A Power - free Wide - swing Voltage - controlled High - performance RF Integrated Switch

Abstract

The present invention belongs to the technical field of radio frequency switches, and specifically provides a power - free wide - swing voltage - controlled high - performance radio frequency integrated switch to solve the problem that existing radio frequency integrated switches require a high control voltage, that is, a low - voltage control signal will cause the radio frequency switch to completely fail in the absence of an external power supply voltage. Based on the negative - voltage module composed of an LDO module, a negative - voltage charge pump module, and a three - phase logic conversion module, the present invention creatively proposes a voltage detection module to adaptively monitor the input control voltage, distinguish the voltage amplitude of the input control signal. When the input control voltage meets the working voltage required by traditional radio frequency integrated switches, the control signal directly controls the radio frequency switch through the negative - voltage module; when the input control voltage does not meet the working voltage required by traditional radio frequency integrated switches, the control signal will enter the boost module to be multiplied and then control the radio frequency switch through the negative - voltage module, that is, to achieve the low - voltage control effect and ensure the radio frequency performance of the switch.

Description

Technical Field

[0001] The present invention belongs to the technical field of radio frequency switches, and particularly provides a power - free wide - swing voltage - controlled high - performance radio frequency integrated switch. Background Art

[0002] With the development of 5G communication, the large - scale MIMO technology has been developed. The number of MIMO antennas can be hundreds or thousands. Therefore, the role of radio frequency switches is extremely important. However, with the development of advanced processes, low - power design makes the output control voltage of many control circuits much lower than the turn - on voltage of radio frequency switches, resulting in serious deterioration of isolation and insertion loss during the operation of the switches, thus affecting the performance of the entire communication system.

[0003] The most basic series - type single - pole double - throw switch is as Figure 1 shown. The transmitting branch is controlled by transistor M 1 , and the receiving branch is controlled by transistor M 2 . The control signals V 1 and V 2 of the two transistors are anti - phase signals. When the transmitting branch TX is working, the control voltage V 1 applied to transistor M 1 is at a high level, transistor M 1 conducts, the transmitting branch is closed, the voltage V 2 on transistor M 2 is at a low level, transistor M 2 is open, and the receiving branch is open. On the contrary, when the receiving branch RX is working, a high level is applied to transistor M 2 , and a low level is applied to transistor M 1 . In switch design, designers always hope that the insertion loss is as small as possible. To reduce the on - resistance R on , larger - sized transistors will be used. However, the larger the transistor size, the larger the off - capacitance C off of the transistor, and more energy leaks from the open - circuit branch, making it difficult for the switch to meet the isolation requirements in the radio frequency band and also increasing the insertion loss to a certain extent. To ensure the isolation requirements of radio frequency switches, a more classic series - parallel single - pole double - throw switch structure has emerged, as Figure 2 shown. It adds two transistors M Figure 1 3 and M 4 as parallel branches on the basis of. When the series branch is closed, the control signal controls the parallel branch to conduct to ground. Since no additional control signal is added, the effective IO ports are not increased. When working in the transmit mode, transistors M 1 and M 4 conduct, and transistors M 2 and M 3Cut-off; compared with the switch structure in series form, the switch in series-parallel form has better isolation. Reasonably adjusting the gate width ratios of transistors M 1 、M 2 and M 3 、M 4 can ensure the requirements of insertion loss and isolation at the same time.

[0004] Furthermore, the schematic diagram of the working principle of the above single-pole double-throw switch in series-parallel form is as Figure 3 shown. Although the stacked transistor technology can effectively improve the linearity of the switch, when the input signal power is high, the switching transistor (V off = 0V) of the off-branch is affected by the average voltage division, making it switch to the on state for some time during the large-signal period; considering the symmetry of the drain-source region of the transistor, the gate-source parasitic capacitance is equal to the gate-drain parasitic capacitance, that is, C gs = C gd , and the control voltage when the transistor is off is 0V. Therefore, the gate-source voltage V gs is 0.5 times the source-drain voltage V ds . When the gate-source voltage V gs is greater than the transistor threshold voltage V th during the large-signal period, there must be V ds ≥ V gs - V th , and the transistor operates in the saturation state, that is, the transistor is on. At this time, the switch will have a very large power leakage, resulting in large insertion loss and low linearity. In order to maintain the linearity of the series-parallel switch, so that the state of the off-branch transistor does not change due to the input large-signal power, and at the same time to reduce the number of stacked transistors, it is an effective method to use a switch controller to provide a negative voltage to the circuit; when the control voltage of the transistor is negative, the large-signal swing of V ds and V gs will shift downward, making the positive half-cycle of the large signal of V gs not exceed the threshold voltage. This method can significantly improve the power handling capacity of the antenna switch; in engineering design, the control voltage is generally selected as ±2.5V to realize the design of high-performance RF switches. When the control signal is positive, the switch is turned on, and the other path is turned off with negative voltage. Since the gate is at negative voltage, it is more difficult for the direct carriers in the transistor channel to move, so the overall switch performance will be optimized.

[0005] In summary, in the existing RF switch designs, in order to improve the power handling capacity and isolation of the switch and enhance the switch performance, a negative voltage module needs to be designed to provide a negative voltage for the control voltage of the transistor. In the traditional negative voltage module design, an external power supply needs to be introduced, and an on-chip LDO and analog circuits are used to generate a negative voltage control signal. However, currently, most of the switches used are passive structures. When there is no external power supply, the voltage required to control the switch is uniformly generated by the control signal, and the control signal is often required to be 3.3V or 5V. With the application of low power consumption, the control signal of the chip is much lower than 3.3V. When the input control signal is lower than the voltage required by the negative voltage module, traditional internal circuits such as LDO will not work. Therefore, when there is no external power supply, the switch cannot achieve its normal function. Summary of the Invention

[0006] The object of the present invention is to provide a power - free wide - swing voltage - controlled high - performance RF integrated switch to solve the problem that the existing RF integrated switch requires a high control voltage, that is, a low - voltage control signal will cause the RF switch to completely fail in the absence of an external power supply voltage. The present invention creatively proposes that a voltage detection module adaptively monitors the input control voltage, discriminates the voltage amplitude of the input control signal. When the input control signal meets the operating voltage required by the RF switch, the control signal directly passes through a negative voltage module (composed of an LDO module, a negative voltage charge pump module, and a three - phase logic conversion module) to control the RF switch; when the input control signal does not meet the voltage required by the switch, the control signal will enter a boost module to be multiplied and then pass through the negative voltage module to control the RF switch, that is, to achieve the low - voltage control effect and ensure the RF performance of the switch.

[0007] To achieve the above object, the technical solution adopted by the present invention is as follows:

[0008] A power - free wide - swing voltage - controlled high - performance RF integrated switch includes: a single - pole double - throw RF switch module, an LDO module, a three - phase logic conversion module, a negative voltage charge pump module, a boost module, and a voltage detection module; wherein, the LDO module, the negative voltage charge pump module, and the three - phase logic conversion module constitute a negative voltage module. The LDO module provides a positive voltage bias for the negative voltage charge pump module and the three - phase logic converter module, the negative voltage charge pump module provides a negative voltage bias for the three - phase logic converter module, and the three - phase logic conversion circuit provides a three - phase control signal for the RF switch. It is characterized in that the input control voltage V 1 and V 2 are respectively combined into an internal voltage V DD after passing through diodes, and the voltage detection module adaptively monitors the internal voltage V DD . When the internal voltage V DD is greater than or equal to the switching voltage of the voltage detection module, the internal voltage V DD is input to the LDO module; otherwise, the internal voltage VDD After being multiplied by the boost module, it is input to the LDO module.

[0009] Further, the voltage detection module includes: NMOS transistors M 1 , M 2 , M 3 , M 4 , M 5 , PMOS switches S 1 , S 2 , S 3 , a clamping resistor R, and a three-stage inverter. Among them, each NMOS transistor is connected in a diode bias (i.e., the gate is connected to the drain). The NMOS transistors M 3 , M 4 , M 5 are connected in series in sequence. The source of the NMOS transistor M 3 is connected to the internal voltage V DD . The drain of the NMOS transistor M 5 is connected to the input end of the three-stage inverter. The output of the second-stage inverter of the three-stage inverter is connected to the control ends of the PMOS switches S 1 and S 2 . The PMOS switch S 1 is connected between the internal voltage V DD and the input end of the boost module. The PMOS switch S 2 is connected between the output end of the boost module and the source of the NMOS transistor M 1 . The output of the third-stage inverter of the three-stage inverter is connected to the control end of the PMOS switch S 3 . The PMOS switch S 3 is connected between the internal voltage V DD and the source of the NMOS transistor M 2 . The drains of the NMOS transistors M 1 and M 2 are both connected to the input end of the LDO module. One end of the clamping resistor R is connected to the input end of the three-stage inverter and the other end is grounded.

[0010] Furthermore, by adjusting the resistance value of the clamping resistor R, the switching voltage setting of the voltage detection module can be realized.

[0011] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0012] The present invention provides a power - free wide - swing voltage - controlled high - performance RF integrated switch. Based on a traditional RF integrated switch composed of a single - pole double - throw RF switch module and a negative - voltage module (composed of an LDO module, a negative - voltage charge - pump module, and a three - phase logic conversion module), a voltage detection module is creatively proposed to adaptively monitor the input control voltage and distinguish the voltage amplitude of the input control signal. When the input control voltage meets the required operating voltage of the traditional RF integrated switch (greater than or equal to the switching voltage of the voltage detection module), the control signal directly controls the RF switch through the negative - voltage module; when the input control signal does not meet the required operating voltage of the traditional RF integrated switch (less than the switching voltage of the voltage detection module), the control signal enters a boost module for multiplication and then controls the RF switch through the negative - voltage module, thus achieving a low - voltage control effect and ensuring the RF performance of the switch; moreover, the switching voltage of the voltage detection module can be configured through a clamping resistor. It can be seen that the present invention realizes the design of a power - free wide - swing voltage - controlled high - performance RF integrated switch based on the SOI process. Without sacrificing the switch performance, it greatly expands the range of the control voltage used by the switch and has the advantages of being configurable, high in integration, and compatible with passive switches. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a schematic structural diagram of a traditional single - pole double - throw switch in a series form.

[0014] Figure 2 It is a schematic structural diagram of a traditional single - pole double - throw switch in a series - parallel form.

[0015] Figure 3 is Figure 2 a schematic diagram of the working principle of the single - pole double - throw switch in the shown series - parallel form.

[0016] Figure 4 It is a schematic structural diagram of the power - free wide - swing voltage - controlled high - performance RF integrated switch in the present invention.

[0017] Figure 5 It is a schematic diagram of the working principle of the power - free wide - swing voltage - controlled high - performance RF integrated switch in the present invention.

[0018] Figure 6 It is a simulation result diagram of the voltage detection circuit in the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0019] To make the objectives, technical solutions, and beneficial effects of the present invention more clear and understandable, the present invention will be further described in detail below with reference to the drawings and embodiments.

[0020] This embodiment provides a power - free wide - swing voltage - controlled high - performance RF integrated switch, and its structure is as Figure 4As shown, it specifically includes: a single-pole double-throw RF switch module, an LDO module, a three-phase logic conversion module, a negative voltage charge pump module, a boost module, and a voltage detection module; among them, the input control voltage V 1 and V 2 are respectively combined into an internal voltage V DD after passing through diodes, and the voltage detection module adaptively monitors the internal voltage V DD . When the internal voltage V DD is greater than or equal to the switching voltage of the voltage detection module, the internal voltage V DD is input to the LDO module; otherwise, the internal voltage V DD is multiplied by the boost module and then input to the LDO module; the LDO module provides a positive voltage bias for the negative voltage charge pump module and the three-phase logic converter module, the negative voltage charge pump module provides a negative voltage bias for the three-phase logic converter module, and the three-phase logic conversion circuit provides a three-phase control signal for the RF switch.

[0021] Furthermore, the voltage detection module includes: NMOS transistors M 1 , M 2 , M 3 , M 4 , M 5 , PMOS switches S 1 , S 2 , S 3 , a clamping resistor R, and a three-stage inverter. Among them, each NMOS transistor is connected in a diode bias (i.e., the gate is connected to the drain). NMOS transistors M 3 , M 4 , M 5 are connected in series in turn. The source of NMOS transistor M 3 is connected to the internal voltage V DD , and the drain of NMOS transistor M 5 is connected to the input end of the three-stage inverter; the output of the second-stage inverter of the three-stage inverter is connected to the control ends of PMOS switches S 1 and S 2 . PMOS switch S 1 is connected between the internal voltage V DD and the input end of the boost module. PMOS switch S 2 is connected between the output end of the boost module and the source of NMOS transistor M 1 ; the output of the third-stage inverter of the three-stage inverter is connected to the control end of PMOS switch S 3 . PMOS switch S 3 is connected between the internal voltage V DD and the source of NMOS transistor M 2 ; NMOS transistors M 1 and M2 The drains are all connected to the input end of the LDO module; one end of the clamping resistor R is connected to the input end of the three-stage inverter and the other end is grounded. Further, by adjusting the resistance value of the clamping resistor R, the switching voltage setting of the voltage detection module can be realized.

[0022] In terms of the working principle:

[0023] This embodiment provides a power - free wide - swing voltage - controlled high - performance RF integrated switch, which has six external interfaces, namely the TX terminal, the RX terminal, the ANT terminal, the GND terminal and two control signal terminals; among them, V 1 and V 2 are external control signals, which respectively control the conduction and cut - off of the TX terminal and the RX terminal; since there is no external power supply, the power supply of the internal circuit is realized by the synthesis of V 1 and V 2 through diodes. Due to the unidirectional conductivity of the diodes, as long as any one of the signals in V 1 and V 2 is at a high level, that is, V DD_ctrl = max{V 1 , V 2}, then the internal synthesized power supply V DD = V DD_ctrl - V th_diode , V th_diode is the threshold voltage of the diode (the threshold voltage of the diode used in this embodiment is about 0.65V);

[0024] In this embodiment, the voltage range of the external control signals V 1 and V 2 is 1.8V - 6V. After being synthesized by diodes, the voltage input to the inside drops by a diode threshold voltage of 0.65V. The voltage range of the synthesized internal power supply V DD_ctrl is 1.15V - 5.35V. Therefore, the decision voltage inflection point is set to 3.3 - 0.65 = 2.65V; that is, when the external input voltage is 1.8V - 3.3V, the internal voltage is 1.15V - 2.65V. After passing through the boost module, the minimum voltage entering the LDO module is greater than 2.5V (for the LDO to work properly, the input voltage needs to be higher than the regulated voltage. Since 2.5V voltage is required inside, the minimum voltage output by the boost module should be greater than 2.5V, that is, the 1.15V after voltage doubling should be greater than 2.5V), and it is regulated to 2.5V through the LDO module; when the external input voltage is 3.3V - 6V, the internal voltage is 2.65V - 5.35V, and the LDO module can directly regulate to 2.5V without boosting; specifically, the synthesized internal power supply V DD will pass through the voltage monitoring circuit for judgment: when V DD DD ​When the voltage is ≥ 2.65V, the boost module will not start, and the internal power supply is directly stabilized to 2.5V through the LDO module to provide a positive voltage for the negative charge pump module and the three-phase logic converter module; when V DD < 2.65V, the boost module starts, the internal power supply is disconnected from the LDO module, and the internal power supply V DD is doubled through the boost circuit to obtain the boosted voltage V DD_UP , and the voltage V DD_UP after doubling is > 2.5V. The LDO module stabilizes the output to 2.5V to provide a positive voltage for the negative charge pump module and the three-phase logic converter module; after the negative charge pump module is stabilized, it provides a negative voltage for the three-phase logic converter module, and the three-phase logic conversion circuit provides a three-phase control signal for the RF switch; thus, the RF integrated switch of the present invention realizes stable operation without external power supply bias, and has excellent switch performance, greatly expanding the applicable range of the control voltage.

[0025] It should be noted that: the three-phase logic converter, the negative charge pump module, and the LDO module are all basic circuit structures in traditional negative voltage modules. The boost module uses a traditional Dickson boost circuit to achieve voltage multiplication, which will not be elaborated in the present invention. The core of the present invention lies in the creative design and use of the voltage detection module. The high power supply voltage directly enters the LDO module through the voltage detection circuit, and the low power supply voltage enters the boost module through the voltage detection module. After voltage multiplication, it enters the LDO module. Both methods output a stable 2.5V bias voltage after passing through the LDO module; more specifically:

[0026] As Figure 5 shown, transistors M 1 , M 2 , M 3 , M 4 , M 5 are all NMOS transistors, and the gate and drain of each transistor are connected to each other to form a diode biasing connection method; the transistors M 3 , M 4 , M 5 are equivalent to diodes in series. The source of transistor M 3 is connected to the internal power supply V DD . When V DD exceeds the sum of the threshold voltages (V th ) of transistors M 3 , M 4 , M 5 , the diodes formed by transistors M 3 , M 4 , M 5 are forward-biased. Due to the existence of the clamping resistor R, the voltage passes through transistors M 3 , M 4 , M5 It then becomes V IN Approaches V DD -3V th , the larger the clamping resistor R is, the closer V IN is to V DD -3V th ; therefore, the output curve of V IN will increase as V DD increases. When V IN reaches the inversion voltage of the inverter, the three-stage inverter starts to work; the second-stage inverter outputs a level opposite to that of the third-stage inverter (the control signals PD of the PMOS switches S 1 and S 2 , the control signal PD2 of the PMOS switch S 3 ), respectively controlling the closing and opening of the PMOS switches S 1 and S 2 , S 3 ;

[0027] When V DD is lower than the set switching voltage, V IN is equivalent to a low level. After passing through the inverter output, the switches S 1 and S 2 close, the switch S 3 opens, and the boost circuit starts to work. V DD is doubled to 2V DD , and 2V DD enters the input terminal of the LDO (low dropout linear regulator) module through the transistor M 1 , thereby driving the subsequent LDO module. The LDO module is regulated to 2.5V to provide bias for the negative charge pump and the three-phase logic conversion circuit;

[0028] When V DD is higher than (equal to) the set switching voltage, V IN is equivalent to a high level. After passing through the inverter output, the switches S 1 and S 2 open, the switch S 3 closes, and the boost circuit does not work. V DD directly enters the input terminal of the LDO module through the switch S 3 and the transistor M 2 , thereby driving the subsequent LDO module. The LDO module is regulated to 2.5V to provide bias for the negative charge pump and the three-phase logic conversion circuit;

[0029] Utilize the circuit characteristic that the reverse bias voltage of the diode is very large; the transistors M 1 , M 2 constitute a diode to achieve unidirectional voltage transmission, ensuring that the two branches do not interfere with each other during operation;

[0030] In this embodiment, since the internal power supply V DD is obtained by synthesizing diodes, the internal voltage will be lower than the control signal by the threshold voltage of one diode (the threshold voltage of the diode used in this embodiment is about 0.65V). Therefore, for an external input voltage (control signal V 1 and V 2 ) of 3.3V, the internal voltage V DD synthesized by the diodes is around 2.65V. Thus, the switching voltage is set to 2.65V in the simulation. The simulation results of the voltage detection module in this embodiment are as shown in Figure 6 . Among them, V DD is the internal power supply, PD is the control signal of PMOS switches S 1 and S 2 , PD2 is the control signal of PMOS switch S 3 , LDO-IN is the input voltage of the LDO module, and LDO-OUT is the output voltage of the LDO module. It can be seen from the figure that when the input of the internal power supply V DD is less than 2.65V, the LDO module cannot work stably, and the LDO module needs to be powered by a boost circuit; when the input of the internal power supply V DD is greater than 2.65V, the LDO module can stabilize the output voltage at 2.51V, and the LDO module is directly powered by the internal power supply, that is, the function of circuit monitoring is realized.

[0031] In summary, the voltage detection module designed by the present invention can detect the switching voltage and select whether to double the voltage according to the magnitude of the V DD voltage. The two branches finally enter the input end of the LDO module, and a stable 2.5V bias voltage is output through the LDO module to provide bias for the subsequent circuit.

[0032] The above is only the specific implementation manner of the present invention. Any feature disclosed in this specification, unless specifically described, can be replaced by other equivalent or similar-purpose alternative features; all the features disclosed, or all the steps in any method or process, except for mutually exclusive features and / or steps, can be combined in any way.

Claims

1. A power - free wide - swing voltage - controlled high - performance RF integrated switch, comprising: Single-pole double-throw RF switch module, LDO module, three-phase logic conversion module, negative voltage charge pump module, boost module and voltage detection module; among them, the LDO module, negative voltage charge pump module and three-phase logic conversion module constitute a negative voltage module, the LDO module provides a positive voltage bias for the negative voltage charge pump module and the three-phase logic converter module, the negative voltage charge pump module provides a negative voltage bias for the three-phase logic converter module, and the three-phase logic conversion circuit provides a three-phase control signal for the RF switch; it is characterized in that the input control voltage V 1 and V 2 are respectively combined into an internal voltage V DD after passing through diodes, and the voltage detection module adaptively monitors the internal voltage V DD . When the internal voltage V DD is greater than or equal to the switching voltage of the voltage detection module, the internal voltage V DD is input to the LDO module; otherwise, the internal voltage V DD is multiplied by the boost module and then input to the LDO module.

2. The power - free wide - swing voltage - controlled high - performance RF integrated switch according to claim 1, characterized in that, The voltage detection module includes: NMOS transistors M 1 、M 2 、M 3 、M 4 、M 5 , PMOS switches S 1 、S 2 、S 3 , a clamping resistor R, and a three-stage inverter. Among them, each NMOS transistor is connected in a diode-biased manner. NMOS transistors M 3 、M 4 、M 5 are connected in series in sequence. The source of NMOS transistor M 3 is connected to the internal voltage V DD . The drain of NMOS transistor M 5 is connected to the input terminal of the three-stage inverter; the output of the second-stage inverter of the three-stage inverter is connected to the control terminals of PMOS switches S 1 and S 2 . PMOS switch S 1 is connected between the internal voltage V DD and the input terminal of the boost module. PMOS switch S 2 is connected between the output terminal of the boost module and the source of NMOS transistor M 1 ; the output of the third-stage inverter of the three-stage inverter is connected to the control terminal of PMOS switch S 3 . PMOS switch S 3 is connected between the internal voltage V DD and the source of NMOS transistor M 2 ; the drains of NMOS transistors M 1 and M 2 are both connected to the input terminal of the LDO module; one end of the clamping resistor R is connected to the input terminal of the three-stage inverter and the other end is grounded.

3. The power - free wide - swing voltage - controlled high - performance RF integrated switch according to claim 2, characterized in that, Adjusting the resistance value of the clamping resistor R can achieve the switching voltage setting of the voltage detection module.

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