Tuning switch circuit and RF chip

Abstract

The present invention provides a tuning switch circuit and a radio frequency chip, wherein the tuning switch circuit comprises a switch bias unit and a tuning switch unit connected in sequence; the switch bias unit is used to output a gate control signal and a body control signal; the tuning switch unit comprises a stacked branch field effect tube circuit formed by a plurality of first field effect tube units connected in series in sequence and a stacked common field effect tube circuit formed by a plurality of second field effect tube units connected in series in sequence; the stacked branch field effect tube circuit comprises at least two; the tuning switch unit is used to control the on and off of each first field effect tube in each stacked branch field effect tube circuit, and at the same time control the on and off of each second field effect tube in the stacked common field effect tube circuit. The tuning switch circuit in the present invention can reduce its area under the condition of the same on-resistance, or obtain a smaller on-resistance under the condition of the same area.

Description

Technical Field

[0001] The present invention relates to the field of wireless communication technology, and in particular to a tuning switch circuit and a radio frequency chip. Background Art

[0002] With the rapid development of integrated circuits and wireless communication technologies, smart electronic devices such as mobile phones, phone watches, and tablets have become necessities in people's lives. After entering the 5G era, as users' requirements for data transmission and reception speed and stability continue to increase, the number of frequency bands, functions, and modes required for the operation of smart electronic devices is also increasing.

[0003] In order to meet the above requirements, the wireless communication field generally uses CA (carrier aggregation), MIMO (multiple input multiple output) and new broadband 5G frequency bands to provide higher data rates, so more antennas are needed in smart electronic devices. More antennas will reduce the space for a single antenna, which will eventually reduce the antenna efficiency.

[0004] In order to overcome the problems caused by the reduction of antenna area and efficiency, the mainstream method is to use antenna tuning devices to tune the antenna (Tuner), and small-sized antenna tuning switches are an indispensable part of antenna tuning devices. The on-resistance (Ron) of the antenna tuning switch will directly affect its power loss. The smaller the on-resistance, the lower the power loss and the higher the antenna efficiency. At the same time, the on-resistance of the antenna tuning switch is inversely proportional to its area, that is, the smaller the on-resistance, the larger the area of ​​the antenna tuning switch.

[0005] like Figure 1 As shown, in the prior art, the antenna tuning switch 100 mainly includes a switch bias unit 101 and a switch unit 102 connected in sequence, the first end of the switch unit 102 is grounded, and the second end of the switch unit 102 is used to connect the antenna. In order to meet the higher voltage resistance requirements of the application end, the switch unit 101 is usually implemented by a multi-stage stacked field effect transistor 1021 connected in series. If the application requires that the power resistance requirement of the antenna tuning switch 100 is 48dBm, under the condition of 50 ohms, the converted voltage is nearly 80V.

[0006] The withstand voltage of a single field effect tube in the multi-stage stacked field effect tube 1021 is about 3V, so in order to meet the application requirements, at least 27 field effect tubes need to be connected in series. If a certain antenna tuning switch 100 is a single-pole four-throw switch, the area of ​​a single field effect tube is Xμm 2 , then the area calculation formula of the antenna tuning switch 100 is as follows:

[0007] ;

[0008] in, is the total area of ​​the antenna tuning switch 100, is the total number of field effect transistors required to be connected in series, is the area of ​​a single field effect transistor.

[0009] The on-resistance requirement of the antenna tuning switch 100 is about several ohms. For the antenna tuning switch 100 composed of field effect transistors, since the field effect transistors work in the linear region, the on-resistance is the channel resistance, and the calculation formula of the equivalent on-resistance can be obtained as follows:

[0010] ;

[0011] in, is the equivalent on-resistance, is the transconductance of the field effect transistor, is the carrier mobility of the field effect transistor, is the gate oxide capacitance per unit area of ​​the field effect transistor, is the gate-source voltage of the field effect transistor, is the threshold voltage of the field effect transistor, is the gate width of the field effect transistor, is the gate length of the field effect transistor.

[0012] It can be seen from this that the on-resistance of the field effect tube and is proportional to the gate length of the field effect tube. Due to the limitation that the process node cannot be reduced indefinitely, a large gate width W (Width) value of the field effect transistor is required to meet the requirement. However, this will result in the area of ​​the antenna tuning switch 100 being very large in order to meet the on-resistance index requirement in its application. Summary of the invention

[0013] In view of the above deficiencies in the prior art, the present invention proposes a tuning switch circuit and a radio frequency chip to solve the problem that the antenna tuning switch in the prior art requires a large area to meet the on-resistance index requirement in its application.

[0014] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0015] In a first aspect, the present invention provides a tuning switch circuit, which includes a switch bias unit and a tuning switch unit connected in sequence;

[0016] The switch bias unit is used to output a gate control signal and a body control signal;

[0017] The tuning switch unit comprises a stacked branch field effect tube circuit formed by a plurality of first field effect tube units connected in series in sequence and a stacked common field effect tube circuit formed by a plurality of second field effect tube units connected in series in sequence; the stacked branch field effect tube circuit comprises at least two;

[0018] The first end of each stacked branch field effect tube circuit is grounded; the first field effect tube unit of each level includes a first resistor and a first field effect tube;

[0019] In each stage of the first field effect tube unit, the first end of the first resistor is connected to the gate control end of the switch bias unit, the second end of the first resistor is connected to the gate of the first field effect tube, and the body end of the first field effect tube is connected to the body control end of the switch bias unit;

[0020] The second end of each of the stacked branch field effect transistor circuits is respectively connected to the first end of the stacked common field effect transistor circuit;

[0021] The second end of the stacked common field effect tube circuit is used to connect to the antenna; the second field effect tube unit of each level includes a second resistor and a second field effect tube;

[0022] In each stage of the second field effect tube unit, the first end of the second resistor is connected to the gate control end of the switch bias unit, the second end of the second resistor is connected to the gate of the second field effect tube, and the body end of the second field effect tube is connected to the body control end of the switch bias unit;

[0023] The tuning switch unit is used to receive the body control signal and the gate control signal, and control the on and off of each of the first field effect transistors in each of the stacked branch field effect transistor circuits according to the body control signal and the gate control signal, and simultaneously control the on and off of each of the second field effect transistors in the stacked common field effect transistor circuit.

[0024] Preferably, the tuning switch unit also includes a plurality of third resistors whose number is the same as the number of the stacked branch field effect transistor circuits; the first ends of the plurality of third resistors are respectively connected to the gate control end of the switch bias unit, and the second end of each of the third resistors is respectively connected to the first end of the first resistor in each level of the first field effect transistor unit in one of the stacked branch field effect transistor circuits.

[0025] Preferably, the tuning switch unit also includes a plurality of fourth resistors whose number is the same as the number of the stacked branch field effect transistor circuits; the first ends of the plurality of fourth resistors are respectively connected to the body control end of the switch bias unit, and the second end of each of the fourth resistors is respectively connected to the body end of the first field effect transistor in each level of the first field effect transistor unit in one of the stacked branch field effect transistor circuits.

[0026] Preferably, the tuning switch unit also includes a fifth resistor; the first end of the fifth resistor is connected to the gate control end of the switch bias unit, and the second end of the fifth resistor is respectively connected to the first end of the second resistor in each level of the second field effect tube unit in the stacked common field effect tube circuit.

[0027] Preferably, the tuning switch unit also includes a sixth resistor; the first end of the sixth resistor is connected to the body control end of the switch bias unit, and the second end of the sixth resistor is respectively connected to the body end of the second field effect transistor in each level of the second field effect transistor unit in the stacked common field effect transistor circuit.

[0028] Preferably, the tuning switch unit includes a negative voltage generating module, a positive voltage generating module, a voltage driving module and a logic control module;

[0029] The negative voltage generating module is used to generate a negative bias voltage;

[0030] The positive voltage generating module is used to generate a positive bias voltage;

[0031] The input end of the voltage driving module is respectively connected to the output end of the negative voltage generating module and the output end of the positive voltage generating module, and is used to receive the negative bias voltage and the positive bias voltage, and output a corresponding driving voltage according to the received negative bias voltage and the positive bias voltage;

[0032] The input end of the logic control module is connected to the output end of the voltage driving module, the first output end of the logic control module serves as the gate control end of the tuning switch unit, and the second output end of the logic control module serves as the body control end of the tuning switch unit; the logic control module is used to receive the driving voltage and output the gate control signal and the body control signal according to the driving voltage.

[0033] In a second aspect, the present invention provides a radio frequency chip, which includes the tuning switch circuit as described above.

[0034] Compared with the prior art, the tuning switch circuit in the present invention is designed to be a stacked shared field effect transistor circuit connected to at least two stacked branch field effect transistor circuits, which is equivalent to changing the field effect transistors in multiple stacked branch field effect transistor circuits to share a part of the field effect transistors. Therefore, under the condition of the same on-resistance, the total number of field effect transistors in the tuning switch circuit can be reduced, that is, the area of ​​the tuning switch circuit is reduced, or under the condition of the same area, the total number of field effect transistors in the tuning switch circuit can be increased to obtain a smaller on-resistance. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] The present invention will be described in detail below in conjunction with the accompanying drawings. The above and other aspects of the present invention will become clearer and easier to understand through the detailed description made in conjunction with the following drawings. In the accompanying drawings:

[0036] Figure 1 A circuit structure diagram of an antenna tuning switch circuit provided by the prior art;

[0037] Figure 2 A circuit structure diagram of a tuning switch circuit provided in an embodiment of the present invention;

[0038] Figure 3 A circuit structure diagram of a switch bias unit of a tuning switch circuit provided in an embodiment of the present invention;

[0039] Figure 4 A partial circuit structure diagram of a tuning switch circuit provided by an embodiment of the present invention, including one stacked branch field effect transistor circuit, a third resistor and a fourth resistor;

[0040] Figure 5 Another partial circuit structure diagram of the tuning switch circuit provided by the embodiment of the present invention includes a stacked shared field effect transistor circuit, a fifth resistor and a sixth resistor. DETAILED DESCRIPTION

[0041] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by technicians in the technical field of the present application; the terms used in the specification of the application herein are only for the purpose of describing specific embodiments and are not intended to limit the present application; the terms "including" and "having" and any variations thereof in the specification and claims of the present application and the above-mentioned drawings are intended to cover non-exclusive inclusions. The terms "first", "second", etc. in the specification and claims of the present application or the above-mentioned drawings are used to distinguish different objects, not to describe a specific order.

[0042] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present application. The appearance of the phrase in various locations in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0043] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0044] The embodiment of the present invention provides a tuning switch circuit 200, combined with Figures 2 to 5 As shown, it includes a switch bias unit 201 and a tuning switch unit 202 connected in sequence.

[0045] The switch bias unit 201 is used to output a gate control signal Vgate and a body control signal Vbody.

[0046] The tuning switch unit 202 includes a negative voltage generating module 2011 , a positive voltage generating module 2012 , a voltage driving module and a logic control module.

[0047] The negative voltage generating module 2011 is used to generate a negative bias voltage; the positive voltage generating module 2012 is used to generate a positive bias voltage.

[0048] The input end of the voltage driving module is respectively connected to the output end of the negative voltage generating module 2011 and the output end of the positive voltage generating module 2012, and is used to receive the negative bias voltage and the positive bias voltage, and output the corresponding driving voltage according to the received negative bias voltage and the positive bias voltage.

[0049] The input end of the logic control module is connected to the output end of the voltage driving module, the first output end of the logic control module serves as the gate control end of the tuning switch unit 202, and the second output end of the logic control module serves as the body control end of the tuning switch unit 202; the logic control module is used to receive the driving voltage and output the gate control signal Vgate and the body control signal Vbody according to the driving voltage.

[0050] like Figure 3 As shown, the voltage driving module and the logic control module together constitute the driving logic module 2013, that is, the driving logic module 2013 includes the voltage driving module and the logic control module.

[0051] The tuning switch unit 202 includes a stacked branch field effect tube circuit 2021 formed by a plurality of first field effect tube units 20211 connected in series in sequence, and a stacked common field effect tube circuit 2022 formed by a plurality of second field effect tube units 20221 connected in series in sequence; the stacked branch field effect tube circuit 2021 includes at least two. In this embodiment, the stacked branch field effect tube circuit 2021 includes four. Of course, according to actual needs, it can also be designed to be two, three, five, etc.

[0052] The first end of each stacked branch field effect tube circuit 2021 is grounded; each first field effect tube unit 20211 includes a first resistor and a first field effect tube.

[0053] In each first field effect tube unit 20211, the first end of the first resistor is connected to the gate control end of the switch bias unit 201, the second end of the first resistor is connected to the gate of the first field effect tube, and the body end of the first field effect tube is connected to the body control end of the switch bias unit 201.

[0054] The second end of each stacked branch FET circuit 2021 is respectively connected to the first end of the stacked common FET circuit 2022 .

[0055] The second end of the stacked shared field effect tube circuit 2022 is used to connect to the antenna; each level of the second field effect tube unit 20221 includes a second resistor and a second field effect tube.

[0056] In each second field effect tube unit 20221, the first end of the second resistor is connected to the gate control end of the switch bias unit 201, the second end of the second resistor is connected to the gate of the second field effect tube, and the body end of the second field effect tube is connected to the body control end of the switch bias unit 201.

[0057] like Figure 4 As shown, the first field effect tube units 20211 connected in series in each stacked branch field effect tube circuit 2021 are Stack1-1, Stack1-2 to Stack1-A-1, Stack1-A; in each stacked branch field effect tube circuit 2021, the first resistors in the first field effect tube units 20211 connected in series in sequence are R1-1, R1-2 to R1-A-1, R1-A; in each stacked branch field effect tube circuit 2021, the first field effect tubes in the first field effect tube units 20211 connected in series in sequence are M1-1, M1-2 to M1-A-1, M1-A; Figure 4 A in the figure represents the number of stages of the first field effect transistor units 20211 in each stacked branch field effect transistor circuit 2021 or the number of first field effect transistors in each stacked branch field effect transistor circuit 2021 .

[0058] like Figure 5 As shown, the second field effect tube units 20221 connected in series in the stacked common field effect tube circuit 2022 are Stack2-1, Stack2-2 to Stack2-B-1, Stack2-B; the second resistors in the second field effect tube units 20221 connected in series are R2-1, R2-2 to R2-B-1, R2-B; the second field effect tubes in the second field effect tube units 20221 connected in series are M2-1, M2-2 to M2-B-1, M2-B; Figure 5 B in the figure represents the number of stages of the second field effect transistor units 20221 in the stacked shared field effect transistor circuit 2022 or the number of second field effect transistors in the stacked shared field effect transistor circuit 2022 .

[0059] The tuning switch unit 202 is used to receive the body control signal Vbody and the gate control signal Vgate, and control the on-off of each first field effect transistor in each stacked branch field effect transistor circuit 2021 according to the body control signal Vbody and the gate control signal Vgate, and at the same time control the on-off of each second field effect transistor in the stacked common field effect transistor circuit 2022.

[0060] The tuning switch unit 202 also includes a plurality of third resistors R3, the number of which is the same as the number of the stacked branch field effect transistor circuits 2021; the first ends of the plurality of third resistors R3 are respectively connected to the gate control end of the switch bias unit 201, and the second end of each third resistor R3 is respectively connected to the first end of the first resistor 20211 in each level of the first field effect transistor unit in one of the stacked branch field effect transistor circuits 2021.

[0061] The tuning switch unit 202 also includes a plurality of fourth resistors R4, the number of which is the same as the number of the stacked branch field effect transistor circuits 2021; the first ends of the plurality of fourth resistors R4 are respectively connected to the body control end of the switch bias unit 201, and the second end of each fourth resistor R4 is respectively connected to the body end of the first field effect transistor of each level of the first field effect transistor unit 20211 in one of the stacked branch field effect transistor circuits 2021.

[0062] The tuning switch unit 202 also includes a fifth resistor R5; the first end of the fifth resistor R5 is connected to the gate control end of the switch bias unit 201, and the second end of the fifth resistor R5 is respectively connected to the first end of the second resistor in each level of the second field effect tube unit 20221 in the stacked common field effect tube circuit 2022.

[0063] The tuning switch unit 202 also includes a sixth resistor R6; the first end of the sixth resistor R6 is connected to the body control end of the switch bias unit 201, and the second end of the sixth resistor R6 is respectively connected to the body end of the second field effect transistor in each level of the second field effect transistor unit 20221 in the stacked common field effect transistor circuit 2022.

[0064] The "body end" of the field effect transistor mentioned above is also called "substrate", and the gate control signal and body control signal mentioned above are bias voltage signals.

[0065] In the present embodiment, the number of stages of the second field effect tube unit 20221 of the stacked shared field effect tube circuit 2022, that is, the number of common field effect tubes, mainly depends on the number of channels (number of branches) in the off state in the application and the total number D of field effect tubes that need to be connected in series in each stacked branch field effect tube circuit 2021; in general application scenarios, only one channel is turned on and the other channels are in the off state. For example, in a four-channel application, one channel is turned on and the other three channels are turned off. Considering that only the field effect tubes in the off state need to withstand voltage, the maximum value B of the shared field effect tubes can be determined as: A=(1-1 / (C-1))*D, where C is the number of channels.

[0066] In this embodiment, the number of field effect tubes of the tuning switch unit 202 is changed from E*C in the prior art to B+F*C, where E is the number of field effect tubes that each stacked field effect tube 1021 needs to be connected in series, and F is the total number of field effect tubes required by the switch unit 102 minus the number of second field effect tubes in the stacked common field effect tube circuit 2022 in this embodiment, which is equivalent to E=B+D. It can be seen that under the same on-resistance index, the tuning switch unit 202 in this embodiment can reduce the number of field effect tubes of the switch unit 102 in the prior art by B*C.

[0067] Assume that the switch unit 102 in the prior art requires 28 field effect transistors and is divided into four channels, and the area of ​​each field effect transistor is 1 mm 2 , then the area of ​​the switch unit 102 is: 28*4*1mm²=112mm²; and if the stacked common field effect tube circuit 2022 of the tuning switch unit 202 in this embodiment uses 14 field effect tubes, then the area of ​​the tuning switch unit 202 is: 14+(10*4)=54mm²; By comparison, it can be seen that the tuning switch unit 202 in this embodiment saves about 50% of the area of ​​the switch unit 102 in the prior art, and accordingly, the area of ​​the tuning switch circuit 200 is also saved by about 50%.

[0068] Compared with the prior art, the tuning switch circuit 200 in this embodiment is designed with a stacked common field effect transistor circuit 2022 connected to at least two stacked branch field effect transistor circuits 2021, which is equivalent to changing the field effect transistors in multiple stacked branch field effect transistor circuits 2021 to share a part of the field effect transistors, thereby reducing the total number of field effect transistors in the tuning switch circuit 200 under the same on-resistance, that is, reducing the area of ​​the tuning switch circuit 200, or increasing the total number of field effect transistors in the tuning switch circuit 200 under the same area to obtain a smaller on-resistance.

[0069] The present invention further provides an embodiment of a radio frequency chip, which includes the tuning switch circuit 200 in the above embodiment. Since the radio frequency chip in this embodiment includes the tuning switch circuit 200 in the above embodiment, it can also achieve the technical effect achieved by the tuning switch circuit 200 in the above embodiment, which will not be described in detail here.

[0070] It should be noted that the various embodiments described above with reference to the accompanying drawings are only used to illustrate the present invention rather than to limit the scope of the present invention. Those skilled in the art should understand that any modification or equivalent substitution of the present invention without departing from the spirit and scope of the present invention should be included within the scope of the present invention. In addition, unless otherwise indicated by the context, words appearing in the singular include the plural form, and vice versa. In addition, unless otherwise specified, all or part of any embodiment may be used in combination with all or part of any other embodiment.

Claims

1. A tuning switch circuit, characterized in that: The tuning switch circuit comprises a switch bias unit and a tuning switch unit connected in sequence; The switch bias unit is used to output a gate control signal and a body control signal; The tuning switch unit comprises a stacked branch field effect tube circuit formed by a plurality of first field effect tube units connected in series in sequence and a stacked common field effect tube circuit formed by a plurality of second field effect tube units connected in series in sequence; the stacked branch field effect tube circuit comprises at least two; The first end of each stacked branch field effect tube circuit is grounded; the first field effect tube unit of each level includes a first resistor and a first field effect tube; In each stage of the first field effect tube unit, the first end of the first resistor is connected to the gate control end of the switch bias unit, the second end of the first resistor is connected to the gate of the first field effect tube, and the body end of the first field effect tube is connected to the body control end of the switch bias unit; The second end of each of the stacked branch field effect transistor circuits is respectively connected to the first end of the stacked common field effect transistor circuit; The second end of the stacked common field effect tube circuit is used to connect to the antenna; the second field effect tube unit of each level includes a second resistor and a second field effect tube; In each stage of the second field effect tube unit, the first end of the second resistor is connected to the gate control end of the switch bias unit, the second end of the second resistor is connected to the gate of the second field effect tube, and the body end of the second field effect tube is connected to the body control end of the switch bias unit; The tuning switch unit is used to receive the body control signal and the gate control signal, and control the on and off of each of the first field effect transistors in each of the stacked branch field effect transistor circuits according to the body control signal and the gate control signal, and simultaneously control the on and off of each of the second field effect transistors in the stacked common field effect transistor circuit.

2. The tuning switch circuit according to claim 1, characterized in that: The tuning switch unit also includes a plurality of third resistors whose number is the same as the number of the stacked branch field effect transistor circuits; the first ends of the plurality of third resistors are respectively connected to the gate control end of the switch bias unit, and the second end of each of the third resistors is respectively connected to the first end of the first resistor in each level of the first field effect transistor unit in one of the stacked branch field effect transistor circuits.

3. The tuning switch circuit according to claim 1, characterized in that: The tuning switch unit also includes a plurality of fourth resistors whose number is the same as the number of the stacked branch field effect transistor circuits; the first ends of the plurality of fourth resistors are respectively connected to the body control end of the switch bias unit, and the second end of each of the fourth resistors is respectively connected to the body end of the first field effect transistor in each level of the first field effect transistor unit in one of the stacked branch field effect transistor circuits.

4. The tuning switch circuit according to claim 1, characterized in that: The tuning switch unit also includes a fifth resistor; the first end of the fifth resistor is connected to the gate control end of the switch bias unit, and the second end of the fifth resistor is respectively connected to the first end of the second resistor in each level of the second field effect tube unit in the stacked common field effect tube circuit.

5. The tuning switch circuit according to claim 1, characterized in that: The tuning switch unit also includes a sixth resistor; the first end of the sixth resistor is connected to the body control end of the switch bias unit, and the second end of the sixth resistor is respectively connected to the body end of the second field effect transistor in each level of the second field effect transistor unit in the stacked common field effect transistor circuit.

6. The tuning switch circuit according to claim 1, characterized in that: The tuning switch unit includes a negative voltage generating module, a positive voltage generating module, a voltage driving module and a logic control module; The negative voltage generating module is used to generate a negative bias voltage; The positive voltage generating module is used to generate a positive bias voltage; The input end of the voltage driving module is respectively connected to the output end of the negative voltage generating module and the output end of the positive voltage generating module, and is used to receive the negative bias voltage and the positive bias voltage, and output a corresponding driving voltage according to the received negative bias voltage and the positive bias voltage; The input end of the logic control module is connected to the output end of the voltage driving module, the first output end of the logic control module serves as the gate control end of the tuning switch unit, and the second output end of the logic control module serves as the body control end of the tuning switch unit; the logic control module is used to receive the driving voltage and output the gate control signal and the body control signal according to the driving voltage.

7. A radio frequency chip, characterized in that: The radio frequency chip comprises the tuning switch circuit according to any one of claims 1 to 6.

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