An RF and EMS shared circuit

Abstract

The utility model provides a kind of RF and EMS common circuit, including high frequency radio frequency circuit, RFADC skin detection circuit, EMS circuit, EMS and RF isolation circuit, the RF power supply of high frequency radio frequency circuit is provided by DC-DC boost, high frequency radio frequency circuit receives the high frequency signal RFIN input by MCU, through MOS tube Q1 drive LC resonant circuit, in RF output point generation with the AC RF signal of RFIN same frequency, signal amplitude is decided by VCC-RF;RFADC skin detection circuit input end is connected with the output end of high frequency radio frequency circuit, whether contact skin is judged by detecting the voltage change of RFADC detection point when contact skin.The utility model has the beneficial effects that:1.The utility model's EMS and RF isolation circuit use inductance to isolate the interference of RF radio frequency circuit, to realize the common use of RF and EMS technology;2.It can realize 3MHZ above RF radio frequency.

Description

Technical Field

[0001] This utility model relates to the field of electronic circuit technology, and in particular to a shared circuit for RF and EMS. Background Technology

[0002] 1. Currently, the RF and EMS sharing technology uses a transformer to implement both RF and EMS technologies. The drawback is that it can only achieve frequency sharing below 3MHz. Alternatively, a transformer can be used to implement RF technology below 3MHz, while a separate EMS circuit can be used for sharing. The drawback is that the frequency can only be below 3MHz.

[0003] 2. One of the current high-frequency RF technology solutions (which can achieve RF frequencies above 3MHz) is to use PWM to drive MOSFETs at high frequency, thereby generating high-frequency AC through the charging and discharging of inductors and capacitors in the circuit, thus realizing high-frequency RF technology. The drawback is the lack of an EMS (Electromagnetic System). Utility Model Content

[0004] To address the problems in the prior art, this utility model provides a shared RF and EMS circuit, including a high-frequency radio frequency circuit, an RFADC skin detection circuit, an EMS circuit, and an EMS and RF isolation circuit. The RF power supply of the high-frequency radio frequency circuit is provided by a DC-DC boost converter. The high-frequency radio frequency circuit receives the high-frequency signal RFIN input from the MCU and drives an LC resonant circuit through a MOS transistor Q1 to generate an AC RF signal with the same frequency as RFIN at the RF output point. The signal amplitude is determined by VCC-RF. The input terminal of the RFADC skin detection circuit is connected to the output terminal of the high-frequency radio frequency circuit. It determines whether skin contact has occurred by detecting the voltage change at the RFADC detection point when the skin is in contact. The EMS circuit is driven by a boost converter T1. The primary side of the transformer T1 is used to receive external drive signals, and the secondary side of the transformer T1 is responsible for outputting a high-voltage EMS waveform. The input terminal of the EMS and RF isolation circuit is connected to the output terminal of the EMS circuit, and the output terminals of the EMS and RF isolation circuit are respectively connected to the high-frequency radio frequency circuit and the RFADC skin detection circuit, realizing the coexistence of EMS signals and high-frequency RF signals at the same contact point.

[0005] As a further improvement of this utility model, the EMS and RF isolation circuit includes a third inductor L3 and a fourth inductor L4. The output terminal of the EMS circuit is connected to one end of the third inductor L3 and the fourth inductor L4 respectively. The other end of the third inductor L3 is connected to the high-frequency radio frequency circuit and the RFADC skin detection circuit. The other end of the fourth inductor L4 is grounded. As a further improvement of this utility model, the LC resonant circuit includes a first inductor L1, a second inductor L2, a first capacitor C1, a second capacitor C2, a third capacitor C3, a fourth capacitor C4, a fifth capacitor C5, a sixth capacitor C6, and a seventh capacitor C7. The high-frequency radio frequency circuit includes a first resistor R1 and a first MOSFET Q1.

[0006] One end of the first inductor L1 is connected to the RF power supply, and the other end is connected to one end of the second inductor L2;

[0007] The other end of the second inductor L2 is connected to the first end of the first capacitor network formed by the first capacitor C1, the second capacitor C2, the third capacitor C3, and the fourth capacitor C4 connected in parallel;

[0008] The fifth capacitor C5, the sixth capacitor C6, and the seventh capacitor C7 are connected in parallel to form a second capacitor network. The first end of the second capacitor network is connected to the second end of the first capacitor network formed by the first capacitor C1, the second capacitor C2, the third capacitor C3, and the fourth capacitor C4. The connection node between the second end of the first capacitor network and the first end of the second capacitor network is connected to the first contact point TP1 of the RFADC skin detection circuit and the other end of the third inductor L3.

[0009] The second terminal of the second capacitor network is grounded;

[0010] One end of the first resistor R1 is connected to the high-frequency signal RFIN, and the other end of the first resistor R1 is connected to the gate of the first MOS transistor Q1.

[0011] The source of the first MOSFET Q1 is grounded, and the drain of the first MOSFET Q1 is connected to the other end of the first inductor L1 and one end of the second inductor L2, respectively.

[0012] As a further improvement of this utility model, the transformer T1 includes a first primary winding E1 and a second primary winding E2. The first primary winding E1 and the second primary winding E2 are respectively connected to the EMS power supply node VCC-EMS. The secondary winding of the transformer T1 is connected to the input terminal of the EMS and RF isolation circuit.

[0013] As a further improvement of this utility model, one end of the secondary winding of the transformer T1 is connected to one end of the third inductor L3, and the other end of the third inductor L3 is also connected to the first contact point TP1 of the RFADC skin detection circuit.

[0014] The other end of the secondary winding of the transformer T1 is connected to one end of the fourth inductor L4, and the other end of the fourth inductor L4 is grounded.

[0015] As a further improvement of this utility model, the RFADC skin detection circuit determines the skin contact state by detecting the voltage change of the first contact point TP1 and the second contact point TP2: when the first contact point TP1 and the second contact point TP2 contact the skin, a load loop is formed, causing the voltage of the RF output point to drop relative to the no-load state. The RFADC realizes contact detection by quantifying the voltage drop.

[0016] The beneficial effects of this utility model are: 1. The EMS and RF isolation circuit of this utility model uses an inductor to isolate the interference of the RF radio frequency circuit, thereby realizing the electrical isolation between the EMS signal and the high-frequency RF signal, and ensuring that the two can coexist and work on the same contact point; 2. The circuit structure of this utility model can realize RF radio frequency above 3MHz. Attached Figure Description

[0017] Figure 1 This is a block diagram of the shared RF and EMS circuit of this utility model. Detailed Implementation

[0018] RF: Radio frequency;

[0019] EMS: Electromagnetic stimulation;

[0020] RFADC: For skin detection signals (a named network of detection points);

[0021] like Figure 1As shown, this utility model discloses a shared RF and EMS circuit, including a high-frequency radio frequency circuit, an RFADC skin detection circuit, an EMS circuit, and an EMS and RF isolation circuit. The RF power supply of the high-frequency radio frequency circuit is provided by a DC-DC boost converter. The high-frequency radio frequency circuit receives the high-frequency signal RFIN input from the MCU and drives the LC resonant circuit through MOSFET Q1 to generate an AC RF signal with the same frequency as RFIN at the RF output point. The signal amplitude is determined by VCC-RF. The input terminal of the RFADC skin detection circuit is connected to the output terminal of the high-frequency radio frequency circuit. It determines whether skin contact has occurred by detecting the voltage change at the RFADC detection point when the skin is in contact. The EMS circuit is driven by a boost converter T1. The primary side of the transformer T1 is used to receive external drive signals, and the secondary side of the transformer T1 is responsible for outputting a high-voltage EMS waveform. The input terminal of the EMS and RF isolation circuit is connected to the output terminal of the EMS circuit. The output terminals of the EMS and RF isolation circuits are respectively connected to the high-frequency radio frequency circuit and the RFADC skin detection circuit, realizing the coexistence of EMS signals and RF signals at the same contact point. The RFADC skin detection circuit is prior art and will not be described in detail here. This circuit has an RFADC skin detection point.

[0022] The EMS and RF isolation circuit includes a third inductor L3 and a fourth inductor L4. The output of the EMS circuit is connected to one end of the third inductor L3 and one end of the fourth inductor L4, respectively. The other end of the third inductor L3 is connected to the high-frequency radio frequency circuit and the RFADC skin detection circuit. The other end of the fourth inductor L4 is grounded.

[0023] The LC resonant circuit includes a first inductor L1, a second inductor L2, a first capacitor C1, a second capacitor C2, a third capacitor C3, a fourth capacitor C4, a fifth capacitor C5, a sixth capacitor C6, and a seventh capacitor C7. The high-frequency radio frequency circuit includes a first resistor R1 and a first MOSFET Q1.

[0024] One end of the first inductor L1 is connected to the RF power supply, and the other end is connected to one end of the second inductor L2.

[0025] The other end of the second inductor L2 is connected to the first end of the first capacitor network formed by the first capacitor C1, the second capacitor C2, the third capacitor C3, and the fourth capacitor C4 connected in parallel.

[0026] The fifth capacitor C5, the sixth capacitor C6, and the seventh capacitor C7 are connected in parallel to form a second capacitor network. The first end of the second capacitor network is connected to the second end of the first capacitor network, which is connected in parallel with the first capacitor C1, the second capacitor C2, the third capacitor C3, and the fourth capacitor C4. The connection node between the second end of the first capacitor network and the first end of the second capacitor network is connected to the first contact point TP1 of the RFADC skin detection circuit and the other end of the third inductor L3.

[0027] The second terminal of the second capacitor network is grounded;

[0028] One end of the first resistor R1 is connected to the high-frequency signal RFIN, and the other end of the first resistor R1 is connected to the gate of the first MOS transistor Q1.

[0029] The source of the first MOSFET Q1 is grounded, and the drain of the first MOSFET Q1 is connected to the other end of the first inductor L1 and one end of the second inductor L2, respectively.

[0030] The first inductor L3 and the second inductor L4 are used to suppress high-frequency RF signals, while the first capacitor C1 to the seventh capacitor C7 (C1, C2, C3, C4, C5, C6, C7) are used to block EMS signals, thereby ensuring that the RF circuit will not interfere with the EMS circuit when it is working, and at the same time, the EMS circuit will not affect the RF circuit or cause interference to it when it is working.

[0031] Transformer T1 includes a first primary winding E1 and a second primary winding E2. The first primary winding E1 and the second primary winding E2 are respectively connected to the EMS power supply node VCC-EMS. The secondary winding of transformer T1 is connected to the input terminal of EMS and RF isolation circuit.

[0032] One end of the secondary winding of transformer T1 is connected to one end of the third inductor L3, and the other end of the third inductor L3 is also connected to the first contact point TP1 of the RFADC skin detection circuit.

[0033] The other end of the secondary winding of transformer T1 is connected to one end of the fourth inductor L4, and the other end of the fourth inductor L4 is grounded.

[0034] The first primary winding E1 and the second primary winding E2 are complementary. The PWM signal is adjusted so that the secondary winding of transformer T1 outputs the required EMS waveform. The EMS waveform output by the secondary winding of transformer T1 is connected to the first contact point TP1 and the second contact point TP2 through the third inductor L3 and the fourth inductor L4.

[0035] The RFADC skin detection circuit determines the skin contact state by detecting the voltage change at the first contact point TP1 and the second contact point TP2: when the first contact point TP1 and the second contact point TP2 contact the skin, a load loop is formed, causing the voltage at the RF output point to drop relative to the no-load state. The RFADC realizes contact detection by quantifying this voltage drop.

[0036] The circuit of this invention can be divided into four parts: a high-frequency RF circuit, an RFADC skin detection circuit, an EMS circuit, and an EMS and RF isolation circuit. The working process is as follows:

[0037] 1. High-frequency RF section: The RF power supply can be provided by DC-DC boost. The MCU outputs a high-frequency signal RFIN to drive the MOSFET Q1 to charge and discharge the first inductor L1, the second inductor L2, the first capacitor C1, the second capacitor C2, the third capacitor C3, the fourth capacitor C4, the fifth capacitor C5, the sixth capacitor C6, and the seventh capacitor C7 in the figure. This results in the output of an AC RF signal with the VCC-RF power supply voltage at the RF output point. The signal frequency is consistent with the drive signal RFIN.

[0038] 2. RFADC Skin Detection Section: Detects RFADC voltage. When the skin is in contact with the first contact point TP1 and the second contact point TP2, a load is applied between the output terminals TP1 and TP2. The voltage at the RF points will decrease relative to the no-load voltage, thus determining whether there is contact with the skin.

[0039] 3. EMS circuit section: The drive signals from E1 and E2 are given to the primary winding of the transformer, which drives the transformer T1, so that the secondary winding of the transformer outputs the EMS waveform after the transformer has stepped up the voltage.

[0040] 4. EMS and RF isolation circuit: Due to the high-frequency AC characteristics of inductors, the EMS frequency is relatively low and can be output to TP1 and TP2 through the third inductor L3 and the fourth inductor L4 without significant change in intensity. The high frequency of RF above 3MHz is blocked by the third inductor L3 and the fourth inductor L4, so that it will not affect the EMS circuit. At the same time, the power consumption of RF to the transformer section when in contact with the skin can be reduced or even ignored. Therefore, both RF and EMS can be output to the first contact point TP1 and the second contact point TP2.

[0041] The above description, in conjunction with specific preferred embodiments, provides a further detailed explanation of the present invention. It should not be construed that the specific implementation of the present invention is limited to these descriptions. For those skilled in the art, various simple deductions or substitutions can be made without departing from the concept of the present invention, and all such modifications and substitutions should be considered within the protection scope of the present invention.

Claims

1. A shared circuit for RF and EMS, characterized in that: It includes a high-frequency radio frequency circuit, an RFADC skin detection circuit, an EMS circuit, and an EMS and RF isolation circuit. The RF power supply of the high-frequency radio frequency circuit is provided by a DC-DC boost converter. The high-frequency radio frequency circuit receives the high-frequency signal RFIN input from the MCU and drives the LC resonant circuit through the MOS transistor Q1 to generate an AC RF signal with the same frequency as RFIN at the RF output point. The signal amplitude is determined by VCC-RF. The input terminal of the RFADC skin detection circuit is connected to the output terminal of the high-frequency radio frequency circuit. It determines whether skin contact has occurred by detecting the voltage change at the RFADC detection point when the skin is in contact. The EMS circuit is driven by a transformer T1. The primary side of the transformer T1 is used to receive external driving signals, and the secondary side of the transformer T1 is responsible for outputting high-voltage EMS waveforms. The input terminal of the EMS and RF isolation circuit is connected to the output terminal of the EMS circuit. The output terminals of the EMS and RF isolation circuits are respectively connected to the high-frequency radio frequency circuit and the RFADC skin detection circuit, realizing the coexistence of EMS signals and high-frequency RF signals at the same contact point.

2. The RF and EMS shared circuit according to claim 1, characterized in that: The EMS and RF isolation circuit includes a third inductor L3 and a fourth inductor L4. The output terminal of the EMS circuit is connected to one end of the third inductor L3 and the fourth inductor L4, respectively. The other end of the third inductor L3 is connected to the high-frequency radio frequency circuit and the RFADC skin detection circuit. The other end of the fourth inductor L4 is grounded.

3. The RF and EMS shared circuit according to claim 2, characterized in that: The LC resonant circuit includes a first inductor L1, a second inductor L2, a first capacitor C1, a second capacitor C2, a third capacitor C3, a fourth capacitor C4, a fifth capacitor C5, a sixth capacitor C6, and a seventh capacitor C7. The high-frequency radio frequency circuit includes a first resistor R1 and a first MOSFET Q1. One end of the first inductor L1 is connected to the RF power supply, and the other end is connected to one end of the second inductor L2; the other end of the second inductor L2 is connected to the first end of the first capacitor network formed by the first capacitor C1, the second capacitor C2, the third capacitor C3, and the fourth capacitor C4 connected in parallel. The fifth capacitor C5, the sixth capacitor C6, and the seventh capacitor C7 are connected in parallel to form a second capacitor network. The first end of the second capacitor network is connected to the second end of the first capacitor network formed by the first capacitor C1, the second capacitor C2, the third capacitor C3, and the fourth capacitor C4. The connection node between the second end of the first capacitor network and the first end of the second capacitor network is connected to the first contact point TP1 of the RFADC skin detection circuit and the other end of the third inductor L3. The second terminal of the second capacitor network is grounded; One end of the first resistor R1 is connected to the high-frequency signal RFIN, and the other end of the first resistor R1 is connected to the gate of the first MOS transistor Q1. The source of the first MOSFET Q1 is grounded, and the drain of the first MOSFET Q1 is connected to the other end of the first inductor L1 and one end of the second inductor L2, respectively.

4. The RF and EMS shared circuit according to claim 3, characterized in that: The transformer T1 includes a first primary winding E1 and a second primary winding E2. The first primary winding E1 and the second primary winding E2 are respectively connected to the EMS power supply node VCC-EMS. The secondary winding of the transformer T1 is connected to the input terminal of the EMS and RF isolation circuit.

5. The RF and EMS shared circuit according to claim 4, characterized in that: One end of the secondary winding of the transformer T1 is connected to one end of the third inductor L3, and the other end of the third inductor L3 is also connected to the first contact point TP1 of the RFADC skin detection circuit. The other end of the secondary winding of the transformer T1 is connected to one end of the fourth inductor L4, and the other end of the fourth inductor L4 is grounded.

6. The RF and EMS shared circuit according to claim 1, characterized in that: The RFADC skin detection circuit determines the skin contact state by detecting the voltage change at the first contact point TP1 and the second contact point TP2: when the first contact point TP1 and the second contact point TP2 contact the skin, a load loop is formed, causing the voltage at the RF output point to drop relative to the no-load state. The RFADC realizes contact detection by quantifying this voltage drop.

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