TR circuit of single-pole single-throw switch, chip and signal transceiving control method

Abstract

The invention discloses a TR circuit of a single-pole single-throw switch, a chip and a signal transceiving control method, and belongs to the technical field of radio frequency communication, the TR circuit comprises a power amplifier, an antenna and a low-noise amplifier, a 50-ohm transmission line is arranged between the output end of the power amplifier and the antenna, a 1 / 4 wavelength transmission line is arranged between the antenna and the input end of the low-noise amplifier, and the 1 / 4 wavelength transmission line is connected with the power amplifier. And a field effect transistor is connected in parallel between the input end of the low noise amplifier and the 1 / 4 wavelength transmission line. A 1 / 4 wavelength transmission line of an emission branch and a switch structure of a parallel field effect transistor (FET) are replaced by a 50-ohm transmission line, impedance conversion is carried out through the 50-ohm transmission line to realize the effect of switching off the switch, the insertion loss of the switch of the emission branch is effectively reduced, the linearity pressure of the FET is reduced, and the reliability of the emission branch is improved. Therefore, the overall output power and efficiency of the transmitting branch in the TR circuit are improved.

Description

Technical Field

[0001] The present invention relates to the field of radio frequency communication technology, and in particular to a TR circuit, a chip and a signal receiving and transmitting control method of a single-pole single-throw switch. Background Art

[0002] TR circuit (transceiver circuit) is a multifunctional chip that integrates power amplifier, switch and low noise amplifier, and is usually used in the front end of the transceiver system. Since the TR circuit integrates functions such as signal amplification, switch control and noise reduction, its transceiver performance is crucial to the performance of the entire system. Among them, output power and efficiency are the most critical indicators of the TR circuit transmission branch, which directly determines the performance of the transmission branch of the entire transceiver system.

[0003] like Figure 1 As shown, in the transmitting branch of the traditional TR circuit, a 1 / 4 wavelength transmission line is provided between the output end of the power amplifier PA and the antenna ANT, and a first field effect transistor FET1 is connected in parallel between the output end of the power amplifier PA and the 1 / 4 wavelength transmission line; in the receiving branch of the TR circuit, a 1 / 4 wavelength transmission line is provided between the antenna ANT and the input end of the low noise amplifier LNA, and a second field effect transistor FET2 is connected in parallel between the input end of the low noise amplifier LNA and the 1 / 4 wavelength transmission line. It can be seen that the traditional TR circuit uses a single-pole double-throw switch (first field effect transistor FET1 + second field effect transistor FET2) to isolate the output end of the power amplifier PA and the input end of the low noise amplifier LNA. Therefore, the insertion loss and linearity of the single-pole double-throw switch will directly affect the output power and efficiency of the system transmitting branch. However, with the increase of frequency and power, the insertion loss of the single-pole double-throw switch will increase significantly, greatly affecting the output power and efficiency of the transmitting branch of the TR circuit.

[0004] In order to solve the problem of significant drop in transmission power and efficiency in TR circuits due to switch insertion loss, the invention patent application with publication number CN118199665A and titled "Transceiver matching network and RF front-end circuit and chip" performs multi-modal design on the output matching of the power amplifier PA to simultaneously meet the matching requirements of the transmitting branch and the receiving branch. This greatly increases the complexity of the output matching of the power amplifier PA, and is highly dependent on the joint optimization of the power amplifier PA and the low-noise amplifier LNA during the design process, increasing the design difficulty and design cycle. The invention patent with publication number CN116232259A and titled "RF front-end, RF circuit and chip based on post-matching architecture" achieves high impedance by absorbing the parasitic capacitance of the final transistor of the power amplifier PA into the switch, and at the same time multiplexes the receiving branch and the transmitting branch with the post-matching circuit. This structure will greatly deteriorate the noise of the receiving branch. Summary of the invention

[0005] The purpose of the present invention is to overcome the problems of the prior art and to provide a TR circuit, a chip and a signal receiving and transmitting control method of a single-pole single-throw switch.

[0006] The objective of the present invention is achieved through the following technical scheme: a TR circuit of a single-pole single-throw switch, the TR circuit comprising a power amplifier, an antenna and a low-noise amplifier, a 50-ohm transmission line is provided between the output end of the power amplifier and the antenna, a 1 / 4 wavelength transmission line is provided between the antenna and the input end of the low-noise amplifier, and a field effect transistor is connected in parallel between the input end of the low-noise amplifier and the 1 / 4 wavelength transmission line.

[0007] In one example, the drain of the field effect transistor is connected between the input end of the low noise amplifier and the 1 / 4 wavelength transmission line, the gate of the field effect transistor is connected to the control circuit, and the source of the field effect transistor is grounded.

[0008] In one example, the field effect transistor includes a metal oxide semiconductor field effect transistor, a complementary metal oxide semiconductor transistor, a junction field effect transistor, a metal semiconductor field effect transistor, and a high electron mobility transistor.

[0009] It should be further explained that the technical features corresponding to the above TR circuit examples can be combined or replaced with each other to form a new technical solution.

[0010] The present invention also includes a chip, including the TR circuit formed by any one of the above examples or a combination of multiple examples.

[0011] The present invention also includes a signal receiving and sending control method of a TR circuit of a single-pole single-throw switch, which is applied to the TR circuit formed by any one of the above examples or a combination of multiple examples, and the method includes the following steps: Turn on the power amplifier, turn on the field effect transistor, and the TR circuit works in the signal transmission state; The power amplifier is cut off, the low noise amplifier is turned on, the field effect transistor is turned off, and the TR circuit works in the signal receiving state.

[0012] In one example, when the transmitting branch is working, it also includes: cutting off the low noise amplifier.

[0013] In one example, when the TR circuit operates in a signal transmission state, the state between the antenna and the 1 / 4 wavelength transmission line is transformed into a high impedance state.

[0014] In one example, when the TR circuit operates in a signal receiving state, the impedance between the 50-ohm transmission line and the antenna is transformed into a high impedance state.

[0015] It should be further explained that the technical features corresponding to the various examples of the above method can be combined or replaced with each other to form a new technical solution.

[0016] Compared with the prior art, the present invention has the following beneficial effects: The present invention replaces the switch structure of the 1 / 4 wavelength transmission line and the parallel field effect transistor FET of the transmitting branch with a 50-ohm transmission line, and realizes the switch shutdown effect by impedance transformation through the 50-ohm transmission line, effectively reducing the insertion loss of the transmitting branch switch, alleviating the linearity pressure of the effect transistor FET, thereby improving the overall output power and efficiency of the transmitting branch in the TR circuit.

[0017] At the same time, the present invention removes the switch FET at the output end of the power amplifier PA, and the overall circuit design is simple, without complicating the design of the power amplifier PA output matching, and does not need to rely on the joint optimization of the power amplifier PA and the low noise amplifier LNA. In addition, the present invention utilizes the impedance characteristics of the transistor turn-off in the power amplifier PA, and transforms the turn-off impedance of the power amplifier PA through a 50-ohm transmission line under the premise of matching the output of the power amplifier PA, so as to achieve the matching effect when the receiving branch is working, and can reduce the switching loss of the transmitting branch while ensuring that the noise of the receiving branch will not be significantly deteriorated. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The specific implementation methods of the present invention are further described in detail below in conjunction with the accompanying drawings. The accompanying drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The same reference numerals are used in these drawings to represent the same or similar parts. The schematic embodiments of the present application and their descriptions are used to explain the present application and do not constitute improper limitations on the present application.

[0019] Figure 1 It is a schematic diagram of the principle of the traditional TR circuit; Figure 2 A schematic diagram of a TR circuit principle provided for an example of the present invention; Figure 3 A schematic diagram of a TR circuit principle provided for another example of the present invention; Figure 4 A comparison diagram of simulation results of the insertion loss of the transmitting branch switch in the TR circuit of the present invention and the insertion loss of the transmitting branch switch in the traditional TR circuit is provided as an example of the present invention. DETAILED DESCRIPTION

[0020] The technical solution of the present invention is described clearly and completely below in conjunction with the accompanying drawings. 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.

[0021] In the description of the present invention, it should be noted that the directions or positional relationships indicated by "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside", etc. are directions or positional relationships based on the drawings, which are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. In addition, the use of ordinal numbers (e.g., "first and second", "first to fourth", etc.) is to distinguish objects, and is not limited to this order, and cannot be understood as indicating or implying relative importance.

[0022] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, "installation", "connection" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0023] In addition, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0024] In one example, if Figure 2 As shown, a TR circuit of a single-pole single-throw switch includes a power amplifier PA, an antenna ANT and a low-noise amplifier LNA, wherein the power amplifier and the antenna constitute a transmitting branch, and the RF signal is amplified and processed by the power amplifier and then radiated outward through the antenna; the antenna and the low-noise amplifier constitute a receiving branch, and a specific signal is received by the antenna and transmitted to the low-noise amplifier for low-noise amplification processing to improve the quality of the received signal and facilitate subsequent analysis and processing. Specifically, the power amplifier includes a plurality of transistors, such as mainly including an N-channel MOS tube and a P-channel MOS tube connected together, and the operating point is stabilized by a bias resistor. The low-noise amplifier is mainly composed of one or more low-noise field effect transistors (usually N-channel or P-channel MOS tubes) and corresponding bias circuits, input and output matching networks.

[0025] Further, a 50-ohm transmission line is provided between the output end of the power amplifier and the antenna, a 1 / 4 wavelength transmission line is provided between the antenna and the input end of the low-noise amplifier, and a field effect transistor FET is connected in parallel between the input end of the low-noise amplifier and the 1 / 4 wavelength transmission line. Optionally, the field effect transistor FET includes a metal oxide semiconductor field effect transistor, a complementary metal oxide semiconductor transistor, a junction field effect transistor, a metal semiconductor field effect transistor, a high electron mobility transistor, etc.

[0026] In this example, the switch structure of the 1 / 4 wavelength transmission line plus parallel FET in the transmitting branch is replaced with a 50 ohm transmission line. When the receiving branch is working, the impedance characteristics of the power amplifier when it is turned off are used to transform the impedance through the 50 ohm transmission line to achieve the effect of switching off. When the transmitting branch is working, the output end of the power amplifier is matched to 50 ohms, and low-loss transmission can be performed through the 50 ohm transmission line, thereby reducing power loss and improving the output power and efficiency of the T / R transmitting branch. At the same time, using a 50 ohm transmission line instead of the traditional 1 / 4 wavelength line plus parallel FET switch structure can effectively reduce the area of ​​the TR circuit, thereby reducing the cost of tape-out.

[0027] At the same time, the present invention removes the switch FET at the output end of the power amplifier PA, and the overall circuit design is simple, without complicating the design of the power amplifier PA output matching, and does not need to rely on the joint optimization of the power amplifier PA and the low noise amplifier LNA. In addition, the present invention utilizes the impedance characteristics of the transistor turn-off in the power amplifier PA, and transforms the turn-off impedance of the power amplifier PA through a 50-ohm transmission line under the premise of matching the output of the power amplifier PA, so as to achieve the matching effect when the receiving branch is working, and can reduce the switching loss of the transmitting branch while ensuring that the noise of the receiving branch will not be significantly deteriorated.

[0028] In one example, the drain of the field effect transistor is connected between the input of the low noise amplifier and the 1 / 4 wavelength transmission line, the source of the field effect transistor is grounded, and the gate of the field effect transistor is connected to the control circuit. At this time, the switching state of the field effect transistor is controlled by the controller to facilitate the switching of the transceiver branch of the TR circuit.

[0029] The present invention also includes a chip having the same inventive concept as the TR circuit formed by any one of the above examples or a combination of two examples, and the chip is encapsulated with the TR circuit formed by any one of the above examples or a combination of two examples.

[0030] The present invention also includes a signal receiving and sending control method of a TR circuit of a single-pole single-throw switch, which has the same inventive concept as the TR circuit formed by any one of the above examples or a combination of two examples, and the signal receiving and sending control method includes the following steps:

[0031] When the transmitting branch is working, the power amplifier is turned on and the field effect transistor is turned on. At this time, the TR circuit works in the signal transmitting state. Figure 3 As shown, between the antenna and the 1 / 4 wavelength transmission line ( Figure 3 The output terminal A of the power amplifier has an impedance of 50 ohms, and the signal can be transmitted with low loss through a 50 ohm transmission line and radiated outward through the antenna.

[0032] When the receiving branch is working, the power amplifier is pinched off, the low noise amplifier is turned on, the field effect transistor is turned off, and the TR circuit works in the signal receiving state. At this time, when the transistor in the power amplifier is in the pinch-off state, it can be equivalent to a small resistor R and a small capacitor C in series, such as Figure 3 As shown, after the output of the power amplifier is matched ( Figure 3 The impedance of point A in the middle is usually also located at the edge of the Smith chart, so it can be transformed into a high impedance state through a 50-ohm transmission line, that is, the impedance between the 50-ohm transmission line and the antenna is transformed into a high impedance state ( Figure 3 Point B in the middle) to achieve the effect of switching off.

[0033] In one example, when the transmitting branch is working, in order to protect the low noise amplifier from being damaged by the high power transmitting signal, the low noise amplifier is clamped off, that is, when the transmitting branch is working, the power amplifier is turned on, the low noise amplifier is clamped off, and the field effect transistor is turned on.

[0034] To illustrate the beneficial effects of the TR circuit of the present invention, the insertion loss from the power amplifier output end (point A) to the antenna when the transmitting branch is working is compared with the traditional single-pole double-throw structure. The simulation results are as follows: Figure 4 As shown, Figure 4 The horizontal axis is the frequency in GHZ, and the vertical axis is the insertion loss of the transmitting branch switch. It can be seen that the present invention utilizes the impedance characteristics when the power amplifier is turned off and uses a 50-ohm transmission line to replace the traditional single-pole double-throw switch structure, which not only simplifies the circuit structure, but also reduces the insertion loss of the transmitting branch switch, effectively reduces power loss, and improves the output power and efficiency of the transmitting branch. The transmitting branch performance of the high-frequency, high-power, multifunctional TR circuit is significantly improved.

[0035] The above specific implementation methods are detailed descriptions of the present invention. It cannot be determined that the specific implementation methods of the present invention are limited to these descriptions. For ordinary technicians in the technical field to which the present invention belongs, several simple deductions and substitutions can be made without departing from the concept of the present invention, which should be regarded as belonging to the protection scope of the present invention.

Claims

1. A TR circuit of a single-pole single-throw switch, comprising a power amplifier, an antenna and a low-noise amplifier, characterized in that: A 50-ohm transmission line is provided between the output end of the power amplifier and the antenna, a 1 / 4 wavelength transmission line is provided between the antenna and the input end of the low-noise amplifier, and a field effect transistor is connected in parallel between the input end of the low-noise amplifier and the 1 / 4 wavelength transmission line.

2. The TR circuit of the single-pole single-throw switch according to claim 1, characterized in that: The drain of the field effect transistor is connected between the input end of the low noise amplifier and the 1 / 4 wavelength transmission line, the gate of the field effect transistor is connected to the control circuit, and the source of the field effect transistor is grounded.

3. The TR circuit of the single-pole single-throw switch according to claim 1, characterized in that: The field effect transistors include metal oxide semiconductor field effect transistors, complementary metal oxide semiconductor transistors, junction field effect transistors, metal semiconductor field effect transistors, and high electron mobility transistors.

4. A chip, characterized in that: The TR circuit comprises the TR circuit according to any one of claims 1 to 3.

5. A signal receiving and sending control method of a TR circuit of a single-pole single-throw switch, characterized in that: The following steps are involved: Turn on the power amplifier, turn on the field effect transistor, and the TR circuit works in the signal transmission state; The power amplifier is cut off, the low noise amplifier is turned on, the field effect transistor is turned off, and the TR circuit works in the signal receiving state.

6. The signal receiving and sending control method of the TR circuit of the single-pole single-throw switch according to claim 5, characterized in that: When the transmitting branch is working, it also includes: pinching off the low noise amplifier.

7. The signal receiving and sending control method of the TR circuit of a single-pole single-throw switch according to claim 5, characterized in that: When the TR circuit operates in a signal transmission state, the state between the antenna and the 1 / 4 wavelength transmission line is transformed into a high impedance state.

8. The signal receiving and sending control method of the TR circuit of a single-pole single-throw switch according to claim 5, characterized in that: When the TR circuit operates in a signal receiving state, the impedance between the 50-ohm transmission line and the antenna is transformed into a high impedance state.

Images