CN211556883U

CN211556883U - Wireless charging circuit

Info

Publication number: CN211556883U
Application number: CN201921578288.5U
Authority: CN
Inventors: 罗岳峰
Original assignee: Shenzhen H&T Intelligent Control Co Ltd
Current assignee: Shenzhen H&T Intelligent Control Co Ltd
Priority date: 2019-09-20
Filing date: 2019-09-20
Publication date: 2020-09-22
Anticipated expiration: 2029-09-20

Abstract

The embodiment of the utility model provides a wireless charging circuit is provided in the field of relating to wireless charging. The wireless charging circuit comprises a pulse generating circuit, a reference pulse generating circuit and a charging circuit, wherein the pulse generating circuit is connected with an external power supply and used for generating a reference pulse signal; the resonance transmitting circuit is connected with the pulse generating circuit and used for receiving the reference pulse signal, generating high-frequency alternating electromagnetic waves and outputting resonance voltage; the resonance receiving circuit is used for inducing high-frequency alternating electromagnetic waves, converting the high-frequency alternating electromagnetic waves into induced voltage, and adjusting the amplitude of the resonance voltage output by the resonance transmitting circuit according to the distance between the resonance receiving circuit and the resonance transmitting circuit; and the first switch circuit is respectively connected with the pulse generating circuit, the resonance transmitting circuit and the external power supply and is used for working in an on state or an off state according to the amplitude of the resonance voltage so as to control the working state of the pulse generating circuit. The embodiment of the utility model provides a non-contact wireless charging who conveniently charges has been realized.

Description

Wireless charging circuit

[ technical field ] A method for producing a semiconductor device

The embodiment of the utility model provides a relate to wireless field of charging, especially relate to a wireless charging circuit.

[ background of the invention ]

At present, generally adopt the charging cable to connect product and the charging source that charges, realize charging the built-in rechargeable battery of product that charges, this charging mode leads to charging inconveniently because cable constraint and frequent plug interface.

[ Utility model ] content

The embodiment of the utility model aims at providing a wireless charging circuit who conveniently charges.

In order to solve the above technical problem, an embodiment of the utility model provides a wireless charging circuit, include:

the pulse generating circuit is connected with an external power supply and used for generating a reference pulse signal;

the resonance transmitting circuit is connected with the pulse generating circuit and used for receiving the reference pulse signal, generating high-frequency alternating electromagnetic waves and outputting resonance voltage;

the resonance receiving circuit is used for inducing the high-frequency alternating electromagnetic wave, converting the high-frequency alternating electromagnetic wave into induced voltage, and adjusting the amplitude of the resonance voltage output by the resonance transmitting circuit according to the distance between the resonance receiving circuit and the resonance transmitting circuit;

and the first switch circuit is respectively connected with the pulse generating circuit, the resonance transmitting circuit and the external power supply and is used for working in an on state or an off state according to the amplitude of the resonance voltage so as to control the working state of the pulse generating circuit.

Optionally, the pulse generating circuit comprises:

the square wave generating circuit is connected with the external power supply and is used for generating a square wave pulse signal;

and the second switching circuit is respectively connected with the square wave generating circuit, the resonance transmitting circuit and the external power supply and is used for receiving the square wave pulse signal and outputting the reference pulse signal.

Optionally, the pulse generating circuit further includes a third switching circuit, and the third switching circuit is connected between the square wave generating circuit and the second switching circuit, and is configured to amplify the square wave pulse signal.

Optionally, the square wave generating circuit includes a timer, a first capacitor, a first resistor, a second capacitor, a third resistor, and a third capacitor, the second switch circuit includes an NMOS transistor and a fourth resistor, and the third switch circuit includes a fifth resistor, a first NPN transistor, and a sixth resistor;

the first end of the timer is grounded, the second end of the timer is connected with the sixth end of the timer, the positive electrode of the first capacitor and one end of the first resistor, the third end of the timer is connected with one end of the second resistor and one end of the fifth resistor, the fourth end of the timer is connected with the first switch circuit, the fifth end of the timer is connected with the positive electrode of the second capacitor, the seventh end of the timer is connected with the other end of the first resistor and one end of the third resistor, and the eighth end of the timer is connected with one end of the third capacitor; the negative electrode of the first capacitor is grounded; the other end of the second resistor is connected with the external power supply; the negative electrode of the second capacitor is grounded; the other end of the third resistor is connected with the external power supply; the other end of the third capacitor is grounded;

the grid electrode of the NMOS tube is connected with the collector electrode of the first NPN triode and one end of the sixth resistor, the source electrode of the NMOS tube is connected with one end of the fourth resistor, and the drain electrode of the NMOS tube is connected with the external power supply; the other end of the fourth resistor is connected with the resonance transmitting circuit;

the other end of the fifth resistor is connected with the base electrode of the first NPN triode; the emitting electrode of the first NPN triode is grounded; the other end of the sixth resistor is connected with the external power supply.

Optionally, the resonant transmitting circuit comprises a first inductor and a fourth capacitor, and the resonant receiving circuit comprises a second inductor;

one end of the first inductance coil is connected with one end of the fourth capacitor, the other end of the fourth resistor and the first switch circuit, and the other end of the first inductance coil and the other end of the fourth capacitor are grounded.

Optionally, the first switching circuit comprises:

the first voltage sampling circuit is respectively connected with the second switch circuit and the resonance transmitting circuit and is used for sampling the resonance voltage and outputting a first sampling voltage;

the first voltage stabilizing circuit is connected with the first voltage sampling circuit and used for stabilizing the first sampling voltage;

and the first switch is respectively connected with the first voltage stabilizing circuit, the square wave generating circuit and the external power supply and is used for working in an on state when the difference value between the first sampling voltage subjected to voltage stabilization and the output voltage of the external power supply is smaller than a conducting voltage, and working in an off state when the difference value between the first sampling voltage subjected to voltage stabilization and the output voltage of the external power supply is larger than the conducting voltage.

Optionally, the first voltage sampling circuit includes a seventh resistor, an eighth resistor, a ninth resistor, and a tenth resistor, the first voltage stabilizing circuit includes a first voltage stabilizing diode, and the first switch includes a PNP triode;

one end of the seventh resistor is connected to one end of the first inductance coil, one end of the fourth capacitor and the second switch circuit, the other end of the seventh resistor is connected to one end of the eighth resistor, the other end of the eighth resistor is connected to one end of the ninth resistor, the cathode of the first voltage regulator diode and the base of the PNP triode, the other end of the ninth resistor is connected to one end of the tenth resistor, and the other end of the tenth resistor and the anode of the first voltage regulator diode are both grounded; and the emitter of the PNP triode is connected with the external power supply, and the collector of the PNP triode is connected with the square wave generating circuit.

Optionally, the wireless charging circuit further comprises:

the wireless charging circuit further comprises:

the input filter circuit is connected with the external power supply and is used for filtering the output voltage of the external power supply;

the rectification filter circuit is connected with the resonance receiving circuit and is used for carrying out rectification filtering processing on the induction voltage;

the second voltage stabilizing circuit is connected with the rectifying and filtering circuit and used for stabilizing the voltage of the induction voltage after the rectifying and filtering processing and outputting charging voltage;

and the fourth switch circuit is connected between the second voltage stabilizing circuit and the rechargeable battery and is used for working in an on state when the voltage of the rechargeable battery is smaller than a preset voltage, the rechargeable battery is charged by the charging voltage through the fourth switch circuit, and when the voltage of the rechargeable battery is larger than the preset voltage, the fourth switch circuit works in an off state, and the charging voltage stops being charged by the rechargeable battery.

Optionally, the fourth switching circuit comprises:

the second voltage sampling circuit is connected with the second voltage stabilizing circuit and is used for sampling the charging voltage;

and the amplitude discrimination circuit is respectively connected with the second voltage sampling circuit and the rechargeable battery and is used for sampling the voltage of the rechargeable battery, and when the voltage of the rechargeable battery is less than the preset voltage, the amplitude discrimination circuit works in a turn-off state, and when the voltage of the rechargeable battery is greater than the preset voltage, the amplitude discrimination circuit works in a turn-on state.

And the second switch is respectively connected with the amplitude discrimination circuit, the second voltage sampling circuit and the rechargeable battery and is used for working in an on state when the amplitude discrimination circuit works in an off state and working in an off state when the amplitude discrimination circuit works in the on state.

Optionally, the second voltage sampling circuit includes an eleventh resistor and a twelfth resistor, the amplitude discrimination circuit includes a controllable voltage source, a thirteenth resistor and a fourteenth resistor, and the second switch includes a second NPN transistor;

one end of the eleventh resistor is connected with the second voltage stabilizing circuit and the collector of the second NPN triode, and the other end of the eleventh resistor is connected with one end of the twelfth resistor, the base of the second NPN triode and the cathode of the controllable voltage source; the other end of the twelfth resistor is grounded; a control electrode of the controllable voltage source is connected with one end of the thirteenth resistor and one end of the fourteenth resistor, and an anode of the controllable voltage source and the other end of the fourteenth resistor are both grounded; the other end of the thirteenth resistor is connected with the emitter of the second NPN triode and the rechargeable battery.

The utility model has the advantages that: compared with the prior art, the embodiment of the utility model provides a wireless charging circuit is provided. The pulse generator circuit generates a reference pulse signal, the resonance transmitting circuit receives the reference pulse signal, high-frequency alternating electromagnetic waves are generated and resonance voltage is output, the resonance receiving circuit induces the high-frequency alternating electromagnetic waves and converts the high-frequency alternating electromagnetic waves into the induction voltage, in addition, the amplitude of the resonance voltage is adjusted according to the distance between the resonance receiving circuit and the resonance transmitting circuit, the first switch circuit works in an opening state or a closing state according to the amplitude of the resonance voltage, and the working state of the pulse generator circuit is controlled, therefore, the cable binding and frequent plugging and unplugging interfaces are avoided, and the non-contact type wireless charging which is convenient to charge is realized.

[ description of the drawings ]

One or more embodiments are illustrated by way of example in the accompanying drawings, which correspond to the figures in which like reference numerals refer to similar elements and which are not to scale unless otherwise specified.

Fig. 1 is a schematic structural diagram of a wireless charging circuit according to an embodiment of the present invention;

fig. 2 is a schematic diagram of a structure of a pulse generating circuit and a connection between the pulse generating circuit and an external power source and a resonant transmitting circuit according to an embodiment of the present invention;

fig. 3 is a schematic diagram of a structure of a first switch circuit and connection between the first switch circuit and an external power source, a square wave generating circuit, a resonant transmitting circuit, and a second switch circuit according to an embodiment of the present invention;

fig. 4 is a schematic structural diagram of a wireless charging circuit according to another embodiment of the present invention;

fig. 5 is a schematic diagram of a structure of a fourth switching circuit and connection between the fourth switching circuit and the second voltage stabilizing circuit as well as the rechargeable battery according to an embodiment of the present invention;

fig. 6 is a schematic circuit connection diagram of a wireless charging circuit according to an embodiment of the present invention.

[ detailed description ] embodiments

To facilitate an understanding of the present application, the present application is described in more detail below with reference to the accompanying drawings and detailed description. It will be understood that when an element is referred to as being "connected" to another element, it can be directly connected to the other element or intervening elements may be present. Furthermore, the terms "first," "second," and the like are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the term "and/or" includes any and all combinations of one or more of the associated listed items.

In addition, the technical features mentioned in the different embodiments of the present application described below may be combined with each other as long as they do not conflict with each other.

An embodiment of the utility model provides a wireless charging system, wireless charging system is including the product of charging, wireless charger and the disclosed wireless charging circuit of following each embodiment, wireless charging circuit set up respectively in the product of charging with wireless charger, modes such as wireless charger accessible electric field coupling, electromagnetic induction, magnetic field resonance, radio wave realize right the charging of the product of charging.

Specifically, the resonant transmitting circuit of the wireless charging circuit is arranged in the wireless charger, the resonant receiving circuit of the wireless charging circuit is arranged in the charging product, for example, electromagnetic induction is used, the resonant transmitting circuit of the wireless charging circuit converts electric energy provided by an external power supply into magnetic energy, the resonant receiving circuit of the wireless charging circuit induces the magnetic energy, converts the magnetic energy into electric energy, and provides charging voltage for a charging battery arranged in the charging product.

Wherein, the product of charging includes electric toothbrush, intelligent lock, intelligent wrist-watch, smart mobile phone etc. wireless charger includes wireless treasured, wireless charging panel, the wireless body that charges etc.. The wireless charging system realizes non-contact wireless charging convenient to charge according to the wireless charging circuit, and meanwhile realizes flexible non-contact wireless charging between the charging product and the charger according to the distance between the charging product and the charger (or the resonance receiving circuit and the resonance transmitting circuit), and the charging product is placed in the charging range of the charger, so that the charging product can be charged, the charging product is removed out of the charging range of the charger, charging of the charging product can be finished, and the use experience of a user is improved.

Fig. 1 is a schematic structural diagram of a wireless charging circuit according to an embodiment of the present invention. As shown in fig. 1, the wireless charging circuit 100 includes a pulse generating circuit 10, a resonant transmitting circuit 20, a resonant receiving circuit 30, and a first switching circuit 40.

The pulse generating circuit 10 is connected to an external power source 11 for generating a reference pulse signal.

Referring to fig. 2, the pulse generating circuit 10 includes a square wave generating circuit 101, a second switching circuit 102, and a third switching circuit 103.

The square wave generating circuit 101 is connected to the external power source 11, and is configured to generate a square wave pulse signal.

Referring to fig. 6, the square wave generating circuit 101 includes a timer U1, a first capacitor C1, a first resistor R1, a second resistor R2, a second capacitor C2, a third resistor R3, and a third capacitor C3. Wherein, the first terminal 1(GND pin) of the timer U1 is grounded, the second terminal 2(TRIG pin) of the timer U1 is connected with the sixth terminal 6(THRE pin) of the timer U1, the positive electrode of the first capacitor C1 and one terminal of the first resistor R1, the third terminal 3(OUT pin) of the timer U1 is connected with one terminal of the second resistor R2 and one terminal of the fifth resistor R5, the fourth terminal 4(REST pin) of the timer U1 is connected with the first switch circuit 40, the fifth terminal 5(CONT pin) of the timer U1 is connected with the positive electrode of the second capacitor C2, the seventh terminal 7(DISCH pin) of the timer U1 is connected with the other terminal of the first resistor R1 and one terminal of the third resistor R3, and the eighth terminal 8 (VCC) of the timer U1 is connected with one terminal of the third capacitor R3; the negative electrode of the first capacitor C1 is grounded; the other end of the second resistor R2 is connected to the external power supply 11; the negative electrode of the second capacitor C2 is grounded; the other end of the third resistor R3 is connected to the external power supply 11; the other end of the third capacitor C3 is grounded.

In this embodiment, the timer U1 adopts an SE555 timer, the first capacitor C1, the first resistor R1, the second resistor R2, the second capacitor C2 and the third resistor R3 form a multivibrator, and the multivibrator is configured to output the square wave pulse signal. The oscillation period T ═ R ═ T + T, where T is the charge time of the first capacitor C, T is the discharge time of the first capacitor C, T ═ ln ═ R ≈ C (R + R) ≈ 0.7 ≈ R (R + R), and the discharge time T ═ ln ≈ R ≈ C0.7 ≈ R C, so that the oscillation period T ═ T + T ═ ln (R + R) ≈ C ≈ R ≈ C ≈ 0.7 (2R + R) (/) C of the square wave pulse signal, and the oscillation frequency f ═ T ═ 1.43/[ (2R + R)/[ (R): C)/(C): output drive duty (R)/[ 2 ═ R ]/[ C ] } R ] } C ], (R ═ C ═ R ═ C The ratio q3 of the discharge time to the charge time is T2/T1-ln 2-R1-C1/[ ln2 (R1+ R3) -C1-R1/(R1 + R3). Therefore, by changing the values of the first resistor R1, the third resistor R3, and the first capacitor C1, the period and frequency of the square wave pulse signal can be changed.

It is understood that the square wave generating circuit is not limited to the specific implementation manner disclosed in this embodiment, for example, the square wave generating circuit includes a hysteresis comparing circuit and an RC charging and discharging circuit, an input terminal of the hysteresis comparing circuit is connected to an output terminal of the RC charging and discharging circuit, an output terminal of the hysteresis comparing circuit is connected to an input terminal of the RC charging and discharging circuit, an output terminal of the hysteresis comparing circuit is used for outputting the square wave pulse signal, the square wave pulse signal includes a high level state and a low level state, and the RC charging and discharging circuit can be used to determine the maintaining time of the high level state and the low level state, so as to implement the periodic variation of the square wave pulse signal.

The second switch circuit 102 is respectively connected to the square wave generating circuit 101, the resonant transmitting circuit 20 and the external power source 11, and is configured to receive the square wave pulse signal and output the reference pulse signal.

In this embodiment, the second switch circuit 102 includes an NMOS transistor Q1 and a fourth resistor R4. A gate of the NMOS transistor Q1 is connected to a collector of the first NPN transistor Q2 and one end of the sixth resistor R6, a source of the NMOS transistor Q1 is connected to one end of the fourth resistor R4, and a drain of the NMOS transistor Q1 is connected to the external power source 11; the other end of the fourth resistor R4 is connected to the resonant transmission circuit 20.

When the square wave pulse signal is in a high level state, the grid of the NMOS transistor Q1 receives the square wave pulse signal with high level, the conduction condition of the NMOS transistor Q1 is met, and the NMOS transistor Q1 is conducted; when the square wave pulse signal is in a low level state, the gate of the NMOS transistor Q1 receives the square wave pulse signal of a low level, the on condition of the NMOS transistor Q1 is not satisfied, and the NMOS transistor Q1 is turned off, so that the second switch circuit 102 outputs the reference pulse signal with a certain frequency to the resonant transmitting circuit 20 to resonate the resonant transmitting circuit 20.

The third switch circuit 103 is connected between the square wave generator circuit 101 and the second switch circuit 102, and is configured to amplify the square wave pulse signal.

In this embodiment, the third switch circuit 103 includes a fifth resistor R5, a first NPN transistor Q2, and a sixth resistor R6. The other end of the fifth resistor R5 is connected with the base of the first NPN triode Q2; the emitter of the first NPN triode Q2 is grounded; the other end of the sixth resistor R6 is connected to the external power supply 11.

It can be understood that, since the square wave pulse signal is easily interfered by the outside, the third switch circuit 103 is added to amplify the square wave pulse signal, so as to avoid the outside interference, thereby improving the reliability of the second switch circuit 102. In some embodiments, the third switch circuit 103 may be omitted.

Since the voltage input range of the VCC pin of the SE555 timer is generally 5V to 15V, the output voltage of the external power supply 11 is 15V in this embodiment. The external power source 11 is disposed in the wireless charger, and is configured to provide a direct current voltage of 15V for the square wave generating circuit 101, the second switching circuit 102, the third switching circuit 103, and the first switch 403 (as shown in fig. 3).

The resonant transmitting circuit 20 is connected to the pulse generating circuit 10, and is configured to receive the reference pulse signal, generate a high-frequency alternating electromagnetic wave, and output a resonant voltage.

Referring to fig. 6, the resonant transmitting circuit 20 includes a first inductor L1 and a fourth capacitor C4. One end of the first inductor L1 is connected to one end of the fourth capacitor C4, the other end of the fourth resistor R4, and the first switch circuit 40, and the other end of the first inductor L1 and the other end of the fourth capacitor C4 are both grounded.

The first inductor L1 and the fourth capacitor C4 form an LC oscillating device, when the fourth capacitor C4 discharges, the first inductor L1 generates a reverse recoil current, and the first inductor L1 charges; when the voltage of the first inductor L1 reaches the maximum, the fourth capacitor C4 finishes discharging, and this is repeated, which is called the resonance of the first inductor L1 and the fourth capacitor C4. In order to improve the efficiency of the resonant transmitting circuit 20, the first inductor L1 and the fourth capacitor C4 with lower impedance are selected. The amplitude of the resonance voltage can be adjusted by adjusting the frequency of the reference pulse signal according to the resonance curve of the LC oscillation device.

The resonant receiving circuit 30 is configured to induce the high-frequency alternating electromagnetic wave, convert the high-frequency alternating electromagnetic wave into an induced voltage, and adjust the amplitude of the resonant voltage output by the resonant transmitting circuit 20 according to the distance between the resonant receiving circuit 30 and the resonant transmitting circuit 20.

In the present embodiment, the resonant receiving circuit 30 includes a second inductor L2. Due to the mutual inductance between the second inductor L2 and the first inductor L1, when the second inductor L2 approaches or leaves the first inductor L1, the inductance of the first inductor L1 is shifted, so that the resonance curve of the first inductor L1 and the resonance curve of the fourth capacitor C4 are changed, and the amplitude of the resonance voltage is changed.

The first switch circuit 40 is respectively connected to the pulse generating circuit 10, the resonant transmitting circuit 20 and the external power source 11, and is configured to operate in an on state or an off state according to the amplitude of the resonant voltage, so as to control the operating state of the pulse generating circuit 10.

Referring to fig. 3, the first switch circuit 40 includes a first voltage sampling circuit 401, a first voltage regulator circuit 402, and a first switch 403.

The first voltage sampling circuit 401 is connected to the second switching circuit 402 and the resonant transmitting circuit 20, and is configured to sample the resonant voltage and output a first sampled voltage. The first voltage stabilizing circuit 402 is connected to the first voltage sampling circuit 401, and is configured to perform voltage stabilization on the first sampled voltage. The first switch 403 is respectively connected to the first voltage stabilizing circuit 402, the square wave generating circuit 101, and the external power supply 11, and is configured to operate in an on state when a difference between the first sampling voltage after voltage stabilization and the output voltage of the external power supply 11 is smaller than an on voltage, and operate in an off state when the difference between the first sampling voltage after voltage stabilization and the output voltage of the external power supply 11 is larger than the on voltage.

As shown in fig. 6, the first voltage sampling circuit 401 includes a seventh resistor R7, an eighth resistor R8, a ninth resistor R9 and a tenth resistor R10, the first voltage regulating circuit 402 includes a first zener diode D1, and the first switch 403 includes a PNP transistor Q3. One end of the seventh resistor R7 is connected to one end of the first inductor L1, one end of the fourth capacitor C4, and the second switch circuit 102, the other end of the seventh resistor R7 is connected to one end of the eighth resistor R8, the other end of the eighth resistor R8 is connected to one end of the ninth resistor R9, the cathode of the first zener diode D1, and the base of the PNP triode Q3, the other end of the ninth resistor R9 is connected to one end of the tenth resistor R10, and the other end of the tenth resistor R10 and the anode of the first zener diode D1 are both grounded; the emitter of the PNP transistor Q3 is connected to the external power source 11, and the collector of the PNP transistor Q3 is connected to the square wave generating circuit 101.

Specifically, the seventh resistor R7, the eighth resistor R8, the ninth resistor R9, and the tenth resistor R10 are connected in series and used for sampling the resonant voltage, a connection point of the eighth resistor R8 and the ninth resistor R9 is a sampling point of the first voltage sampling circuit 401, and the sampling point is used for outputting the first sampling voltage; the first voltage stabilizing diode D1 is connected between the sampling point and the ground and is used for stabilizing the first sampling voltage; the first sampling voltage is regulated by the first voltage regulation diode D1 and then input to the base of the PNP transistor Q3, the emitter of the PNP transistor Q3 is connected to the external power supply 11, so the input voltage of the emitter of the PNP transistor Q3 is 15V, when the difference between the regulated first sampling voltage V1 and 15V is smaller than the on-state voltage, the PNP transistor Q3 is operated in the on-state, the SE555 timer is continuously operated, when the difference between the regulated first sampling voltage V1 and 15V is greater than the on-state voltage, the PNP transistor Q3 is operated in the off-state, the SE555 timer is stopped, wherein the on-state voltage is the forward voltage drop of the PNP transistor Q3 when the PNP transistor Q3 is turned on.

Please refer to fig. 4, which is a schematic structural diagram of a wireless charging circuit according to another embodiment of the present invention. As shown in fig. 4, the wireless charging circuit 200 includes the wireless charging circuit 100 according to the above embodiments, and please refer to the above embodiments for the same parts, which are not described in detail herein. The wireless charging circuit 200 further includes an input filter circuit 50, a rectifying filter circuit 60, a second voltage regulator circuit 70, and a fourth switch circuit 80.

The input filter circuit 50 is connected to the external power supply 11, and is configured to filter an output voltage of the external power supply 11.

In this embodiment, the input filter circuit 50 adopts a plurality of filter capacitors (not shown) connected in parallel for filtering the high-frequency signal of the output voltage (as shown in the figure, 15V dc voltage) of the external power source 11. In some embodiments, when the filter capacitor is an electrolytic capacitor, the output voltage of the external power source 11 is filtered by using the charging and discharging characteristics of the electrolytic capacitor, so that the pulsating direct current of the external power source 11 becomes a relatively stable direct current voltage.

The rectifying and filtering circuit 60 is connected to the resonant receiving circuit 30, and is configured to perform rectifying and filtering processing on the induced voltage. The second voltage stabilizing circuit 70 is connected to the rectifying and filtering circuit 60, and is configured to perform voltage stabilization on the induction voltage after the rectifying and filtering process, and output a charging voltage.

In the present embodiment, the rectifying-filtering circuit 60 includes a rectifying bridge (not shown) and an electrolytic capacitor (not shown), and the second regulator circuit 70 includes a zener diode (not shown). The second inductor L2 induces the high-frequency alternating electromagnetic wave around the first inductor L1, and converts the high-frequency alternating electromagnetic wave into a high-frequency alternating current according to the electromagnetic conversion principle, the high-frequency alternating current is output by the output end of the second inductor L2 under the action of the inductive impedance of the second inductor L2, and the induced voltage is rectified by the rectifier bridge, filtered by the electrolytic capacitor, stabilized by the zener diode, and the charging voltage VCC is output.

The fourth switching circuit 80 is connected between the second voltage stabilizing circuit 70 and the rechargeable battery 12, and is configured to, when the voltage of the rechargeable battery 12 is smaller than a preset voltage, operate the fourth switching circuit 80 in an on state, charge the rechargeable battery 12 by the charging voltage through the fourth switching circuit 80, and when the voltage of the rechargeable battery 12 is larger than the preset voltage, operate the fourth switching circuit 80 in an off state, and stop charging the rechargeable battery 12 by the charging voltage.

Referring to fig. 5, the fourth switch circuit 80 includes a second voltage sampling circuit 801, an amplitude discrimination circuit 802, and a second switch 803.

The second voltage sampling circuit 801 is connected to the second voltage stabilizing circuit 70, and is configured to sample the charging voltage. The amplitude discrimination circuit 802 is respectively connected to the second voltage sampling circuit 801 and the rechargeable battery 12, and is configured to sample the voltage of the rechargeable battery 12, and operate in an off state when the voltage of the rechargeable battery 12 is smaller than a preset voltage, and operate in an on state when the voltage of the rechargeable battery 12 is larger than the preset voltage. The second switch 803 is respectively connected to the amplitude discrimination circuit 802, the second voltage sampling circuit 801, and the rechargeable battery 12, and is configured to operate in an on state when the amplitude discrimination circuit 802 operates in an off state, and operate in an off state when the amplitude discrimination circuit 802 operates in an on state.

As shown in fig. 6, the second voltage sampling circuit 801 includes an eleventh resistor R11 and a twelfth resistor R12, the amplitude discrimination circuit 802 includes a controllable voltage source U2, a thirteenth resistor R13 and a fourteenth resistor R14, and the second switch 803 includes a second NPN transistor Q4. One end of the eleventh resistor R11 is connected to the second voltage regulator circuit 70 and the collector of the second NPN transistor Q4, and the other end of the eleventh resistor R11 is connected to one end of the twelfth resistor R12, the base of the second NPN transistor Q4, and the cathode of the controllable voltage source U2; the other end of the twelfth resistor R12 is grounded; a control electrode of the controllable voltage source U2 is connected to one end of the thirteenth resistor R13 and one end of the fourteenth resistor R14, and an anode of the controllable voltage source U2 and the other end of the fourteenth resistor R14 are both grounded; the other end of the thirteenth resistor R13 is connected to the emitter of the second NPN transistor Q4 and the rechargeable battery 12.

In the present embodiment, the controllable voltage source U2 is a TL431 precision controllable voltage source. Specifically, the thirteenth resistor R13 and the fourteenth resistor R14 form a voltage sampling circuit, which is used for sampling the voltage VBAT of the rechargeable battery 12, and a connection point of the thirteenth resistor R13 and the fourteenth resistor R14 is a sampling point, and outputs a sampling voltage to a control electrode of the TL431 precision controllable voltage source; when the voltage VBAT of the rechargeable battery 12 is smaller than a preset voltage, i.e., the input voltage of the gate of the TL431 precise controllable voltage source is smaller than the reference voltage (e.g., 2.5V) of the TL431 precise controllable voltage source, the turn-on condition of the TL431 precise controllable voltage source is not satisfied, the TL431 precision controllable voltage source is turned off, at this time, the base voltage of the second NPN transistor Q4 is equal to the voltage division of the charging voltage VCC by the eleventh resistor R11 and the twelfth resistor R12, the voltage division of the charging voltage VCC by the eleventh resistor R11 and the twelfth resistor R12 is greater than the voltage VBAT of the rechargeable battery 12 (at this time, the voltage VBAT of the rechargeable battery 12 is smaller), so as to satisfy the conduction condition of the second NPN transistor Q4, the second NPN transistor Q4 is turned on, and the charging voltage VCC charges the rechargeable battery 12 through the second NPN transistor Q4; when the voltage VBAT of the rechargeable battery 12 is greater than a preset voltage, that is, when the input voltage of the control electrode of the TL431 precise controllable voltage source is greater than the reference voltage (for example, 2.5V) of the TL431 precise controllable voltage source, the on condition of the TL431 precise controllable voltage source is satisfied, the TL431 precise controllable voltage source is turned on, at this time, the base voltage of the second NPN triode Q4 is pulled low, the on condition of the second NPN triode Q4 is not satisfied, and the second NPN triode Q4 is turned off, so as to cut off the charging circuit of the rechargeable battery 12 by the charging voltage VCC.

The embodiment of the utility model provides a wireless charging circuit, produce reference pulse signal through pulse generation circuit, resonance transmitting circuit receives reference pulse signal, produce high frequency alternation electromagnetic wave and output resonance voltage, resonance receiving circuit response high frequency alternation electromagnetic wave, turn into induced voltage with high frequency alternation electromagnetic wave, and, according to resonance receiving circuit and resonance transmitting circuit's distance, adjust resonance voltage's range, first switch circuit is according to resonance voltage's range, work is opening state or off-state, with control pulse generation circuit's operating condition, therefore, the cable constraint and frequent plug interface have been avoided, the non-contact wireless charging of convenient charging has been realized.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solution of the present invention, and not to limit it; within the idea of the invention, also technical features in the above embodiments or in different embodiments can be combined, steps can be implemented in any order, and there are many other variations of the different aspects of the invention as described above, which are not provided in detail for the sake of brevity; although the present invention has been described in detail with reference to the foregoing embodiments, it should be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; such modifications and substitutions do not depart from the spirit and scope of the present invention.

Claims

1. A wireless charging circuit, comprising:

2. The wireless charging circuit of claim 1, wherein the pulse generation circuit comprises:

3. The wireless charging circuit of claim 2, wherein the pulse generating circuit further comprises a third switching circuit connected between the square wave generating circuit and the second switching circuit for amplifying the square wave pulse signal.

4. The wireless charging circuit of claim 3, wherein the square wave generating circuit comprises a timer, a first capacitor, a first resistor, a second capacitor, a third resistor and a third capacitor, the second switching circuit comprises an NMOS transistor and a fourth resistor, and the third switching circuit comprises a fifth resistor, a first NPN transistor and a sixth resistor;

5. The wireless charging circuit of claim 4, wherein the resonant transmit circuit comprises a first inductor winding and a fourth capacitor, and wherein the resonant receive circuit comprises a second inductor winding;

6. The wireless charging circuit of claim 2, wherein the first switching circuit comprises:

and the first switch is respectively connected with the first voltage stabilizing circuit, the square wave generating circuit and the external power supply.

7. The wireless charging circuit of claim 6, wherein the first voltage sampling circuit comprises a seventh resistor, an eighth resistor, a ninth resistor, and a tenth resistor, the first voltage regulator circuit comprises a first voltage regulator diode, and the first switch comprises a PNP transistor;

8. The wireless charging circuit of any of claims 1-7, further comprising:

and the fourth switching circuit is connected between the second voltage stabilizing circuit and the rechargeable battery.

9. The wireless charging circuit of claim 8, wherein the fourth switching circuit comprises:

the amplitude discrimination circuit is respectively connected with the second voltage sampling circuit and the rechargeable battery;

and the second switch is respectively connected with the amplitude discrimination circuit, the second voltage sampling circuit and the rechargeable battery.

10. The wireless charging circuit of claim 9, wherein the second voltage sampling circuit comprises an eleventh resistor and a twelfth resistor, the amplitude discrimination circuit comprises a controllable voltage source, a thirteenth resistor and a fourteenth resistor, and the second switch comprises a second NPN transistor;