Radio frequency circuit
By setting the temperature compensation mechanism of transistors and resistors in the RF circuit, the performance deterioration caused by heat dissipation problems in the RF circuit is solved, and higher circuit performance stability is achieved.
Patent Information
- Application Number
- CN202311475442.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Priority Date
- 2023-10-13
- Filing Date
- 2023-11-07
- Publication Date
- 2025-04-15
AI Technical Summary
With the miniaturization of RF circuits and the development of high power, the heat dissipation problem has become more and more serious, resulting in the reduction of the critical voltage of the transistors inside the power amplifier, the increase of the output power, and generate more heat energy, which in turn deteriorates the circuit performance.
A radio frequency circuit with temperature compensation is designed. By setting transistors and resistors near the amplifier circuit, using transistors as temperature sensors, detecting temperature and adjusting bias signals to reduce heat consumption and improve the stability of circuit performance.
Through the temperature compensation mechanism, the heat consumption of the radio frequency circuit is effectively reduced, the operation performance stability of the circuit is improved, and performance deterioration caused by thermal energy accumulation is avoided.
Smart Images
Figure CN119834745A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to a radio frequency circuit, in particular to a radio frequency circuit with temperature compensation. Background Art
[0002] Radio Frequency (RF) circuit is a circuit that processes radio frequency signals. RF circuit includes power amplifier, which is used to amplify radio frequency signals so that the radio frequency signals can be transmitted to a longer distance. RF circuit is widely used in various communication products such as mobile phones, tablet computers, base stations, Wi-Fi access points, Bluetooth transceivers, and network communication products.
[0003] As RF circuits develop towards miniaturization and high power, the heat dissipation problem of RF circuits becomes more and more serious, resulting in a decrease in the critical voltage of transistors inside the power amplifier, an increase in output power, and more heat energy, which in turn deteriorates circuit performance. Summary of the invention
[0004] An embodiment of the present invention provides a radio frequency circuit, including an amplifier circuit and a bias circuit. The amplifier circuit is used to receive a bias signal and amplify the radio frequency signal. The bias circuit is coupled to the amplifier circuit and is used to provide a bias signal. The bias circuit includes a transistor and a resistor. The transistor is arranged near the amplifier circuit. The resistor is arranged near the amplifier circuit, a first end of the resistor is coupled to a transmission line, an interference signal is coupled to the transmission line, and a second end of the resistor is coupled to a control end of the transistor. The resistor is located between the transistor and the transmission line. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 It is a circuit diagram of a radio frequency circuit in an embodiment of the present invention. Figure 2 yes Figure 1 Schematic diagram of the layout of the RF circuit. Figure 3A The relationship between the output current signal and the output power of the power amplifier circuit is shown. Figure 3B It is a schematic diagram of the input and output signals of the power amplifier circuit. Figure 4 It is a circuit diagram of another radio frequency circuit in an embodiment of the present invention. Figure 5 It is a circuit diagram of another radio frequency circuit in an embodiment of the present invention. Figure 6 It is a circuit diagram of another radio frequency circuit in an embodiment of the present invention.
Explanation of symbols
[0005] Figure 1 1 is a circuit diagram of a radio frequency circuit 1 in an embodiment of the present invention. The radio frequency circuit 1 may include a power amplifier, and the radio frequency circuit 1 may be used to amplify a radio frequency signal RFin to output an amplified radio frequency signal RFout.
[0006] The RF circuit 1 may include a bias circuit 10 and an amplifier circuit 12. The bias circuit 10 may be coupled to the amplifier circuit 12 and provide a bias signal Sb for the amplifier circuit 12 to operate normally. The bias signal Sb may be a current. The amplifier circuit 12 may receive the bias signal Sb and amplify the RF signal RFin to generate an amplified RF signal RFout. Since the amplifier circuit 12 generates heat energy during operation, causing the temperature to rise, the bias circuit 10 may detect the temperature and adjust the bias signal Sb according to the temperature, thereby adjusting the output power of the amplifier circuit 12, reducing heat consumption, and improving the stability of the operating performance of the RF circuit 1.
[0007] The bias circuit 10 may include a transistor T1 and a resistor Rb. The transistor T1 may be used as a temperature sensor, and the transistor T1 may be disposed near the amplifier circuit 12 to sense the temperature of the amplifier circuit 12. The threshold voltage of the transistor T1 and the current at the first terminal of the transistor T1 may change with temperature. The threshold voltage of the transistor T1 may be complementary to absolute temperature (CTAT), and the current at the first terminal of the transistor T1 may be proportional to absolute temperature (PTAT). When the temperature rises, the threshold voltage of the transistor T1 may decrease, thereby sensing the temperature.
[0008] The resistor Rb can be used for current limiting and voltage stabilization, thereby increasing the current stability of the bias circuit 10. In addition, the resistor Rb can be arranged near the amplifier circuit 12 to reduce the amplitude of the adjacent interference signal. In an embodiment, the first end of the resistor Rb is coupled to the transmission line Ln1, and the second end of the resistor Rb is coupled to the control end of the transistor T1. The resistor Rb can be arranged between the transistor T1 and the transmission line Ln1. The interference signal can be coupled to the transmission line Ln1. When the interference signal is coupled to the transmission line Ln1, the resistor Rb can reduce the amplitude of the interference signal at the second end of the resistor Rb, thereby reducing the influence of the interference signal on the voltage of the control end of the transistor T1, so that the transistor T1 can correctly sense the temperature of the amplifier circuit 12. The resistance value of the resistor Rb needs to be sufficient to reduce the amplitude of the interference signal, for example, it can be greater than or equal to 300 ohms (Ω). In some embodiments, the resistor Rb can be divided into a first resistor and a second resistor connected in series, wherein the first resistor can be set near the amplifier circuit 12, and the second resistor can be set at a position away from the amplifier circuit 12. The first resistor can be greater than or equal to 300 ohms, for example, the first resistor can be 300 ohms, and the second resistor can be 200 ohms.
[0009] The amplifier circuit 12 may include an amplifier 120, and the amplifier 120 is, for example, a power amplifier (PA). The bias circuit 10 may be coupled to the amplifier 120 and provide a bias signal Sb to the amplifier 120. The transmission line Ln1 may be located between the resistor Rb and the interference source, and the interference source may be a power amplifier or other signal source. The interference source may be coupled to the transmission line Ln2, and the transmission line Ln2 may not be directly coupled to the transmission line Ln1. Since the radio frequency signal RFin is a high-frequency and high-power signal, the amplifier 120 may form an interference source, and the interference signal comes from the interference source, and the interference signal may include the radio frequency signal RFin. The amplifier 120 may be coupled to the transmission line Ln2, and the transmission line Ln2 may transmit the radio frequency signal RFin. The interference signal may be coupled from the transmission line Ln2 to the transmission line Ln1. The resistor Rb may reduce the amplitude of the interference signal and reduce the influence of the interference signal on the voltage of the control terminal of the transistor T1. In some embodiments, the interference signal may also include the amplified radio frequency signal RFout. Furthermore, the distance between the transmission line Ln2 and the transmission line Ln1 is, for example, less than 3 micrometers (μm). In this case, the interference signal is easily coupled from the transmission line Ln2 to the transmission line Ln1.
[0010] The bias circuit 10 may further include a capacitor C, a resistor R1 and a resistor R2. The resistor R1 includes a first end and a second end, wherein the first end of the resistor R1 is coupled to the bias power supply 14. The bias power supply 14 may be located outside the RF circuit 1 and may provide a fixed voltage VCC1, such as 2.8V. The resistor R2 includes a first end and a second end, wherein the first end of the resistor R2 is coupled to the bias power supply 16. The bias power supply 16 may be located outside the RF circuit 1 and may provide a fixed voltage VCC2, such as 5V. The first end of the transistor T1 is coupled to the bias power supply 14 via the second end of the resistor R1, and the second end of the transistor T1 is coupled to the reference voltage end. The reference voltage end may provide a voltage VSS, such as 0V. The resistor R1 and the resistor R2 may have a fixed resistance and may be used for current limiting to ensure current stability. The resistance value of the resistor R1 may be between 200 ohms and 400 ohms, and the resistance value of the resistor R2 may be between 200 ohms and 400 ohms. In some embodiments, the resistors R1 and R2 may also be removed from the bias circuit 10. The capacitor C may be used for voltage stabilization, thereby increasing the current stability of the bias circuit 10. The capacitor C includes a first terminal and a second terminal, the first terminal of the capacitor C is coupled to the second terminal of the resistor R1, and the second terminal of the capacitor C is coupled to the reference voltage terminal.
[0011] The bias circuit 10 may further include a transistor T2. The transistor T2 includes a control terminal, a first terminal, and a second terminal, wherein the control terminal of the transistor T2 is coupled between the first terminal of the transistor T1 and the bias power source 14 (e.g., coupled between the first terminal of the transistor T1 and the second terminal of the resistor R1); the first terminal of the transistor T2 is coupled to the bias power source 16 via the second terminal of the resistor R2; and the second terminal of the transistor T2 is coupled to the amplifier circuit 12 to provide the bias signal Sb to the amplifier circuit 12.
[0012] The RF circuit 1 may further include a resistor R3 and a transistor T3. The transistor T3 includes a control end, a first end and a second end. The control end of the transistor T3 is coupled to the second end of the resistor R1, the first end of the transistor T1 and the control end of the transistor T2; the first end of the transistor T3 is coupled to the second end of the resistor R2; the second end of the transistor T3 is coupled to the first end of the resistor Rb. The transmission line Ln1 may be located between the transistor T3 and the resistor Rb. The resistor R3 includes a first end and a second end. The first end of the resistor R3 is coupled to the second end of the transistor T3, and the second end of the resistor R3 is coupled to the reference voltage end (providing the voltage VSS). The resistor R3 can be used for current limiting, thereby increasing the current stability of the bias circuit 10. In addition, the sum of the critical voltage of the transistor T1 and the critical voltage of the transistor T3 can be used to establish the voltage of the control end of the transistor T2. For example, if the threshold voltages of transistors T3 and T1 are both 0.65V, the voltage at the control end of transistor T2 is 1.3 (= 0.65 + 0.65) V, so that transistor T2 is turned on, thereby generating a bias signal Sb. When the amplifier circuit 12 is in operation, heat energy is generated, which causes the threshold voltage of the adjacent transistor T1 to decrease, and the voltage at the control end of transistor T2 to decrease, thereby reducing the bias signal Sb. For example, if the threshold voltage of transistor T1 decreases to 0.6V, the voltage at the control end of transistor T2 will decrease to 1.25 (= 0.6 + 0.65) V, so the bias signal Sb will also decrease accordingly, thereby reducing the output power of the amplifier 120 and reducing heat consumption, so as to improve the stability of the operating performance of the RF circuit 1.
[0013] In some embodiments, the transistor T3 may also be disposed near the amplifier circuit 12. When the temperature of the amplifier circuit 12 rises, the threshold voltage of the adjacent transistor T3 will also decrease, so as to further enhance the temperature sensing capability. For example, if the threshold voltage of the transistor T1 drops to 0.6V and the threshold voltage of the transistor T3 drops to 0.6V, the voltage of the control terminal of the transistor T2 will drop to 1.2 (= 0.6 + 0.6) V, so the bias signal Sb will be further reduced, reducing the output power of the amplifier 120 and reducing more heat consumption, so as to further enhance the stability of the operating performance of the RF circuit 1. In some embodiments, the transistor T3 may be disposed at a position that does not overlap with the transmission line Ln2, or at a position that is at an appropriate distance from the transmission line Ln2, so as to avoid interference signals affecting the voltage of the control terminal of the transistor T3, thereby increasing the accuracy of temperature sensing.
[0014] The transistor T2 may be disposed at a position away from the resistor Rb, for example, a position away from the resistor Rb relative to another element, or a position at an appropriate distance from the resistor Rb. Taking the distance between the transistor T1 and the resistor Rb as an example, the transistor T1 may have a first distance from the resistor Rb, and the transistor T2 may have a second distance from the resistor Rb, wherein the first distance is smaller than the second distance. The ratio of the second distance to the first distance is greater than 20. The first distance may be, for example, 3 μm to 5 μm, and the second distance may be, for example, 100 μm to 150 μm.
[0015] Figure 2 is a schematic diagram of the layout of the radio frequency circuit 1. The transistor T1 and the resistor Rb can be arranged near the amplifier circuit 12, and the transistor T2 can be arranged away from the amplifier circuit 12. The distance d between the transistor T1 and the resistor Rb and the amplifier circuit 12 can be, for example, 5 μm. The resistor Rb and the transmission line Ln2 can be arranged in the same layer or in different layers (i.e., the resistor Rb can overlap the transmission line Ln2).
[0016] A first distance d1 between the transistor T1 and the resistor Rb may be smaller than a second distance d2 between the transistor T2 and the resistor Rb. The first distance d1 between the transistor T1 and the resistor Rb may be smaller than a second distance d2 between the transistor T2 and the resistor Rb.
[0017] If an interference signal including the radio frequency signal RFin is coupled to the transmission line Ln1 and / or the resistor Rb, the resistor Rb will reduce the amplitude of the interference signal, thereby increasing the accuracy of temperature sensing and achieving temperature compensation of the amplifier circuit 12 .
[0018] Figure 3AThe relationship between the output current signal and the output power of the power amplifier circuit is shown in Figure 1, where the horizontal axis is the output power Pout (expressed in decibel relative to one milliwatt, dBm) and the vertical axis is the output current signal ICC (expressed in ampere, A). The output current signal ICC is a DC current signal and can be used as a reference. Figure 3B , Figure 3B This is a schematic diagram of the input and output signals of the power amplifier circuit. Figure 3A In the figure, curve 30 represents the output current signal ICC of the embodiment of the present invention, and curve 32 represents the output current signal of the related art embodiment in which the resistor Rb is not set near the amplifier circuit 12. Curve 30 shows that in the embodiment of the present invention, when the output power is 4-16dbm, the absolute value of the current change rate of the output current signal ICC is less than 2%. Curve 32 shows that in the related art embodiment, when the output power is 4-16dbm, the absolute value of the current change rate of the output current signal is about 3%, which exceeds the current change rate of the embodiment of the present invention. In addition, curve 30 shows that in the embodiment of the present invention, when the output power is 4-16dbm, the current change rate of the output current signal ICC is greater than 0%, indicating that the supply current is normal. Curve 32 shows that in the related art embodiment, when the output power is 4-16dbm, the current change rate of the output current signal may be less than 0%, indicating that the output current signal decreases and the supply current is insufficient, which is usually undesirable. Figure 3B In the embodiment, the amplifier 120 can output an amplified signal, and the amplified signal can include a direct current (DC) component and an amplified radio frequency signal RFout. The amplified radio frequency signal RFout can be an alternating current (AC) signal. The direct current component can be positively correlated with the output current signal ICC. The DC blocking capacitor Co can receive the amplified signal from the amplifier 120, block the direct current component from passing through, and allow the amplified radio frequency signal RFout to pass through, and the output current signal ICC can flow to the reference voltage terminal.
[0019] The transistors T1 to T3 may be, for example, N-type bipolar junction transistors (BJT), the control terminal may be the base terminal, the first terminal may be the collector terminal, and the second terminal may be the emitter terminal. In some embodiments, the transistors T1 to T3 may also be N-type metal-oxide-semiconductor field-effect transistors (MOSFET), the control terminal may be the gate terminal, the first terminal may be the drain terminal, and the second terminal may be the source terminal.
[0020] Figure 4 : is a circuit diagram of another RF circuit 4 in an embodiment of the present invention. The main difference between the RF circuit 4 and the RF circuit 1 is the connection of transistors T1 to T3. The following is a description of the connection of transistors T1 to T3. The connection and operation of other components are similar to those of the RF circuit 1 and will not be repeated here.
[0021] The transistor T1 includes a control terminal, a first terminal and a second terminal, wherein the control terminal of the transistor T1 is coupled to the first terminal of the resistor Rb; the first terminal of the transistor T1 is coupled to the second terminal of the resistor Rb; the second terminal of the transistor T1 is coupled to the second terminal of the capacitor C. The transistor T3 includes a control terminal, a first terminal and a second terminal, wherein the control terminal of the transistor T3 is coupled to the bias power supply 14; the first terminal of the transistor T3 is coupled to the control terminal of the transistor T3; the second terminal of the transistor T3 is coupled to the second terminal of the resistor Rb. The transistor T2 includes a control terminal, a first terminal and a second terminal, wherein the control terminal of the transistor T2 is coupled to the first terminal of the transistor T3 and the bias power supply 14; the first terminal of the transistor T2 is coupled to the bias power supply 16; the second terminal of the transistor T2 is coupled to the amplifier 120 for providing the bias signal Sb.
[0022] The transistor T1 and the resistor Rb may be disposed near the amplifier 120 , thereby reducing the amplitude of the interference signal, increasing the accuracy of temperature sensing, and achieving temperature compensation of the amplifier 120 .
[0023] Figure 5 is a circuit diagram of another RF circuit 5 in an embodiment of the present invention. The main difference between the RF circuit 5 and the RF circuit 1 is that the amplifier circuit 52 includes an amplifier 120 and an amplifier 122 coupled to each other. The connection and operation of other components in the RF circuit 5 are similar to those of the RF circuit 1, and will not be described in detail here. The following is an explanation of the amplifier 120 and the amplifier 122.
[0024] The bias circuit 10 can be coupled to the amplifier 120 and provide the bias signal Sb to the amplifier 120. The amplifier 122 can be a preamplifier of the amplifier 120. The amplifier 122 can form an interference source, and the interference signal comes from the interference source. In other embodiments, the amplifier 122 can also be Figure 6 Amplifier circuits other than 12, for example, Figure 6 The interference source 70 of the embodiment may be an external amplifier 122. In addition, whether the amplifier 122 is a preamplifier of the amplifier 120 or the amplifier 122 is an amplifier other than the amplifier circuit 12, the transmission line Ln1 is located between the resistor Rb and the amplifier 122, the amplifier 122 is coupled to the transmission line Ln2, and the transmission line Ln2 is not directly coupled to the transmission line Ln1.
[0025] The transistor T1 and the resistor Rb may be disposed near the amplifier 122 , thereby reducing the amplitude of the interference signal, increasing the accuracy of temperature sensing, and achieving temperature compensation of the amplifier 120 .
[0026] Figure 6 is a circuit diagram of another RF circuit 6 in an embodiment of the present invention. The main difference between the RF circuit 6 and the RF circuit 1 is that the transistor T1 and the resistor Rb are arranged near the other interference source 70. The connection and operation of other components in the RF circuit 6 are similar to those of the RF circuit 1 and will not be described in detail here. The following is an explanation of the interference source 70.
[0027] The interference source 70 may be other amplifiers other than other amplifier circuits, or other signal sources that generate or transmit high-frequency signals. In some embodiments, the radio frequency circuit 6 may also include an interference source 70, which may be other amplifiers other than the amplifier circuit 12, or radio frequency components such as oscillators. The other amplifiers described herein are not coupled to the bias circuit 10, and the interference signal comes from other amplifiers. The transistor T1 and the resistor Rb may be disposed near the interference source 70 and / or the amplifier circuit 12, thereby reducing the amplitude of the interference signal, increasing the accuracy of temperature sensing, and achieving temperature compensation of the amplifier 120.
[0028] The above descriptions are only preferred embodiments of the present invention. All equivalent changes and modifications made within the scope of the claims of the present invention should fall within the scope of the present invention.
Claims
1. A radio frequency circuit, characterized in that: include: an amplifier circuit for receiving a bias signal and amplifying a radio frequency signal; as well as A bias circuit is coupled to the amplifier circuit and is used to provide the bias signal. The bias circuit includes: a first transistor disposed near the amplifier circuit, and A first resistor is arranged near the amplifier circuit, a first end of the first resistor is coupled to a first transmission line, an interference signal is coupled to the first transmission line, a second end of the first resistor is coupled to a control end of the first transistor, wherein the first resistor is located between the first transistor and the first transmission line.
2. The radio frequency circuit according to claim 1, characterized in that: A first terminal of the first transistor is coupled to a first bias power source, and a second terminal of the first transistor is coupled to a reference voltage terminal.
3. The radio frequency circuit according to claim 2, characterized in that: A current at the first end of the first transistor changes with temperature.
4. The radio frequency circuit according to claim 2, characterized in that: A second transistor is also included. A second end of the second transistor is coupled to the amplifier circuit, and the second transistor is used to provide the bias signal to the amplifier circuit.
5. The radio frequency circuit according to claim 4, characterized in that: Also included is a third transistor, comprising: a control terminal coupled to the first terminal of the first transistor and a control terminal of the second transistor; a first terminal; and A second end is coupled to the first end of the first resistor.
6. The radio frequency circuit according to claim 4, characterized in that: Also included is a third transistor, comprising: a control terminal coupled to the first bias power source and a control terminal of the second transistor; a first terminal coupled to the control terminal of the third transistor; and A second end is coupled to the second end of the first resistor.
7. The radio frequency circuit according to claim 5 or 6, characterized in that: The third transistor is arranged near the amplifier circuit.
8. The radio frequency circuit according to claim 7, characterized in that: A first terminal of the second transistor is coupled to a second bias power source.
9. The radio frequency circuit according to claim 7, characterized in that: A control terminal of the second transistor is coupled between the first terminal of the first transistor and the first bias power source.
10. The radio frequency circuit according to claim 7, characterized in that: There is a first distance between the first transistor and the first resistor, there is a second distance between the second transistor and the first resistor, and the first distance is smaller than the second distance.
11. The radio frequency circuit according to claim 10, characterized in that: A ratio of the second distance to the first distance is greater than 20.
12. The radio frequency circuit according to claim 1, characterized in that: The resistance value of the first resistor is greater than or equal to 300 ohms (Ω).
13. The radio frequency circuit according to claim 1, characterized in that: The first resistor is used to reduce the amplitude of the interference signal at the second end of the first resistor.
14. The radio frequency circuit according to claim 1, characterized in that: The interference signal includes the radio frequency signal or an amplified radio frequency signal.
15. The radio frequency circuit according to claim 1, characterized in that: The amplifier circuit includes a first amplifier. The bias circuit is coupled to the first amplifier and provides the bias signal to the first amplifier. The first amplifier forms an interference source, and the interference signal comes from the interference source.
16. The radio frequency circuit according to claim 1, characterized in that: The amplifier circuit includes a first amplifier and a second amplifier coupled to each other, the bias circuit is coupled to the first amplifier and provides the bias signal to the first amplifier, the second amplifier is a preamplifier of the first amplifier, the second amplifier forms an interference source, and the interference signal comes from the interference source.
17. The radio frequency circuit according to claim 1, characterized in that: The device also includes a second amplifier which is not coupled to the bias circuit. The second amplifier forms an interference source, and the interference signal comes from the interference source.
18. The radio frequency circuit according to any one of claims 15 to 17, characterized in that: The first transmission line is located between the first resistor and the interference source, the interference source is coupled to a second transmission line, and the second transmission line is not directly coupled to the first transmission line.
19. The radio frequency circuit according to claim 1, characterized in that: When the power of the bias signal is 4-16 dBm, an absolute value of a current change rate of the bias signal is less than 2%.
20. The radio frequency circuit according to claim 1, characterized in that: When a power of the bias signal is 4-16 dBm, a current change rate of the bias signal is greater than 0%.