CN205960805U - Cavity self -adaptation resonant mode wireless charging equipment - Google Patents

Abstract

The utility model provides a cavity self -adaptation resonant mode wireless charging equipment, including casing, receiving module and be located the control circuit of casing, the outer wall of casing is equipped with the open cavity of one end, and the cavity is used for restricting the electromagnetic radiation scattering, improves the electromagnetic radiation concentration class, the bottom of cavity is equipped with the axis direction perpendicular to of the leading bar magnet of being made by magnetic materials, leading bar magnet the opening direction of cavity, the winding has a main induction coil on the leading bar magnet, main induction coil's both ends with control circuit connects, the receiving module cover is established in the cavity, be equipped with the vice magnetic conduction stick parallel with leading bar magnet in the receiving module, the winding has vice induction coil on the vice magnetic conduction stick, and vice induction coil's both ends and charging load are connected. The utility model discloses cavity self -adaptation resonant mode wireless charging equipment, simple structure is compact, has improved the conversion rate greatly, has reduced energy loss, has improved wireless charge efficiency to wireless charge time has significantly reduced.

Description

A kind of cavity self-adapting resonance formula wireless charging device

Technical field

The present invention relates to wireless charging field, particularly to a kind of cavity self-adapting resonance formula wireless charging device.

Background technology

If in general, electronic installation is equipped with a rechargeable battery, when the not enough power supply of the rechargeable battery in electronic installation When, user can be charged to rechargeable battery using a charging device.Existing charging device have a transformer and One connecting line, this transformer is plugged in power supply and makes this connecting line be inserted in electronic installation by user, makes the existing dress that charges Put permeable connecting line and transmit electric current to electronic installation.However, existing charging device is before charging, user must utilize Both hands grasp electronic installation and connecting line respectively, to execute the action that connecting line is plugged in electronic installation；After charging finishes, User also must recycle both hands to grasp electronic installation and connecting line respectively, is pulled away connecting line in electronic installation with executing Action, convenience is in fact had no on charging operations.

Growing with charging technique, occur in that wireless charging technology in the market.Wireless charging technology (Wireless charging technology；Wireless charge technology), come from wireless power transmission skill Art, low-power wireless charges, and frequently with the charging of induction high-power wireless, frequently with resonant mode, (most of electric automobile fills Electricity adopts this mode) device of electricity consumption is transmitted its energy to by power supply unit (charger), this device is using the energy receiving Battery is charged, and is used for itself running simultaneously.Due to energy being transmitted with magnetic field between charger and power device, both Between do not run wires to, therefore the device of charger and electricity consumption can accomplish that no conductive junction point exposes.

A kind of wireless charging device is disclosed in prior art, refering to Fig. 1 and Fig. 2, including：Transmiting signal source 1', flat board Electric capacity first electrode plate 2', capacity plate antenna second electrode plate 3', energy-storage module 4', receiving terminal coaxial cable 5', receiving coil 6', transmitting coil 7', transmitting terminal coaxial cable 8'.Emitter 1' is connected with transmitting terminal coaxial cable 8', transmitting terminal coaxial cable The inner wire of the other end of 8' and a joint connection, the outer conductor of transmitting terminal coaxial cable 8' and the emission lines of transmitting coil 7' Another joint of circle 7' connects.The inner wire of transmitting terminal coaxial cable 8' also connects with capacity plate antenna first electrode plate 2.Transmitting The outer conductor ground connection of end coaxial cable 8'.Energy-storage module 4' is connected with receiving terminal coaxial cable 5', receiving terminal coaxial cable 5''s The inner wire of the other end and a joint connection, the outer conductor of receiving terminal coaxial cable 5' and the receiving coil 6' of receiving coil 6' Another joint connect.The inner wire of receiving terminal coaxial cable 5' also connects with capacity plate antenna second electrode plate 3'.Receiving terminal The outer conductor ground connection of coaxial cable 5'.

From figure 2 it can be seen that the magnetic induction line of wireless charging device of the prior art scatters to periphery, secondary induction coil Extremely low to electromagnetic radiation utilization rate produced by main induction coil, energy loss is serious.

This wireless charging device as existing all wireless charging devices on the market, i.e. transmitting coil and receiving coil It is coaxially disposed, this kind of mode makes electromagnetic radiative losses high, thus reducing utilization rate, and the electric current producing, voltage are little, make no Line charge efficiency is extremely low, and the charging interval is long.Electric current produced by traditional wireless charging device is 500mA, and conversion ratio Only 10%～30%, waste serious；And the electromagnetic radiation that scatters everywhere all has certain harm to human body and periphery electrical equipment.

Content of the invention

【1】Technical problem to be solved

The technical problem to be solved in the present invention is to provide a kind of simple and compact for structure, charge efficiency high, high conversion rate, power Greatly, the cavity self-adapting resonance formula wireless charging device that loss is low and safety coefficient is high.

【2】The technical scheme of solve problem

The present invention provide a kind of cavity self-adapting resonance formula wireless charging device, it include housing, receiver module 102 and Control circuit in described housing；

The outer wall of described housing is provided with the cavity of open at one end, and described cavity is used for limit electromagnetic radiation and scatters, and improves electricity Magnetic radiation concentration class；The bottom of described cavity is provided with the leading bar magnet 901 being made up of permeability magnetic material, the axis of described leading bar magnet Direction, perpendicular to the opening direction of described cavity, described leading bar magnet is wound with main induction coil 9, described main induction coil Two ends be connected with described control circuit；

Described receiver module is set in described cavity or is located at directly over described cavity, be provided with described receiver module with The parallel secondary magnetic conductive rod 101 of described leading bar magnet, described pair magnetic conductive rod is wound with secondary induction coil 10, described secondary induction coil Two ends be connected with charging load.

Further, the two ends of described leading bar magnet form U-shaped magnetic conductive rod towards the opening direction bending of described cavity, described Main induction coil is wrapped on described U-shaped magnetic conductive rod.

Further, the outside of described cavity is provided with and is made up of metal material and for reflecting and shielding electromagnetic radiation Reflector.

Further, the side wall of described cavity is provided with the first radial positioning portion, and the side wall of described receiver module is provided with and institute Corresponding second radial positioning portion of the first radial positioning portion that states, described second radial positioning portion and described first radial positioning portion phase Coordinate and make described pair magnetic conductive rod and described leading bar magnet to be generally aligned in the same plane interior.

Further, the outside of described cavity is provided with the cavity 902 for placing described leading bar magnet, fills out in described cavity It is filled with plastic foam.

Further, described control circuit include rectification silicon bridge 1, APFC circuit 2, transformer 3, AD/DC module 4, CPU5, Driving chip 6 and MOS module 7, described rectification silicon bridge 1, described APFC circuit 2, described transformer 3 and described AD/DC module 4 according to Secondary connection, the output end of described AC/DC module is connected with described CPU, driving chip and MOS module respectively and is used for powering, institute The signal output part stating CPU is connected with the signal input part of described driving chip, the signal output part of described driving chip and institute The signal input part stating MOS module connects, and described main induction coil is located at the output end of described MOS module with described AC/DC's Between output end.

Further, described APFC circuit is MT7933 or LNK330B.

Further, also include testing circuit, described testing circuit includes the detection sense parallel with described main induction coil Answer coil 8, one end of described detection induction coil is connected with described CPU, other end ground connection.

The present invention also provides a kind of control method of cavity self-adapting resonance formula wireless charging device, and it includes following step Suddenly：

A, silicon bridge rectification, external ac power source is rectified into required direct current by rectification silicon bridge 1, and this direct current is conveyed To APFC circuit；

B, APFC, the direct current obtaining from rectification silicon bridge output end is carried out active power by APFC circuit Factor correcting, is conveyed to transformer after improving power factor；

C, transformation, the direct current obtaining from APFC circuit output end is carried out transformation process by transformer, and obtains required High-frequency alternating current；

D, high-frequency direct-current conversion, the alternating current obtaining from transformer output end is changed and is exported straight by AC/DC module Stream electricity, for being powered to CPU, driving chip, MOS module and main induction coil 9；

E, charging load detection, when receiver module insertion cavity, detect the impedance of secondary induction coil by testing circuit, And feed back to CPU, the frequency of charging load is calculated by CPU；

F, output control, data-signal is passed to driving chip after calculating by CPU, and driving chip promotes the output of MOS module One frequency matching with charging load, realizes magnetic resonance, thus completing output control.

Further, in step E, CPU calculates inductance value, frequency, power and the secondary magnetic conductive rod of charging load simultaneously Size.

【3】Beneficial effect

Cavity self-adapting resonance formula wireless charging device of the present invention, simple and compact for structure, transmitting coil and receiving coil are not It is coaxially disposed, and is arranged in cavity, so that the electromagnetic radiation that transmitting coil produces is strapped in cavity, and so that it is concentrated towards reception Coil transmissions, substantially increase conversion ratio, reduce energy loss, improve wireless charging efficiency, and greatly reduce wireless Charging interval；And the permeability magnetic material of transmitting terminal adopts U-shaped structure, further increase energy transformation ratio and charge efficiency；Can produce Raw larger current and voltage；By conversion system, frequency is shaken according to different load regulation, can automatically generate with load corresponding Electric current, voltage.

Brief description

Fig. 1 is the structural representation of wireless charging device of the prior art；

Fig. 2 is the magnetic induction line schematic diagram of wireless charging device of the prior art；

Fig. 3 is the charging curve schematic diagram of the charging load of wireless charging device of the prior art；

Fig. 4 is the control circuit structural representation of cavity self-adapting resonance formula wireless charging device of the present invention；

Fig. 5 is the structural representation of cavity self-adapting resonance formula wireless charging device embodiment one of the present invention；

Fig. 6 is the structural representation of cavity self-adapting resonance formula wireless charging device embodiment two of the present invention；

Fig. 7 is the structural representation of cavity self-adapting resonance formula wireless charging device embodiment three of the present invention；

Fig. 8 is the structural representation of cavity self-adapting resonance formula wireless charging device example IV of the present invention；

Fig. 9 is the structural representation of cavity self-adapting resonance formula wireless charging device embodiment five of the present invention；

Figure 10 is the structural representation of cavity self-adapting resonance formula wireless charging device embodiment six of the present invention；

Figure 11 is the use schematic diagram of cavity self-adapting resonance formula wireless charging device of the present invention；

Figure 12 is the magnetic induction line schematic diagram of cavity self-adapting resonance formula wireless charging device of the present invention；

Figure 13 is the charging curve schematic diagram of the charging load of cavity self-adapting resonance formula wireless charging device of the present invention；

Figure 14 is the circuit diagram of the APFC (MT7933) of cavity self-adapting resonance formula wireless charging device of the present invention；

Figure 15 is the startup program schematic diagram of the MT7933 of cavity self-adapting resonance formula wireless charging device of the present invention；

Figure 16 is the MT7933 PFC schematic diagram of cavity self-adapting resonance formula wireless charging device of the present invention；

Figure 17 is that the MT7933 assists winding detection function of cavity self-adapting resonance formula wireless charging device of the present invention is illustrated Figure

Specific embodiment

Below in conjunction with the accompanying drawings, the embodiment of the present invention is discussed in detail.

Refering to Fig. 4 to Figure 17, the present invention provides a kind of cavity self-adapting resonance formula wireless charging device, and it includes housing 11st, receiver module 102 and the control circuit being located in housing；

It is provided with the cavity (being equivalent to jack) of open at one end (opening) in the outer wall of housing, cavity is used for limit electromagnetic radiation Scattering, makes electromagnetic radiation towards open-end reflection, improves electromagnetic radiation builds degree and bulk strength, and reduce loss；In cavity Bottom is provided with the leading bar magnet 901 being made up of permeability magnetic material, the axis direction of this leading bar magnet perpendicular to the opening direction of cavity, Main induction coil 9 is wound with leading bar magnet, leading bar magnet and main induction coil constitute transmitting terminal, the two of this main induction coil End is connected with control circuit；

Receiver module can be set in plug in cavity (being equivalent to plug), and as plug-in type wireless charging, in this reception It is provided with the secondary magnetic conductive rod 101 parallel with leading bar magnet in module, secondary induction coil 10, secondary magnetic conductive rod are wound with secondary magnetic conductive rod Constitute receiving terminal with secondary induction coil, the two ends of secondary induction coil are connected with charging load, charging load include all kinds of mobile phones, All kinds of portable equipment such as MP3, MP4, PAD portable power source.

This receiver module can also be located at directly over cavity, and now, cavity depth is shallower, and leading bar magnet is within the cavity, And in cavity built with filler, whole cavity is filled up by this filler, make cavity hatch end concordant with housing, that is, form one Plane, now, receiver module is placed and be can achieve wireless charging, as attaching type wireless charging on this plane.

In order to improve property easy to use, this cavity can be made into the form of strip groove, and charging load, such as mobile phone, PAD etc. can It is directly placed in this strip groove, uses in charging, now housing plays the effect of support base；In order to improve using comfortable Property, this strip groove is obliquely installed, refering to Figure 11.

In order to improve conversion ratio further, improve charge efficiency, the two ends of this leading bar magnet are towards the opening direction folding of cavity Bending becomes U-shaped magnetic conductive rod, i.e. overall U-shaped, and main induction coil is wrapped on U-shaped magnetic conductive rod.In order to improve the collection of electromagnetic radiation In, and shield electromagnetic radiation and leak, thus improving the security of equipment, it is to avoid periphery human body and electronic equipment are caused hinder Evil, is provided with, in the outside of cavity, the reflector being made up of metal material, and this reflector can reflect the electromagnetic radiation of transmitting terminal generation, So that it is assembled towards receiving terminal side, be avoided that scattering damages, in the present embodiment, this reflector is by aluminium alloy system simultaneously Become.In making leading bar magnet parallel with secondary magnetic conductive rod when receiver module inserts or being generally aligned in the same plane, in the side of cavity Wall is provided with the first radial positioning portion, and the side wall of receiver module is provided with second radial positioning portion corresponding with the first radial positioning portion, Second radial positioning portion matches with the first radial positioning portion to merge to be made in secondary magnetic conductive rod and leading bar magnet be generally aligned in the same plane, in order to Cavity can be made cuboid by convenient processing.Outside in cavity is provided with the cavity 902 for placing leading bar magnet simultaneously, It is filled with plastic foam, leading bar magnet can be fixed in cavity for this plastic foam in cavity.

Different structure below for transmitter module and receiver module is illustrated；

Transmitter module includes leading bar magnet and is wrapped in the main induction coil on this leading bar magnet；

Receiver module includes secondary magnetic conductive rod and is wrapped in the secondary induction coil on this secondary magnetic conductive rod；

In following examples, difference is only the position relationship between leading bar magnet and secondary magnetic conductive rod and respective shape On difference；

Embodiment one, refering to Fig. 5, leading bar magnet overall U-shaped, secondary magnetic conductive rod is vertical bar shaped, and this receiver module can be inserted Enter in cavity, and so that secondary magnetic conductive rod is located between leading bar magnet；Now transmitter module is equivalent to socket, and receiver module is equivalent to Plug；

Embodiment two, refering to Fig. 6, cavity depth is shallower, and leading bar magnet is also U-shaped and within the cavity, simultaneously in cavity Built with filler, whole cavity is filled up by this filler, and makes cavity hatch end concordant with housing, that is, form a plane, Now, receiver module is jointly mounted to Radiation Module upper surface, and now, the secondary magnetic conductive rod in receiver module is vertical bar shaped, and should The length of secondary permeability magnetic material is less than the distance between leading bar magnet two bending section；

Embodiment three, refering to Fig. 7, cavity depth is shallower, and leading bar magnet is also U-shaped and within the cavity, simultaneously in cavity Built with filler, whole cavity is filled up by this filler, and makes cavity hatch end concordant with housing, that is, form a plane, Now, receiver module is jointly mounted to Radiation Module upper surface, and now, the secondary magnetic conductive rod in receiver module is vertical bar shaped, and should The length of secondary permeability magnetic material is more than or equal to the distance between leading bar magnet two bending section；

Example IV, refering to Fig. 8, cavity depth is shallower, and leading bar magnet is also U-shaped and within the cavity, simultaneously in cavity Built with filler, whole cavity is filled up by this filler, and makes cavity hatch end concordant with housing, that is, form a plane, Now, receiver module is jointly mounted to Radiation Module upper surface, and the secondary magnetic conductive rod in receiver module also be U-shape, and its with Leading bar magnet is symmetrical arranged；

Embodiment five, refering to Fig. 9, leading bar magnet is in integrally the U-shaped structure of opening upwards, and secondary magnetic conductive rod is what Open Side Down U-shaped structure, and this receiver module can insert in cavity, and so that secondary magnetic conductive rod is located between leading bar magnet；Now transmitter module phase When in socket, and receiver module is equivalent to plug；

Embodiment six, refering to Figure 10, is only defined to leading bar magnet in this embodiment, the leading bar magnet in this embodiment For I-shaped.；

Above-described embodiment is only the preferred embodiment of the application.

In the application, secondary magnetic conductive rod is inserted into leading bar magnet interior (plug-in type wireless charging) or is located on leading bar magnet End (attaching type wireless charging), and secondary magnetic conductive rod can be vertical bar shaped, U-shaped or I-shaped etc., and the two ends of leading bar magnet are respectively It is provided with extension, main induction coil can be wrapped in leading bar magnet main body or extend on the extension at two ends, this extension Can extend to direction, that is, form U-shape, or extend to both direction, that is, formed I-shaped it is also possible to three or many Individual direction extends, and belongs to the protection domain of the application.

Electromagnetic radiation produced by main induction coil on wireless charging device in the application is concentrated to secondary induction coil Position is radiated, and secondary induction coil is high to electromagnetic radiation utilization rate produced by main induction coil, and energy loss is little, thus carrying High charge efficiency, decreases the charging interval.

The size of induced electromotive force is as follows with the relation of the magnetic flux through closed circuit：

In wireless charging technology in prior art, the magnetic flux of secondary coil is less than the 1/2 of main coil magnetic flux, and in reality In application, add other stray radiations and coil loss, actual converted rate is less than 20%, constrain answering of wireless charging technology With.Pass through bipolar resonance trough in the application, by the magnetic flux of closing coil, 100% can be up in theory, experimental prototype Actual converted efficiency up to more than 85%, and prototyping testing can be provided.

Hereinafter the structure of control circuit is described in detail；

This control circuit includes rectification silicon bridge 1, APFC circuit 2, transformer 3, AD/DC module 4, CPU5, driving chip 6 With MOS module 7, rectification silicon bridge 1, APFC circuit 2, transformer 3 and AD/DC module 4 be sequentially connected, rectification silicon bridge and external power source Connect, the output end of AC/DC is connected with described CPU, driving chip and MOS module respectively and is used for powering, the signal of described CPU Output end is connected with the signal input part of described driving chip, the signal output part of described driving chip and described MOS module Signal input part connects, and described main induction coil is located between output end and the output end of described AC/DC of described MOS module, APFC circuit in the present embodiment adopts MT7933 or LNK330B；In order to improve the equipment scope of application so as to can be according to different Equipment carries out electric current, voltage is harmonized, and also includes testing circuit, this testing circuit includes parallel with main induction coil in the present embodiment Detection induction coil 8, one end of detection induction coil is connected with CPU, the other end is grounded, and this detection induction coil is used for detecting The impedance of secondary induction coil, and this resistance value is conveyed to CPU, calculates the inductance value, frequently of this secondary induction coil by CPU The size of rate, power and secondary magnetic conductive rod, can judge the type loading, realize adaptive inductive charging, it is to avoid produce too high voltage Circuit damage charging load or produce too low voltage x current and extend the charging interval.

The present invention also provides the control method of above-mentioned cavity self-adapting resonance formula wireless charging device, and it includes following step Suddenly：

A, silicon bridge rectification, the AC power of outside 220V is rectified into required direct current by rectification silicon bridge 1, and by this direct current Electricity is conveyed to APFC circuit；

B, APFC, the direct current obtaining from rectification silicon bridge output end is carried out active power by APFC circuit Factor correcting, is conveyed to transformer after improving power factor；

C, transformation, the direct current obtaining from APFC circuit output end is carried out transformation process by transformer, and obtains required Alternating current；

D, AC-DC conversion, the alternating current obtaining from transformer output end is changed and is exported direct current by AC/DC module Electricity, for being powered to CPU, driving chip, MOS module and main induction coil 9；

E, charging load detection, when receiver module insertion cavity, detect the impedance of secondary induction coil by testing circuit, And feed back to CPU, the inductance value of charging load, the size of frequency, power and secondary magnetic conductive rod are calculated by CPU；

F, output control, data-signal is passed to driving chip after calculating by CPU, and driving chip promotes the output of MOS module One frequency matching with charging load, realizes magnetic resonance, thus completing output control.

In order to improve automaticity, it is to avoid CPU, in unloaded Spatio-temporal operation, can be provided for detection in cavity and receive mould The receiver module detection means whether block inserts, this receiver module detection means may be installed cavity bottom, can be distance perspective Answer device or proximity switch or mechanical type contact switch.

Below by way of the wireless charging technology movement to same model simultaneously in conventional wireless charging technique and the application Terminal is charged comparing, and charge efficiency curve refers to Fig. 3 (conventional art) and Figure 14 (present techniques), and detail parameters refer to Tables 1 and 2, wherein, table 1 is the experimental data of wireless charging technology of the prior art, and table 2 is wireless charging skill in the application The experimental data of art；

Table 1 (experimental data in prior art)

Charging terminal	1h	2h	3h	4h	5h	6h	7h	8h	9h	10h
											Terminal 1 (600mA)	18%	35%	51%	65%	77%	84%	90%	95%	98%	100%
Terminal 2 (400mA)	25%	48%	65%	79%	88%	95%	100%

Table 2 (experimental data in the application)

Charging terminal

0.5h

1h

1.5h

2h

2.5h

3h

3.5h

Terminal 1 (600mA)

30%

58%

85%

100%

Terminal 2 (400mA)

60%

100%

Hereinafter the APFC circuit in the application is described in detail, in the present embodiment, this APFC adopt MT7933 or LNK330B；

MT7933, its circuit diagram refers to Figure 15；

MT7933 is single-stage, a High Power Factor, and primary-side-control exchange turns DC driven chip.On MT7933 integration slice PFC (PFC) function, runs it is achieved that High Power Factor reduce power MOS pipe and open under critical conduction mode Close loss.Using the bright scientific and technological distinctive control technology of U.S. core, just can accurately modulate electricity without optocoupler and secondary sensing device Stream.

MT7933 is simultaneously achieved various defencive functions, including overcurrent protection (OCP), overvoltage protection (OVP), short-circuit protection (SCP) and overtemperature protection (OTP) etc., reliably worked with guaranteeing system.

It includes 6 pins, refering to table 3；

Table 3 (explanation of MT7933 pin)

And its electrical parameter refers to table 4；

Table 4 (MT7933 electrical parameter)

Current control,

By detecting former limit electrical parameter, MT7933 being capable of accurate adjustment electric current.Electric current can by equation below very Readily arrange：

In formula, NP is the primary side winding number of turn, and NS is secondary winding turns；VFB (=400mV) is internal reference level, and RS is One foreign current inductive reactance.

Start-up course

In start-up course, VDD is charged by the startup resistance being connected to bus.When VDD reaches 18V, COMP quilt Internal circuit is pre-charged.After COMP reaches 0.8V, inner control loop has built up, and sends " LoopOK " internal signal. Then pwm signal is sent to DRV pin, makes system startup work.Once the voltage in assists winding rises sufficiently high, chip Power supply will be provided by assists winding.When VDD is less than 7.2V, pwm signal will close (under-voltage locking threshold voltage).Meanwhile, COMP pin electric capacity is discharged into zero.Whole startup program is as illustrated in fig. 15.

PFC

In the ON time of outside metal-oxide-semiconductor, primary current can increase linearly to peak value from 0mA, and this electric current passes through sensing Resistance is detected by CS pin.When primary current reaches threshold limit, MT7933 can close metal-oxide-semiconductor immediately.When secondary current exhausts, MT7933 can be again turned on metal-oxide-semiconductor.By the proprietary technology of the bright science and technology of U.S. core, the threshold value of peak point current can follow the tracks of the mother after rectification The sinusoidal waveform of line voltage.Therefore, the envelope of inductive current is also sinusoidal waveform, thus can achieve High Power Factor, refering to figure 16.

Assists winding electrical parameter detects

Opening of power MOS pipe is to be determined by detecting DSEN pin waveform, and this waveform passes through resitstance voltage divider in auxiliary On winding, sampling obtains.When DSEN waveform when off interior less than 0V, this indicates that power MOS pipe drain voltage has fallen to The lowest point or near, MT7933 will be again started up power MOS pipe.Additionally, minimum turn-off time mechanism ensure that the anti-of system Interference performance.In addition, MT7933 also has the functions such as short circuit, open circuit and overcurrent protection, and these functions are all by detection The shape information of assists winding is triggering.This is because within the power MOS pipe turn-off time, auxiliary winding voltage is electric with output Pressure (secondary winding voltage) is directly proportional.The detection of auxiliary winding voltage be by DSEN pin after gate drive signal terminates through one After the individual lead-edge-blanking time, sampled.Assists winding detection function is as shown in figure 17.

Overvoltage protection

The built-in two overvoltage protection mechanism of MT7933：(1) DSEN pin voltage is higher than 3.2V and occurs three times, then be judged as Output open circuit.MT7933 will close pwm switching signal, and vdd voltage is gradually decreased to UVLO threshold value, and enters restarting mode.Output The overvoltage protection threshold VOUT_OV of voltage can be set by following formula：

In formula, Ns is secondary windings, and Na is assists winding, and VD3 is the forward voltage drop of secondary windings commutation diode.(2) such as More than 24V tri- times, MT7933 is automatically switched off pwm signal to the voltage of fruit VDD pin, and VDD is progressively down to UVLO threshold value, and enters and restart Pattern.Suggestion designs suitable transformer Na and Ns ratio.Vdd voltage is arranged between 12V to 22V.

Short-circuit protection

If DSEN pin voltage is interior when off and continues 5～10 milliseconds less than 400mV, then open short-circuit protection work( Energy.PWM drive signal will stop.When vdd voltage is gradually decreased to less than UVLO threshold value, system will enter restarting mode.Above-mentioned Restarting process will repeat always, until short circuit eliminates.

Overcurrent protection

Once CS pin voltage will immediately turn off power MOS pipe more than 1.8V, MT7933.The side of this Cycle by Cycle over-current detection Formula protects the element of correlation to avoid damaging, such as power MOS pipe, transformer etc..

MT7933 is that a single-stage, the exchange of primary side feedback turn direct-current LED driving chip.By detecting former limit power information, LED current can accurately be modulated.MT7933 integrated power factor correcting function, eliminates the current harmonics pollution to electricity network. It is operated in CRM (critical conduction mode), reduces switching loss, improves system effectiveness.

Cavity self-adapting resonance formula wireless charging device in the present embodiment, by conventional wireless charging equipment electric current 500mA is promoted to 5A, and conversion ratio is promoted to 80%～85% by traditional 20%～40%.

Cavity self-adapting resonance formula wireless charging device of the present invention, simple and compact for structure, transmitting coil and receiving coil are not It is coaxially disposed, and is arranged in cavity, so that the electromagnetic radiation that transmitting coil produces is strapped in cavity, and so that it is concentrated towards reception Coil transmissions, substantially increase conversion ratio, reduce energy loss, improve wireless charging efficiency, and greatly reduce wireless Charging interval；And the permeability magnetic material of transmitting terminal adopts U-shaped structure, further increase energy transformation ratio and charge efficiency；Can produce Raw larger current and voltage；By conversion system, frequency is shaken according to different load regulation, can automatically generate with load corresponding Electric current, voltage.

The above is only the preferred embodiment of the present invention it is noted that ordinary skill people for the art For member, on the premise of without departing from the technology of the present invention principle, some improvements and modifications can also be made, these improvements and modifications Also should be regarded as protection scope of the present invention.

Claims (8)

1. a kind of cavity self-adapting resonance formula wireless charging device it is characterised in that：Including housing, receiver module (102) and position Control circuit in described housing；

The outer wall of described housing is provided with the cavity of open at one end, and described cavity is used for limit electromagnetic radiation and scatters, and improves electromagnetism spoke Penetrate concentration class；The bottom of described cavity is provided with the leading bar magnet (901) being made up of permeability magnetic material, the axis side of described leading bar magnet To the opening direction perpendicular to described cavity, described leading bar magnet is wound with main induction coil (9), described main induction coil Two ends are connected with described control circuit；

Described receiver module is set in described cavity or is located at directly over described cavity, be provided with described receiver module with described The parallel secondary magnetic conductive rod (101) of leading bar magnet, described pair magnetic conductive rod is wound with secondary induction coil (10), described secondary induction coil Two ends be connected with charging load.

2. cavity self-adapting resonance formula wireless charging device as claimed in claim 1 it is characterised in that：Described leading bar magnet Two ends form U-shaped magnetic conductive rod towards the opening direction bending of described cavity, and described main induction coil is wrapped in described U-shaped magnetic conductive rod On.

3. cavity self-adapting resonance formula wireless charging device as claimed in claim 1 it is characterised in that：The outside of described cavity It is provided with the reflector being made up and for reflecting and shielding electromagnetic radiation of metal material.

4. cavity self-adapting resonance formula wireless charging device as claimed in claim 1 it is characterised in that：The side wall of described cavity It is provided with the first radial positioning portion, the side wall of described receiver module is provided with corresponding with described first radial positioning portion second radially to be determined Position portion, described second radial positioning portion matches with described first radial positioning portion to merge makes described pair magnetic conductive rod and described leading magnetic In rod is generally aligned in the same plane.

5. cavity self-adapting resonance formula wireless charging device as claimed in claim 1 it is characterised in that：The outside of described cavity It is provided with the cavity (902) for placing described leading bar magnet, in described cavity, be filled with plastic foam.

6. cavity self-adapting resonance formula wireless charging device as claimed in claim 1 it is characterised in that：Described control circuit bag Include rectification silicon bridge (1), APFC circuit (2), transformer (3), AD/DC module (4), CPU (5), driving chip (6) and MOS module (7), described rectification silicon bridge (1), described APFC circuit (2), described transformer (3) and described AD/DC module (4) are sequentially connected, The output end of described AC/DC module is connected with described CPU, driving chip and MOS module respectively and is used for powering, described CPU's Signal output part is connected with the signal input part of described driving chip, the signal output part of described driving chip and described MOS mould The signal input part of block connects, described main induction coil be located at the output end of described MOS module and described AC/DC output end it Between.

7. cavity self-adapting resonance formula wireless charging device as claimed in claim 6 it is characterised in that：Described APFC circuit is MT7933 or LNK330B.

8. cavity self-adapting resonance formula wireless charging device as claimed in claim 6 it is characterised in that：Also include detection electricity Road, described testing circuit includes the detection induction coil (8) parallel with described main induction coil, and the one of described detection induction coil End is connected with described CPU, other end ground connection.