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

Abstract

The utility model discloses a wireless charger and receiving load capable of upward compatibility and automatic identification of fast and slow charging, 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 DC 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 utility model 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 improve and their oral health becomes increasingly important, wireless power receiving loads (such as electric toothbrushes) are becoming increasingly commonplace due to their efficient cleaning capabilities. These toothbrushes utilize a rechargeable battery to drive a DC motor with variable speeds and directions, as well as a vibration function, to power the brush head for efficient, comprehensive cleaning. Considering the environmental requirements of their use, they must meet certain waterproof and dustproof requirements. The mainstream charging method is electromagnetic coupling wireless charging, which eliminates physical contact between the charger and the power receiving circuit of the wireless power receiving load (such as an electric toothbrush). The fast-paced lifestyles and travel demands for portable devices are driving the demand for faster and more convenient wireless charging. Fast-charging chargers are required to not only quickly charge fast-charging loads but also be backwards compatible, offering a protective, slower charging capability for older-generation loads. This avoids potential safety hazards, protects user rights, and meets the varying charging needs of different users. Utility Model Content

[0003] The purpose of the utility model 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 utility model provides a wireless charger and receiving load that are upwardly compatible and automatically identify fast and slow charging. The charger circuit includes a two-speed variable DC voltage regulator circuit, a main resonant circuit, and a resonant current sampling, voltage division, and comparison circuit. The receiving load circuit includes a receiving load resonant circuit. The two-speed variable DC voltage regulator circuit is used to convert the AC input voltage of the power grid into two variable stable DC output voltages of low voltage or high voltage. The resonant current sampling, voltage division, and comparison circuit is used to control the output voltage level of the two-speed variable DC voltage regulator 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 and charges a rechargeable battery after passing through a subsequent rectifier and filter circuit and a CC / CV charging control circuit. Different receiving loads are distinguished and charging is achieved by comparing the LC resonant frequency of the receiving circuit of the receiving load with the resonant frequency of the main resonant circuit in the charger circuit.

[0005] Preferably, in no-load application, the resonant current of the main resonant circuit is very low. After the resonant current sampling, voltage division and comparison circuit processing, the output voltage of the two-speed variable DC voltage regulator circuit is automatically controlled to the 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-charging receiving load, the main resonant circuit at the charger end and the resonant circuit of the slow-charging receiving load are proportionally coupled by 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-charging receiving load.

[0007] Preferably, when applied to a fast charging receiving load, the main resonant circuit at the charger end and the resonant circuit of the fast charging receiving load undergo strong resonance and strong coupling, 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 post-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 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 the 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 connected to 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 and the current inflow end of the shunt resistor R5 of the resonant current sampling voltage divider and comparison circuit; 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 switching element Q5002; the current inflow end of the voltage stabilizing drive switching 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 switching 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 divider 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, one end of the positive feedback voltage divider capacitor C5002, one end of the main resonant switch upper bias resistor R7, and one end of the current bias resistor R6 of the resonant current sampling voltage divider 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 positive electrode of the main filter capacitor C5001, one end of the positive feedback voltage divider capacitor C5002, one end of the main resonant switch upper bias resistor R7, and one end of the current bias resistor R6 of the resonant current sampling voltage divider and comparison circuit. connected to the anode of the reverse current prevention diode D2; the cathode of the reverse current prevention diode D2 is connected to the other end of the main resonant capacitor C11, the other end of the positive feedback voltage divider capacitor C5002, one end of the resonant current sampling resistor R10, and one end of the current sampling upper voltage divider resistor R12 of the resonant current sampling voltage divider and comparison circuit; the control end of the main resonant switch Q5003 is connected to the other end of the main resonant switch upper bias resistor R7 and one end of the main resonant switch lower bias resistor R8; the other end of the main resonant switch lower bias resistor R8 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 divider and comparison circuit includes a current sampling upper end voltage divider resistor R12, a current sampling lower end voltage divider resistor R11, a current sampling lower end 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 end voltage divider resistor R12 is connected to the cathode network of the reverse current protection diode D2; the other end of the current sampling upper end voltage divider resistor R12 is connected to one end of the current sampling lower end voltage divider resistor R11 and one end of the current sampling lower end 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, 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, 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 is 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 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 is 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 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:

[0013] The utility model discloses a 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 includes a two-speed variable DC voltage regulator 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 regulator 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 regulator circuit. The main resonant circuit uses a single-tube resonant circuit to convert DC energy into high-frequency AC energy and emit magnetic field energy through a T5001_A coil; the receiving load resonant circuit receives the magnetic field energy and charges the rechargeable battery after passing through a post-stage rectifier and filter circuit and a CC / CV charging control circuit. Charging is carried out by comparing the LC resonant frequency point of the receiving circuit of the receiving load with the resonant frequency point of the main resonant circuit in the charger-end circuit, distinguishing different receiving loads and realizing charging, utilizing the inherent low-frequency fluctuation phenomenon of the AC power grid 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 are needed, 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, achieving high cost performance of the entire circuit and improving the competitiveness of the product; at the same time, the resonant current difference generated by the resonant frequency difference of the fast-charging and slow-charging receiving loads is utilized to automatically adjust the supply voltage of the main resonant circuit, realizing compatible charging of the fast-charging and slow-charging receiving loads. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 The utility model is a circuit block diagram of a wireless charger that is upwardly compatible with automatic fast and slow charging identification and a charging end that receives a load.

[0015] Figure 2 The utility model is a circuit block diagram of a wireless charger and a receiving load end of a receiving load that is upwardly compatible and automatically identifies fast and slow charging. DETAILED DESCRIPTION

[0016] The present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0017] Please see the attached Figure 1 To the attached Figure 2A wireless charger and receiving load that is upwardly compatible and automatically identifies fast and slow charging, including a charger-end circuit and a receiving load-end circuit. The charger-end circuit includes a two-speed variable DC voltage regulator 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 regulator circuit is used to convert the grid AC input voltage 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 regulator 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 of 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 transistor, post-rectifier diode D1, main filter capacitor C5001, feedforward voltage sampling upper end voltage divider resistor R1, feedforward voltage sampling lower end 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 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 divider 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; the resonant The current sampling voltage divider and comparison circuit includes a current sampling upper end voltage divider resistor R12, a current sampling lower end voltage divider resistor R11, a current sampling lower end 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.

[0018] The operating principle of the circuits at the charging and receiving load ends of this embodiment is as follows: after the wireless charger applies a grid input voltage of 100-240V, the AC input voltage is rectified by the DB5001 rectifier bridge, forming a 100Hz / 120Hz DC pulsating sinusoidal voltage waveform 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 this pulsating sinusoidal voltage. When the amplitude of this DC pulsating sinusoidal voltage is less than 60V (low output voltage range), Z1 and Q5002 cannot conduct, allowing the switching MOSFET tube Q5001 channel and anti-reverse diode D1 to conduct, charging the filter capacitor C5001 and simultaneously powering the main resonant circuit.

[0019] When the amplitude of this pulsating sinusoidal voltage exceeds 60V, Z1 and Q5002 conduct, pulling the gate drive of switching MOSFET Q5001 low. This closes the channel of switching MOSFET Q5001, effectively shutting down the charging circuit for filter capacitor C5001. During this period, C5001's stored energy maintains power to the main resonant circuit. In steady state, C5001 is repeatedly charged and discharged at twice the power frequency (100 / 120Hz), with the voltage across it balanced at approximately 60V (low-voltage output range). This voltage is then supplied to the downstream main resonant circuit, placing it in low-power resonant mode. The entire charger circuit operates in a power-saving standby mode with an input power of less than 0.1W. This standby mode remains in effect when the wireless charger is unloaded. Because this circuit utilizes the inherent fluctuations of the AC power grid at twice the power frequency, the switching frequency of switching MOSFET Q5001 is only 100 / 120Hz, resulting in very low switching losses in the entire voltage stabilization circuit. Furthermore, it eliminates the need for expensive control chips and complex peripheral circuitry. 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.

[0020] When the wireless charger is in standby mode, if the slow-charge receiving load is placed at its output coupling position, the resonant component combination Lr_s and Cr_s at the slow-charge receiving load end cannot resonate with the charger because the inherent resonant frequency of the resonant circuit inside the slow-charge receiving load is much higher than the transmitting frequency of the wireless charger. At this time, the supply current of the main resonant circuit is sampled by R10 and divided by R12 and R11, and filtered by C2. The sampled voltage is sent to the reference voltage input 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 of U1 maintains a high impedance to the reference ground. The Zener diode 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. The voltages on the left and right ends of the two-speed 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-speed variable output voltage circuit, and the two-speed variable output voltage circuit maintains its 60V (low-speed 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 overvoltage, overcurrent and over-power stress, while realizing a compatible slow charging function for the battery.

[0021] 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 to be close to the transmission 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 point, the larger supply current generated by the main resonant circuit is sampled by R10, divided by R12 and R11, and filtered by C2. The sampled voltage is then sent to the reference voltage input of voltage comparator U1. Due to the strong resonance intensity at this time, the sampled input voltage is higher than U1's internal reference voltage (2.495V). Therefore, U1's output terminal forms a low impedance with respect to the reference ground. Even though the parallel-connected Zener diode Z3 is powered via pull-up resistor R6, the voltage across Z3 is still clamped to approximately 2V by the low impedance of U1's output terminal. Current can flow through the two-speed variable output voltage adjustment resistor R5. Therefore, R5 is connected in series with U1's low-impedance output terminal and then in parallel with the lower sampling voltage divider resistor R2 of the two-speed variable output voltage circuit. A higher pulsating sinusoidal voltage is required to turn on Z1 and Q5002, thereby shutting off Q5001's charging circuit. The two-speed variable DC voltage regulator circuit switches to the 120V output (high 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 its battery is achieved.

[0022] The above description is only a preferred embodiment of the present invention and does not constitute any form of limitation to the present invention. Although the present invention is disclosed as above in terms of a preferred embodiment, it is not intended to limit the present invention. Any technician familiar with the profession can, without departing from the scope of the technical solution of the present invention, make some changes or modifications to the technical contents disclosed above into equivalent embodiments with equivalent changes. However, any simple modifications, equivalent changes and modifications made to the above embodiments according to the technology of the present invention without departing from the content of the technical solution of the present invention are within the scope 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: The device comprises a charger-end circuit and a receiving load-end circuit. The charger-end circuit comprises a two-speed variable DC voltage regulator circuit, a main resonant circuit, and a resonant current sampling, voltage division, and comparison circuit. The receiving load-end circuit comprises a receiving load resonant circuit. The two-speed variable DC voltage regulator 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 division, and comparison circuit is used to control the output voltage level of the two-speed variable DC voltage regulator 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 the T5001_A coil. The receiving load resonant circuit receives the magnetic field energy and charges the rechargeable battery after passing through a subsequent rectifier and filter circuit and a CC / CV charging control circuit. Different receiving loads are distinguished and charging is achieved by comparing the LC resonant frequency point of the receiving circuit of the receiving load with 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 the resonant current sampling, voltage division and comparison circuit processing, the output voltage of the two-speed variable DC voltage regulator circuit is automatically controlled to the 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-charging receiving load, the main resonant circuit at the charger end and the resonant circuit of the slow-charging receiving load are proportionally coupled by an ordinary transformer. The resonant current of the main resonant circuit is lower than the set value. After the resonant current sampling voltage division and comparison circuit processing, the output voltage of the two-speed variable DC voltage regulator circuit is automatically controlled to the low voltage level, thereby realizing a low-power compatible charging mode for the slow-charging 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 and the resonant circuit of the fast-charging receiving load undergo strong resonance and strong coupling, 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 gear, 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 post-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. The overcurrent protection The other end of the element RF5001 is connected to one end of the AC input of the pre-rectifier 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-rectifier element DB5001; the DC output positive end of the pre-rectifier 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-rectifier element DB5001 is connected to the current input end of the main switch Q5001. The network is designated as 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 terminal of the main filter capacitor C5001; the negative terminal of the main filter capacitor C5001 is connected to the reference ground AGND; the other terminal of the upper-end voltage divider resistor R1 for feedforward voltage sampling is connected to one terminal of the lower-end voltage divider resistor R2 for feedforward voltage sampling, the cathode of the reference voltage stabilizing element Z1, and the current inflow terminal of the shunt resistor R5 of the resonant current sampling voltage division and comparison circuit; the other terminal of the lower-end voltage divider resistor R2 for feedforward voltage sampling is connected to the reference ground AGND; the anode of the reference voltage stabilizing element Z1 is connected to the control terminal of the voltage stabilizing drive switch element Q5002; the current inflow terminal of the voltage stabilizing drive switch element Q5002 is connected to the other terminal of the main switch element driving bias resistor R3 and the control terminal of the main switch Q5001; and the current outflow terminal of the voltage stabilizing drive 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 divider 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, one end of the positive feedback voltage divider capacitor C5002, one end of the main resonant switch upper bias resistor R7, and one end of the current bias resistor R6 of the resonant current sampling voltage divider 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 prevention diode D2; the cathode of the reverse current prevention diode D2 is connected to the other end of the main resonant capacitor C11, the other end of the positive feedback voltage divider capacitor C5002, one end of the resonant current sampling resistor R10, and one end of the current sampling upper voltage divider resistor R12 of the resonant current sampling voltage divider and comparison circuit; the control end of the main resonant switch Q5003 is connected to the other end of the main resonant switch upper bias resistor R7 and one end of the main resonant switch lower bias resistor R8; the other end of the main resonant switch lower bias resistor R8 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 includes a current sampling upper end voltage dividing resistor R12, a current sampling lower end voltage dividing resistor R11, a current sampling lower end 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 end 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 end voltage dividing resistor R12 is connected to one end of the current sampling lower end voltage dividing resistor R11 and one end of the current sampling lower end 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, the other end of the current sampling lower end filter capacitor C2, and the ground level common terminal of the benchmark 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 benchmark comparison control device U1, 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 is 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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