CN205051447U - Wireless charging circuit topological structure of low -power - Google Patents
Wireless charging circuit topological structure of low -power Download PDFInfo
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- CN205051447U CN205051447U CN201520699272.5U CN201520699272U CN205051447U CN 205051447 U CN205051447 U CN 205051447U CN 201520699272 U CN201520699272 U CN 201520699272U CN 205051447 U CN205051447 U CN 205051447U
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- circuit
- resonant circuit
- resonance circuit
- former limit
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Abstract
The utility model relates to a wireless charging circuit topological structure of low -power, including inverter circuit, former limit resonance circuit, vice limit resonance circuit, a rectification circuit, the switch reduction voltage circuit, the full -bridge inverter circuit of inverter circuit for becoming by 4 low MOS nests of tubes that switch on the impedance, become alternating current output with the direct current of input, output meets the electric capacity cp by establishing ties, the former limit resonance circuit's that wireless transmitting coil lp constitutes both ends, a serial communication port, vice limit resonance circuit is parallel resonance circuit, by electric capacity cs, wireless receiving coil ls is parallelly connected to be constituteed, former limit resonance circuit and vice limit resonance circuit pass through the high frequency magnetic field coupling, the electric energy transmits vice limit resonance circuit from former limit resonance circuit's output, the direct current is exported to vice limit resonance circuit output interflow electricity after the rectifier circuit rectification, be the required voltage of load through switch step -down circuit adjusts again. The efficiency of the wireless power transmission distance who charges with is improved.
Description
Technical field
The utility model relates to a kind of wireless charging technology, particularly a kind of low-power wireless charging circuit topology.
Background technology
The formal name used at school of wireless charging technology is called wireless power transmission again, its principle is very similar to transformer, all produce an alternating current by radiating circuit to pass through primary coil, thus an alternating electromagnetic field is produced on primary coil, secondary coil, by receiving this alternating electromagnetic field thus producing induced current, realizes the transmission of the energy by electromagnetic induction.
But carried out the high degree of coupling of conduct electricity magnetic energy formation by magnetic core compared to transformer, the conducting path of wireless charging is air, this makes the degree of coupling between Wireless charging coil be significantly less than transformer, this is also directly cause the short and inefficient maximum bottleneck place of wireless charging transmission range, and present stage wireless charging to overcome the main way of weak coupling be exactly respectively connect the electric capacity of certain capacitance to improve distance and the efficiency of wireless transmission at transmitting coil and receiving coil.
The mainstream standard of current wireless charging industry is the QI standard that WPC alliance dominates.QI standard is global first wireless charging standardization body, and this standard is also promote in all standards the most extensively, and maximum standards is applied in market, and on market, the product of the overwhelming majority is all based on QI standard.QI preferred circuit connection diagram as shown in Figure 1, what the launching and receiving part of this standard adopted is two series resonant circuits being in same resonance frequency, and load voltage mainly regulates by the pressure drop of metal-oxide-semiconductor.The transmission range of this technology is once more than 5mm, and efficiency of transmission will sharply decline pole; Meanwhile, the scope within transmission range 5mm, if the power of transmission is lower than 2W, the efficiency of transmission can sharply decline too.This technology of these two main drawbacks limit mainly can only be applied between 2W to 5W, and transmission range is less than the application of 5mm.
Summary of the invention
The utility model is for the present wireless charging circuit Problems existing based on QI standard, proposes a kind of low-power wireless charging circuit topology, effectively can improve the circuit topological structure of efficiency of transmission under wireless charging transmission range and low-power.If this topological structure is then less than 2W in through-put power under being applied in QI standard, within transmission range 5mm, system average transmission efficiency can remain on more than 70%; When transmission range is 30mm time, system transfers efficiency is 48%, and improves along with shortening of transmission range.This circuit topological structure is specially adapted to some needs certain transmission range and the not high application scenario of through-put power, such as Wearable device.
The technical solution of the utility model is: a kind of low-power wireless charging circuit topology, comprise inverter circuit, former limit resonant circuit, secondary resonant circuit, rectification circuit, switch buck circuit, inverter circuit is the full bridge inverter be made up of the metal-oxide-semiconductor of 4 low conduction impedances, the direct current of input is become alternating current to export, exporting connects by the electric capacity Cp connected, the two ends of the former limit resonant circuit that wireless transmission coil Lp forms, secondary resonant circuit is parallel resonant circuit, by electric capacity Cs, wireless receive coil Ls composes in parallel, former limit resonant circuit is coupled by high frequency magnetic field with secondary resonant circuit, electric energy is delivered to secondary resonant circuit from the output of former limit resonant circuit, secondary resonant circuit output AC electricity exports direct current after rectifier circuit rectifies, again through switch buck circuit adjustment be load required voltage.
Described switch buck circuit is made up of the metal-oxide-semiconductor of two low conduction impedances, inductance and filter capacitor, the metal-oxide-semiconductor series connection of two low conduction impedances, and series connection point and direct current negative pole connect the inductance and filter capacitor of connecting, and filter capacitor two ends are output.
The beneficial effects of the utility model are: the utility model low-power wireless charging circuit topology, improve the power delivery Distance geometry efficiency of wireless charging.
Accompanying drawing explanation
Fig. 1 is QI preferred circuit connection diagram;
Fig. 2 is the utility model low-power wireless charging circuit topology schematic diagram;
Fig. 3 is a kind of wireless charging circuit system schematic applying the utility model circuit topological structure;
Fig. 4 is the utility model efficiency by inputoutput test curve chart of the present utility model under QI standard.
Embodiment
Low-power wireless charging circuit topology schematic diagram as shown in Figure 2, comprises inverter circuit, former limit resonant circuit, secondary resonant circuit, rectification circuit, switch buck circuit, inverter circuit is the full bridge inverter be made up of the metal-oxide-semiconductor of 4 low conduction impedances, the direct current of input is become alternating current to export, exporting connects by the electric capacity Cp connected, the two ends of the former limit resonant circuit that wireless transmission coil Lp forms, secondary resonant circuit is parallel resonant circuit, by electric capacity Cs, wireless receive coil Ls composes in parallel, former limit resonant circuit is coupled by high frequency magnetic field with secondary resonant circuit, electric energy is delivered to secondary resonant circuit from the output of former limit resonant circuit, secondary resonant circuit output AC electricity exports direct current after rectifier circuit rectifies, again through switch buck circuit adjustment be load required voltage.
Switch buck circuit is made up of the metal-oxide-semiconductor of two low conduction impedances, inductance and filter capacitor, the metal-oxide-semiconductor series connection of two low conduction impedances, and series connection point and direct current negative pole connect the inductance and filter capacitor of connecting, and filter capacitor two ends are output.
When the low coupling coil electric energy transmission system of analysis, reflected umpedance is a kind of well analytical method.If whole wireless transmitting system is observed from radiating portion, then whole receiving terminal can be equivalent to the reflected umpedance that is series at transmitting terminal; The power that transmitting terminal consumes on reflected umpedance then can be equivalent to the power received by receiving terminal; The size of reflected umpedance directly reflects the impact of receiving terminal for transmitting terminal, reflected umpedance is larger, then receiving terminal and transmitting terminal contact is more tight, and the efficiency transferring energy to receiving terminal from transmitting terminal is also higher, the efficiency of whole system and transmission range are also higher, otherwise then no.
In existing technology, secondary resonant circuit is series resonant circuit, is W at the reflected umpedance of transmitting terminal under its resonance condition
2m
2/ R
l, wherein, W is resonance frequency, and M is mutual inductance, R
lit is load.Along with the raising of transmission range, M can be less, then reflected umpedance is also less.Why this also just further illustrate, and wireless charging transmission range can only at below 5mm in prior art.
From W
2m
2/ R
lin it can also be seen that R
lless, then reflected umpedance is larger.Under certain load voltage, load current is larger, then R
lless, and present stage wireless charging standard maximum output be 5V, 1A, being converted into load is 5 ohm, and that is least-loaded value also just only has 5 ohm present stage, this also just further illustrate why in prior art wireless charging can not reach very high efficiency under low-power.
In the utility model, secondary resonant circuit is antiresonant circuit, is M at the reflected umpedance of transmitting terminal under its resonance condition
2r
l/ L
s2, wherein, M is mutual inductance, R
lload, L
sit is secondary coil inductance.As can be seen from formula, R
llarger, then reflected umpedance is larger.
In the utility model, real crucial technology point is the combination of BUCK switch buck circuit and secondary antiresonant circuit, because BUCK switch buck circuit has the effect of amplifying load, according to formula R
in=D
2r
outthe raising along with D can be drawn, R
inalso proportional raising, wherein R
infor the input impedance of BUCK switch buck circuit, R
outfor the output impedance of BUCK switch buck circuit, D is duty ratio.Therefore by the function that the load of BUCK switch buck circuit is amplified, the reflected umpedance of transmitting terminal can be improved greatly, thus also just explain why the utility model has higher efficiency and farther transmission range than prior art.
The resonance frequency of described former limit resonant circuit (Lp, Cp)
with the resonance frequency of secondary resonant circuit (Ls, Cs)
not identical, its ratio f
s/ f
pscope be 1.1 ~ 2.0.
Apply a wireless charging circuit system schematic for the utility model circuit topological structure as shown in Figure 3, comprise transmitter module and receiver module, this wireless charging circuit system is compatible QI standard to a certain extent.
The circuit introducing transmitter module and receiver module below forms:
Transmitter module comprises DC constant voltage power supply DC, transmitting terminal switch buck circuit, inverter circuit, series resonant circuit (Lp, Cp), transmitting terminal communication control module.Wherein transmitting terminal switch buck circuit is synchronous rectification reduction voltage circuit, is made up of the metal-oxide-semiconductor of two low conduction impedances, inductance and filter capacitor; Inverter circuit forms full bridge inverter by the metal-oxide-semiconductor of four low conduction impedances; Series resonant circuit is made up of series resonant capacitance and wireless transmission coil; Transmitting terminal communication control module is made up of MCU, communication module, control driver module.
Receiver module comprises antiresonant circuit (Ls, Cs), rectification circuit, receiving terminal switch buck circuit, load, receiving terminal communication control module.Wherein receiving terminal switch buck circuit is synchronous rectification reduction voltage circuit, is made up of the metal-oxide-semiconductor of two low conduction impedances, inductance and filter capacitor.Rectification circuit forms full bridge rectifier by four Schottky diodes, after connect filter capacitor.Antiresonant circuit is made up of parallel resonance electric capacity and wireless receive coil.Receiving terminal communication control module is made up of MCU, communication module, control driver module.
DC constant voltage power supply in transmitter module is connected to the input of transmitting terminal switch buck circuit; The output of transmitting terminal switch buck circuit is connected with the input of inverter circuit; The output of inverter circuit is connected with series resonant circuit; Communication module is connected with series resonant circuit, gathers the resonance potential of series resonant circuit; Communication module output signal, by after MCU process, outputs a control signal to control module, and control module output drive signal is to the control end of transmitting terminal switch buck circuit and inverter circuit.
The antiresonant circuit of receiver module is connected with the input of rectification circuit; The output of rectification circuit is connected with the input of receiving terminal switch buck circuit; The output of receiving terminal switch buck circuit is connected with load; Communication module is connected with antiresonant circuit, and MCU is between communication module and control module; The digital signal that the input signal of receiving terminal communication module sends for MCU, output signal is impedance control signal, this control signal is by controlling conducting and the shutoff of metal-oxide-semiconductor and then controlling reflected umpedance and carry out minor variations within the specific limits, and transmitting terminal passes through this minor variations of detection of reflected impedance thus realizing circuit communication.
The telecommunication circuit of QI standard that what two communication modules of this Circuits System adopted is, communication mode is one direction communication, communicates identical with existing wireless charging with control overflow.
Transmitting terminal switch buck circuit is for regulating input direct voltage.It is alternating voltage that inverter circuit is used for DC voltage conversion.Series resonant circuit is for launching electromagnetic field thus propagating electric energy.Transmitting terminal communication control module is used for communicating with receiver module and driving switch reduction voltage circuit and inverter circuit.
Receiving terminal switch buck circuit is for regulating Output Voltage in Rectified Circuits to load required voltage.Rectification circuit is used for alternating voltage and is transformed to direct voltage and filtering.Antiresonant circuit is for receiving electromagnetic field thus propagating electric energy.Receiving terminal communication control module is used for communicating and driving switch reduction voltage circuit with transmitting terminal.
Transmitting coil and receiving coil size all can by making QI standard to set.Transmitting coil race diameter 43mm, inner ring diameter 20mm, ferrite is enclosed at the coil back side simultaneously.Transmitting terminal wireless transmission coil value 7.4uH, series resonant capacitance value 330nF.Receiving coil race diameter 43mm, inner ring diameter 20mm, ferrite is enclosed at the coil back side simultaneously.Receiving terminal wireless receive coil value 12uH, parallel resonance electric capacity value 100nF.The electromagnetic field emissions frequency range of wireless transmission coil is 100Khz ~ 200KHz.
System need adjust the controling parameters of transmitting terminal switch buck circuit, inverter circuit and receiving terminal switch buck circuit in real time according to electric current needed for the degree of coupling of coil and load thus reach the highest delivery of electrical energy efficiency.
Through actual measurement, export at 5V, within 500mA, system average transmission efficiency can reach more than 70%, and when transmission range 30mm, system also has the efficiency of transmission of 48%, and improves along with shortening of transmission range, and concrete efficiency curve diagram as shown in Figure 4.
Claims (2)
1. a low-power wireless charging circuit topology, comprise inverter circuit, former limit resonant circuit, secondary resonant circuit, rectification circuit, switch buck circuit, inverter circuit is the full bridge inverter be made up of the metal-oxide-semiconductor of 4 low conduction impedances, the direct current of input is become alternating current to export, exporting connects by the electric capacity Cp connected, the two ends of the former limit resonant circuit that wireless transmission coil Lp forms, it is characterized in that, secondary resonant circuit is parallel resonant circuit, by electric capacity Cs, wireless receive coil Ls composes in parallel, former limit resonant circuit is coupled by high frequency magnetic field with secondary resonant circuit, electric energy is delivered to secondary resonant circuit from the output of former limit resonant circuit, secondary resonant circuit output AC electricity exports direct current after rectifier circuit rectifies, again through switch buck circuit adjustment be load required voltage.
2. low-power wireless charging circuit topology according to claim 1, it is characterized in that, described switch buck circuit is made up of the metal-oxide-semiconductor of two low conduction impedances, inductance and filter capacitor, the metal-oxide-semiconductor series connection of two low conduction impedances, series connection point and direct current negative pole connect the inductance and filter capacitor of connecting, and filter capacitor two ends are for exporting.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201520699272.5U CN205051447U (en) | 2015-09-10 | 2015-09-10 | Wireless charging circuit topological structure of low -power |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201520699272.5U CN205051447U (en) | 2015-09-10 | 2015-09-10 | Wireless charging circuit topological structure of low -power |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN205051447U true CN205051447U (en) | 2016-02-24 |
Family
ID=55344989
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201520699272.5U Expired - Fee Related CN205051447U (en) | 2015-09-10 | 2015-09-10 | Wireless charging circuit topological structure of low -power |
Country Status (1)
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|---|---|
| CN (1) | CN205051447U (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107634586A (en) * | 2016-07-15 | 2018-01-26 | 通用汽车环球科技运作有限责任公司 | Double sensings/conduct direct current coupled recharging systems |
| CN108964217A (en) * | 2018-09-29 | 2018-12-07 | 深圳维普创新科技有限公司 | The compound circuit of wireless charging and wired charging |
-
2015
- 2015-09-10 CN CN201520699272.5U patent/CN205051447U/en not_active Expired - Fee Related
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107634586A (en) * | 2016-07-15 | 2018-01-26 | 通用汽车环球科技运作有限责任公司 | Double sensings/conduct direct current coupled recharging systems |
| CN108964217A (en) * | 2018-09-29 | 2018-12-07 | 深圳维普创新科技有限公司 | The compound circuit of wireless charging and wired charging |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| CF01 | Termination of patent right due to non-payment of annual fee | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20160224 Termination date: 20190910 |