Upward compatible wireless charger capable of automatically identifying fast and slow charging and receiving load

Abstract

The invention discloses an upward compatible wireless charger capable of automatically identifying fast and slow charging and a receiving load, which comprises a charger end circuit and a receiving load end circuit, and is characterized in that the charger end circuit comprises a two-gear variable direct current voltage stabilizing circuit, a main resonance circuit and a resonance current sampling voltage division and comparison circuit; the receiving load end circuit comprises a receiving load resonance circuit, different receiving loads are distinguished and charging is achieved according to comparison of a receiving circuit LC resonance frequency point of the receiving loads and a resonance frequency point of a main resonance circuit in the charger end circuit, only universal circuit components need to be adopted, the circuit is simple, the size is small, the cost is low, and the charging efficiency is high. The circuit is simple in structure, low in energy consumption, safe, effective and reliable, high cost performance of the whole circuit is achieved, and meanwhile compatible charging of fast-charging and slow-charging receiving loads is achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of wireless charging circuits, and in particular to a wireless charger and a receiving load that are upwardly compatible and capable of automatically identifying fast and slow charging. Background Art

[0002] As people's living standards continue to improve, they pay more and more attention to oral health. Wireless power receiving loads (such as electric toothbrushes) have begun to enter thousands of households with their efficient cleaning functions. This toothbrush uses a rechargeable battery to drive a DC motor to achieve different speeds and directions as well as vibration functions to drive the toothbrush head to achieve efficient and non-dead-angle cleaning of teeth. Considering its use environment conditions, it must meet certain waterproof and dustproof requirements. Its supporting mainstream charging method is electromagnetic coupling wireless charging, and the charger has no physical contact with the wireless power receiving load (such as electric toothbrush) receiving circuit. According to the needs of users' fast-paced life and the need for travel and portability, faster and more convenient wireless charging speeds are required. It is required that the fast charging charger can not only quickly charge the fast charging receiving load, but also be upward compatible and perform protective slow compatible charging on the previous generation receiving load. It avoids potential safety hazards, protects the rights and interests of users, and meets the fast and slow charging needs of different users. Summary of the invention

[0003] The purpose of the present invention is to solve the technical problem of compatible charging of a fast-charge receiving load and a slow-charge receiving load by a charger.

[0004] The present invention provides a wireless charger and receiving load which are upwardly compatible and automatically identify fast and slow charging, including a charger end circuit and a receiving load end circuit, wherein the charger end circuit includes a two-speed variable DC voltage stabilizing circuit, a main resonant circuit, and a resonant current sampling voltage division and comparison circuit, and the receiving load end circuit includes a receiving load resonant circuit, wherein the two-speed variable DC voltage stabilizing circuit is used to convert a power grid AC input voltage into a low voltage or high voltage two-speed variable stable DC output voltage, wherein the resonant current sampling voltage division and comparison circuit is used to control the output voltage gear of the two-speed variable DC voltage stabilizing circuit, wherein the main resonant circuit adopts a single-tube resonant circuit to convert DC energy into high-frequency AC energy and emits magnetic field energy through a T5001_A coil; the receiving load resonant circuit receives the magnetic field energy, and charges a rechargeable battery after passing through a post-stage rectifier filter circuit and a CC / CV charging control circuit, and distinguishes different receiving loads and realizes charging according to the comparison between the LC resonant frequency point of the receiving circuit of the receiving load and the resonant frequency point of the main resonant circuit in the charger end circuit.

[0005] Preferably, in no-load applications, the resonant current of the main resonant circuit is very low, and after being processed by the resonant current sampling voltage divider and comparison circuit, the output voltage of the two-speed variable DC voltage regulator circuit is automatically controlled to a low voltage level; the resonant energy intensity of the main resonant circuit is very weak, and the entire charger circuit operates in a low-power power-saving standby mode.

[0006] Preferably, when applied to a slow-charge receiving load, the main resonant circuit at the charger end and the resonant circuit of the slow-charge receiving load are proportionally coupled with an ordinary transformer, and the resonant current of the main resonant circuit is lower than the set value. After being processed by the resonant current sampling voltage divider and comparison circuit, the output voltage of the two-speed variable DC voltage regulator circuit is automatically controlled to a low voltage level, thereby realizing a low-power compatible charging mode for the slow-charge receiving load.

[0007] Preferably, when applied to a fast charging receiving load, the main resonant circuit at the charger end strongly resonates and strongly couples with the resonant circuit of the fast charging receiving load, and the resonant current of the main resonant circuit exceeds the set value. After being processed by the resonant current sampling voltage divider and comparison circuit, the output voltage of the two-speed variable DC voltage regulator circuit is automatically controlled to a high voltage level, thereby realizing a stable normal high-power fast charging mode for the fast charging receiving load.

[0008] Preferably, the two-speed variable DC voltage regulator circuit includes an overcurrent protection element RF5001, a front rectifier element DB5001 (full-bridge rectifier or half-wave rectifier), a main switch element Q5001 (MOSFET or transistor), a rear rectifier diode D1, a main filter capacitor C5001, a feedforward voltage sampling upper voltage divider resistor R1, a feedforward voltage sampling lower voltage divider resistor R2, a reference voltage regulator element Z1, a voltage regulator drive switch element Q5002 and a main switch element drive bias resistor R3. The inputs of the two-speed variable DC voltage regulator circuit are respectively connected to a single-phase AC The live wire L and the neutral wire N of the AC mains power supply are connected, the live wire L (or the neutral wire N) is connected to one end of the overcurrent protection element RF5001, the other end of the overcurrent protection element RF5001 is connected to one end of the AC input of the front rectifier element DB5001, and the neutral wire N (or the live wire L) is connected to the other end of the AC input of the front rectifier element DB5001; the DC output positive end of the front rectifier element DB5001 is connected to the current input end of the main switch Q5001, and is also connected to one end of the voltage divider resistor R1 at the upper end of the feedforward voltage sampling and the main switch The negative terminal of the DC output of the front rectifier element DB5001 is named as the reference ground AGND; the current output terminal of the main switch Q5001 is connected to the anode of the post-rectifier diode D1; the cathode of the post-rectifier diode D1 is connected to the positive electrode of the main filter capacitor C5001; the negative electrode of the main filter capacitor C5001 is connected to the reference ground AGND; the other end of the upper end voltage divider resistor R1 of the feedforward voltage sampling is connected to one end of the lower end voltage divider resistor R2 of the feedforward voltage sampling and the reference voltage stabilizing element Z1 the cathode of the resonant current sampling voltage divider and comparison circuit and the current inflow end of the shunt resistor R5; the other end of the feedforward voltage sampling lower end voltage divider resistor R2 is connected to the reference ground AGND; the anode of the reference voltage stabilizing element Z1 is connected to the control end of the voltage stabilizing drive switch element Q5002; the current inflow end of the voltage stabilizing drive switch element Q5002 is connected to the other end of the main switch element driving bias resistor R3 and the control end of the main switch Q5001; the current outflow end of the voltage stabilizing drive switch element Q5002 is connected to the reference ground AGND.

[0009] Preferably, the main resonant circuit includes a main resonant inductor T5001-A, a main resonant capacitor C11, a main resonant switch Q5003, an anti-reverse current diode D2, a positive feedback voltage-dividing capacitor C5002, a resonant current sampling resistor R10, a main resonant switch upper bias resistor R7 and a main resonant switch lower bias resistor R8; one end of the main resonant inductor T5001-A is connected to the positive electrode of the main filter capacitor C5001 and one end of the positive feedback voltage-dividing capacitor C5002 and one end of the bias resistor R7 on the main resonant switch and one end of the current bias resistor R6 of the resonant current sampling voltage-dividing and comparison circuit; the other end of the main resonant inductor T5001-A is connected to the current inflow end of the main resonant switch Q5003 and one end of the main resonant capacitor C11; the current outflow end of the main resonant switch Q5003 Connected to the anode of the reverse current protection diode D2; the cathode of the reverse current protection diode D2 is connected to the other end of the main resonant capacitor C11 and the other end of the positive feedback voltage-dividing capacitor C5002 and one end of the resonant current sampling resistor R10 and one end of the current sampling upper voltage-dividing resistor R12 of the resonant current sampling voltage-dividing and comparison circuit; the control end of the main resonant switch Q5003 is connected to the other end of the bias resistor R7 on the main resonant switch and one end of the bias resistor R8 on the main resonant switch; the other end of the bias resistor R8 on the main resonant switch is connected to the reference ground AGND; the other end of the resonant current sampling resistor R10 is also connected to the reference ground AGND; there is a magnetic field coupling relationship between the main resonant inductor T5001-A and the receiving end resonant inductor Lr_s of the receiving load resonant circuit.

[0010] Preferably, the resonant current sampling voltage-dividing and comparison circuit includes a current sampling upper voltage-dividing resistor R12, a current sampling lower voltage-dividing resistor R11, a current sampling lower filter capacitor C2, a reference comparison control device U1, a voltage-stabilizing element Z3, a current bias resistor R6, and a shunt resistor R5; one end of the current sampling upper voltage-dividing resistor R12 is connected to the cathode network of the reverse current protection diode D2; the other end of the current sampling upper voltage-dividing resistor R12 is connected to one end of the current sampling lower voltage-dividing resistor R11 and one end of the current sampling lower filter capacitor C2 and the reference comparison control device The reference voltage input terminal of U1; the other end of the current sampling lower end voltage divider resistor R11 and the other end of the current sampling lower end filter capacitor C2 and the ground level common terminal of the reference comparison control device U1 are all connected to the reference ground AGND; one end of the current bias resistor R6 is connected to the positive electrode network of the main filter capacitor C5001; the other end of the current bias resistor R6 is connected to the current inflow terminal of the reference comparison control device U1 and the cathode of the voltage stabilizing element Z3 and the current outflow terminal of the shunt resistor R5; the anode of the voltage stabilizing element Z3 is connected to the reference ground AGND.

[0011] Preferably, the receiving load resonant circuit includes a receiving end resonant inductor Lr_s, a receiving end resonant capacitor Cr_s, a receiving end rectifier diode D_s, a receiving end filter capacitor Cf_s, a receiving end charging control switch Qsw_s, a receiving end charging current sampling resistor Rcs_s, a receiving end rechargeable battery Vbatt, and a receiving end CC / CV charging control circuit functional block; there is a magnetic field coupling relationship between the receiving end resonant inductor Lr_s and the main resonant inductor T5001-A of the wireless charger transmitting end; the receiving end resonant inductor Lr_s and the receiving end resonant capacitor Cr_s are connected in parallel (or in series); one end of the receiving end resonant inductor Lr_s and the receiving end resonant capacitor Cr_s are connected to the anode of the receiving end rectifier diode D_s; the other end of the receiving end resonant inductor Lr_s and the receiving end resonant capacitor Cr_s is named as the reference ground of the receiving end; the connection The cathode of the receiving-end rectifier diode D_s is connected to one end of the receiving-end filter capacitor Cf_s, the current inflow end of the receiving-end charging control switch Qsw_s, and the voltage sampling end of the receiving-end CC / CV charging control circuit functional block; the other end of the receiving-end filter capacitor Cf_s and the ground level common end of the receiving-end CC / CV charging control circuit functional block are connected to the reference ground of the receiving end; the current outflow end of the receiving-end charging control switch Qsw_s is connected to one end of the receiving-end charging current sampling resistor Rcs_s and the current sampling positive end of the receiving-end CC / CV charging control circuit functional block; the other end of the receiving-end charging current sampling resistor Rcs_s is connected to the positive electrode of the receiving-end rechargeable battery Vbatt and the current sampling negative end of the receiving-end CC / CV charging control circuit functional block; the negative electrode of the receiving-end rechargeable battery Vbatt is connected to the reference ground of the receiving end.

[0012] Compared with the prior art, the present invention has the following beneficial effects: The present invention discloses a wireless charger and receiving load that are upwardly compatible and can automatically identify fast and slow charging, including a charger end circuit and a receiving load end circuit, wherein the charger end circuit includes a two-speed variable DC voltage stabilization circuit, a main resonant circuit, and a resonant current sampling voltage division and comparison circuit, and the receiving load end circuit includes a receiving load resonant circuit, wherein the two-speed variable DC voltage stabilization circuit is used to convert the AC input voltage of the power grid into a low voltage or high voltage two-speed variable stable DC output voltage, wherein the resonant current sampling voltage division and comparison circuit is used to control the output voltage gear of the two-speed variable DC voltage stabilization circuit, wherein the main resonant circuit uses a single-tube resonant circuit to convert DC energy into high-frequency AC energy and emits magnetic field energy through a T5001_A coil; the receiving load resonant circuit receives the magnetic field energy, and performs a rectifier filter circuit and a CC / CV charging control circuit on the rechargeable battery. Charging, according to the comparison between the LC resonant frequency point of the receiving circuit of the receiving load and the resonant frequency point of the main resonant circuit in the charger end circuit, different receiving loads are distinguished and charging is realized, and the inherent low-frequency fluctuation phenomenon of the AC power grid is used for clipping and voltage stabilization. The switching frequency of the switching tube is only 100 / 120Hz, and the loss of the entire voltage stabilization circuit is very low; and no special expensive control chip and peripheral circuit are required, only general circuit components need to be used, the circuit is simple, small in size, low in cost, safe, effective and reliable; at the same time, the EMI radiation problem derived from high-frequency switching and the need for complex noise suppression countermeasures are avoided, the high cost performance of the entire circuit is achieved, and the competitiveness of the product is improved; at the same time, the resonant current difference generated by the resonant frequency difference of the fast-charging and slow-charging receiving loads is used to automatically adjust the supply voltage of the main resonant circuit, and compatible charging of the fast-charging and slow-charging receiving loads is achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 The present invention is a circuit block diagram of a wireless charger that is upwardly compatible with automatic fast and slow charging identification and a charging end circuit that receives a load.

[0014] Figure 2 The present invention is a circuit block diagram of a wireless charger that is upwardly compatible with automatic fast and slow charging identification and a receiving load end of a receiving load. DETAILED DESCRIPTION

[0015] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0016] Please see attached Figure 1 To Attachment Figure 2A wireless charger and receiving load that are upwardly compatible and automatically identify fast and slow charging, including a charger end circuit and a receiving load end circuit, the charger end circuit including a two-speed variable DC voltage stabilization circuit, a main resonant circuit, a resonant current sampling voltage division and comparison circuit, the receiving load end circuit including a receiving load resonant circuit, the two-speed variable DC voltage stabilization circuit is used to convert the AC input voltage of the power grid into a low voltage or high voltage two-speed variable stable DC output voltage, the resonant current sampling voltage division and comparison circuit is used to control the output voltage gear of the two-speed variable DC voltage stabilization circuit, the main resonant circuit adopts a single-tube resonant circuit Convert DC energy into high-frequency AC energy and emit magnetic field energy through the T5001_A coil; the receiving load resonant circuit receives the magnetic field energy, charges the rechargeable battery after passing through the subsequent rectifier filter circuit and CC / CV charging control circuit, and distinguishes different receiving loads and realizes charging according to the comparison between the LC resonant frequency point of the receiving circuit of the receiving load and the resonant frequency point of the main resonant circuit in the charger end circuit; the two-speed variable DC voltage stabilizing circuit includes an overcurrent protection element RF5001, a front rectifier element DB5001 full-bridge rectifier or half-wave rectifier, and a main switch element Q5001 MOSFET or crystal triode, post-rectifier diode D1, main filter capacitor C5001, feedforward voltage sampling upper voltage divider resistor R1, feedforward voltage sampling lower voltage divider resistor R2, reference voltage stabilizing element Z1, voltage stabilizing drive switch element Q5002 and main switch element drive bias resistor R3; the main resonant circuit includes main resonant inductor T5001-A, main resonant capacitor C11, main resonant switch Q5003, reverse current protection diode D2, positive feedback voltage divider capacitor C5002, resonant current sampling resistor R10, main resonant switch upper bias resistor R7 and main resonant switch lower bias resistor R8; the resonant The current sampling voltage division and comparison circuit includes a current sampling upper voltage division resistor R12, a current sampling lower voltage division resistor R11, a current sampling lower filter capacitor C2, a reference comparison control device U1, a voltage stabilizing element Z3, a current bias resistor R6, and a shunt resistor R5; the receiving load resonant circuit includes a receiving end resonant inductor Lr_s, a receiving end resonant capacitor Cr_s, a receiving end rectifier diode D_s, a receiving end filter capacitor Cf_s, a receiving end charging control switch Qsw_s, a receiving end charging current sampling resistor Rcs_s, a receiving end rechargeable battery Vbatt, and a receiving end CC / CV charging control circuit functional block.

[0017] The working principle of the circuit of the charging end and the receiving load end of this embodiment is as follows: after the wireless charger applies the grid input voltage of 100-240V, the AC input voltage is rectified by the DB5001 rectifier bridge, and a 100Hz / 120Hz DC pulsating sinusoidal voltage waveform is formed at the positive and negative output ends of the DB5001 rectifier bridge. R1, R2, Z1, and Q5002 form a feedforward voltage sampling and reference comparison circuit for the pulsating sinusoidal voltage. When the amplitude of the DC pulsating sinusoidal voltage is less than 60V (low output voltage range), Z1 and Q5002 cannot be turned on, and the switching MOSFET tube Q5001 channel and the anti-reverse diode D1 can be turned on to charge the filter capacitor C5001 and supply power to the main resonant circuit at the same time.

[0018] When the amplitude of the pulsating sinusoidal voltage is greater than 60V, Z1 and Q5002 can be turned on, the gate drive of the switching MOSFET tube Q5001 is pulled down, and the channel of the switching MOSFET tube Q5001 closes the charging circuit for the filter capacitor C5001. During this period, the stored energy of C5001 maintains the power supply to the main resonant circuit. In steady state, C5001 is continuously charged and discharged at twice the power frequency of 100 / 120Hz, and the voltage at both ends is balanced at about 60V (low voltage output gear). Supplying the main resonant circuit of the subsequent stage makes the main resonant circuit in low-power resonant mode, and the entire charger circuit works in a power-saving standby mode with an input power of less than 0.1W. When there is no load, the wireless charger will always maintain this standby mode. Since this circuit utilizes the inherent fluctuation phenomenon of twice the power frequency of the AC power grid, the switching frequency of the switching MOSFET tube Q5001 is only 100 / 120Hz, so the switching loss of the entire voltage stabilization circuit is very low. And no special high-priced control chip and complex peripheral circuit are required. It also avoids the radiated EMI (electromagnetic interference) problem derived from high-frequency switching and the need for complex anti-interference filtering components, achieving a high performance-price ratio for the entire circuit.

[0019] When the wireless charger is in standby mode, if the slow charging receiving load is placed at its output coupling position, since the inherent resonant frequency of the internal resonant circuit of the slow charging receiving load is much higher than the transmitting frequency of the wireless charger, the resonant element combination Lr_s and Cr_s at the slow charging receiving load end cannot resonate with the charger. At this time, the power supply current of the main resonant circuit is sampled by R10 and divided by R12 and R11 and filtered by C2, and the sampled voltage is sent to the reference voltage input terminal of the voltage comparator U1. Since the resonance intensity is weak at this time, the sampled input voltage is lower than the internal reference voltage of U1 (2.495V), so the output terminal of U1 maintains high impedance to the reference ground, and the voltage regulator Z3 connected in parallel is powered by the above-mentioned 60V through the pull-up resistor R6, so that the voltage across Z3 is clamped at its regulated value of 12V, and the voltages at the left and right ends of the two-stage variable output voltage adjustment resistor R5 are almost equal, and almost no current flows through R5. Therefore, R5 is equivalent to an open circuit at this time, that is, R5 does not participate in the sampling and voltage division work of the two-stage variable output voltage circuit, and the two-stage variable output voltage circuit maintains its 60V (low-stage voltage) output mode. In this mode, the slow-charging receiving load can only receive relatively weak magnetic field energy through the proportional coupling principle of ordinary transformer windings and convert it into weaker electrical energy, thereby protecting the corresponding power components of its internal circuit from the hazards of over-voltage, over-current and over-power stress, while realizing a compatible slow charging function for the battery.

[0020] When the wireless charger is in standby mode, if the fast-charge receiving load is placed at its output coupling position, since the inherent resonant frequency of the internal resonant circuit of the fast-charge receiving load is set close to the transmitting frequency of the wireless charger, the load-end resonant element combination Lr_s and Cr_s can produce a strong resonance phenomenon with the charger, and the load can couple to stronger energy to charge the battery. At this time, the larger supply current generated by the main resonant circuit is sampled by R10 and divided by R12 and R11 and filtered by C2, and the sampled voltage is sent to the reference voltage input terminal of the voltage comparator U1. Since the resonance intensity is strong at this time, the sampled input voltage is higher than the internal reference voltage (2.495V) of U1, so the output terminal of U1 forms a low impedance to the reference ground. Even if the voltage regulator Z3 connected in parallel is powered by the pull-up resistor R6, the voltage across Z3 can still be clamped at about 2V by the low impedance of the output terminal of U1, and the two-speed variable output voltage adjustment resistor R5 can have current flowing. Therefore, R5 is connected in series with the low-impedance output terminal of U1 and then connected in parallel to the lower sampling voltage divider resistor R2 of the two-speed variable output voltage circuit. A higher pulsating sinusoidal voltage is required to open Z1 and Q5002, thereby closing the Q5001 charging circuit, and the two-speed variable DC voltage regulator circuit realizes the jump to the output 120V (high-end voltage) mode. After the high-end voltage mode is supplied to the main resonant circuit of the subsequent stage, the output power of the entire main resonant circuit surges, and the resonant current exceeds the set value more, ensuring the maintenance of the 120V output voltage mode of the two-speed variable DC voltage regulator circuit. In this mode, the fast charging receiving load receives magnetic field energy with higher intensity than the 60V mode through resonant coupling, and converts it into high-power electrical energy. After rectification and filtering and the charging control circuit, high-power fast charging of the battery is achieved.

[0021] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Although the present invention is disclosed as a preferred embodiment as above, it is not used to limit the present invention. Any technician familiar with this profession can make some changes or modifications to equivalent embodiments of equivalent changes by using the technical contents disclosed above without departing from the scope of the technical solution of the present invention. However, any simple modification, equivalent changes and modifications made to the above embodiments according to the technology of the present invention are within the scope of the technical solution of the present invention without departing from the content of the technical solution of the present invention.

Claims

1. A wireless charger and receiving load that is upwardly compatible with automatic identification of fast and slow charging, characterized in that: It includes a charger end circuit and a receiving load end circuit. The charger end circuit includes a two-speed variable DC voltage stabilizing circuit, a main resonant circuit, and a resonant current sampling voltage divider and comparison circuit. The receiving load end circuit includes a receiving load resonant circuit. The two-speed variable DC voltage stabilizing circuit is used to convert the AC input voltage of the power grid into two-speed variable stable DC output voltages of low voltage or high voltage. The resonant current sampling voltage divider and comparison circuit is used to control the output voltage gear of the two-speed variable DC voltage stabilizing circuit. The main resonant circuit uses a single-tube resonant circuit to convert DC energy into high-frequency AC energy and emits magnetic field energy through a T5001_A coil; the receiving load resonant circuit receives the magnetic field energy, charges the rechargeable battery after passing through a post-stage rectifier filter circuit and a CC / CV charging control circuit, and distinguishes different receiving loads and realizes charging according to the comparison between the LC resonant frequency point of the receiving circuit of the receiving load and the resonant frequency point of the main resonant circuit in the charger end circuit.

2. The upwardly compatible wireless charger and receiving load capable of automatically identifying fast and slow charging according to claim 1, characterized in that: In no-load applications, the resonant current of the main resonant circuit is very low. After being processed by the resonant current sampling voltage divider and comparison circuit, the output voltage of the two-speed variable DC voltage regulator circuit is automatically controlled to a low voltage level. The resonant energy intensity of the main resonant circuit is very weak, and the entire charger circuit operates in a low-power power-saving standby mode.

3. The upwardly compatible wireless charger and receiving load capable of automatically identifying fast and slow charging according to claim 1, characterized in that: When applied to a slow-charge receiving load, the main resonant circuit at the charger end and the resonant circuit of the slow-charge receiving load are proportionally coupled by an ordinary transformer. The resonant current of the main resonant circuit is lower than the set value. After being processed by the resonant current sampling voltage divider and comparison circuit, the output voltage of the two-speed variable DC voltage regulator circuit is automatically controlled to a low voltage level, thereby realizing a low-power compatible charging mode for the slow-charge receiving load.

4. The upwardly compatible wireless charger and receiving load capable of automatically identifying fast and slow charging according to claim 1, characterized in that: When applied to a fast-charging receiving load, the main resonant circuit at the charger end strongly resonates and strongly couples with the resonant circuit of the fast-charging receiving load, and the resonant current of the main resonant circuit exceeds the set value. After being processed by the resonant current sampling voltage divider and comparison circuit, the output voltage of the two-speed variable DC voltage regulator circuit is automatically controlled to a high voltage level, thereby realizing a stable normal high-power fast-charging mode for the fast-charging receiving load.

5. The upwardly compatible wireless charger and receiving load capable of automatically identifying fast and slow charging according to claim 1, characterized in that: The two-speed variable DC voltage stabilizing circuit includes an overcurrent protection element RF5001, a front rectifier element DB5001 full-bridge rectifier or half-wave rectifier, a main switch element Q5001 MOSFET or transistor, a rear rectifier diode D1, a main filter capacitor C5001, a feedforward voltage sampling upper end voltage divider resistor R1, a feedforward voltage sampling lower end voltage divider resistor R2, a reference voltage stabilizing element Z1, a voltage stabilizing drive switch element Q5002 and a main switch element drive bias resistor R3. The inputs of the two-speed variable DC voltage stabilizing circuit are respectively connected to the live wire L and the neutral wire N of the single-phase AC mains power supply, the live wire L or the neutral wire N is connected to one end of the overcurrent protection element RF5001, and the overcurrent protection The other end of the element RF5001 is connected to one end of the AC input of the pre-rectifying element DB5001, and the neutral line N or the live line L is connected to the other end of the AC input of the pre-rectifying element DB5001; the DC output positive end of the pre-rectifying element DB5001 is connected to the current input end of the main switch Q5001, and is also connected to one end of the upper end voltage divider resistor R1 of the feedforward voltage sampling and one end of the main switch element driving bias resistor R3; the DC output negative end of the pre-rectifying element DB5001 is connected to the current input end of the main switch Q5001, and is also connected to one end of the upper end voltage divider resistor R1 of the feedforward voltage sampling and one end of the main switch element driving bias resistor R3; The network is named as reference ground AGND; the current output end of the main switch Q5001 is connected to the anode of the post-rectifier diode D1; the cathode of the post-rectifier diode D1 is connected to the positive electrode of the main filter capacitor C5001; the negative electrode of the main filter capacitor C5001 is connected to the reference ground AGND; the other end of the feed-forward voltage sampling upper end voltage-dividing resistor R1 is connected to one end of the feed-forward voltage sampling lower end voltage-dividing resistor R2 and the cathode of the reference voltage-stabilizing element Z1 and the current inflow end of the shunt resistor R5 of the resonant current sampling voltage-dividing and comparison circuit; the other end of the feed-forward voltage sampling lower end voltage-dividing resistor R2 is connected to the reference ground AGND; the anode of the reference voltage-stabilizing element Z1 is connected to the control end of the voltage-stabilizing driving switch element Q5002; the current inflow end of the voltage-stabilizing driving switch element Q5002 is connected to the other end of the main switch element driving bias resistor R3 and the control end of the main switch Q5001; the current outflow end of the voltage-stabilizing driving switch element Q5002 is connected to the reference ground AGND.

6. The upwardly compatible wireless charger and receiving load capable of automatically identifying fast and slow charging according to claim 5, characterized in that: The main resonant circuit includes a main resonant inductor T5001-A, a main resonant capacitor C11, a main resonant switch Q5003, an anti-reverse current diode D2, a positive feedback voltage-dividing capacitor C5002, a resonant current sampling resistor R10, a main resonant switch upper bias resistor R7 and a main resonant switch lower bias resistor R8; one end of the main resonant inductor T5001-A is connected to the positive electrode of the main filter capacitor C5001 and one end of the positive feedback voltage-dividing capacitor C5002 and one end of the bias resistor R7 on the main resonant switch and one end of the current bias resistor R6 of the resonant current sampling voltage-dividing and comparison circuit; the other end of the main resonant inductor T5001-A is connected to the current inflow end of the main resonant switch Q5003 and one end of the main resonant capacitor C11; the current outflow end of the main resonant switch Q5003 is connected to The anode of the reverse current protection diode D2; the cathode of the reverse current protection diode D2 is connected to the other end of the main resonant capacitor C11, the other end of the positive feedback voltage-dividing capacitor C5002, one end of the resonant current sampling resistor R10, and one end of the current sampling upper voltage-dividing resistor R12 of the resonant current sampling voltage-dividing and comparison circuit; the control end of the main resonant switch Q5003 is connected to the other end of the bias resistor R7 on the main resonant switch and one end of the bias resistor R8 on the main resonant switch; the other end of the bias resistor R8 on the main resonant switch is connected to the reference ground AGND; the other end of the resonant current sampling resistor R10 is also connected to the reference ground AGND; there is a magnetic field coupling relationship between the main resonant inductor T5001-A and the receiving end resonant inductor Lr_s of the receiving load resonant circuit.

7. The upwardly compatible wireless charger and receiving load capable of automatically identifying fast and slow charging according to claim 6, characterized in that: The resonant current sampling voltage-dividing and comparison circuit comprises a current sampling upper voltage-dividing resistor R12, a current sampling lower voltage-dividing resistor R11, a current sampling lower filter capacitor C2, a reference comparison control device U1, a voltage-stabilizing element Z3, a current bias resistor R6, and a shunt resistor R5; one end of the current sampling upper voltage-dividing resistor R12 is connected to the cathode network of the reverse current protection diode D2; the other end of the current sampling upper voltage-dividing resistor R12 is connected to one end of the current sampling lower voltage-dividing resistor R11 and one end of the current sampling lower filter capacitor C2 and the reference comparison control device U1. Reference voltage input terminal; the other end of the current sampling lower end voltage divider resistor R11 and the other end of the current sampling lower end filter capacitor C2 and the ground level common terminal of the reference comparison control device U1 are all connected to the reference ground AGND; one end of the current bias resistor R6 is connected to the positive electrode network of the main filter capacitor C5001; the other end of the current bias resistor R6 is connected to the current inflow terminal of the reference comparison control device U1 and the cathode of the voltage stabilizing element Z3 and the current outflow terminal of the shunt resistor R5; the anode of the voltage stabilizing element Z3 is connected to the reference ground AGND.

8. The upwardly compatible wireless charger and receiving load capable of automatically identifying fast and slow charging according to claim 7, characterized in that: The receiving load resonant circuit includes a receiving end resonant inductor Lr_s, a receiving end resonant capacitor Cr_s, a receiving end rectifier diode D_s, a receiving end filter capacitor Cf_s, a receiving end charging control switch Qsw_s, a receiving end charging current sampling resistor Rcs_s, a receiving end rechargeable battery Vbatt, and a receiving end CC / CV charging control circuit functional block; there is a magnetic field coupling relationship between the receiving end resonant inductor Lr_s and the main resonant inductor T5001-A of the wireless charger transmitting end; the receiving end resonant inductor Lr_s and the receiving end resonant capacitor Cr_s are connected in parallel or in series; one end of the receiving end resonant inductor Lr_s and the receiving end resonant capacitor Cr_s are connected to the anode of the receiving end rectifier diode D_s; the other end of the receiving end resonant inductor Lr_s and the receiving end resonant capacitor Cr_s is named as the reference ground of the receiving end; the receiving end rectifier The cathode of the diode D_s is connected to one end of the receiving end filter capacitor Cf_s, the current inflow end of the receiving end charging control switch Qsw_s, and the voltage sampling end of the receiving end CC / CV charging control circuit functional block; the other end of the receiving end filter capacitor Cf_s and the ground level common end of the receiving end CC / CV charging control circuit functional block are connected to the reference ground of the receiving end; the current outflow end of the receiving end charging control switch Qsw_s is connected to one end of the receiving end charging current sampling resistor Rcs_s and the current sampling positive end of the receiving end CC / CV charging control circuit functional block; the other end of the receiving end charging current sampling resistor Rcs_s is connected to the positive electrode of the receiving end rechargeable battery Vbatt and the current sampling negative end of the receiving end CC / CV charging control circuit functional block; the negative electrode of the receiving end rechargeable battery Vbatt is connected to the reference ground of the receiving end.

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