Autotransformer, output stage circuit and broadband radio frequency power amplifier
By adopting the autotransformer design in a broadband RF power amplifier, a low-pass filtering network is formed by using a wide primary coil and a narrow secondary coil, the problems of large size and high cost caused by the large number of inductors in the prior art are solved, and the effects of miniaturization, low cost and high-efficiency harmonic suppression are achieved.
Patent Information
- Application Number
- CN202421554927.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-07-02
- Publication Date
- 2025-05-02
- Estimated Expiration
- 2034-07-02
AI Technical Summary
When existing broadband RF power amplifiers suppress higher-order harmonics and expand operating bandwidth, they need to use multiple inductors, resulting in large size and high cost problems.
Using an autotransformer, the primary coil is composed of a wider primary coil and a narrower secondary coil. The primary coil is arranged in a spiral shape, and the secondary coil is arranged in a spiral shape along one side of the primary coil to form an efficient low-pass filtering network, reducing the number of inductors.
It realizes full integration within a smaller size, with small product size, low cost and good consistency, and effectively suppresses higher-order harmonics.
Smart Images
Figure CN222826194U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to a transformer and a power amplifier, in particular to an autotransformer, an output stage circuit and a broadband radio frequency power amplifier. Background Art
[0002] Harmonics are frequency-multiplied components generated by the nonlinearity of transistor devices. Since the frequency of harmonics is relatively dispersed, passive filters are generally used to attenuate harmonic components to achieve the effect of suppressing harmonics. RF power amplifier circuits often use low-pass filter circuits at the output end to filter out high-order harmonics. In order to enhance the suppression of high-order harmonics and expand the working bandwidth, low-pass filter networks often use second-order, third-order or even higher-order networks, using more than two inductors and capacitors to achieve. If the output stage of a broadband RF power amplifier uses a choke inductor and a multi-stage cascade structured low-pass filter circuit to achieve suppression of high-order harmonics, more than three inductors must be used to achieve this. In RF integrated circuit design, the larger the inductor size, the more inductors are used, the larger the size occupied and the higher the cost. Utility Model Content
[0003] In view of the deficiencies in the prior art, the utility model discloses an autotransformer, an output stage circuit and a broadband radio frequency power amplifier.
[0004] The technical solution adopted by the utility model is as follows:
[0005] An autotransformer, comprising:
[0006] a primary coil having a first width;
[0007] The secondary coil has a second width, wherein the first width is greater than the second width;
[0008] The primary coil is arranged in a spiral shape, and the secondary coil is arranged in a spiral shape along one side of an edge of the primary coil according to the arrangement direction of the primary coil.
[0009] Its further technical solution is:
[0010] The primary coil includes a first segment, a second segment, ..., and an nth segment which are linear and gradually increase in length; n is a natural number;
[0011] The first end of the first segment is a first line connection end; the first end of the second segment is connected to the second end of the first segment, and the second segment is perpendicular to the first segment; ... one end of the n-1 segment is connected to the second end of the n segment, and the n segment is perpendicular to the n-1 segment; the second end of the n segment is a second line connection end;
[0012] The secondary coil is arranged along one side of the primary coil and is parallel to the edge of the primary coil; the first end of the secondary coil is the third line connection end connected to the first line connection end, and the second end of the secondary coil is the fourth line connection end.
[0013] A further technical solution is that the primary coil is arranged in a spiral shape, including at least two adjacent sections, and a middle gap is formed between the two adjacent ends; the secondary coil starts from the inner side of the primary coil, passes through the middle gap, and surrounds the outer side of the primary coil.
[0014] A further technical solution is that the outer frame of the autotransformer forms a rectangle.
[0015] A further technical solution is that the first line connection end of the primary coil and the third line connection end of the secondary coil extend from the first edge of the autotransformer; the second line connection end of the primary coil extends from the second edge of the autotransformer; and the fourth line connection end of the secondary coil extends from the third edge of the autotransformer.
[0016] A further technical solution is that the first width is 2-10 um, and the second width is 4-20 um.
[0017] A further technical solution is that the first width is wider than the second width by 0 to 18 um.
[0018] An output stage circuit comprises an autotransformer as described in any one of the above items; the output stage circuit also comprises a low-pass filter network; the same-name end of the primary coil and the same-name end of the secondary coil of the autotransformer are both connected to a power supply voltage; the opposite-name end of the primary coil is used for inputting a signal; the opposite-name end of the secondary coil is connected to the input end of the low-pass filter network; and the output end of the low-pass filter network is used for outputting a signal.
[0019] A broadband radio frequency power amplifier, comprising:
[0020] An autotransformer as described in any of the preceding clauses;
[0021] an amplifier circuit, the input end of which is used to receive an input signal and amplify the input signal, and the output end of which is connected to the primary coil of the autotransformer;
[0022] A low-pass filter has an input end connected to the secondary coil of the autotransformer and an output end serving as the output end of the amplifier.
[0023] A further technical solution is that the amplifier circuit comprises a first-stage amplifier circuit, a second-stage amplifier circuit and a third-stage amplifier circuit connected in sequence;
[0024] The first-stage amplifier circuit includes a first-stage amplifier tube Q1, a first feedback loop and a first-stage bias circuit; two ends of the first feedback loop are respectively connected to the collector and base of the first-stage amplifier tube Q1; the power supply voltage VCC is connected to the collector of the first-stage amplifier tube Q1 through the inductor L4; the reference voltage VREG is connected to the base of the first-stage amplifier tube Q1 through the first-stage bias circuit;
[0025] The second-stage amplifier circuit includes a second-stage amplifier tube Q2, a driver-stage bias circuit and a second feedback loop; two ends of the second feedback loop are respectively connected to the collector and base of the second-stage amplifier tube Q2; the power supply voltage VCC is connected to the base of the second-stage amplifier tube Q2 through the inductor L7; the reference voltage VREG is connected to the base of the second-stage amplifier tube Q2 through the driver-stage bias circuit;
[0026] The third-stage amplifier circuit includes an output-stage bias circuit and a third-stage amplifier tube Q3; the reference voltage VREG is connected to the base of the third-stage amplifier tube Q3 through the output-stage bias circuit; the collector of the third-stage amplifier tube Q3 is connected to the primary coil of the autotransformer.
[0027] The beneficial effects of the utility model are as follows:
[0028] The utility model discloses an autotransformer, and also discloses an output stage circuit and a broadband radio frequency power amplifier based on the autotransformer. The autotransformer is composed of a primary coil with a wider metal wire width and a secondary coil with a narrower wire width. The primary coil with a wider metal wire width ensures that a larger working current can flow through it and output a larger power; the secondary coil with a narrower wire width surrounds the primary coil, occupies a smaller chip area, and can be used as an inductor of an output stage low-pass filter network. The output stage circuit based on the autotransformer can be fully integrated in a smaller size, and the broadband radio frequency power amplifier based on the autotransformer realizes the full integration of components such as amplification, matching, and filtering, and the product has a small size, low cost, and good consistency. BRIEF DESCRIPTION OF THE DRAWINGS
[0029] Figure 1 It is a structural schematic diagram of an autotransformer according to an embodiment of the utility model.
[0030] Figure 2 The schematic diagram of the autotransformer according to the embodiment of the utility model is shown in FIG.
[0031] Figure 3 4 is a circuit diagram of an output stage circuit in an embodiment of the utility model.
[0032] Figure 4 Schematic diagram of the structure of the output stage circuit in the embodiment of the utility model.
[0033] Figure 5It is a circuit diagram of a broadband radio frequency power amplifier in an embodiment of the utility model. DETAILED DESCRIPTION
[0034] The RF power amplifier is located at the end of the transmission link. It is used to amplify the RF power to a large enough power to drive the antenna to radiate the wireless signal far enough so that the receiving device can correctly demodulate the signal and achieve undistorted transmission of the wireless signal. It is a core component in the wireless communication system.
[0035] In the front-stage circuit of the transmitter, the RF signal power generated by the modulated oscillation circuit is very small, and it needs to go through a series of amplifications such as pre-stage amplification, intermediate drive amplification, and final power amplification before it can obtain a sufficiently large RF power. The output signal of an ideal amplifier should reflect the input signal truthfully, that is, the waveform should be the same, but because the transistor amplifier itself is not an ideal linear device and is affected by parasitic parameters, the output signal of the RF power amplifier is no longer exactly the same as the input signal waveform. When the input signal increases to a certain level, the RF power amplifier will enter the nonlinear region of the transistor, resulting in a decrease in the amplifier gain, generating a series of harmonics, third-order intermodulation and sideband components, and nonlinearity will also cause the signal constellation diagram and EVM to deteriorate.
[0036] Harmonics are frequency-multiplied components generated by the nonlinearity of transistor devices. Harmonic control is an effective design method to improve the efficiency and linearity of RF power amplifiers, and is also an effective way to enable products to pass CE, FCC and other certifications. Since the frequency of harmonics is relatively dispersed, passive filters are generally used to attenuate harmonic components to achieve the effect of suppressing harmonics.
[0037] Based on the above content, the specific implementation of the present utility model is described below in conjunction with the accompanying drawings.
[0038] Example 1.
[0039] Embodiment 1 discloses a structure of an autotransformer. Figure 1 Schematic diagram of the structure of the autotransformer of the utility model embodiment. Figure 1 As shown, the autotransformer includes a primary coil Lp and a secondary coil Ls. The primary coil Lp has a first width d1. The secondary coil Ls has a second width d2. The first width d1 is greater than the second width d2. A large working current flows through the primary coil 1, and its metal line width is relatively wide. Only an AC signal flows through the secondary coil 2, and only a narrow metal line width is required to meet the requirements.
[0040] Preferably, the first width d1 is 4-20 um, and the second width d2 is 2-10 um. Preferably, the first width d1 is 0-18 um larger than the second width d2. Within the preferred width range, the signal can be transmitted smoothly without overheating, and the volume of the autotransformer can be kept as small as possible.
[0041] The primary coil 1 is arranged in a spiral shape, and the secondary coil 2 is also arranged in a spiral shape at one side edge of the primary coil along the winding direction of the primary coil 1. The primary coil 1 is arranged in a spiral shape, and the narrow secondary coil 2 is arranged around the primary coil, which reduces the area occupied by the autotransformer.
[0042] In this embodiment, the primary coil 1 includes a first section, a second section, ..., and a sixth section, which are straight and gradually increase in length, that is, the primary coil 1 is spirally wound one and a half turns. The first end of the first section is a first line connection end, which is used to connect the power supply voltage VCC in the circuit. The second section is perpendicular to the first section, and the first end of the second section is connected to the second end of the first section. Similarly, the first end of the sixth section is connected to the second end of the fifth section and is perpendicular to the fifth section. The second end of the sixth end is a third line connection end, which is used to connect to an external circuit. The secondary coil 2 is arranged on one side of the primary coil 1 and is parallel to the edge of the primary coil 1. The first end of the secondary coil 2 is a third line connection end, which is connected to the first line connection end and is also used to connect the power supply voltage VCC. The second end of the secondary coil 2 is a fourth line connection end, both of which are used to connect to an external circuit. That is, in this embodiment, the primary coil 1 and the secondary coil 2 are at right angles at the turning point of the line, so that the autotransformer is surrounded as a rectangle. Compared with a circularly wound coil, the autotransformer is easier to be arranged with other circuit structures, further reducing the area of the overall circuit. Those skilled in the art will appreciate that the primary coil 1 and the secondary coil 2 may also be wound with different numbers of turns according to actual needs of the circuit, and the number of turns in this embodiment is not limiting.
[0043] Furthermore, when the primary coil 1 is arranged in a spiral shape, there will be two adjacent parts, and an intermediate gap will be formed between the two adjacent parts. The secondary coil 2 starts from the inner side of the primary coil 1, is parallel to the edge of the primary coil 1, passes through the intermediate gap, and finally surrounds the outside of the autotransformer. The outer edge of the autotransformer is a rectangle.
[0044] Furthermore, the first line connection end of the primary coil 1 and the third line connection end of the secondary coil 2 extend from the first edge of the autotransformer and are connected to the power supply voltage VCC. The second line connection end of the primary coil 1 extends from the second edge of the autotransformer, and the fourth line connection end of the secondary coil 2 extends from the third edge of the autotransformer, and are respectively connected to other structures of the circuit, wherein the first edge, the second edge, and the third edge are different edges of the rectangular autotransformer. This arrangement ensures that the various connection terminals of the autotransformer do not interfere with each other, and can better cooperate with other circuit structures in the circuit structure diagram, making it convenient to arrange the layout of other circuit structures, so that the area of the entire circuit is smaller.
[0045] Figure 2 The schematic diagram of the autotransformer of the utility model embodiment is shown in FIG. Figure 1 and Figure 2 The same-name ends of the thicker primary coil and the thinner secondary coil are connected to the power supply voltage terminal. The opposite-name end of the primary coil is connected to the signal input circuit, and the opposite-name end of the secondary coil is connected to the signal output circuit.
[0046] Example 2.
[0047] Based on the autotransformer structure of embodiment 1, embodiment 2 discloses an output stage circuit.
[0048] Figure 3 FIG. 1 is a circuit diagram of an output stage circuit in an embodiment of the utility model. Figure 3 As shown, the output stage circuit includes an autotransformer and a low-pass filter network.
[0049] The primary coil of the autotransformer is connected to the output end of the amplifier circuit. In this embodiment, the amplifier circuit is shown as an amplifier tube Q3. The opposite end of the primary coil is connected to the collector of the amplifier tube Q3. The secondary coil of the autotransformer is connected to the input end of the low-pass filter network.
[0050] like Figure 3 As shown, in the present embodiment, the low-pass filter network is a second-order low-pass filter network, including capacitor C9, capacitor C10, capacitor C11 and inductor L9. The two ends of capacitor C9 are respectively connected to the opposite-name terminal of the secondary coil and the ground terminal. The first end of inductor L9 is connected to the common end of the secondary coil and capacitor C9. The two ends of capacitor C10 are respectively connected to the second end of inductor L9 and the ground terminal. The first end of capacitor C11 is connected to the common end of inductor L9 and capacitor C10, and capacitor C11 is connected to output resistor RL. The low-pass filter network is used to filter out high-order harmonics, and at the same time realizes the impedance transformation from load RL to the optimal output impedance of output stage power tube.
[0051] Figure 4 Schematic diagram of the structure of the output stage circuit in the embodiment of the utility model. Figure 4It can be seen that after the autotransformer structure of Example 1 is applied to the output stage circuit, the area of the output stage circuit structure can be further reduced as a whole, and full integration is achieved in a smaller size.
[0052] Example 3.
[0053] Based on the autotransformer structure of Example 1 and the output stage circuit of Example 2, Example 3 discloses a broadband radio frequency power amplifier.
[0054] Figure 5 FIG. 1 is a circuit diagram of a broadband radio frequency power amplifier in an embodiment of the present utility model. Figure 5 As shown, the broadband RF power amplifier includes an input matching network, an amplifying circuit and an output stage circuit.
[0055] In this embodiment, the input matching network is a second-order high-pass structure, and the input signal RFIN is input to the amplifier circuit through the input matching network composed of the inductor L1, the capacitor C1, the inductor L2 and the capacitor C2.
[0056] The amplifier circuit includes a first-stage amplifier circuit, a second-stage amplifier circuit, and a third-stage amplifier circuit which are connected in sequence.
[0057] The first-stage amplifier circuit includes a first-stage amplifier tube Q1, a first feedback loop and a first-stage bias circuit. The first feedback loop is formed by connecting a capacitor C3, an inductor L3 and a resistor R1 in series in sequence. The two ends of the first feedback loop are respectively connected to the collector and the base of the first-stage amplifier tube Q1 to form a negative feedback, thereby improving the gain flatness of the first-stage amplifier circuit and expanding the bandwidth. A first inter-stage matching network is connected between the first-stage amplifier circuit and the second-stage amplifier circuit. The first inter-stage matching network includes an inductor L4, a capacitor C4, a capacitor C5 and an inductor L5. The power supply voltage VCC supplies power to the collector of the first-stage amplifier tube Q1 through the inductor L4, and the reference voltage VREG is connected to the base of the first-stage amplifier tube Q1 through the first-stage bias circuit, and provides a base bias current for the first-stage amplifier tube Q1.
[0058] The second-stage amplifier circuit includes a second-stage amplifier tube Q2, a driver-stage bias circuit and a second feedback loop. The second feedback loop is formed by a capacitor C6, an inductor L6 and a resistor R2 connected in series. The two ends of the second feedback loop are respectively connected to the collector and the base of the second-stage amplifier tube Q2. A second inter-stage matching network is connected between the second-stage amplifier circuit and the third-stage amplifier circuit. The second inter-stage matching network includes an inductor L7, a capacitor C7, an inductor L8 and a capacitor C8. The power supply VCC supplies power to the second-stage amplifier tube Q2 through the inductor L7, and the reference voltage VREG is connected to the base of the second-stage amplifier tube Q2 through the first-stage bias circuit, and provides a base bias current for the second-stage amplifier tube Q2.
[0059] The third-stage amplifier circuit includes an output-stage bias circuit and a third-stage amplifier tube Q3. The reference voltage VREG is connected to the base of the third-stage amplifier tube Q3 through the output-stage bias circuit and provides a base bias current for the second-stage amplifier tube Q2. The collector of the third-stage amplifier tube Q3 is connected to the opposite-name end of the primary coil of the autotransformer.
[0060] The broadband RF power amplifier in this embodiment realizes full integration of components such as amplification, matching, and filtering, and has a small product size, low cost, and good consistency.
[0061] The above description is an explanation of the utility model, not a limitation of the utility model. The scope of the utility model is defined by the claims. The utility model can be modified in any form without violating the basic structure of the utility model.
Claims
1. An autotransformer, characterized in that: include: a primary coil having a first width; The secondary coil has a second width, wherein the first width is greater than the second width; The primary coil is arranged in a spiral shape, and the secondary coil is arranged in a spiral shape along one side of an edge of the primary coil according to the arrangement direction of the primary coil.
2. The autotransformer according to claim 1, characterized in that: The primary coil includes a first segment, a second segment, ..., and an nth segment which are linear and gradually increase in length; n is a natural number; The first end of the first segment is a first line connection end; the first end of the second segment is connected to the second end of the first segment, and the second segment is perpendicular to the first segment; ... one end of the n-1 segment is connected to the second end of the n segment, and the n segment is perpendicular to the n-1 segment; the second end of the n segment is a second line connection end; The secondary coil is arranged along one side of the primary coil and is parallel to the edge of the primary coil; the first end of the secondary coil is the third line connection end connected to the first line connection end, and the second end of the secondary coil is the fourth line connection end.
3. The autotransformer according to claim 2, characterized in that: The primary coil is arranged in a spiral shape, including at least two adjacent sections, and a middle gap is formed between the two adjacent ends; the secondary coil starts from the inner side of the primary coil, passes through the middle gap, and surrounds the outer side of the primary coil.
4. The autotransformer according to claim 2, characterized in that: The outer frame of the autotransformer forms a rectangle.
5. The autotransformer according to claim 2, characterized in that: The first line connection end of the primary coil and the third line connection end of the secondary coil extend from the first edge of the autotransformer; the second line connection end of the primary coil extends from the second edge of the autotransformer; and the fourth line connection end of the secondary coil extends from the third edge of the autotransformer.
6. The autotransformer according to claim 1, characterized in that: The first width is 4 to 20 um, and the second width is 2 to 10 um.
7. The autotransformer according to claim 1, characterized in that: The first width is wider than the second width by 0 to 18 um.
8. An output stage circuit, characterized in that: It comprises the autotransformer as described in any one of claims 1 to 7; the output stage circuit also comprises a low-pass filter network; the same-name ends of the primary coil and the same-name ends of the secondary coil of the autotransformer are both connected to the power supply voltage; the opposite-name ends of the primary coil are used for input signals; the opposite-name ends of the secondary coil are connected to the input end of the low-pass filter network; and the output end of the low-pass filter network is used for output signals.
9. A broadband radio frequency power amplifier, characterized in that: include: An autotransformer as claimed in any one of claims 1 to 7; an amplifier circuit, the input end of which is used to receive an input signal and amplify the input signal, and the output end of which is connected to the primary coil of the autotransformer; A low-pass filter has an input end connected to the secondary coil of the autotransformer and an output end serving as the output end of the amplifier.
10. The broadband radio frequency power amplifier according to claim 9, characterized in that: The amplifier circuit comprises a first-stage amplifier circuit, a second-stage amplifier circuit and a third-stage amplifier circuit connected in sequence; The first-stage amplifier circuit includes a first-stage amplifier tube Q1, a first feedback loop and a first-stage bias circuit; two ends of the first feedback loop are respectively connected to the collector and base of the first-stage amplifier tube Q1; the power supply voltage VCC is connected to the collector of the first-stage amplifier tube Q1 through the inductor L4; the reference voltage VREG is connected to the base of the first-stage amplifier tube Q1 through the first-stage bias circuit; The second-stage amplifier circuit includes a second-stage amplifier tube Q2, a driver-stage bias circuit and a second feedback loop; two ends of the second feedback loop are respectively connected to the collector and base of the second-stage amplifier tube Q2; the power supply voltage VCC is connected to the base of the second-stage amplifier tube Q2 through the inductor L7; the reference voltage VREG is connected to the base of the second-stage amplifier tube Q2 through the driver-stage bias circuit; The third-stage amplifier circuit includes an output-stage bias circuit and a third-stage amplifier tube Q3; the reference voltage VREG is connected to the base of the third-stage amplifier tube Q3 through the output-stage bias circuit; the collector of the third-stage amplifier tube Q3 is connected to the primary coil of the autotransformer.