CN217590387U - NFC power-taking terminal - Google Patents

Abstract

The utility model discloses NFC gets electric terminal, the antenna that charges receives outside main NFC module transmission signal, varactor BD1 by antenna and series connection charges, electric capacity C2 constitutes resonance tuning network and receives, later through varactor BD2 of back to back, BD3, electric capacity C5 carries out output high frequency voltage after the frequency deviation compensation, resonance tuning network's frequency is by best operating point 13.56MHz of discriminator and resonance, the passband is 12KHz, whether output resonance is voltage feedback adjusts, outside main NFC module sends signal frequency when high or low, output voltage feeds back varactor BD1 or BD 2's negative pole, carry out the frequency deviation compensation, compensating frequency to best operating point 13.56MHz when reducing the distortion, the rectifier circuit that gets into PWM control, adopt switch tube Q1, Q2, Q3, supply power for the battery charging outfit behind the rectifier main circuit rectification that Q4 constitutes for required direct current, switch tube Q1, Q2, Q3, Q4's switching frequency is controlled by the model STC89C 52U 1 produces PWM, can realize supplying power as required.

Description

NFC power-taking terminal

Technical Field

The utility model relates to the field of communication technology, especially, relate to NFC gets electric terminal.

Background

Near Field Communication (NFC) is a short-range high-frequency radio technology, an NFC antenna has a wireless charging function in addition to Communication, an existing NFC antenna gets a power terminal, and after an external host NFC module sends a signal, a 13.56MHz wireless magnetic field is generated, and after the charging antenna senses the wireless magnetic field, the wireless magnetic field is usually resonated with a 13.56MHz frequency through a resonant capacitor to exchange energy, and then the energy is converted into direct current through a rectifier to supply power to a charging device.

However, in practical use, due to factors such as element parameters and environment, the frequency of the signal sent by the external host NFC module and the frequency generated by the charging antenna induction and the resonant capacitor may generate phenomena of detuning and loss, which affects the efficiency of exchanging energy.

SUMMERY OF THE UTILITY MODEL

To the above-mentioned condition, for overcoming prior art's defect, the utility model provides an NFC gets electric terminal, the effectual prior art that has solved can produce the phenomenon of detuning, loss because of factors such as component parameter, environment, influences the problem of the efficiency of exchange energy.

The technical scheme includes that the charging antenna receives signals sent by an external main NFC module, an induced magnetic field enters the tuned filter, high-frequency voltage is output after tuning of a tuning network and frequency offset compensation, and the induced magnetic field enters the PWM-controlled rectifying circuit to be rectified into required direct current and then supplies power to charging equipment.

Preferably, the tuning filter comprises a charging antenna, one end of the charging antenna is respectively connected with the anode of the varactor diode BD1, one end of the capacitor C6, one end of the capacitor C1, and one end of the primary coil of the transformer T1, the other end of the charging antenna is respectively connected with one end of the capacitor C2, one end of the capacitor C5, the cathode of the varactor diode BD3, the other end of the capacitor C1, and the other end of the primary coil of the transformer T1, the cathode of the varactor diode BD1 is respectively connected with one end of the capacitor C2 and one end of the resistor R1, the other end of the capacitor C6 is respectively connected with the other end of the capacitor C5 and the cathode of the varactor diode BD2, one end of a secondary coil of the transformer T1 is connected with the ground, the other end of the secondary coil of the transformer T1 is connected with one end of a capacitor C3, the other end of the capacitor C3 is respectively connected with one end of a crystal oscillator Y1, the other end of a resistor R1, the anode of a diode D1, one end of a resistor R2 and the cathode of a variable capacitance diode BD3, the other end of the crystal oscillator Y1 is respectively connected with one end of a ground capacitor C4, the cathode of the diode D1, the cathode of the diode D2, the other end of the resistor R2, one end of a ground resistor R3 and the cathode of the variable capacitance diode BD2, and the anode of the diode D2 is connected with the ground;

the rectifier circuit comprises a switch tube Q1, a switch tube Q2, a switch tube Q3 and a switch tube Q4, wherein the base electrodes of the switch tube Q1, the switch tube Q2, the switch tube Q3 and the switch tube Q4 are respectively connected with a pin 25, a pin 24, a pin 23 and a pin 22 of a single-chip microcomputer U1, the emitter electrode of the switch tube Q1 is respectively connected with the collector electrode of the switch tube Q2, the anode electrode of the diode D3 and the cathode electrode of the diode D6 varactor BD2, the collector electrode of the switch tube Q1, the collector electrode of the switch tube Q3, the cathode electrode of the diode D5 and one end of a capacitor C7 output positive power signals, the emitter electrode of the switch tube Q2, the emitter electrode of the switch tube Q4, the anode electrode of the diode D6 and the other end of the capacitor C7 output negative power signals, a pin 40 of the switch tube U1 is connected with a power supply +5V, the ground connection pin 20 of the single-chip microcomputer U1 is connected with the ground connection pin 9, the ground connection pin of the capacitor U1 is respectively connected with a pin E1, the cathode connection pin of the capacitor C1 and the anode connection pin of the capacitor C8, the left end of the capacitor C1 is respectively connected with the capacitor C8, and the capacitor C8, the left end of the capacitor C8, and the electrolysis capacitor C8.

The utility model discloses think about ingenious, by the varactor BD1 of charging antenna and series connection, electric capacity C2 constitutes resonance tuning network and receives outside main NFC module and sends the signal, later through varactor BD2 back to back, BD3, electric capacity C5 carries out output high frequency voltage after the frequency deviation compensation, resonance tuning network's frequency is by frequency discriminator and resonant best operating point 13.56MHz, the passband is 12KHz, whether voltage feedback regulation of output resonance, when outside main NFC module sends signal frequency height or low, output voltage feeds back to varactor BD 1's negative pole, output voltage feeds back to varactor BD 3's negative pole when the frequency is high, output voltage feeds back to varactor BD 2's negative pole when the frequency is low, carry out the frequency deviation compensation, compensate the frequency to best operating point 13.56MHz when reducing the distortion;

a rectifier main circuit composed of switching tubes Q1, Q2, Q3 and Q4 is adopted to supply power to charging equipment after being rectified into required direct current, and the switching frequencies of the switching tubes Q1, Q2, Q3 and Q4 are controlled by PWM generated by a single chip microcomputer U1 with the model of STC89C52, so that power supply can be realized as required.

Drawings

Fig. 1 is a schematic circuit diagram of the present invention.

Detailed Description

The technical solutions of the embodiments of the present invention will be described in detail and completely with reference to the accompanying drawings, and it is to be understood that the described embodiments are only some embodiments of the present invention, but not all embodiments.

The following description will be made in detail with reference to fig. 1 of the drawings.

The NFC power taking terminal comprises a charging antenna, a tuning filter and a rectifying circuit, wherein the charging antenna receives a signal sent by an external main NFC module, a resonant tuning network consisting of the charging antenna and serially connected variable capacitance diodes BD1 and capacitors C2 receives the signal sent by the external main NFC module, then the signal is subjected to frequency deviation compensation through the back-to-back variable capacitance diodes BD2, BD3 and capacitors C5, a high-frequency voltage is output and enters the rectifying circuit controlled by PWM, the rectifying main circuit consisting of switching tubes Q1, Q2, Q3 and Q4 is adopted to rectify the signal into required direct current and then supply power to charging equipment, and the switching frequencies of the switching tubes Q1, Q2, Q3 and Q4 are controlled by PWM generated by a single chip microcomputer U1 with the model of STC89C52, so that power supply can be realized as required.

The tuning filter receives a signal sent by an external main NFC module, a magnetic field induced by the charging antenna enters the tuning filter, a resonant tuning network formed by the charging antenna and the series-connected variable capacitance diodes BD1 and capacitor C2 receives the signal sent by the external main NFC module, and then a high-frequency voltage is output after frequency deviation compensation is carried out on the signals through the back-to-back variable capacitance diodes BD2, BD3 and capacitor C5, specifically, the frequency of the resonant tuning network is resonated by a frequency discriminator formed by a transformer T1, a capacitor C3, a capacitor C4, diodes D1 and D2, a resistor R1 and a resistor R2 and an optimal working point 13.56MHz of resonance, the passband is 12KHz, during resonance, voltages at two ends of a crystal oscillator Y1 and the capacitor C4 are mutually offset, the frequency of the resonant tuning network is not changed, when the frequency of the signal sent by the external main NFC module is high or low, the output voltage is fed back to the cathode of the variable capacitance diode BD1, so that the frequency of the resonant tuning network is changed, the frequency deviation compensation is carried out by feeding back the output voltage to the cathode of the variable capacitance diode BD3 when the frequency is high, feeding back the output voltage to the cathode of the variable capacitance diode BD2 when the frequency is low, and compensating the frequency to the optimal working point of 13.56MHz while reducing distortion, the frequency deviation compensation device comprises a charging antenna, wherein one end of the charging antenna is respectively connected with the anode of the variable capacitance diode BD1, one end of a capacitor C6, one end of a capacitor C1 and one end of a primary coil of a transformer T1, the other end of the charging antenna is respectively connected with one end of the capacitor C2, one end of a capacitor C5, the cathode of the variable capacitance diode BD3, the other end of the capacitor C1 and the other end of the primary coil of the transformer T1, the cathode of the variable capacitance diode BD1 is respectively connected with one end of the capacitor C2 and one end of a resistor R1, the other end of the capacitor C6 is respectively connected with the other end of the capacitor C5 and the cathode of the variable capacitance diode BD2, one end of a secondary coil of the transformer T1 is connected with the ground, and the other end of a secondary coil of the transformer T3 is connected with one end of the capacitor C3, the other end of the capacitor C3 is respectively connected with one end of a crystal oscillator Y1, the other end of the resistor R1, one end of the resistor R2 and the cathode of the variable capacitance diode BD3, and the other end of the crystal oscillator Y1 is respectively connected with one end of a grounding capacitor C4, the other end of the resistor R2, one end of the grounding resistor R3 and the cathode of the variable capacitance diode BD 2;

the rectifier circuit adopts a rectifier main circuit composed of switch tubes Q1, Q2, Q3 and Q4 to rectify the direct current to required direct current and then supply power to the charging equipment, the switching frequency of the switch tubes Q1, Q2, Q3 and Q4 is controlled by PWM generated by a single chip microcomputer U1 with the model of STC89C52, the power supply can be realized according to the requirement, the single chip microcomputer U1 can carry out comprehensive analysis by combining the charging equipment charging voltage detected by a Hall voltage sensor and the charging equipment charging temperature detected by a thermistor and outputs PWM, for example, when a lithium battery is charged, the single chip microcomputer U1 adopts PWM output by a three-stage charging strategy according to the residual electric quantity and the temperature of the battery, which is the prior art and is not detailed any more, the rectifier circuit comprises the switch tubes Q1, Q2, Q3 and Q4, the base electrodes of the switch tubes Q1, Q2, Q3 and Q4 are respectively connected with a pin 25, a pin 24, a pin 23 and a pin 22 of the single chip microcomputer U1, the emitter of the switch tube Q1 is respectively connected with the collector of the switch tube Q2, the anode of the diode D3 and the cathode of the varactor BD2 of the diode D4, the emitter of the switch tube Q3 is respectively connected with the collector of the switch tube Q4, the anode of the diode D5 and the cathode of the varactor BD3 of the diode D6, the collector of the switch tube Q1, the collector of the switch tube Q3, the cathode of the diode D5 and one end of the capacitor C7 output positive power signals, the emitter of the switch tube Q2, the emitter of the switch tube Q4, the anode of the diode D6 and the other end of the capacitor C7 output negative power signals, the pin 40 of the singlechip U1 is connected with the power supply +5V, the pin 20 of the singlechip U1 is connected with the ground, the pin 9 of the singlechip U1 is respectively connected with the cathode of the electrolytic capacitor E1 and one end of the ground resistor R4, the anode of the electrolytic capacitor E1 is connected with the power supply +5V, a pin 18 of the singlechip U1 is respectively connected with one end of the grounding capacitor C8 and the left end of the crystal oscillator Y2, and a pin 19 of the singlechip U1 is respectively connected with one end of the grounding capacitor C9 and the right end of the crystal oscillator Y2.

Claims (3)

1. The NFC power taking terminal comprises a charging antenna, a tuned filter and a rectifying circuit and is characterized in that the charging antenna receives a signal sent by an external main NFC module, an induced magnetic field enters the tuned filter, a high-frequency voltage is output after tuning of a tuning network and frequency offset compensation, and the induced magnetic field enters the rectifying circuit controlled by PWM to be rectified into required direct current and then supplies power to charging equipment.
2. 2. The NFC power taking terminal according to claim 1, wherein the tuning filter comprises a charging antenna, one end of the charging antenna is connected with an anode of a varactor BD1, one end of a capacitor C6, one end of a capacitor C1 and one end of a primary coil of a transformer T1 respectively, the other end of the charging antenna is connected with one end of a capacitor C2, one end of a capacitor C5, a cathode of a varactor BD3, the other end of a capacitor C1 and the other end of a primary coil of a transformer T1 respectively, a cathode of the varactor BD1 is connected with one end of a capacitor C2 and one end of a resistor R1 respectively, the other end of the capacitor C6 is connected with the other end of a capacitor C5 and the cathode of a varactor BD2 respectively, one end of a secondary coil of the transformer T1 is connected with ground, the other end of a secondary coil of the transformer T1 is connected with one end of a capacitor C3, the other end of the capacitor C3 is connected with one end of a crystal oscillator Y1, the other end of a resistor R1, one end of a resistor R2 and the cathode of a varactor BD3, and the other end of a capacitor Y1 is connected with one end of a grounded capacitor C4, the other end of a resistor R2 respectively;

   the rectifier circuit comprises a switch tube Q1, a switch tube Q2, a switch tube Q3 and a switch tube Q4, wherein the base electrodes of the switch tube Q1, the switch tube Q2, the switch tube Q3 and the switch tube Q4 are respectively connected with a pin 25, a pin 24, a pin 23 and a pin 22 of a single-chip microcomputer U1, the emitter electrode of the switch tube Q1 is respectively connected with the collector electrode of the switch tube Q2, the anode electrode of the diode D3 and the cathode electrode of the diode D6 varactor BD2, the collector electrode of the switch tube Q1, the collector electrode of the switch tube Q3, the cathode electrode of the diode D5 and one end of a capacitor C7 output positive power signals, the emitter electrode of the switch tube Q2, the emitter electrode of the switch tube Q4, the anode electrode of the diode D6 and the other end of the capacitor C7 output negative power signals, a pin 40 of the switch tube U1 is connected with a power supply +5V, the ground connection pin 20 of the single-chip microcomputer U1 is connected with the ground connection pin 9, the ground connection pin of the capacitor U1 is respectively connected with a pin E1, the cathode connection pin of the capacitor C1 and the anode connection pin of the capacitor C8, the left end of the capacitor C1 is respectively connected with the capacitor C8, and the capacitor C8, the left end of the capacitor C8, and the electrolysis capacitor C8.
3. 3. The NFC power taking terminal according to claim 2, wherein a pin 1 of the single chip microcomputer U1 is connected with a charging device charging voltage detected by a Hall voltage sensor;

   and a pin 1 of the singlechip U1 is connected with the charging equipment charging temperature detected by the thermistor.

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