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EP-4738649-A1 - A WIRELESS CHARGER AND RECEIVING LOAD OF BACKWARD COMPATIBILITY THAT AUTOMATICALLY IDENTIFIES FAST AND SLOW CHARGING

EP4738649A1EP 4738649 A1EP4738649 A1EP 4738649A1EP-4738649-A1

Abstract

The present invention discloses a backward-compatible wireless charger that automatically identifies fast and slow charging receiving load, comprising a wireless charger and a receiving load, the wireless charger comprises two-level variable DC voltage regulator circuit, a main resonance circuit, a resonant current sampling voltage divider and comparison circuit, the receiving load comprises a receiving resonant circuit, and the resonant frequency of the receiving load is compared with the resonant frequency of resonant circuit in the wireless charger to distinguish different receiving loads and to charge correspondingly. Only common circuit components are used and the circuit is simple, of small size, at low cost, with low energy consumption, safe, effective and reliable, to achieve the high cost-performance of the whole circuit, and at the same time it realizes the compatible fast charging and slow charging receiving load.

Inventors

  • XIANG, GUANGHUI

Assignees

  • PI POWER PRODUCT (SHENZHEN) COMPANY LIMITED

Dates

Publication Date
20260506
Application Date
20251027

Claims (8)

  1. A wireless charger and receiving load of backward compatibility that automatically identifies fast and slow charging, wherein it comprises a wireless charger and a receiving load, the wireless charger comprises two-level variable DC voltage regulator circuit, a main resonant circuit, a resonant current sampling voltage divider and comparison circuit, the receiving load comprises a receiving resonant circuit, and the two-level variable DC regulator circuit is used for converting the AC input voltage of the power grid into a low-voltage or high-voltage two-level variable stable DC output voltage, the resonant current sampling voltage divider and comparison circuit is used for controlling the output voltage level of the two-level variable DC voltage regulator circuit, and the main resonant circuit adopts a sine wave resonant circuit to convert the DC energy into high-frequency alternating current energy and emits the magnetic field energy through the transmitting coil; the receiving resonant circuit receives the magnetic field energy, charges the rechargeable battery after passing the rectifier filter circuit of the post-stage and the CC/CV charging control circuit, compares the resonant frequency between wireless charger and receiving load, distinguishes different receiving load and realizes charging mode.
  2. The wireless charger and receiving load of backward compatibility that automatically identifies fast and slow charging according to claim 1, wherein when the no-load application, the resonant current of the main resonant circuit is very low, and the output voltage of the two-level variable DC voltage regulator circuit is automatically controlled to have a low voltage output after being processed by the resonant current sampling voltage divider and the comparison circuit; The resonant energy intensity of the main resonant circuit is very weak, and the whole wireless charger circuit works in low-power power-saving standby mode.
  3. The wireless charger and receiving load of backward compatibility that automatically identifies fast and slow charging according to claim 1, wherein when applied to the slow-charging receiving load, the main resonant circuit of the wireless charger and the resonant circuit of the slow-charging receiving load carry out proportional coupling of ordinary transformer, the resonant current of the main resonant circuit is lower than the setting threshold value, and the output voltage of the two-level variable DC voltage regulator circuit is automatically controlled to be a low voltage level after being processed by the resonant current sampling voltage divider and comparison circuit, a compatible low-power slow charging mode is implemented to the slow-charging receiving load.
  4. The wireless charger and receiving load of backward compatibility that automatically identifies fast and slow charging according to claim 1, wherein when applied to the fast-charging receiving load, the main resonant circuit of the wireless charger carries out strong resonance and strong coupling with the resonant circuit of the fast-charging receiving load, the resonant current of the main resonant circuit exceeds the setting threshold value, and the output voltage of the two-level variable DC voltage regulator circuit is automatically controlled to deliver a high voltage level after being processed by the resonant current sampling voltage divider and comparison circuit, realizes the stable normal high-power fast charging mode of the fast-charging receiving load.
  5. The wireless charger and receiving load of backward compatibility that automatically identifies fast and slow charging according to claim 1, wherein the two-level variable DC voltage regulator circuit comprises an overcurrent protection component RF5001, a front rectifier device (or component) DB5001 (full-bridge rectifier or half-wave rectifier), a main switching device Q5001 (MOSFET or BJT or other switching device), a rear rectifier diode D1, a main filter capacitor C5001, a feedforward voltage sampling upper voltage divider resistor R1, a feedforward voltage sampling lower side voltage divider resistor R2, reference voltage regulator component Z1, a voltage regulator driving switch Q5002 and a main switching device driving bias resistor R3, the input of described two-level variable DC voltage regulator circuit is connected to the live L and neutral line N terminals of single-phase alternating current mains power supply respectively, live L (or neutral wire N) is connected to one terminal of described overcurrent protection component RF5001, and the another terminal of described overcurrent protection component RF5001 is connected to one terminal of AC input of described front rectifier device (or component) DB5001, the neutral wire N (or the live L) is connected to the another terminal of the AC input of the former rectifier device (or component) DB5001; the DC output positive terminal of described front rectifier device (or component) DB5001 is connected to the current input terminal of described main switching device Q5001, and is connected to one terminal of voltage divider resistor R1 at the upper terminal of described feedforward voltage sampling and one terminal of driving bias resistor R3 of described main switching device simultaneously; the DC output negative terminal network of the former rectifier device (or component) DB5001 is named the reference ground AGND; The current output terminal of described main switching device Q5001 is connected to the anode of described rear rectifier diode D1; the cathode of described rear rectifier diode D1 is connected to the positive terminal of described main filter capacitor C5001; the negative terminal of the main filter capacitor C5001 is connected to the reference ground AGND; the another terminal of the feedforward voltage sampling upper side voltage divider resistor R1 is connected to one terminal of the feedforward voltage sampling lower side voltage divider R2 and the cathode of the reference voltage regulator component Z1 and the current inflow terminal of the shunt resistor R5 of the resonant current sampling voltage divider and comparison circuit; the another terminal of the feedforward voltage sampling lower side voltage divider resistor R2 is connected to the reference ground AGND; The anode of described reference voltage regulator component Z1 is connected to the control terminal of described voltage regulator driving switch Q5002; The current inflow terminal of described voltage regulator driving switch Q5002 is connected to the another terminal of described main switching device driving bias resistor R3 and the control terminal of described main switching device Q5001; The current outflow terminal of described voltage regulator driving switch Q5002 is connected to described reference ground AGND.
  6. The wireless charger and receiving load of backward compatibility that automatically identifies fast and slow charging according to claim 5, wherein the main resonant circuit comprises 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 upper bias resistor R7 of the main resonant switch and a lower bias resistor R8 of the main resonant switch; one terminal of the main resonant inductor T5001-A is connected to one terminal of the positive terminal of the main filter capacitor C5001 and the positive feedback voltage dividing capacitor C5002 and one terminal of the upper bias resistor R7 of the main resonant switch and one terminal of the current bias resistor R6 of the resonant current sampling divider and comparison circuit; the another terminal of the main resonant inductor T5001-A is connected to the current inflow terminal of the main resonant switch Q5003 and one terminal of the main resonant capacitor C11; The current outflow terminal of described main resonant switch Q5003 is connected to the anode of described anti-reverse current diode D2; the cathode of the anti-reverse current diode D2 is connected to the another terminal of the main resonant capacitor C11 and the another terminal of the positive feedback voltage divider C5002 and one terminal of the resonant current sampling resistor R10 and the one terminal of the current sampling upper terminal of the resonant current sampling voltage divider and the comparison circuit; The control terminal of described main resonant switch Q5003 is connected to the another terminal of upper bias resistor R7 of described main resonant switch and one terminal of lower bias resistor R8 of described main resonant switch; The another terminal of lower bias resistor R8 of described main resonant switch is connected to described reference ground AGND; The another terminal of described resonant current sampling resistor R10 is also connected to described reference ground AGND; There is a magnetic field coupling relationship between the main resonant inductor T5001-A and the receiving resonant inductance Lr_s of the receiving load.
  7. The wireless charger and receiving load of backward compatibility that automatically identifies fast and slow charging according to claim 6, wherein the resonant current sampling voltage divider and comparison circuit comprises a current sampling upper side voltage divider resistor R12, a current sampling lower side voltage divider resistor R11, a current sampling lower side filter capacitor C2, a voltage comparing control device U1, a voltage regulator component Z3, a current bias resistor R6, and a shunt resistor R5; One terminal of described current sampling upper side voltage divider resistor R12 is connected with the cathode network of described anti-reverse current diode D2; the another terminal of described current sampling upper side voltage divider resistor R12 is connected to one terminal of described current sampling lower side voltage divider resistor R11 and one terminal of described current sampling lower side filter capacitor C2 and described reference voltage input terminal of voltage comparing control device U1; the another terminal of the voltage divider resistor R11 at the lower terminal of the current sampling and the another terminal of the filter capacitor C2 at the lower terminal of the current sampling and the ground level common terminal of the voltage comparing control device U1 are all connected to the reference ground AGND together; One terminal of described current bias resistor R6 is connected with the positive terminal network of described main filter capacitor C5001; the another terminal of described current bias resistor R6 is connected to the current inflow terminal of described voltage comparing control device U1 and the cathode of described voltage regulator component Z3 and the current outflow terminal of described shunt resistor R5; The anode of the voltage regulator component Z3 is connected to the reference ground AGND.
  8. The wireless charger and receiving load of backward compatibility that automatically identifies fast and slow charging according to claim 7, wherein the receiving resonant circuit comprises a resonant inductance Lr_s, a resonant capacitor Cr_s, a rectifier diode D_s, a filter capacitor Cf_s, a charging control switch Qsw_s, a charging current sampling resistor Rcs_s, a rechargeable battery Vbatt, and a CC/CV charging control circuit function block; there is a magnetic field coupling relationship between the resonant inductor Lr_s and the main resonant inductor T5001-A at the transmitting terminal of the wireless charger; the resonant inductance Lr_s and resonant capacitor Cr_s are parallel connection relationship (or series connection relationship); one terminal of the resonant inductance Lr_s and resonant capacitor Cr_s connects to the anode of the rectifier diode D_s; the another terminal of the resonant inductance Lr_s and the resonant capacitance Cr_s is named as the reference ground; the cathode of the rectifier diode D_s is connected to one terminal of the filter capacitor Cf_s and the current inflow terminal of the charge control switch Qsw_s and the voltage sampling terminal of the CC/CV charge control circuit function block; The another terminal of the filter capacitor Cf_s and the ground level common terminal of the CC/CV charging control circuit function block are connected to the reference ground together; The current outflow terminal of the charging control switch Qsw_s is connected to one terminal of the charging current sampling resistor Rcs_s and the current sampling positive terminal of the CC/CV charging control circuit function block; the another terminal of the charging current sampling resistor Rcs_s is connected to the positive terminal of the rechargeable battery Vbatt and the negative terminal of the current sampling of the CC/CV charging control circuit function block; The negative terminal of the rechargeable battery Vbatt at is connected to the reference ground.

Description

Technical field The present invention relates to the technical field of wireless charging circuit, in particular to a wireless charger that is backward-compatible with automatic identification of fast and slow charging according to receive load. Background technology With the increasing improvement of people's living standards and the increasing importance of oral health, wireless power receiving loads (such as electric toothbrushes) have begun to widely enter into thousands of households with their efficient cleaning functions, which use rechargeable batteries to drive DC motors to achieve different speeds and directions and vibration functions to drive the toothbrush head to achieve efficient cleaning of teeth without dead corners. Considering its use of environmental conditions, it must achieve a certain need for waterproof and dustproof, and its supporting mainstream charging method is electromagnetic coupling wireless charging, and the wireless charger has no physical contact with the receiving circuit of the wireless power receiving load (such as: electric toothbrush). According to the needs of users' fast-paced life and the need for portable travel, the requirements for faster and more convenient wireless charging speed are proposed. The fast-charging wireless charger is required to not only achieve fast charging to receiving load, but also be backward-compatible and protect the slow-speed compatible charging of the previous generation of receiving loads. It avoids potential safety hazards, protects the rights and interests of users, and also meets the fast and slow charging needs of different users. Contents of the invention The object of the present invention is to solve the technical problem of the compatible charging of the wireless charger to the fast-charging receiving load and the slow-charging receiving load. The present invention provides a backward-compatible wireless charger and a receiving load that automatically identifies fast and slow charging, comprises a wireless charger and a receiving load, the wireless charger comprises two-level variable DC voltage regulator circuit, a main resonance circuit, a resonant current sampling voltage divider and comparison circuit, the receiving load comprises a receiving load resonance circuit. and the two-level variable DC regulator circuit is used for converting the AC input voltage of the power grid into a low-voltage or high-voltage two-level variable stable DC output voltage, the resonant current sampling voltage divider and comparison circuit is used for controlling the output voltage level of the two-level variable DC voltage regulator circuit, and the main resonant circuit adopts a sine wave resonant circuit to convert the DC energy into high-frequency alternating current energy and emits the magnetic field energy through the transmitting coil; the receiving resonant circuit receives the magnetic field energy, charges the rechargeable battery after passing through the rectifier filter circuit of the post-stage and the CC/CV charging control circuit, compares the resonant frequency point of LC in the receiving load with the resonant frequency point of the main resonant circuit in the wireless charger, distinguishes different receiving loads and realizes charging mode. Preferably, in a no-load application, the resonant current of the main resonant circuit is very low, and the output voltage of the two-level variable DC voltage regulator circuit is automatically controlled as a low voltage level after being processed by the resonant current sampling voltage divider and the comparison circuit; The resonant energy intensity of the main resonant circuit is very weak, and the whole wireless charger circuit works in low-power power-saving standby mode. Preferably, when applied to the slow-charging receiving load, the main resonant circuit at the wireless charger is proportionally coupled with the resonant circuit of the slow-charging receiving load for ordinary transformers style, the resonant current of the main resonant circuit is lower than the setting threshold value, and the output voltage of the two-level variable DC voltage regulator circuit is automatically controlled into a low voltage level after being processed by the resonant current sampling voltage divider and comparison circuit, so that the low-power compatible charging mode of the slow-charging receiving load is realized. Preferably, when applied to the fast-charging receiving load, the main resonant circuit at the wireless charger carries out strong resonance and strong coupling with the resonant circuit of the fast-charging receiving load, the resonant current of the main resonant circuit exceeds the setting threshold value, and the output voltage of the two-level variable DC regulator circuit is automatically controlled into a high-voltage level after being processed by the resonant current sampling voltage divider and comparison circuit, so that the stable normal high-power fast-ch