (model MAX13487EESA). The power supply pin VCC of the RS485 transceiver chip U13 is connected to a 5V intermediate voltage, and its ground pin GND is grounded.

[0035] On the logic side, the data input pin DI of the RS485 transceiver chip U13 is connected to the serial transmit pin TX of the control core unit through a first resistor R29. The data output pin RO of the RS485 transceiver chip U13 is connected to the serial receive pin RX of the control core unit through a second resistor R28.

[0036] On the control side, the driver enable pin DE and receiver enable pin RE# of the RS485 transceiver chip U13 are interconnected and connected to a 3.3V logic voltage through a pull-up resistor R30. This configuration keeps the RS485 transceiver chip U13 in a always-enabled state, operating in half-duplex mode.

[0037] On the bus side, the non-inverting output pin A and the inverting output pin B of the RS485 transceiver chip U13 are directly connected to the A and B lines of the external RS485 bus, respectively.

[0038] Reference Figure 2The control core unit is the control center of the system. The control core unit uses a microcontroller U6 (model STM32F103C8T6). All power supply pins of the microcontroller U6 (such as VDD, VDDA) are connected to a 3.3V logic voltage, and all ground pins (such as VSS, VSSA) are grounded. Multiple Class I filter capacitors (such as filter capacitors C14, C15, C16, and C17) are connected in parallel between the 3.3V logic voltage and ground for power supply decoupling.

[0039] The high-speed external clock pin of microcontroller U6 (first high-speed external clock pin (PD0-OSC_)) IN) Second high-speed external clock pin (PD0-OSC) The _OUT) is connected to the two ends of an external crystal oscillator X2 (e.g., 8MHz). The two ends of the crystal oscillator X2 are grounded through the first load capacitor C13 and the second load capacitor C11, respectively, to provide a stable clock source.

[0040] The serial debug clock pin (PA14 / SWCLK) and serial debug data input / output pin (PA13 / SWDIO) of the microcontroller U6 are connected to the corresponding pins of the debug interface for program download and debugging.

[0041] The first serial communication transmit pin (PA9 / USART1_TX) and the first serial communication receive pin (PA10 / USART1_RX) of the microcontroller U6 are connected to the RS485 transceiver chip U13 of the communication unit.

[0042] The general-purpose input / output pins of the microcontroller U6 are configured as Serial Peripheral Interface (SPI) control signals, specifically including: Master Output Slave Input pin (PA7 / SPI_MOSI), connected to the data input pin of the first-level high-voltage driver chip; Serial Clock pin (PA5 / SPI1_SCK), connected to the clock pin of all high-voltage driver chips; Output Enable pin (PA3), connected to the output enable pin of all high-voltage driver chips; and Latch Enable pin (PA4), connected to the latch enable pin of all high-voltage driver chips.

[0043] Reference Figure 3 The high-voltage drive unit generates and expands the high-voltage drive signal. The high-voltage drive unit includes at least one high-voltage drive chip (such as the first-stage high-voltage drive chip U14 and the last-stage high-voltage drive chip U15 provided in this embodiment, model HV9308PJ-G).

[0044] Each high-voltage driver chip's logic power supply pin VDD is connected to a 3.3V logic voltage. Each high-voltage driver chip's high-voltage power supply pin VPP is connected to an externally input second voltage VCC2 (e.g., 50V). High-voltage filter capacitors (e.g., C29 and C30 on the first-stage high-voltage driver chip U14 side; C28 and C31 on the second-stage high-voltage driver chip U15 side) are connected in parallel between each high-voltage driver chip's high-voltage power supply pin VPP and ground. Each high-voltage driver chip's ground pin GND is grounded.

[0045] The clock pin CLK of all high-voltage driver chips is connected to the serial clock pin PA5 of microcontroller U6. The latch enable pin of all high-voltage driver chips is connected to the latch enable pin PA4 of microcontroller U6. The output enable pin of all high-voltage driver chips is connected to the output enable pin PA3 of microcontroller U6.

[0046] The data input pin DataIn of the first-stage high-voltage driver chip U14 is connected to the master data output pin PB0 of the microcontroller U6. The data output pin DataOut of the first-stage high-voltage driver chip U14 is connected to the data input pin DataIn of the next-stage high-voltage driver chip U15, thereby realizing serial cascading of data and expanding the drive channels.

[0047] Each high-voltage driver chip has multiple high-voltage output pins (HVOUT1 to HVOUT32) connected to the corresponding pins of the MEMS switch interface unit.

[0048] Reference Figure 4 The MEMS switch interface unit provides a physical output interface for high-voltage signals.

[0049] The MEMS switch interface unit consists of a high-density connector P1 (model 9001-32641C00A). Multiple pins of the high-density connector P1 (such as A1 to A32) are connected one-to-one with the high-voltage output pins (HVOUT1 to HVOUT32) of the first-stage high-voltage driver chip U14, and multiple other pins of the high-density connector P1 (such as B1 to B32) are connected one-to-one with the high-voltage output pins (HVOUT1 to HVOUT32) of the final-stage high-voltage driver chip U15, thereby outputting multiple high-voltage drive signals (VPP 1 to VPP 64) to the external MEMS switch array.

[0050] Working principle

[0051] After the system powers on, each module initializes. The host computer sends the target switch status command via the RS485 bus. The RS485 transceiver chip U13 of the communication unit receives the command and transmits it to the microcontroller U6. The microcontroller U6 parses the command and generates the corresponding serial data frame. Subsequently, the microcontroller U6, through its SPI interface and synchronized with the serial clock signal, serially shifts the data frame out through the master device output / slave device input pin PB0. The data is first shifted into the first-stage high-voltage driver chip U14, filling its internal shift register, and then shifted into the next-stage high-voltage driver chip U15 through its data output pin. After all data shifting is complete, the microcontroller U6 generates a latch enable signal, latching the data in the shift register in parallel to the output latches of each high-voltage driver chip. Finally, the microcontroller U6 enables the output enable signal, and each high-voltage driver chip, based on the data in the latch, controls its high-voltage output pin to output the corresponding high-voltage signal (VCC2 or 0V), thereby driving the corresponding switch in the MEMS switch array to close or open, completing the control operation.

[0052] The above are merely preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A MEMS switch high voltage drive control circuit based on RS485 communication, characterized in that, The application relates to a high-voltage MEMS switch array driving system, which comprises the following parts: a power supply unit for converting externally input first voltage VCC1 and second voltage VCC2 into multiple working voltages required by a circuit; a communication unit for receiving external control instructions through an RS485 bus; a control core unit, whose power input end is connected with the logic working voltage output by the power supply unit, and whose serial communication port is connected with the communication unit, for analyzing the control instructions and generating corresponding serial driving signals; a high-voltage driving unit, whose logic power supply end is connected with the logic working voltage output by the power supply unit, whose high-voltage power supply end is connected with the second voltage VCC2, and whose control signal input end is connected with the serial communication port of the control core unit, for converting the received serial driving signals into high-voltage signals required by multiple MEMS switches; a MEMS switch interface unit, whose input end is connected with the high-voltage output end of the high-voltage driving unit, for outputting the high-voltage signals to an external MEMS switch array.

2. The MEMS switch high voltage drive control circuit based on RS485 communication according to claim 1, characterized in that, The power supply unit comprises an anti-reverse connection and buffer protection circuit module and a multi-stage voltage reduction circuit module. The anti-reverse connection and buffer protection circuit module has the following topological relationship: the externally input first voltage VCC1 is connected with a first magnetic bead L6 and a second magnetic bead L7 in series; the node between the first magnetic bead L6 and the second magnetic bead L7 is connected with one end of a first filter capacitor C25 and a second filter capacitor C26 and the cathode of a first transient voltage suppression diode D8; the anodes of the first filter capacitor C25, the second filter capacitor C26 and the first transient voltage suppression diode D8 are all grounded; the output end of the second magnetic bead L7 is connected with the anode of a first diode D7 and one end of a third filter capacitor C24; the cathode of the first diode D7 is connected to the input end of a subsequent DC-DC voltage reduction circuit; the other end of the third filter capacitor C24 is grounded. The topological relationship of the multi-stage voltage reduction circuit module is as follows: the input end VIN of the DC-DC voltage reduction chip U4 is connected with the output end of the anti-reverse connection and buffer protection circuit, the ground pin GND and the enable pin ON / OFF of the DC-DC voltage reduction chip U4 are grounded; the output end OUTPUT of the DC-DC voltage reduction chip U4 is connected with one end of the power inductor L5 and the cathode of the freewheeling diode D6; the anode of the freewheeling diode D6 is grounded; the other end of the power inductor L5 is used as a first-stage voltage reduction output, outputs a 5V intermediate voltage, and is connected with one end of the fourth filter capacitor C23 and the fifth filter capacitor C22; the other ends of the fourth filter capacitor C23 and the fifth filter capacitor C22 are grounded; the 5V intermediate voltage is connected to the anode of the second diode D9; the cathode of the second diode D9 is connected with the input end IN of the linear voltage regulator chip U5, one end of the sixth filter capacitor C21 and one end of the seventh filter capacitor C19; the other ends of the sixth filter capacitor C21 and the seventh filter capacitor C19 are grounded; the ground pin GND of the linear voltage regulator chip U5 is grounded, the output end OUT of the linear voltage regulator chip U5 outputs a 3.3V logic voltage, and the output end OUT is connected with one end of the eighth filter capacitor C18 and one end of the ninth filter capacitor C20; the other ends of the eighth filter capacitor C18 and the ninth filter capacitor C20 are grounded.

3. The MEMS switch high voltage drive control circuit based on RS485 communication according to claim 2, characterized in that, The communication unit adopts an RS485 transceiver chip U13, and the topological relationship is as follows: The data input pin DI of the RS485 transceiver chip U13 is connected with the serial transmission pin TX of the control core unit through the first resistor R29; the data output pin RO of the RS485 transceiver chip U13 is connected with the serial receiving pin RX of the control core unit through the second resistor R28; the driver enable pin DE and the receiver enable pin RE# of the RS485 transceiver chip U13 are connected with each other, and are connected with the 3.3V voltage provided by the power supply unit through a pull-up resistor R30, so that the RS485 transceiver chip U13 is always in a driving and receiving enabled state; the in-phase output pin A and the anti-phase output pin B of the RS485 transceiver chip U13 are directly connected with the A line and the B line of the external RS485 bus respectively.

4. The MEMS switch high voltage drive control circuit based on RS485 communication according to claim 2, characterized in that, The control core unit adopts a microcontroller U6, and the topological relationship is as follows: In the microcontroller U6, the power supply pins are connected with the 3.3V logic working voltage provided by the power supply unit, the ground pins are grounded, a plurality of first-type filter capacitors are connected in parallel between the 3.3V power supply and the ground, and a ground filtering module is formed; The first high-speed external clock pin PD0-OSC-IN and the second high-speed external clock pin PD0-OSC-OUT of the microcontroller U6 are connected with two ends of an external crystal oscillator X2, the nominal frequency of the crystal oscillator is 8MHz, and the two ends of the crystal oscillator X2 are grounded through the first load capacitor C13 and the second load capacitor C11 respectively; The serial debugging clock pin PA14 and the serial debugging data input / output pin PA13 of the microcontroller U6 are connected with the corresponding pins of the debugging interface respectively; The first serial communication sending pin PA9 and the first serial communication receiving pin PA10 of the microcontroller U6 are connected with the RS485 transceiver chip U13 of the communication unit, to form an RS485 communication interface. The general input and output pin of the microcontroller U6 is configured as a serial peripheral interface, specifically including: the master device output and slave device input pin PA7, connected with the data input pin of the first-stage high-voltage driving unit; the serial clock pin PA5, connected with the clock pin of all high-voltage driving units; the output enable pin PA3, connected with the output enable pin of all high-voltage driving units; and the latch enable pin PA4, connected with the latch enable pin of all high-voltage driving units.

5. The MEMS switch high voltage drive control circuit based on RS485 communication according to claim 2, characterized in that, The high-voltage driving unit includes at least one high-voltage driving chip, and the topological relationship is as follows: The logic power pin of each high-voltage driving chip is connected with the 3.3V logic working voltage provided by the power supply unit; the high-voltage power pin of each high-voltage driving chip is connected with the second voltage input from outside, the second voltage being the high voltage required for driving the MEMS switch; and the high-voltage filter capacitor is connected in parallel between the high-voltage power pin of each high-voltage driving chip and the ground; The ground pin of each high-voltage driving chip is grounded; The clock pins of all high-voltage driving chips are commonly connected to the serial clock pin of the control core unit; the latch enable pins of all high-voltage driving chips are commonly connected to the latch enable pin of the control core unit; and the output enable pins of all high-voltage driving chips are commonly connected to the output enable pin of the control core unit; The data input pin of the first-stage high-voltage driving chip is connected to the master device data output pin of the control core unit; the data output pin of the first-stage high-voltage driving chip is connected to the data input pin of the next-stage high-voltage driving chip; and the subsequent high-voltage driving chips are cascaded in turn according to the rule; The multiple high-voltage output pins of each high-voltage driving chip are respectively connected to the corresponding pins of the MEMS switch interface module.

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