A load impedance matching circuit for a radio frequency power supply

Abstract

The utility model provides a kind of load impedance matching circuit for radio frequency power supply.It includes power supply main circuit, matching circuit module and RF handle which are sequentially arranged, the matching circuit module includes first capacitor, second capacitor, third capacitor, fourth capacitor, fifth capacitor and first inductor, the first capacitor, second capacitor and third capacitor are connected in series to form first equivalent capacitor, the fourth capacitor and fifth capacitor are connected in series to form second equivalent capacitor, the first equivalent capacitor and the second equivalent capacitor are connected in parallel, one end of the first inductor is connected with one end of the first capacitor, and the other end is connected with one end of the fourth capacitor.The utility model realizes the function of load impedance matching while reducing the volume of 27MHz radio frequency power supply, improving output energy and reducing production cost, making the power supply function more powerful, smaller in size and lower in cost.

Description

Technical Field

[0001] This utility model relates to the field of radio frequency power supply technology, and in particular to a load impedance matching circuit for radio frequency power supplies. Background Technology

[0002] The load impedance matching circuit of an RF power supply is a key component to ensure its efficient operation. The main function of the impedance matching circuit is to perform impedance transformation, aiming to transform the source impedance to the design-required impedance point to achieve maximum power transfer and minimum reflection loss.

[0003] Existing 27MHz RF power supply load impedance matching circuits use open-type metal sheet variable capacitors composed of 9 stationary plates and 10 moving plates. For example, patent application CN104184435A discloses an antenna device and communication device, in which the matching circuit 11 mainly consists of inductors L11 and L12 and capacitors C11 and C12. Matching circuits composed of variable capacitors are not only large in size, complex to assemble, and costly, but also exhibit antenna effects, radiating energy outwards and causing the output RF energy to attenuate by at least 30%.

[0004] Therefore, it is essential to develop a small, low-energy-attenuation, and low-cost load impedance matching circuit for 27MHz RF power supplies. Utility Model Content

[0005] To address the problems existing in the prior art, this utility model proposes a load impedance matching circuit for radio frequency power supplies, aiming to solve the problems of large size, high production cost, and large attenuation of output radio frequency energy in traditional 27MHz radio frequency power supply load impedance matching circuits.

[0006] To achieve the above objectives, the technical solution adopted by this utility model is: a load impedance matching circuit for an RF power supply, comprising a power supply main circuit, a matching circuit module, and an RF handle arranged sequentially. The matching circuit module includes a first capacitor C1, a second capacitor C2, a third capacitor C3, a fourth capacitor C4, a fifth capacitor C5, and a first inductor L1. The first capacitor C1, the second capacitor C2, and the third capacitor C3 are connected in series to form a first equivalent capacitor Cx. The fourth capacitor C4 and the fifth capacitor C5 are connected in series to form a second equivalent capacitor Cy. The first equivalent capacitor Cx and the second equivalent capacitor Cy are connected in parallel. One end of the first inductor L1 is connected to one end of the first capacitor C1, and the other end is connected to one end of the fourth capacitor C4. The common connection terminal of the first inductor L1 and the first capacitor C1 is provided with an RF input pin, and the common connection terminal of the first inductor L1 and the fourth capacitor is provided with an RF output pin.

[0007] Furthermore, the first capacitor C1, the second capacitor C2, the third capacitor C3, the fourth capacitor C4, and the fifth capacitor C5 are all mica capacitors.

[0008] Furthermore, the capacitance of the first capacitor C1, the second capacitor C2, and the third capacitor C3 is 300pF, and the capacitance of the fourth capacitor C4 and the fifth capacitor C5 is 100pF.

[0009] Furthermore, the hollow coil of the first inductor L1 has an inner diameter of 20mm and 2.5 turns.

[0010] In summary, the beneficial effects achieved by this utility model are as follows: This utility model connects the first capacitor C1, the second capacitor C2, and the third capacitor C3 in series to form a first equivalent capacitor Cx with a capacitance of 100pF, replacing the variable capacitor with an adjustable range of 95-100pF in the previous matching circuit; and connects the fourth capacitor C4 and the fifth capacitor C5 in series to form a second equivalent capacitor Cy with a capacitance of 50pF, replacing the variable capacitor with an adjustable range of 48-52pF in the previous matching circuit. Furthermore, the first capacitor C1, the second capacitor C2, the third capacitor C3, the fourth capacitor C4, and the fifth capacitor C5 are all mica capacitors. Compared with traditional solutions, this utility model reduces the volume by approximately 95% and the cost by approximately 80%, significantly reducing assembly difficulty. Moreover, due to the absence of an open metal sheet antenna effect and no external radiated energy, the RF energy output by the power supply has virtually no attenuation. While reducing the size of the 27MHz RF power supply, increasing output energy, and reducing production costs, it also achieves load impedance matching, making the power supply more powerful, smaller, and cheaper, greatly improving its practicality.

[0011] To more clearly illustrate the above-mentioned features of this utility model and the objectives it aims to achieve, the present utility model will be further described below in conjunction with the accompanying drawings and specific embodiments. Attached Figure Description

[0012] Figure 1 This is the circuit schematic diagram of this utility model.

[0013] The meanings of the reference numerals in the attached figures are as follows:

[0014] 1-Power supply main circuit; 2-Matching circuit module; 3-RF handle. Detailed Implementation

[0015] like Figure 1As shown, this utility model is a load impedance matching circuit for an RF power supply, mainly used in 27MHz high-frequency circuits. It includes a power supply main circuit 1, a matching circuit module 2, and an RF handle 3 arranged sequentially. The power supply main circuit 1 converts 220V AC power into 27MHz RF AC power for output. The matching circuit module 2 includes a first capacitor C1, a second capacitor C2, a third capacitor C3, a fourth capacitor C4, a fifth capacitor C5, and a first inductor L1. The first capacitor C1, the second capacitor C2, and the third capacitor C3 are connected in series to form a first equivalent capacitor Cx. The fourth capacitor C4 and the fifth capacitor C5 are connected in series to form a second equivalent capacitor Cy. The first equivalent capacitor Cx and the second equivalent capacitor Cy are connected in parallel. One end of the first inductor L1 is connected to one end of the first capacitor C1, and the other end is connected to one end of the fourth capacitor C4. The common connection terminal of the first inductor L1 and the first capacitor C1 is provided with an RF input pin, and the common connection terminal of the first inductor L1 and the fourth capacitor is provided with an RF output pin. When the RF handle 3 comes into contact with human skin, it forms a circuit, allowing 27MHz RF AC power to be conducted to the human body.

[0016] Preferably, the first capacitor C1, the second capacitor C2, the third capacitor C3, the fourth capacitor C4, and the fifth capacitor C5 are all mica capacitors. Compared with other capacitors such as ceramic chip capacitors, CBB film capacitors, and high-voltage ceramic capacitors, the mica capacitors have the characteristics of low dielectric loss, high insulation resistance, and low temperature coefficient, which can ensure the signal transmission quality and stability, and are suitable for high-frequency circuits such as 27MHz. Ceramic chip capacitors cause severe output energy attenuation, while other capacitors such as CBB film capacitors and high-voltage ceramic capacitors have high dielectric loss and generate more heat, requiring cooling fans for heat dissipation, resulting in reduced product output power, increased cost, and increased size.

[0017] Preferably, the capacitances of the first capacitor C1, the second capacitor C2, and the third capacitor C3 are all 300pF, and the capacitances of the fourth capacitor C4 and the fifth capacitor C5 are all 100pF. Furthermore, the rated voltages of the first capacitor C1, the second capacitor C2, the third capacitor C3, the fourth capacitor C4, and the fifth capacitor C5 are all 500V. By connecting the first capacitor C1, the second capacitor C2, and the third capacitor C3 in series, a first equivalent capacitor Cx with a capacitance of 100pF is formed, replacing the variable capacitor with an adjustable range of 95-100pF in the conventional matching circuit; and by connecting the fourth capacitor C4 and the fifth capacitor C5 in series, a second equivalent capacitor Cy with a capacitance of 50pF is formed, replacing the variable capacitor with an adjustable range of 48-52pF in the conventional matching circuit.

[0018] Preferably, the hollow coil of the first inductor L1 has an inner diameter of 20mm and 2.5 turns.

[0019] In summary, compared with traditional solutions, this invention reduces the volume by approximately 95% and the cost by approximately 80%, significantly reducing assembly difficulty. Moreover, since there is no open metal sheet antenna effect and no external radiated energy, the RF energy output by the power supply is essentially unaffected. While reducing the size of the 27MHz RF power supply, increasing output energy, and reducing production costs, it also achieves load impedance matching, making the power supply more powerful, smaller, and cheaper, greatly improving its practicality.

[0020] The specific implementation of this embodiment is as follows: The main power supply circuit 1 generates a 27MHz RF AC output with an asymmetrical alternating waveform. After filtering by the matching circuit module 2, the waveform at the RF output pin is transformed into a more perfect sine wave, symmetrical left and right, and harmonized up and down, resulting in a more stable energy output without attenuation, achieving a more ideal user experience. Finally, the 27MHz RF AC power is conducted to the human body through the circuit created by the contact between the RF handle and the human skin.

[0021] The above description is only the optimal solution embodiment of this utility model and is not intended to limit this utility model. Various modifications or substitutions made by those skilled in the art to this utility model without departing from the essence and protection scope of this utility model should also be within the protection scope of this utility model.

Claims

1. A load impedance matching circuit for an RF power supply, characterized in that: The device includes a power supply main circuit (1), a matching circuit module (2), and an RF handle (3) arranged sequentially. The matching circuit module (2) includes a first capacitor C1, a second capacitor C2, a third capacitor C3, a fourth capacitor C4, a fifth capacitor C5, and a first inductor L1. The first capacitor C1, the second capacitor C2, and the third capacitor C3 are connected in series to form a first equivalent capacitor Cx. The fourth capacitor C4 and the fifth capacitor C5 are connected in series to form a second equivalent capacitor Cy. The first equivalent capacitor Cx and the second equivalent capacitor Cy are connected in parallel. One end of the first inductor L1 is connected to one end of the first capacitor C1, and the other end of the first inductor L1 is connected to one end of the fourth capacitor C4. The common connection terminal of the first inductor L1 and the first capacitor C1 is provided with an RF input pin, and the common connection terminal of the first inductor L1 and the fourth capacitor is provided with an RF output pin.

2. The load impedance matching circuit for an RF power supply according to claim 1, characterized in that: The first capacitor C1, the second capacitor C2, the third capacitor C3, the fourth capacitor C4, and the fifth capacitor C5 are all mica capacitors.

3. The load impedance matching circuit for an RF power supply according to claim 1, characterized in that: The capacitance of the first capacitor C1, the second capacitor C2 and the third capacitor C3 is 300pF, and the capacitance of the fourth capacitor C4 and the fifth capacitor C5 is 100pF.

4. A load impedance matching circuit for an RF power supply according to claim 1, characterized in that: The hollow coil of the first inductor L1 has an inner diameter of 20mm and 2.5 turns.

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