Overpower protection high-integration radio frequency switch chip

Abstract

The invention discloses an overpower protection high-integration radio frequency switch chip, and relates to the technical field of electronic devices. A self-adaptive bias network, a high-power branch and an overpower protection branch; the high-power branch and the overpower protection branch are both formed by connecting a plurality of transistor units with one another; the plurality of transistor units form a reflective serial-parallel stacked radio frequency switch; the adaptive bias network at least comprises an envelope detection unit and a common-source amplification unit; the envelope detection unit and the common-source amplification unit are used for detecting input power and generating corresponding direct-current voltage to change switch grid voltage respectively, and over-power protection is provided for the reflective series-parallel stacked radio frequency switch. According to the scheme provided by the invention, the reflective serial-parallel stacked radio frequency switch is established based on the transistor unit, and adaptive bias is introduced on this basis to provide overpower protection for the switch, so that shunt protection when the power is too large is realized, and the failure risk of the radio frequency front-end circuit is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of electronic devices, and in particular to an over-power protection highly integrated radio frequency switch chip. Background Art

[0002] As a control device for microwave signal pathways, high-power switches have been widely used in various microwave front-end modules. Their performance directly affects the performance of the entire communication link. Gallium nitride high electron mobility tube (GaN HEMT) has the advantages of high thermal conductivity, high breakdown voltage, high electron drift rate, high temperature resistance, and high voltage resistance, which are very suitable for the development of microwave high-power switches. The series-parallel stacked GaN RF switch enables the power capacity to reach the order of hundreds of watts. However, for the RF front-end circuit, the power capacity must not only consider the transceiver marking of the applied standard, but also the increase in voltage swing caused by mismatch in specific engineering practice. Because in actual use, the stable matching of the circuit cannot be guaranteed at all times. For example, when the VSWR reaches a mismatch of 4:1, the maximum voltage swing is 1.6 times the voltage peak value during normal matching. Therefore, the degree of increase in voltage swing caused by mismatch is very large. If the power handling capacity including mismatch is not considered during design, the RF switch is likely to be broken down in the case of sudden circuit mismatch, and the RF front-end circuit is also likely to burn out and fail due to excessive power.

[0003] In this case, with the increase of transmission signal power, the over-power challenge faced by the RF front-end circuit becomes more severe. The main way to increase power capacity is to stack multiple transistors, and the number of stacks is determined by the specific working standard requirements of the switch. That is, through the stacking structure, each transistor is connected in series to share the total RF voltage, so it must be ensured that the voltage value shared by each transistor under high power does not exceed the drain-source breakdown voltage BVDSS, which limits the lower limit of the number of transistor stacks in the switch design. However, considering the possibility of circuit mismatch and problems with the front-end power amplifier, the number of stacks should be increased to retain a considerable design margin. In theory, the more transistors stacked on the branch, the greater the power it can withstand, but too large a number of stacks will cause the layout area to increase and the linearity and insertion loss to deteriorate. This leads to performance compromises in switch design. Therefore, there are deficiencies in the prior art.

[0004] Therefore, there is an urgent need to provide a more reliable over-power protection highly integrated RF switch chip. Summary of the invention

[0005] The object of the present invention is to provide a highly integrated radio frequency switch chip for over-power protection, which is used to implement shunt protection when the power is too large, thereby reducing the failure risk of the radio frequency front-end circuit.

[0006] In order to achieve the above object, the present invention provides the following technical solutions:

[0007] In a first aspect, the present invention provides an over-power protection highly integrated radio frequency switch chip, comprising at least:

[0008] Adaptive bias network, high power branch and over power protection branch;

[0009] The high power branch and the over power protection branch are both formed by connecting a plurality of transistor units to each other; the plurality of transistor units form a reflective series-parallel stacked RF switch;

[0010] The adaptive bias network includes at least an envelope detection unit and a common source amplifier unit; the envelope detection unit and the common source amplifier unit are used to respectively detect input power and generate corresponding DC voltage to change the switch gate voltage, thereby providing over-power protection for the reflective series-parallel stacked RF switch.

[0011] Optionally, each of the transistor units includes:

[0012] A transistor and a gate resistor; the transistor is a PHEMT switching transistor;

[0013] One end of the gate resistor is connected to the gate of the transistor, and the other end of the gate resistor is left vacant;

[0014] The transistor comprises a drain and a source; the source of the transistor is the first end of the transistor unit, and the drain of the transistor is the second end of the transistor unit; the vacant end of the gate resistor is the control end of the transistor unit;

[0015] The envelope detection unit and the common source amplification unit both include an adaptive bias transistor and a plurality of bias resistors.

[0016] Optionally, the over-power protection highly integrated RF switch chip also includes:

[0017] A signal transmission common terminal, a high-power signal transmission terminal, and an over-power protection signal transmission terminal;

[0018] The high power branch is connected between the signal transmission common terminal and the high power signal transmission terminal; the over power protection branch is connected between the signal transmission common terminal and the over power protection signal transmission terminal;

[0019] The overpower protection branch includes: an overpower protection series branch and an overpower protection parallel branch;

[0020] The over-power protection series branch and the over-power protection parallel branch are connected between the signal transmission common end and the ground line; the connection point between the over-power protection series branch and the over-power protection parallel branch is the over-power protection signal transmission end.

[0021] Optionally, the high-power signal transmission end includes:

[0022] A high-power series branch and a high-power parallel branch; the high-power series branch and the high-power parallel branch are both connected between the signal transmission common end and the ground line;

[0023] The high-power series branch is formed by sequentially connecting a first number of transistor units;

[0024] The first end of the transistor unit is connected to the second end of the transistor unit adjacent to the signal transmission common end; the second end of the transistor unit is connected to the first end of the transistor unit adjacent to the signal transmission common end in a direction away from the signal transmission common end;

[0025] The first end of the transistor unit closest to the signal transmission common end is connected to the signal transmission common end; the second end of the transistor unit farthest from the signal transmission common end is connected to the high-power parallel branch.

[0026] Optionally, the high-power parallel branch is formed by sequentially connecting a second number of the transistor units; the first number is greater than or equal to the second number;

[0027] The first end of the transistor unit is connected to the second end of the transistor unit adjacent to the signal transmission common end; the second end of the transistor unit is connected to the first end of the transistor unit adjacent to the ground line direction;

[0028] The second end of the transistor unit closest to the ground line is connected to the ground line; the first end of the transistor unit farthest from the ground line is connected to the high-power series branch.

[0029] Optionally, the over-power protection series branch is formed by sequentially connecting a third number of the transistor units;

[0030] The first end of the transistor unit is connected to the second end of the transistor unit adjacent to the signal transmission common end; the second end of the transistor unit is connected to the first end of the transistor unit adjacent to the signal transmission common end in a direction away from the signal transmission common end; the first end of the transistor unit closest to the signal transmission common end is connected to the signal transmission common end; the second end of the transistor unit farthest from the signal transmission common end is connected to the over-power protection parallel branch;

[0031] The over-power protection parallel branch is composed of a fourth number of transistors and DC blocking capacitors at both ends connected in sequence; the first end of the transistor unit is connected to the first DC blocking capacitor, and the other end of the first DC blocking capacitor is connected to the second end of the adjacent transistor unit in the direction of the signal transmission common end; the second end of the transistor unit is connected to the first end of the adjacent transistor unit in the direction of the ground line; the second end of the transistor unit closest to the ground line is connected to the second DC blocking capacitor, and the other end of the second DC blocking capacitor is connected to the ground line; the third number is greater than or equal to the fourth number.

[0032] Optionally, a drain-source inductor is connected between the first end and the second end of all the transistor units in the high-power series branch; the inductance of the drain-source inductor is determined by the capacitance of the transistor turn-off capacitor in the high-power series branch;

[0033] A drain-source inductor is connected between the first end and the second end of all the transistor units in the over-power protection series branch; the inductance of the drain-source inductor is determined by the capacitance of the transistor turn-off capacitor in the over-power protection series branch.

[0034] Optionally, the over-power protection highly integrated RF switch chip also includes:

[0035] A low-pass filter network; the low-pass filter network comprises a series resistor and a grounding capacitor;

[0036] The input end of the envelope detection unit is connected to the transmission signal power detection point, and the output end of the envelope detection unit is connected to the low-pass filter network; the input end of the common source amplification unit is connected to the other end of the low-pass filter network, and the output end of the common source amplification unit is connected to the over-power protection branch gate control end;

[0037] The transmission signal power detection point is located on the signal path between the first transistor unit and the second transistor unit in the signal transmission direction in the high-power branch.

[0038] Optionally, the gate bias of the envelope detection unit is zero or a positive voltage, and the transistor of the envelope detection unit is turned on;

[0039] The drain bias of the envelope detection unit is a negative voltage and provides a gate bias for the common-source amplifier unit. The transistor of the common-source amplifier unit is turned on when high power is not detected. The drain bias of the common-source amplifier unit is a positive voltage.

[0040] Optionally, when the gate-source voltage of the transistor in the transistor unit is greater than a threshold voltage, the transistor is turned on; when the gate-source voltage of the transistor is less than or equal to the threshold voltage, the transistor is turned off;

[0041] The switching state of the transistor unit is turned off by zero voltage and turned on by positive voltage in the overpower protection parallel branch; in the remaining circuits except the overpower protection parallel branch, it is turned off by negative voltage and turned on by zero voltage or positive voltage.

[0042] Compared with the prior art, the present invention provides a highly integrated RF switch chip with over-power protection. It at least includes: an adaptive bias network, a high-power branch and an over-power protection branch; the high-power branch and the over-power protection branch are both composed of a plurality of transistor units connected to each other; a plurality of transistor units constitute a reflective serial-parallel stacked RF switch; the adaptive bias network at least includes an envelope detection unit and a common source amplifier unit; the envelope detection unit and the common source amplifier unit are used to respectively detect the input power and generate a corresponding DC voltage to change the switch gate voltage, thereby providing over-power protection for the reflective serial-parallel stacked RF switch. The scheme of the present invention establishes a reflective serial-parallel stacked RF switch based on transistor units, and on this basis, introduces adaptive biasing to provide over-power protection for the switch. The envelope detection unit and the common source amplifier unit in the adaptive bias circuit are used to respectively detect the input power and generate a corresponding DC voltage to change the switch gate voltage, thereby realizing shunt protection when the power is too large, reducing the failure risk of the RF front-end circuit. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0044] Figure 1 This is an overall circuit diagram of a high-integration radio frequency switch chip for over-power protection provided by the present invention;

[0045] Figure 2 It is a circuit diagram of a transistor unit and a source-drain inductor in a high-integration radio frequency switch chip for over-power protection provided by the present invention;

[0046] Figure 3 It is a signal path equivalent diagram of the over-power protection branch of the over-power protection highly integrated radio frequency switch chip provided by the present invention.

[0047] Reference numerals:

[0048] M-transistor, R-gate resistor, L-drain-source inductor, HTx-high power signal transmission end, OppTx-overpower protection signal transmission end, ANT-signal transmission common end, GND-ground wire. DETAILED DESCRIPTION

[0049] In order to clearly describe the technical solutions of the embodiments of the present invention, in the embodiments of the present invention, words such as "first" and "second" are used to distinguish the same items or similar items with basically the same functions and effects. For example, the first threshold and the second threshold are only used to distinguish different thresholds, and their order is not limited. Those skilled in the art can understand that words such as "first" and "second" do not limit the quantity and execution order, and words such as "first" and "second" do not necessarily limit them to be different.

[0050] It should be noted that, in the present invention, words such as "exemplary" or "for example" are used to indicate examples, illustrations or descriptions. Any embodiment or design described as "exemplary" or "for example" in the present invention should not be interpreted as being more preferred or more advantageous than other embodiments or designs. Specifically, the use of words such as "exemplary" or "for example" is intended to present related concepts in a specific way.

[0051] In the present invention, "at least one" means one or more, and "plurality" means two or more. "And / or" describes the association relationship of associated objects, indicating that three relationships may exist. For example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone, where A and B can be singular or plural. The character " / " generally indicates that the associated objects before and after are in an "or" relationship. "At least one of the following" or similar expressions refers to any combination of these items, including any combination of single or plural items. For example, at least one of a, b or c can mean: a, b, c, the combination of a and b, the combination of a and c, the combination of b and c, or the combination of a, b and c, where a, b, c can be single or multiple.

[0052] First, some of the terms used in the embodiments of this specification are explained:

[0053] GaN PHEMT transistor: can represent pseudomorphic high electron mobility transistor (PHEMT) made of gallium nitride (GaN) material. This type of transistor takes advantage of the unique properties of gallium nitride materials, such as wide bandgap, high breakdown voltage and high electron saturation velocity, and is used in high frequency, high temperature and high power. Gallium nitride PHEMT transistors can also be widely used in RF amplifiers, satellite communications, radar systems and power electronic equipment.

[0054] Next, the solution provided by the embodiments of this specification is described in conjunction with the accompanying drawings:

[0055] Figure 1 This is an overall circuit diagram of a high-integration radio frequency switch chip for over-power protection provided by the present invention, such as Figure 1As shown, the over-power protection highly integrated radio frequency switch chip may include at least the following structures:

[0056] Adaptive bias network, high power branch and over power protection branch;

[0057] The high power branch and the over power protection branch are both formed by connecting a plurality of transistor units to each other; the plurality of transistor units form a reflective series-parallel stacked RF switch;

[0058] The adaptive bias network includes at least an envelope detection unit and a common source amplifier unit; the envelope detection unit and the common source amplifier unit are used to respectively detect input power and generate corresponding DC voltage to change the switch gate voltage, thereby providing over-power protection for the reflective series-parallel stacked RF switch.

[0059] Figure 1 The structure in the invention establishes a reflective series-parallel stacked RF switch based on GaN PHEMT transistor units, and introduces adaptive bias on this basis to provide over-power protection for the switch. The envelope detection unit and the common source amplifier unit in the adaptive bias circuit are used to detect the input power and generate the corresponding DC voltage to change the switch gate voltage, thereby realizing shunt protection when the power is too large. The invention reduces the failure risk of the RF front-end circuit.

[0060] based on Figure 1 The present specification also provides some specific implementations of the structure, which will be described below.

[0061] like Figure 1 as well as Figure 2 As shown, each of the transistor units comprises:

[0062] Transistor and gate resistor; the transistor can be a PHEMT switching transistor. Preferably, the PHEMT switching transistor can be a gallium nitride high electron mobility transistor (GaN HEMT). It should be noted that as long as it is a transistor with high electron mobility, it can be used as the transistor in the present invention to implement the solution. Here, no examples are given one by one.

[0063] One end of the gate resistor is connected to the gate of the transistor, and the other end of the gate resistor is left vacant;

[0064] The transistor comprises a drain and a source; the source of the transistor is the first end of the transistor unit, and the drain of the transistor is the second end of the transistor unit; the vacant end of the gate resistor is the control end of the transistor unit;

[0065] The envelope detection unit and the common source amplification unit both include an adaptive bias transistor and a plurality of bias resistors.

[0066] Furthermore, if Figure 1 As shown, the over-power protection highly integrated RF switch chip may also include:

[0067] A signal transmission common terminal, a high-power signal transmission terminal, and an over-power protection signal transmission terminal;

[0068] The high power branch is connected between the signal transmission common terminal and the high power signal transmission terminal; the over power protection branch is connected between the signal transmission common terminal and the over power protection signal transmission terminal;

[0069] The overpower protection branch may include: an overpower protection series branch and an overpower protection parallel branch;

[0070] The over-power protection series branch and the over-power protection parallel branch are connected between the signal transmission common end and the ground line; the connection point between the over-power protection series branch and the over-power protection parallel branch is the over-power protection signal transmission end.

[0071] Furthermore, for the high-power signal transmission end: the high-power signal transmission end may include a high-power series branch and a high-power parallel branch connected between the signal transmission common end and the ground line. Next, the specific structures of the high-power series branch and the high-power parallel branch are described respectively:

[0072] A high-power series branch can be composed of a first number (for example: A) of transistor units connected in sequence, wherein the first end of the transistor unit is connected to the second end of the adjacent transistor unit in the direction of the signal transmission common end, and the second end of the transistor unit is connected to the first end of the adjacent transistor unit in the direction away from the signal transmission common end; the first end of the transistor unit closest to the signal transmission common end is connected to the signal transmission common end; the second end of the transistor unit farthest from the signal transmission common end is connected to a high-power parallel branch; and the control ends of the A transistor units are connected in parallel to the first receiving gate-source voltage.

[0073] The high-power parallel branch can be composed of a second number (for example: C) of transistor units connected in sequence, the first end of the transistor unit is connected to the second end of the adjacent transistor unit in the direction of the signal transmission common end, and the second end of the transistor unit is connected to the first end of the adjacent transistor unit in the direction of the ground line; the second end of the transistor unit closest to the ground line is connected to the ground line; the first end of the transistor unit farthest from the ground line is connected to the high-power series branch; the control ends of the C transistor units are connected in parallel to the second receiving gate-source voltage; wherein A≥C.

[0074] As an optional implementation, Figure 2A drain-source inductor is connected between the first end and the second end of all the transistor units in the high-power series branch; the inductance of the drain-source inductor is determined by the capacitance of the transistor turn-off capacitor in the high-power series branch.

[0075] In the actual circuit connection structure, the specific structure of the overpower protection branch is described in detail:

[0076] The overpower protection branch may include an overpower protection series branch and an overpower protection parallel branch connected between the signal transmission common end and the ground line; the connection point of the overpower protection series branch and the overpower protection parallel branch is the overpower protection signal transmission end.

[0077] Furthermore, the specific structures of the overpower protection series branch and the overpower protection parallel branch are described respectively:

[0078] The over-power protection series branch may be formed by sequentially connecting a third number (e.g., B) of the transistor units, wherein the first end of the transistor unit is connected to the second end of the adjacent transistor unit in the direction of the signal transmission common end, and the second end of the transistor unit is connected to the first end of the adjacent transistor unit in the direction away from the signal transmission common end; the first end of the transistor unit closest to the signal transmission common end is connected to the signal transmission common end; the second end of the transistor unit farthest from the signal transmission common end is connected to the over-power protection parallel branch; the control ends of the B transistor units are connected in parallel to the first receiving gate-source voltage;

[0079] The over-power protection parallel branch can be composed of a fourth number (such as: D) of the transistors and the DC blocking capacitors at both ends connected in sequence, the first end of the transistor unit is connected to the first DC blocking capacitor, the other end of the first DC blocking capacitor is connected to the second end of the adjacent transistor unit in the direction of the signal transmission common end, and the second end of the transistor unit is connected to the first end of the adjacent transistor unit in the direction of the ground line; the second end of the transistor unit closest to the ground line is connected to the second DC blocking capacitor, and the other end of the second DC blocking capacitor is connected to the ground line; the control ends of the D transistor units are connected in parallel to the second receiving gate-source voltage; wherein, B≥D.

[0080] As an optional implementation, a drain-source inductor is connected between the first end and the second end of all the transistor units in the over-power protection series branch; the inductance of the drain-source inductor is determined by the capacitance of the transistor turn-off capacitor in the over-power protection series branch.

[0081] The signal transmission common end is at the same common point as the connection point of the high-power series branch and the over-power protection series branch; the common point is connected to the ground wire through a grounding resistor; the resistance of the grounding resistor is not less than 5 kilo-ohms.

[0082] For over-power protection highly integrated RF switch chips, it can also include:

[0083] Low-pass filter network; the low-pass filter network includes a series resistor and a grounding capacitor.

[0084] The input end of the envelope detection unit in the adaptive bias network is connected to the transmission signal power detection point, and the output end of the envelope detection unit is connected to the low-pass filter network;

[0085] The input end of the common source amplifier unit is connected to the other end of the low-pass filter network, and the output end of the common source amplifier unit is connected to the over-power protection branch gate control end; the transmission signal power detection point is located on the signal path after the first transistor unit and before the second transistor unit in the signal transmission direction of the high-power branch.

[0086] Furthermore, the gate bias of the envelope detection unit is zero or a positive voltage to keep the transistor of the envelope detection unit turned on, the drain bias of the envelope detection unit is a negative voltage and provides a gate bias for the common-source amplifier unit to keep the transistor of the common-source amplifier unit turned on when high power is not detected; the drain bias of the common-source amplifier unit is a positive voltage.

[0087] In practical applications, when the gate-source voltage Vgs of the transistor in the transistor unit is greater than the threshold voltage Vth, the transistor is turned on; when the gate-source voltage Vgs is less than or equal to the threshold voltage Vth, the transistor is turned off; the switch state of the transistor unit is turned off by zero voltage in the over-power protection parallel branch and turned on by positive voltage. In the rest of the circuit results, negative voltage is used to turn off, and zero voltage or positive voltage is used to turn on.

[0088] Next, in order to explain in detail the over-power protection highly integrated radio frequency switch chip provided by the present invention, Figure 1-3 The technical solution of the present invention is further described:

[0089] The present invention provides an over-power protection high-integration radio frequency switch chip, which may include a single signal transmission common terminal ANT, X switchable high-power signal transmission terminals HTx, Y switchable over-power protection signal transmission terminals OppTx and an adaptive bias network, as well as X high-power branches connected between the signal transmission common terminal ANT and the high-power signal transmission terminal HTx, and Y over-power protection branches connected between the signal transmission common terminal ANT and the over-power protection signal transmission terminal OppTx; the high-power branch and the over-power protection branch are both composed of a plurality of transistor units connected to each other.

[0090] The transistor unit may include: a transistor M and a gate resistor R; the transistor M is a GaN PHEMT switching transistor; one end of the gate resistor is connected to the gate of the transistor M, and the other end is vacant; the transistor M includes a drain and a source; the source of the transistor M is the first end of the transistor unit, and the drain of the transistor M is the second end of the transistor unit; the vacant end of the gate resistor R is the control end of the transistor unit.

[0091] The adaptive bias network includes an envelope detection unit, a low-pass filter network and a common source amplifier unit; the envelope detection unit and the common source amplifier unit are both composed of an adaptive bias transistor and a plurality of bias resistors R b The low-pass filter network is composed of a series resistor R s and grounding capacitor C g Connection composition.

[0092] Furthermore, the high-power part may include a high-power series branch and a high-power parallel branch connected between the signal transmission common terminal ANT and the ground line GND; the high-power series branch is composed of A transistor units connected in sequence, and the specific components of the transistor unit are: a high-power series branch transistor M (Total width = 1.8mm), a gate resistor R (5KΩ).

[0093] The first end of the transistor unit is connected to the second end of the transistor unit adjacent to the signal transmission common terminal ANT, and the second end of the transistor unit is connected to the first end of the transistor unit adjacent to the signal transmission common terminal ANT in the direction away from the signal transmission common terminal ANT; the first end of the transistor unit closest to the signal transmission common terminal ANT is connected to the signal transmission common terminal; the second end of the transistor unit farthest from the signal transmission common terminal ANT is connected to the high-power parallel branch; the control ends of A transistor units are connected in parallel to the first receiving gate-source voltage;

[0094] The high-power parallel branch is composed of C transistor units connected in sequence, and the specific components of the transistor unit are: a high-power series branch transistor M (Total width = 0.15mm), a gate resistor R (2KΩ). The first end of the transistor unit is connected to the second end of the adjacent transistor in the direction of the signal transmission common terminal ANT, and the second end of the transistor unit is connected to the first end of the adjacent transistor unit in the direction of the ground line; the second end of the transistor unit closest to the ground line GND is connected to the ground line; the first end of the transistor unit farthest from the ground line GND is connected to the high-power series branch; the control ends of the C transistor units are connected in parallel to the second receiving gate-source voltage; wherein, since the number of stacked series transistors M is increased to improve the isolation and echo within a wide bandwidth, A≥C.

[0095] Furthermore, a drain-source inductor L is connected between the first and second ends of all transistor units in the high-power series branch; the inductance of the drain-source inductor L is determined by the capacitance of the off capacitance of the transistor in the series branch in the off state. The larger the total gate width of the transistors in the series branch, the larger the off capacitance. The drain-source inductor L is required to compensate for the reactance of the off transistor to improve the performance of the switch. The inductance ranges from tens of pH to thousands of pH.

[0096] Specifically, after the topology design, the required performance of the switch has not yet reached the optimal level. The performance of the switch is also affected by the reactance or susceptance of the transistor, among which the reactance generated by the off capacitor has the most prominent effect. By selecting a suitable drain-source inductance to make the series branch transistor resonate at the center frequency, not only can the isolation between the transmitters be improved, but the switch insertion loss can also be improved to a certain extent.

[0097] Furthermore, the overpower protection branch includes an overpower protection series branch and an overpower protection parallel branch connected between the signal transmission common terminal ANT and the ground wire GND; the connection point of the overpower protection series branch and the overpower protection parallel branch is the power protection signal transmission terminal.

[0098] The over-power protection series branch is formed by sequentially connecting B transistor units, and the specific components of the transistor unit are: an over-power protection series branch transistor M (Total width=0.45mm) and a gate resistor R (5KΩ).

[0099] The first end of the transistor unit is connected to the second end of the transistor unit adjacent to the signal transmission common terminal ANT, and the second end of the transistor unit is connected to the first end of the transistor unit adjacent to the signal transmission common terminal ANT in the direction away from the signal transmission common terminal ANT; the first end of the transistor unit closest to the signal transmission common terminal ANT is connected to the signal transmission common terminal ANT; the second end of the transistor unit farthest from the signal transmission common terminal ANT is connected to the over-power protection parallel branch; the control ends of B transistor units are connected in parallel to the first receiving gate-source voltage.

[0100] The over-power protection parallel branch is composed of D transistors connected in sequence, the high-power series branch transistor M (Total width = 0.3mm), the gate resistor R (2KΩ) and the first end of the transistor connected to the first DC blocking capacitor C 1 (16pF), the other end of the first blocking capacitor is connected to the second end of the transistor unit adjacent to the signal transmission common terminal ANT, the second end of the transistor unit is connected to the first end of the transistor unit adjacent to the ground line; the second end of the transistor unit closest to the ground line is connected to the second blocking capacitor C 2(13pF), the other end of the second DC blocking capacitor is connected to the ground line; the control ends of the D transistor units are connected in parallel to the second receiving gate-source voltage; wherein, since the over-power protection series branch has to bear the signal power of the high-power series branch, B≥D.

[0101] Furthermore, a drain-source inductor L is connected between the first and second ends of all transistor units in the overpower protection series branch; the inductance of the drain-source inductor is determined by the capacitance of the off capacitance of the transistor in the series branch in the off state. The larger the total gate width of the transistors in the series branch, the larger the off capacitance. The drain-source inductor is required to compensate for the reactance of the off transistor to improve the performance of the switch. The inductance ranges from tens of pH to thousands of pH.

[0102] Similarly, as in the case of the high-power transmitting branch, after the topology design, the required performance of the switch has not yet reached the optimal level. The performance of the switch is also affected by the reactance or susceptance of the transistor, among which the reactance generated by the off capacitor has the most prominent effect. By selecting a suitable drain-source inductance to make the series branch transistor resonate at the center frequency, not only can the isolation between the transmitting ends be improved, but the switch insertion loss can also be improved to a certain extent.

[0103] Furthermore, the signal transmission common end is at the same common point as the connection point of the high-power series branch and the over-power protection series branch; the common point is connected to the ground wire through a grounding resistor; the grounding resistor has a resistance of not less than 5 kilo-ohms.

[0104] Specifically, in design and assembly, in order to ensure that the RF signal is not affected by the DC component, a capacitor is usually connected in series at the switch port for decoupling. In this way, if DC leakage occurs inside the switch, it will cause circuit abnormality or even damage. Therefore, it is very important to provide a DC discharge path for the switch through a grounding resistor. The grounding resistor is connected in parallel at the connection point of the high-power series branch and the over-power protection series branch, which affects the insertion loss of both the high-power branch and the over-power protection branch. Therefore, a large resistor needs to be selected to reduce the insertion loss, and the resistance range is usually greater than 5 kilo-ohms.

[0105] Furthermore, the input end of the envelope detection unit in the adaptive bias network is connected to the transmission signal power detection point, and the output end of the envelope detection unit is connected to the low-pass filter network; the input end of the common source amplifier unit is connected to the other end of the low-pass filter network, and the output end of the common source amplifier unit is connected to the over-power protection branch gate control end; the transmission signal power detection point is located in the signal path after the first transistor unit and before the second transistor unit in the signal transmission direction of the high-power branch.

[0106] Specifically, the transmission signal power detection point is selected to be located on the signal path of the switch isolation end. When the series transistor on the signal path is turned off, the equivalent off capacitance causes the input power to attenuate by a certain amount. Therefore, a smaller signal that is strongly related to the input power can be detected at the power detection point, which is convenient for adaptive bias network processing. When the power value at the detection point is lower than the threshold set by the envelope detection unit, the common source amplifier unit transistor is turned on, and the gate voltage of the over-power protection parallel branch transistor is the voltage divided by the on-resistance of the common source amplifier unit transistor and the drain bias resistance. At this time, the over-power protection parallel branch is turned off, and the signal transmission is normal. When the power value at the detection point is higher than the threshold set by the envelope detection unit, the common source amplifier unit transistor is turned off, and the gate voltage of the over-power protection parallel branch transistor is the common source amplifier unit drain bias. At this time, the over-power protection parallel branch is turned on, generating a signal path to ground.

[0107] Furthermore, when the gate-source voltage Vgs of the transistor in the transistor unit is greater than the threshold voltage Vth, the transistor is turned on; when the gate-source voltage Vgs is less than or equal to the threshold voltage Vth, the transistor is turned off; the off state of the transistor unit adopts: zero voltage turns off, positive voltage turns on. Among them, by adjusting the transistor source to a positive voltage, the PHEMT transistor threshold voltage Vth is set to a positive voltage.

[0108] in addition, Figure 1 VG1 represents control voltage 1, with an amplitude of 0 / -30V; VG2 represents control voltage 2, with an amplitude of -30 / 0V. The states of VG1 and VG2 cannot be equal. Q abc represents the adaptive bias transistor; V dabc represents the adaptive bias transistor drain voltage, which is -15V; V sabc Represents the adaptive bias transistor source voltage, which is 0V; V gabc Represents the gate voltage of the adaptive bias transistor. To simplify the power supply, PAD is powered synchronously with the amplitude of VG2. Cbp represents the bypass capacitor.

[0109] Figure 3 The figure shows the equivalent diagram of the switch circuit when the over-power protection function is in effect. Figure 3 It can be seen from the figure that the technical solution provided by the present invention achieves the effect of the over-power protection function when the over-power protection function takes effect. Specifically, in the prior art, the right parallel branch is turned off. In the present application, Figure 3 As shown, when the right branch transistor is turned on, it is equivalent to the on resistor Ron, and when the left branch transistor is turned off, it is equivalent to the off resistor Roff and the off capacitor Coff in parallel. Figure 3 It can be seen that when the over-power protection function takes effect, the right parallel branch is turned on, discharging or providing an impedance discontinuity point to provide additional insertion loss for the power exceeding the threshold to achieve the over-power protection function.

[0110] Specifically, the transistor used in the present invention is a GaN PHEMT transistor, whose turn-on voltage is zero or positive. Since the adaptive bias provides a step of the absolute value of the DC voltage, in order to better realize the function of over-power protection, the over-power protection parallel branch adopts a positive voltage turn-on technology. In addition, when a gate voltage with a small absolute value is used for shutdown (such as 5V), it is easy to be affected by the signal swing, resulting in the branch being unable to shut down normally, and then the signal leakage leads to low power handling capacity. When a gate voltage with a large absolute value (<15V) is used, the power handling capacity of the transistor can be improved when it enters the shutdown state.

[0111] Compared with the traditional series-parallel single-pole multi-throw switch, the embodiment of the present invention realizes the function of over-power protection during signal transmission by introducing an adaptive bias network with positive voltage opening technology. When the input power reaches the threshold, the adaptive bias network outputs a DC voltage step signal, so that the positive voltage-opened over-power protection parallel branch opens the signal path to the ground, thereby protecting the RF front-end circuit.

[0112] Compared with the prior art, the technical solution provided by the present invention can achieve at least the following technical effects:

[0113] 1) The over-power protection highly integrated RF switch chip of the present invention is based on GaN PHEMT transistor units and transistors to establish a reflective series-parallel stacked RF switch. The introduction of the adaptive bias network can solve the problem of excessive power caused by mismatch and power amplifier malfunction that may occur during large signal transmission, thereby providing over-power protection for the RF front-end chip.

[0114] 2) The power detection point of the adaptive bias network is located on the signal path after the first transistor of the high-power series branch close to the signal transmission common end. The adaptive bias network can obtain a voltage signal that is strongly related to the transmission power and provide a DC voltage step at a specific threshold.

[0115] 3) The over-power protection parallel branch adopts positive voltage opening technology to better utilize the DC step provided by the adaptive bias network. When transmitting low power, the gate voltage of the over-power protection parallel branch is close to 0, in the off state, and the signal is transmitted normally; after the transmission power exceeds the threshold, the gate voltage of the over-power protection parallel branch is biased to the drain voltage of the common source amplifier transistor, which is positive, and the over-power protection parallel branch is turned on to generate a signal path to the ground to protect the RF front-end circuit.

[0116] 4) The present invention provides an over-power protection high-integration RF switch chip, which is an over-power protection GaN single-pole multi-throw RF transceiver switch chip in which all branches are used for power transmission. It can meet the power capacity, isolation, return loss and other indicators of each transmitting branch, and on this basis provide over-power protection for large signal transmission paths.

[0117] Although the present invention is described herein in conjunction with various embodiments, in the process of implementing the claimed invention, those skilled in the art may understand and implement other variations of the disclosed embodiments by viewing the drawings, the disclosure, and the appended claims. In the claims, the word "comprising" does not exclude other components or steps, and "one" or "an" does not exclude multiple situations. A single processor or other unit may implement several functions listed in the claims. Certain measures are recorded in different dependent claims, but this does not mean that these measures cannot be combined to produce good results.

[0118] Although the present invention has been described in conjunction with specific features and embodiments thereof, it is apparent that various modifications and combinations may be made thereto without departing from the spirit and scope of the present invention. Accordingly, this specification and the accompanying drawings are merely exemplary illustrations of the present invention as defined by the appended claims and are deemed to cover any and all modifications, variations, combinations or equivalents within the scope of the present invention. Obviously, those skilled in the art may make various modifications and variations to the present invention without departing from the spirit and scope of the present invention. Thus, the present invention is intended to include such modifications and variations if they fall within the scope of the claims of the present invention and their equivalents.

Claims

1. An over-power protection highly integrated radio frequency switch chip, characterized in that: At least: Adaptive bias network, high power branch and over power protection branch; The high power branch and the over power protection branch are both formed by connecting a plurality of transistor units to each other; the plurality of transistor units form a reflective series-parallel stacked RF switch; The adaptive bias network includes at least an envelope detection unit and a common source amplifier unit; the envelope detection unit and the common source amplifier unit are used to respectively detect input power and generate corresponding DC voltage to change the switch gate voltage, thereby providing over-power protection for the reflective series-parallel stacked RF switch.

2. The over-power protection highly integrated radio frequency switch chip according to claim 1, characterized in that: Each of the transistor units comprises: A transistor and a gate resistor; the transistor is a PHEMT switching transistor; One end of the gate resistor is connected to the gate of the transistor, and the other end of the gate resistor is left vacant; The transistor comprises a drain and a source; the source of the transistor is the first end of the transistor unit, and the drain of the transistor is the second end of the transistor unit; the vacant end of the gate resistor is the control end of the transistor unit; The envelope detection unit and the common source amplification unit both include an adaptive bias transistor and a plurality of bias resistors.

3. The over-power protection highly integrated radio frequency switch chip according to claim 2, characterized in that: The over-power protection highly integrated RF switch chip also includes: A signal transmission common terminal, a high-power signal transmission terminal, and an over-power protection signal transmission terminal; The high power branch is connected between the signal transmission common terminal and the high power signal transmission terminal; the over power protection branch is connected between the signal transmission common terminal and the over power protection signal transmission terminal; The overpower protection branch includes: an overpower protection series branch and an overpower protection parallel branch; The over-power protection series branch and the over-power protection parallel branch are connected between the signal transmission common end and the ground line; the connection point between the over-power protection series branch and the over-power protection parallel branch is the over-power protection signal transmission end.

4. The over-power protection highly integrated radio frequency switch chip according to claim 3, characterized in that: The high-power signal transmission end comprises: A high-power series branch and a high-power parallel branch; the high-power series branch and the high-power parallel branch are both connected between the signal transmission common end and the ground line; The high-power series branch is formed by sequentially connecting a first number of transistor units; The first end of the transistor unit is connected to the second end of the transistor unit adjacent to the signal transmission common end; the second end of the transistor unit is connected to the first end of the transistor unit adjacent to the signal transmission common end in a direction away from the signal transmission common end; The first end of the transistor unit closest to the signal transmission common end is connected to the signal transmission common end; the second end of the transistor unit farthest from the signal transmission common end is connected to the high-power parallel branch.

5. The over-power protection highly integrated radio frequency switch chip according to claim 4, characterized in that: The high-power parallel branch is formed by sequentially connecting a second number of the transistor units; the first number is greater than or equal to the second number; The first end of the transistor unit is connected to the second end of the transistor unit adjacent to the signal transmission common end; the second end of the transistor unit is connected to the first end of the transistor unit adjacent to the ground line direction; The second end of the transistor unit closest to the ground line is connected to the ground line; the first end of the transistor unit farthest from the ground line is connected to the high-power series branch.

6. The over-power protection highly integrated radio frequency switch chip according to claim 4, characterized in that: The over-power protection series branch is formed by sequentially connecting a third number of the transistor units; The first end of the transistor unit is connected to the second end of the transistor unit adjacent to the signal transmission common end; the second end of the transistor unit is connected to the first end of the transistor unit adjacent to the signal transmission common end in a direction away from the signal transmission common end; the first end of the transistor unit closest to the signal transmission common end is connected to the signal transmission common end; the second end of the transistor unit farthest from the signal transmission common end is connected to the over-power protection parallel branch; The over-power protection parallel branch is formed by sequentially connecting the fourth number of transistors and the DC blocking capacitors at both ends; the first end of the transistor unit is connected to the first DC blocking capacitor, and the other end of the first DC blocking capacitor is connected to the second end of the adjacent transistor unit in the direction of the signal transmission common end; the second end of the transistor unit is connected to the first end of the adjacent transistor unit in the direction of the ground line; The second end of the transistor unit closest to the ground line is connected to a second DC blocking capacitor, and the other end of the second DC blocking capacitor is connected to the ground line; the third number is greater than or equal to the fourth number.

7. The over-power protection highly integrated radio frequency switch chip according to claim 4, characterized in that: A drain-source inductor is connected between the first end and the second end of all the transistor units in the high-power series branch; the inductance of the drain-source inductor is determined by the capacitance of the transistor turn-off capacitor in the high-power series branch; A drain-source inductor is connected between the first end and the second end of all the transistor units in the over-power protection series branch; the inductance of the drain-source inductor is determined by the capacitance of the transistor turn-off capacitor in the over-power protection series branch.

8. The over-power protection highly integrated radio frequency switch chip according to claim 1, characterized in that: The over-power protection highly integrated RF switch chip also includes: A low-pass filter network; the low-pass filter network comprises a series resistor and a grounding capacitor; The input end of the envelope detection unit is connected to the transmission signal power detection point, and the output end of the envelope detection unit is connected to the low-pass filter network; the input end of the common source amplification unit is connected to the other end of the low-pass filter network, and the output end of the common source amplification unit is connected to the over-power protection branch gate control end; The transmission signal power detection point is located on the signal path between the first transistor unit and the second transistor unit in the signal transmission direction in the high-power branch.

9. The over-power protection highly integrated radio frequency switch chip according to claim 1, characterized in that: The gate bias of the envelope detection unit is zero or a positive voltage, and the transistor of the envelope detection unit is turned on; The drain bias of the envelope detection unit is a negative voltage and provides a gate bias for the common-source amplifier unit. The transistor of the common-source amplifier unit is turned on when high power is not detected. The drain bias of the common-source amplifier unit is a positive voltage.

10. The over-power protection highly integrated radio frequency switch chip according to claim 2, characterized in that: When the gate-source voltage of the transistor in the transistor unit is greater than the threshold voltage, the transistor is turned on; when the gate-source voltage of the transistor is less than or equal to the threshold voltage, the transistor is turned off; The switching state of the transistor unit is turned off by zero voltage and turned on by positive voltage in the overpower protection parallel branch; in the remaining circuits except the overpower protection parallel branch, it is turned off by negative voltage and turned on by zero voltage or positive voltage.

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