Series-parallel RF switch and control system
By designing dynamic power detection and control logic modules in the RF switch control system, the problems of isolation and nonlinear performance at small and medium power in traditional systems are optimized, and better RF performance is achieved.
Patent Information
- Application Number
- CN202111197250.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2021-10-14
- Publication Date
- 2025-03-25
- Estimated Expiration
- 2041-10-14
AI Technical Summary
Traditional RF switches and control systems have excessive isolation redundancy at small and medium power, and insufficient nonlinearity such as harmonics, which cannot meet the strict requirements.
A series-parallel RF switch control system is designed, including logic control module, analog module, dynamic power detection module, power control logic module and N series-parallel RF switch branch modules. Through dynamic power detection and control logic design, the reverse or same direction of the parallel branch and the series branch are selected according to the power dynamic control processed by the RF switching system to optimize RF performance.
The isolation and nonlinear performance at small and medium power are optimized, the overall performance of the RF switching system is improved, and the strict requirements under small and medium power are met.
Smart Images
Figure CN114039590B_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the field of semiconductor devices and manufacturing, mainly to radio frequency front-end circuit design, and in particular to a series-parallel radio frequency switch and control system of a radio frequency front-end. Background Art
[0002] RF switches are commonly used devices in RF paths, used to control the selection and switching related to RF signal transmission. Their performance indicators include isolation, insertion loss, linearity and switching time.
[0003] RF switches include conduction switches and antenna switches. The function of the conduction switch is to connect any one or several of the multiple RF signals through control logic to achieve the switching of different signal paths, including the switching between reception and transmission, and the switching between different frequency bands. It includes mobile communication conduction switches, WiFi switches, etc., which are widely used in mobile smart terminals such as smartphones. Antenna switches are a type of RF switch that is directly connected to the antenna and is mainly used to tune the transmission performance of the antenna signal to achieve the best efficiency at any applicable frequency; or to switch and select the appropriate antenna channel.
[0004] The working principle of the RF switch is mainly: when different voltages are applied to the control port of the RF switch, the ports of the RF switch will show different connectivity.
[0005] In the structure of traditional RF switches and control systems, the series-parallel structure and control design of the RF switch not only affect the RF performance such as insertion loss and isolation of the RF switch, but also affect the nonlinearity such as harmonics of the RF switch, and usually require a compromise balanced design.
[0006] Generally speaking, the traditional RF switch parallel branch control adopts a fixed reverse logic design with the series branch to optimize and improve isolation. However, this method has excessive isolation redundancy during medium and low power reception and transmission, and the nonlinearity such as harmonics is limited by the process level and area cost constraints. The design margin is insufficient, and it cannot meet the challenging requirements of more stringent nonlinearity such as harmonics under medium and low power. Summary of the invention
[0007] The technical problem to be solved by the present invention is to provide a series-parallel radio frequency switch control system to optimize the performance at small, medium and high powers.
[0008] To solve the above problems, the series-parallel RF switch control system described in the present invention includes a logic control module, an analog module, a dynamic power detection module, a power control logic module and N series-parallel RF switch branch modules, where N is a natural number ≥1.
[0009] The logic control module sends out a control signal, and the series-parallel RF switch branch module receives the control signal sent out by the logic control module.
[0010] Each of the series-parallel RF switch branches includes a series branch and a parallel branch; the series branch and the parallel branch each include a potential shifter, a plurality of switch tubes and a bias resistor of the switch tube; the control signal controls the gate of the switch tube through the potential shifter.
[0011] In each of the series branches in the series-parallel RF switch branch modules, the control signal directly controls the potential shifter in the series branch, and the potential shifter controls the first switch tube and the second switch tube; in the parallel branch, the control signal is converted into a reverse signal by an inverter and then transmitted to an input end of an AND gate, and the other input end of the AND gate is connected to the feedback VC signal provided by the power control logic module, and the output end of the AND gate is connected to the potential shifter in the parallel branch, and the potential shifter controls the third switch tube; the power control logic module outputs a feedback signal VC to the dynamic power detection module, and the feedback VC signal is a logic "1" or "0" signal.
[0012] The dynamic power detection module dynamically detects the processing power of the RF switch control system. It receives the feedback VC signal and the power signal on the antenna, and outputs the PC signal to the power control logic module after processing and threshold comparison.
[0013] The analog module provides power to the logic control module, each series-parallel RF switch branch module, the dynamic power detection module and the power control logic module.
[0014] A further improvement is that the structure of the dynamic power detection module is: it includes N diodes connected in series end to end, the cathode of which is connected to the source end of a transistor, the drain of the transistor is grounded through a first resistor, and the anodes of the N series-connected diodes are connected to the antenna.
[0015] The source end of the transistor also outputs a PC signal through a third resistor.
[0016] The gate of the transistor is connected to feedback the VC signal through a second resistor.
[0017] A further improvement is that the transistor is a MOS tube.
[0018] A further improvement is that the MOS tube is a PMOS tube.
[0019] A further improvement is that the dynamic power detection module uses a diode connected in series with a resistor to design a power detection threshold.
[0020] A further improvement is that the analog module provides power and clock signals for other modules, and the analog module includes a BGR circuit, an LDO circuit, a clock circuit and a negative voltage generating circuit.
[0021] A further improvement is that the structure of the power control logic module includes a first and a second transistor connected in series, the gate of the first transistor is connected to the output PC signal of the dynamic power detection module, and the remaining end after the series connection is grounded; the remaining end of the second transistor after the series connection is short-circuited with the gate and then connected to the power supply.
[0022] A node where the first transistor and the second transistor are connected in series is connected to an inverter, and an output end of the inverter outputs a VC signal.
[0023] The third transistor is also included. The source and drain of the third transistor are short-circuited and then grounded. The gate of the third transistor is connected to a node where the first transistor and the second transistor are connected in series.
[0024] A further improvement is that the first transistor is NMOS, the second transistor is NMOS, and the third transistor is NMOS.
[0025] A further improvement is that the power control logic module first amplifies the detection signal and outputs a stable logic after shaping.
[0026] The output of the power control logic module is fed back to the dynamic power detection module after being stabilized. After the PMOS is turned off, the power detection threshold is increased to achieve a single trigger, thereby preventing the dynamic power detection module from affecting the normal working RF performance.
[0027] A further improvement is that the first switch tube, the second switch tube, and the third switch tube in the series-parallel RF switch branch module adopt a stacked switch branch structure for power design.
[0028] A further improvement is that the stacked switch branch structure is that the two control signals after passing through the potential shifter pass through the fourth resistor and the fifth resistor respectively, and then pass through the gate bias resistor and the substrate bias resistor respectively to connect to the switch tube, and there are N switch tubes; resistors are connected across the source and drain ends of the N switch tubes; after the source and drain ends of the N switch tubes are connected in series in sequence, output ends are formed at the head and the tail respectively.
[0029] A further improvement is that the first switch tube in the series branch is an optional design and can be directly removed when the first switch tube is not needed in the circuit design.
[0030] A further improvement is to use a dynamic power detection module to dynamically detect the signal power processed on the antenna of the series-parallel RF switch system: a trigger signal PC is generated when the detection power exceeds the detection power threshold, and is input to the power control logic module so that it outputs a stable control signal VC after processing, and the VC signal is a logically stable "1" or "0" signal; at the same time, the dynamic power detection module also receives the control signal VC output by the power control logic module as a feedback signal to control and adjust the power detection threshold and realize a single trigger, thereby preventing the dynamic power detection circuit from affecting the normal operating RF performance of the antenna end and the RF switch.
[0031] When the series branch control is turned on at "1", the parallel branch is kept turned off and in the opposite direction of the series branch, which does not affect the normal transmission and reception of the RF switch branch.
[0032] When the series branch is controlled to be turned off at "0", according to the VC signal control logic: at high power, the parallel branch is kept open and in the opposite direction of the series branch, and it works in a high-power and high-isolation mode; at small and medium power, the parallel branch is kept closed and in the same direction as the series branch, and it works in a small and medium power, medium isolation, and high linearity optimization mode.
[0033] The power control logic module outputs a feedback VC signal to the dynamic power detection module when it is stable, and increases the power detection threshold after the power detection is triggered to prevent the power detection circuit from affecting the normal working RF performance.
[0034] The series-parallel RF switch control system described in the present invention performs dynamic power detection and series-parallel control logic design for the RF switch system and the series-parallel connection control design, selects the parallel branch and the series branch in the opposite direction or in the same direction according to the power dynamic control processed by the RF switch system, and optimizes the contradiction between excessive isolation margin and insufficient nonlinearity at small and medium powers in the traditional RF switch control system. BRIEF DESCRIPTION OF THE DRAWINGS
[0035] Figure 1 It is a schematic diagram of the structural principle of the series-parallel radio frequency switch control system of the present invention.
[0036] Figure 2 It is a structural schematic diagram of a dynamic power detection module and a power control logic module in a series-parallel radio frequency switch control system of the present invention.
[0037] Figure 3 It is a structural schematic diagram of the stacked switch branch of the present invention.
[0038] Figure 4 It is a simulation curve diagram of isolation and nonlinear harmonics of a traditional series-parallel RF switch control system and the series-parallel RF switch control system of the present invention. DETAILED DESCRIPTION
[0039] The following is a specific implementation of the present invention in conjunction with the accompanying drawings, and the technical solutions in the present invention are clearly and completely described, but the present invention is not limited to the following implementations. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. According to the following description and claims, the advantages and features of the present invention will be clearer. It should be noted that the drawings are all in a very simplified form and use non-precise ratios, which are only used to conveniently and clearly assist in explaining the embodiments of the present invention. All other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.
[0040] It should be understood that the present invention can be implemented in different forms, and should not be interpreted as being limited to the embodiments proposed here. On the contrary, providing these embodiments will make disclosure thorough and complete, and the scope of the present invention will be fully conveyed to those skilled in the art. In the accompanying drawings, for clarity, the size and relative size of the layer and the zone may be exaggerated, and the same reference numerals represent the same elements from beginning to end. It should be understood that when an element or layer is referred to as "on ... ", "adjacent to ... ", "connected to " or "coupled to " other elements or layers, it can be directly on other elements or layers, adjacent to it, connected or coupled to other elements or layers, or there can be an intervening element or layer. On the contrary, when an element is referred to as "directly on ... ", "directly adjacent to ... ", "directly connected to " or "directly coupled to " other elements or layers, there is no intervening element or layer. It should be understood that although the terms first, second, third, etc. can be used to describe various elements, components, zones, layers and / or parts, these elements, components, zones, layers and / or parts should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer or part from another element, component, region, layer or part. Therefore, without departing from the teachings of the present invention, the first element, component, region, layer or part discussed below may be represented as a second element, component, region, layer or part.
[0041] In order to make the technical means, creative features, objectives and effects achieved by the present invention easy to understand, the present invention is further described below with reference to specific diagrams.
[0042] The series-parallel radio frequency switch and control system described in the present invention are as follows Figure 1 As shown, it includes a logic control module, an analog module, a dynamic power detection module, a power control logic module and N series-parallel RF switch branch modules, where N is a natural number ≥1.
[0043] The logic control module receives a multi-bit input logic control signal to perform RF switch logic control processing and output control signals for N series-parallel RF switch branches. The N series-parallel RF switch branch modules respectively receive the logic control signals issued by the logic control module.
[0044] Each of the series-parallel RF switch branches includes a series branch and a parallel branch; Figure 1 Taking the series-parallel RF switch branch 1 in the figure as an example, the series branch and the parallel branch shown in the figure both include a potential shifter, multiple switch tubes and bias resistors of the switch tubes; the control signal controls the gate of the switch tube through the potential shifter.
[0045] In the series branch of each series-parallel RF switch branch module, the control signal directly controls the potential shifter in the series branch, and the potential shifter controls the first switch tube SW1 and the second switch tube SW2; in the parallel branch, the control signal is converted into a reverse signal by an inverter INV1 and then transmitted to an input end of an AND gate AND, and the other input end of the AND gate AND is connected to the output control signal VC of the power control logic module, and the output end of the AND gate is connected to the potential shifter in the parallel branch, and the potential shifter controls the third switch tube SW3.
[0046] It should be noted that the first switch tube SW1 in the above series branch is an optional design and can be directly removed when the first switch tube SW1 is not needed in the circuit design.
[0047] The dynamic power detection module dynamically detects the signal power processed on the antenna of the RF switch system, generates a trigger signal PC when the detection power exceeds the detection power threshold, and inputs it to the power control logic module so that it outputs a stable control signal VC after processing. The VC signal is a logically stable "1" or "0" signal; at the same time, the dynamic power detection module also receives the control signal VC output by the power control logic module as a feedback signal to control and adjust the power detection threshold and realize a single trigger, so as to prevent the dynamic power detection circuit from affecting the normal working RF performance of the antenna end and the RF switch.
[0048] The analog module includes a BGR circuit, an LDO circuit, a clock circuit and a negative voltage generating circuit. The analog module provides power supply VDD, VSS and clock signals to the logic control module, each series-parallel RF switch branch module, the dynamic power detection module and the power control logic module.
[0049] like Figure 2As shown, in one embodiment, the structure of the above-mentioned dynamic power detection module is: comprising n diodes connected in series, the cathode of which is connected to the source end of a PMOS transistor P1, the drain of the transistor is grounded through a first resistor R1, and the anode of the N series-connected diodes is connected to the antenna ANT. The dynamic power detection module uses diodes connected in series and connected in series with resistors to design the power detection threshold.
[0050] The source end of the P1 tube also outputs a PC signal through the third resistor R3.
[0051] The gate of the P1 tube is connected to the feedback VC signal through the second resistor R2.
[0052] like Figure 2 As shown in the dashed box on the right, the structure of the power control logic module includes a first and a second series-connected NMOS tube N1 and N2. The gate of the N1 tube is connected to the output PC signal of the dynamic power detection module, and its source and body are connected to the rear end ground; the drain of the N2 tube is short-circuited with the gate and then connected to the power supply VDD.
[0053] The node where the N1 tube and the N2 tube are connected in series is connected to an inverter INV, and the output end of the inverter INV outputs a VC signal.
[0054] The power control logic module also includes an N3 tube, the source and drain of the N3 tube are short-circuited and grounded, and the gate of the N3 tube is connected to a node where the N1 tube and the N2 tube are connected in series.
[0055] The power control logic module first amplifies the detection signal and outputs a stable logic signal VC after shaping.
[0056] After the output of the power control logic module is stabilized, it is fed back to the dynamic power detection module. After the P1 tube is turned off, the power detection threshold is increased to achieve a single trigger, thereby preventing the dynamic power detection module from affecting the normal working RF performance.
[0057] The SW1 tube, SW2 tube, and SW3 third switch tube in the series-parallel RF switch branch module adopt a stacked switch branch structure for power design. The specific structure is as follows: Figure 3 As shown, the two control signals after passing through the potential shifter pass through the fourth resistor Rgc and the fifth resistor Rbc respectively, and then pass through the gate bias resistors Rg1, Rg2...Rgn and the substrate bias resistors Rb1, Rb2...Rbn to be connected to the switch tubes M1~Mn, and there are N switch tubes; the source and drain ends of the N switch tubes are bridged with resistors Rds1, Rds2...Rdsn; after the source and drain ends of the N switch tubes are connected in series in sequence, output ends are formed at the head and the tail respectively.
[0058] In the structure of the present invention, a dynamic power detection module is used to process dynamic power detection of the series-parallel RF switch control system: when the RF power exceeds the set power detection threshold, a trigger signal PC is generated, and the power control logic circuit outputs a stable VC signal logic "1"; when the low power and medium power are less than the detection threshold, the power detection is not triggered, and a stable VC signal logic "0" is output.
[0059] When the series branch control is turned on at "1", the parallel branch is kept turned off and in the opposite direction of the series branch, which does not affect the normal transmission and reception of the RF switch branch.
[0060] When the series branch is controlled to be turned off at "0", according to the VC signal control logic: at high power, the parallel branch is kept open and in the opposite direction of the series branch, and it works in a high-power and high-isolation mode; at small and medium power, the parallel branch is kept closed and in the same direction as the series branch, and it works in a small and medium power, medium isolation, and high linearity optimization mode.
[0061] The power control logic module outputs a feedback VC signal to the dynamic power detection module when it is stable, and increases the power detection threshold after the power detection is triggered to prevent the power detection circuit from affecting the normal working RF performance.
[0062] like Figure 4 As shown in the figure, it is a curve chart of the rapid startup and switching simulation of the RF switch. The lower the harmonic value, the better, and the higher the isolation, the better. From the isolation and nonlinear harmonic simulation, it can be seen that: at low and medium input power (shown as <29dBm), a certain degree of isolation is sacrificed to obtain a more significant improvement in harmonic nonlinearity; high isolation is maintained at high power.
[0063] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.
Claims
1. A series-parallel radio frequency switch control system, characterized in that: The series-parallel RF switch control system comprises a logic control module, an analog module, a dynamic power detection module, a power control logic module and a series-parallel RF switch; the series-parallel RF switch is composed of N series-parallel RF switch branch modules, where N is a natural number ≥1; The logic control module sends a control signal, and the series-parallel RF switch branch module receives the control signal sent by the logic control module; Each of the series-parallel RF switch branch modules includes a series branch and a parallel branch; the series branch and the parallel branch each include a potential shifter, a plurality of switch tubes and a bias resistor of the switch tube; the control signal controls the switch tube through the potential shifter; In the series branch of each series-parallel RF switch branch module, the control signal directly controls the potential shifter in the series branch, and the potential shifter controls the first switch tube and the second switch tube; in the parallel branch, the control signal is converted into a reverse signal by an inverter and then transmitted to an input end of an AND gate, and the other input end of the AND gate is connected to the output control signal VC provided by the power control logic module, and the output end of the AND gate is connected to the potential shifter in the parallel branch, and the potential shifter controls the third switch tube; the control signal VC output by the power control logic module is fed back to the dynamic power detection module, and the output control signal VC is a signal of logic "1" or "0"; The dynamic power detection module dynamically detects the processing power of the RF switch control system, receives the feedback VC signal and the power signal on the antenna, and outputs the PC signal to the power control logic module after processing and threshold comparison; The analog module provides power to the logic control module, each series-parallel RF switch branch module, the dynamic power detection module and the power control logic module.
2. The series-parallel radio frequency switch control system according to claim 1, characterized in that: The structure of the dynamic power detection module is as follows: it comprises N diodes connected in series, the cathode of which is connected to the source end of a transistor, the drain of the transistor is grounded through a first resistor, and the anodes of the N series-connected diodes are connected to an antenna; The source end of the transistor also outputs a PC signal through a third resistor; The gate of the transistor is connected to the fed-back VC signal via a second resistor.
3. The series-parallel radio frequency switch control system according to claim 2, characterized in that: The transistor is a MOS tube.
4. The series-parallel radio frequency switch control system according to claim 3, characterized in that: The MOS tube is a PMOS tube.
5. The series-parallel radio frequency switch control system according to claim 2, characterized in that: The dynamic power detection module uses a diode connected in series with a resistor to design a power detection threshold.
6. The series-parallel radio frequency switch control system according to claim 1, characterized in that: The analog module provides power and clock signals for other modules, and the analog module includes a BGR circuit, an LDO circuit, and a clock circuit.
7. The series-parallel radio frequency switch control system according to claim 1, characterized in that: The structure of the power control logic module is as follows: it includes a first transistor and a second transistor connected in series, wherein the gate of the first transistor is connected to the output PC signal of the dynamic power detection module, and the remaining end of the first transistor after the series connection is grounded; the remaining end of the second transistor after the series connection is short-circuited with the gate and then connected to the power supply; An inverter is connected to the node where the first transistor and the second transistor are connected in series, and the output end of the inverter outputs a VC signal; The third transistor is also included. The source and drain of the third transistor are short-circuited and then grounded. The gate of the third transistor is connected to a node where the first transistor and the second transistor are connected in series.
8. The series-parallel radio frequency switch control system according to claim 7, characterized in that: The first transistor is NMOS, the second transistor is NMOS, and the third transistor is NMOS.
9. The series-parallel radio frequency switch control system according to claim 7, characterized in that: The power control logic module first amplifies the detection signal, shapes it and then outputs a stable logic; The output of the power control logic module is fed back to the dynamic power detection module after being stabilized. After the PMOS is turned off, the power detection threshold is increased to achieve a single trigger, thereby preventing the dynamic power detection module from affecting the normal working RF performance.
10. The series-parallel radio frequency switch control system according to claim 1, characterized in that: The dynamic power detection module is used to dynamically detect the signal power processed on the antenna of the series-parallel RF switch system: a trigger signal PC is generated when the detection power exceeds the detection power threshold, and is input to the power control logic module so that it outputs a stable control signal VC after processing, and the VC signal is a logically stable "1" or "0" signal; at the same time, the dynamic power detection module also receives the control signal VC output by the power control logic module as a feedback signal to control and adjust the power detection threshold and realize a single trigger, so as to prevent the dynamic power detection circuit from affecting the normal working RF performance of the antenna end and the RF switch; When the series branch control is turned on at "1", the parallel branch is kept off and in the opposite direction of the series branch, which does not affect the normal transmission and reception of the RF switch branch; When the series branch is controlled to be "0" and turned off, according to the VC signal control logic: at high power, the parallel branch is kept open and in the opposite direction of the series branch, and works in a high-power high-isolation mode; at low and medium power, the parallel branch is kept closed and in the same direction as the series branch, and works in a low and medium power medium isolation high linearity optimization mode; The power control logic module outputs a feedback VC signal to the dynamic power detection module when it is stable, and increases the power detection threshold after the power detection is triggered to prevent the power detection circuit from affecting the normal working RF performance.
11. A series-parallel radio frequency switch using the series-parallel radio frequency switch control system according to claim 1, characterized in that: The first switch tube, the second switch tube, and the third switch tube in the series-parallel radio frequency switch branch module adopt a stacked switch branch structure for power design.
12. The series-parallel radio frequency switch according to claim 11, characterized in that: The stacked switch branch structure is that the two control signals after passing through the potential shifter pass through the fourth resistor and the fifth resistor respectively, and then pass through the gate bias resistor and the substrate bias resistor respectively to connect to the switch tube, and there are N switch tubes; resistors are connected across the source and drain ends of the N switch tubes; after the source and drain ends of the N switch tubes are connected in series in sequence, output ends are formed at the head and the tail respectively.
13. The series-parallel radio frequency switch according to claim 11, characterized in that: The first switch tube in the series branch is an optional design and can be directly removed when the first switch tube is not needed in the circuit design.
Citation Information
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