Dynamic Regulation of Wireless Charging Systems

Abstract

The present disclosure relates to dynamic regulation of a wireless charging system. In a wireless charging system having a power transmitter (TX) and a power receiver (RX), the RX has a rectifier that rectifies an AC power signal wirelessly received from the TX into a rectified DC power signal. The RX also has a regulation module that monitors the DC power signal at various different voltage regions having one or more different high voltage regions and one or more different low voltage regions. Each regulation module affects the operation of the wireless charging system in a different way. The regulation module protects the RX from overvoltage and undervoltage conditions.

Description

Technical Field

[0001] The present invention relates generally to wireless charging systems, and more particularly to receivers of wireless charging systems that avoid overvoltage and undervoltage conditions. Background Art

[0002] 1 is a simplified schematic block diagram of a conventional wireless charging system 100 having a power transmitter (TX) 110 and a power receiver (RX) 130. The TX 110 includes a transmitter 112, a TX matching network 114, and a TX inductor coil 116, while the RX 130 includes an RX inductor coil 132, an RX matching network 134, a rectifier (i.e., an AC to DC converter) 136, a communication controller 138, and a communication processor 140. The matching networks 114 and 134 are designed to ensure that the output impedance of the TX 110 matches the input impedance of the RX 130. The TX and RX inductor coils 116 and 132 form an inductive interface 120 for wirelessly (i.e., magnetically) transmitting (i) power from the TX 110 to the RX 130 and (ii) communication signals between the TX and RX 110 and 130.

[0003] The transmitter 112 applies an AC power signal 113 to a TX inductor coil 116 via a TX matching network 114. The AC power signal 113 induces an AC power signal in the RX inductor coil 132, which is applied to a rectifier 136 as an AC power signal 135 via the RX matching network 134. The rectifier 136 rectifies the AC power signal 135 into a DC power signal VRECT, which is applied to power a system load (not shown).

[0004] The communication controller 138 generates communication signals that are sent by the communication processor 140 to the TX 110 through the inductive interface 120. Specifically, the communication controller 138 monitors VRECT and, if appropriate, sends communication signals to (i) instruct the TX 110 to increase the power transmission level if VRECT is too low; and (ii) instruct the TX 110 to decrease the power transmission level if VRECT is too high.

[0005] However, in some cases, the wireless charging system 100 will not operate properly. For example, in some conditions, the power transfer path may interfere with the communication path because they share a common inductive interface 120. Furthermore, in other conditions where VRECT is too high or too low, the traditional feedback signal returned to the TX 110 may be too slow to prevent damage to the load or even the TX 110 and / or RX 130 itself. Therefore, it would be advantageous to have an RX that can avoid overvoltage and undervoltage conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0006] Embodiments of the present invention are described by way of example and are not limited by the accompanying drawings, in which the same reference numerals represent similar elements. Elements in the drawings are illustrated for simplicity and clarity, and are not necessarily drawn to scale. For example, the thickness of layers and regions may be exaggerated for clarity.

[0007] FIG1 is a simplified schematic block diagram of a conventional wireless power transmission system;

[0008] Figure 2 is a block diagram of a power receiver (RX) according to an embodiment of the present invention, which power receiver (RX) may be used in a wireless charging system similar to the wireless charging system of FIG. 1 ;

[0009] Figure 3 shows five different voltage threshold levels defining six different voltage regions of the rectified DC voltage signal VRECT and the actions taken when VRECT falls within these different regions;

[0010] Figure 4 is Figure 2 Flowchart of the process of monitoring VRECT and handling different operating conditions implemented in RX;

[0011] Figure 5 Is to indicate that there is and there is not Figure 2 and Figure 4 A diagram showing voltage levels of VRECT according to different transmission power levels for two different load levels in the case of a voltage regulation process;

[0012] Figure 6 It can be used to implement Figure 2 A schematic circuit diagram of a low voltage regulation (LVR) module of the LVR module; and

[0013] Figure 7 It can be used to implement Figure 2 A schematic circuit diagram of a high voltage regulator (HVR) module of the HVR module. DETAILED DESCRIPTION

[0014] Detailed description embodiments of the present invention are disclosed herein. However, the specific structural and functional details disclosed herein are only for the purpose of describing the exemplary embodiments of the present invention. Embodiments of the present invention can be implemented in many alternative forms and should not be interpreted as being limited to the embodiments set forth herein. In addition, the terms used herein are only used for the purpose of describing specific embodiments and are not intended to be limited to the exemplary embodiments of the present invention.

[0015] As used herein, the singular forms "a", "an", and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It should also be understood that the terms "comprise", "comprising", "having", "having", "including", or "comprising" specify the presence of the features, steps, or components, but do not exclude the presence or addition of one or more other features, steps, or components. It should also be noted that in some alternative embodiments, the functions / actions indicated may not occur in the order shown in the figures. For example, two figures shown in succession may actually be performed substantially simultaneously, or sometimes in the opposite order, depending on the functions / actions involved. Unless otherwise indicated, the term "or" should be interpreted as inclusive.

[0016] In a wireless charging system, unless a relatively light load current is properly regulated, the rectified DC voltage VRECT may be very high, which means that the devices in the power receiver (RX) must be able to withstand the high voltage. On the other hand, when the load is heavy, unless properly regulated, VRECT may be too low to power the wireless charging system, and the RF amplitude may also be too low for data communication.

[0017] According to an embodiment of the present invention, in a wireless charging system having a power transmitter (TX) and a power receiver (RX), in addition to instructing the TX to adjust its transmission power level in a system-level feedback loop, the RX also has a plurality of regulation modules, which locally monitor the rectified DC power signal VRECT for different overvoltage and undervoltage conditions and take appropriate actions to handle these conditions, thereby extending the power transmission and data communication range of the system when the power transmission level is not well regulated at the system level.

[0018] One embodiment of the present invention is a power receiver (RX) for a wireless charging system. The RX includes: a rectifier configured to rectify an AC power signal wirelessly received from a TX into a DC power signal; and a plurality of regulating modules monitoring the DC power signal in a plurality of voltage regions, the plurality of voltage regions including two or more different high voltage regions and two or more different low voltage regions, wherein each regulating module is configured to affect the operation of the wireless charging system in a different manner.

[0019] Reference now Figure 2 , shows a block diagram of an RX 230 that can be used in a wireless charging system similar to the wireless charging system 100 of FIG1 to replace the RX 130. Similar to the RX 130, the RX 230 includes an RX inductor coil 232, an RX matching network 234, a rectifier 236, a communication controller 238, and a communication processor 240, each of which performs functions similar to corresponding elements in the RX 130.

[0020] RX 230 also includes an overvoltage warning (OVW) module 242, a high voltage regulation (HVR) module 244, an overvoltage protection (OVP) module 246, an under-voltage lookout (UVLO) module 248, a low voltage regulation (LVR) module 250, an analog and digital control module 252, a control logic 254, and a switch 256. The OVW, HVR, OVP, UVLO, and LVR modules 242, 244, 246, 248, and 250 are collectively referred to as regulation modules 242-250 because each of these modules monitors VRECT for different overvoltage and undervoltage conditions and, if appropriate, takes action to handle the specific condition of the designed module. Note that a conventional RX such as RX 130 of FIG. 1 (although not explicitly shown in FIG. 1 ) would have a similar Figure 2 The OVP and UVLO modules 246 and 248 are modules.

[0021] In a typical wireless charging system, the analog and digital control module 252 provides reference voltages and currents as well as internal supply voltages for other functional modules in the RX 230. The control module 252 may also provide a power-up / power-down sequence and state machine for the operation of the system.

[0022] Depending on the specific implementation, the RX 230 may be used in a wireless charging system operating as a battery charger, a low dropout (LDO) regulator, a DC / DC converter, or any other suitable application.

[0023] Although the system-level feedback loop can eventually regulate the system at an optimized operating state, it is difficult for the feedback loop to track rapid and dynamic changes in load. As the load changes and other possible operating conditions change, VRECT may move away from its optimal level before the system-level feedback loop can fully function. In this case, according to the present invention, one or more of the HVR, OVP, UVLO and LVR modules 244, 246, 248 and 250 will take local action to change the behavior within RX 230.

[0024] In particular, when the load current is so light that VRECT becomes undesirably high, the HVR module 244 will become active and introduce a dummy load to inhibit VRECT from continuing to increase. If the dummy load is not large enough and VRECT becomes dangerously high, the OVP module 248 will be triggered to detune the RX inductor coil 232 and the RX matching network 234 to essentially stop power rectification.

[0025] When the input power is too low for the entire load current, the LVR module 250 will reduce the load current so that the supply voltage can be maintained high enough to keep the RX 230 operating. With this protection, the wireless charging system can continue to operate even if only very little power is delivered to the output load. If the input power is too low to power all components in the RX 230, the UVLO module 248 will be triggered to shut down some of them (e.g., the LVR module 250 and the analog and digital control module 252) to reduce the current dissipation of the power transmission path and preserve as much power as possible for more critical components (e.g., the communication controller 238 and the communication processor 240).

[0026] Figure 3 Five different voltage threshold levels are shown that define the following six different voltage regions of VRECT and the corresponding actions taken when VRECT falls within these different regions:

[0027] Region 1: (OVP<VRECT)=> Turns off power rectification and instructs TX to reduce power transmission level.

[0028] Region 2: (HVR <VRECT<OVP)=> Inhibits the increase of VRECT and instructs TX to reduce the power transmission level.

[0029] Area 3: (OVW <VRECT<HVR)=> Instructs TX to reduce power transmission level.

[0030] Area 4: (LVR <VRECT<OVW)=> No action required.

[0031] Zone 5: (UVLO <VRECT<LVR)=> Reduces load current and instructs TX to increase power transfer level.

[0032] Area 6: (VRECT<UVLO)=> Turns off certain modules in the RX 230 and instructs the TX to increase the power transmission level.

[0033] Note that if VRECT is above OVW, some form of high voltage regulation is required. Likewise, if VRECT is below LVR, some form of low voltage regulation is required. As described below, the regulation modules 242-250 monitor VRECT in at least six different voltage regions and take appropriate actions, as described below.

[0034] Figure 4 is Figure 2 Flowchart of various processes implemented within RX 230 to monitor VRECT and handle different operating conditions. In step 402, VRECT is monitored by each of the regulation modules 242-250.

[0035] If the UVLO module 248 determines in step 404 that VRECT is below UVLO, then in step 406, the UVLO module 248 signals the control logic 254 to shut down certain RX modules (e.g., the LVR module 250 and the analog and digital control module 252) to preserve power for more critical operations (e.g., the communication controller 238 and the communication processor 240). In addition, the control logic 254 signals the communication controller 238 to instruct the TX to increase the power transmission level.

[0036] If it is determined at step 408 that VRECT is not below UVLO but is below LVR, then at step 410 the LVR module 250 will operate to reduce the load current as described below in conjunction with Figure 6 Further described. Additionally, the LVR module 250 will signal the control logic 254 to signal the communication controller 238 to instruct the TX to increase the power transmission level.

[0037] If VRECT is not less than LVR, then no low voltage regulation is required as shown in step 412 .

[0038] If the OVP module 246 determines in step 414 that VRECT is above OVP, then in step 416, the OVP module 246 signals the control logic 254 to close the switch 256 to detune the RX inductor coil 232 and the RX matching network 234, thereby shutting down the power rectification of the rectifier 236. In addition, the control logic 254 signals the communication controller 238 to instruct the TX to reduce the power transmission level.

[0039] If VRECT is not above OVP but above HVR as determined at step 418, then at step 420 the HVR module 244 will operate to suppress the increase in VRECT by introducing a dummy load as described below in conjunction with Figure 7 Further described. In addition, the HVR module 244 will signal the control logic 254 to signal the communication controller 238 to instruct the TX to reduce the power transmission level.

[0040] If VRECT is not above HVR, but OVW module 242 determines in step 422 that VRECT is above OVW, then in step 424 OVW module 242 will signal control logic 254 to signal communication controller 238 to instruct TX to reduce the power transmission level.

[0041] If VRECT is not above OVW, then high voltage regulation is not required as determined in step 426 .

[0042] Note that OVW module 242, OVP module 246, and UVLO module 248 may be implemented using (i) conventional comparator circuitry to compare VRECT to corresponding threshold levels, and (ii) appropriate logic circuitry to perform the necessary signaling, as will be appreciated by those skilled in the art. Similarly, analog and digital control module 252 and control logic module 254 may be implemented using appropriate digital and / or analog circuitry, as will be appreciated by those skilled in the art.

[0043] Figure 5 Is to indicate that there is and there is not Figure 2 and Figure 4 FIG. 5 is a diagram of the voltage level of VRECT according to different transmission power levels for two different load levels in the case of a voltage regulation process of FIG. Figure 2 and Figure 4 504 represents the same light load condition, but with a conventional regulation process similar to the regulation provided by the OVP and UVLO modules 246 and 248. Figure 2 and Figure 4 Similarly, dashed curve 506 represents the voltage regulation process without Figure 2 and Figure 4 508 represents the same heavy load condition, but with a conventional regulation process similar to the regulation provided by the OVP and UVLO modules 246 and 248. Figure 2 and Figure 4 All voltage regulation is handled by the .

[0044] When VRECT is in region 4 between LVR and OVW, no adjustment is required, so that VRECT varies linearly with the transmission power level. Figure 5 ), eventually VRECT will drop below LVR, and the LVR module 250 will begin to reduce the load current in an attempt to keep VRECT at LVT in order to continue to power the RX 230. As the transmit power level continues to decrease, eventually VRECT will reach UVLO, and the UVLO module 248 will begin to shut down certain components in order to keep the more critical components alive.

[0045] Referring again to VRECT in Region 4, as the transmission power level increases (to Figure 5), eventually VRECT will rise above HVR, and HVR module 244 will begin to add dummy loads to suppress VRECT from increasing. As the transmit power level continues to increase, eventually VRECT will reach OVP, and OVP module 246 will close switch 256, detuning RX inductor coil 232 and RX matching network 234, and terminating the power rectification process of rectifier 236.

[0046] In the light load case of conventional regulation of curve 502 , as the transmit power level increases, VRECT remains unregulated between UVLO at point A and OVP at point B, after which the conventional version of OVP module 246 causes VRECT to drop immediately.

[0047] In the corresponding fully regulated light load case of curve 504, VRECT is flat from point D to point C as the transmission power level decreases, and then decreases to zero from point C. As the transmission power level increases, VRECT is flat from point E to point F, increases from point F to point G, and then decreases immediately after point G.

[0048] In the heavy load case of conventional regulation of curve 506 , VRECT remains at UVLO from point A to point H due to the conventional version of UVLO module 248 , and remains unregulated between UVLO at point H and OVP at point I, after which the conventional version of OVP module 246 causes VRECT to drop immediately.

[0049] In the corresponding regulated heavy load case of curve 508, VRECT is flat from point J to point C as the transmission power level decreases, and then decreases to the origin from point C. As the transmission power level increases, VRECT is flat from point K to point L, increases from point L to point M, and then decreases immediately after point M.

[0050] Figure 5 Compared with a wireless charging system having only a conventional voltage regulation process similar to OVP and UVLO modules 246 and 248, a Figure 2 and Figure 4 The voltage regulation handles how wireless charging systems have an extended power transfer range.

[0051] Figure 6 It can be used to implement Figure 2 A schematic circuit diagram of a low voltage regulation (LVR) module 600 of the LVR module 250 is shown. A person skilled in the art will appreciate that the LVR module 600 is only a circuit diagram of a low voltage regulation (LVR) module 600 of the LVR module 250. Figure 2 When VRECT is lower than LVR, LVR module 600 operates to reduce the load current appearing at output node VOUT.

[0052] In operation, VRECT is applied to a first resistor divider 602, which generates a divided voltage 603 based on the relative sizes of resistors R3 and R4. The divided voltage 603 is applied to the negative input of a first error amplifier 604, whose positive input is a reference voltage VREF12, where LVR=VREF12*(1+R3 / R4). Note that VREF12 can be generated by a bandgap voltage generator or other suitable circuitry that accurately generates a substantially constant voltage level. The resulting amplified error signal 605 is applied to a first voltage-to-current (V2I) converter 606, which generates a current signal 607 and applies the current signal 607 to a current adder 618.

[0053] The voltage at the output node VOUT is applied to a second resistor divider 608, which generates a divided voltage 609 based on the relative sizes of resistors R5 and R6. The divided voltage 609 is applied to the positive input of a second error amplifier 610, whose negative input is VREF12. The resulting amplified error signal 611 is applied to a second V2I converter 612, which generates a current signal 613 and applies the current signal 613 to a current adder 618.

[0054] The current adder 618 also receives a mirror current signal 617 generated by the current mirror 616 based on the current signal 615 tapped at the node 614 .

[0055] The current adder 618 generates a sink current signal 619 corresponding to the sum of the current signals 607, 613, and 617. The I2V converter 620 adds the constant bias current IB to the sink current signal 619 and converts the resulting current signal into a voltage signal 621. The high impedance driver 624 receives power 623 from the charge pump 622 to generate a gate control signal 625 based on the voltage signal 621, wherein the gate control signal 625 controls the transistor 626. In one embodiment, the transistor 626 is an NFET. During stable operation, the impedance driver 624 has a high input impedance, so the magnitude of the sink current signal 619 remains equal to the constant bias current IB.

[0056] When VRECT is above LVR, the error signal 605 from the error amplifier 604 is zero, and the V2I converter 606 generates a zero current signal 607. In this case, the only non-zero contributions to the current adder 618 are the current signals 613 and 617.

[0057] When VRECT is lower than LVR, the error signal 605 from the error amplifier 604 is positive and the V2I converter 606 generates a non-zero current signal 607. In this case, all three current inputs to the current adder 618 are non-zero. Thus, since the current signal 607 is now a non-zero current signal, in order to keep the sink current signal 619 constant, the magnitude of the current signal 613 must decrease or the magnitude of the current signal 617 must decrease or both. When the voltage signal 609 is lower, the magnitude of the current signal 613 will decrease, which means that the current flowing through the first resistor divider 608 is smaller. When the current flowing through the node 614 is smaller, the magnitude of the current signal 617 will decrease. Either way, the load current at the output node VOUT will also be smaller. Therefore, when VRECT is lower than LVR, the LVR module 600 reduces the load current.

[0058] Note that transistor 626 and first resistor divider 608 form the output branch of LVR module 600 .

[0059] Figure 7 It can be used to implement Figure 2 A schematic circuit diagram of a high voltage regulator (HVR) module 700 of the HVR module 244 of FIG. A person skilled in the art will understand that the HVR module 700 is only a circuit diagram of a high voltage regulator (HVR) module 700 of the HVR module 244 of FIG. Figure 2 When VRECT is higher than HVR, the HVR module 700 operates to inhibit the increase of VRECT.

[0060] Transistors 712, 714, 716, and 718 form a comparator 710. Transistors 722 and 724 form a current master 720, while transistors 742 and 744 form a first current mirror 740, and transistors 752 and 754 form a second current mirror 750, which can mirror a reference current IREF as a mirror current through transistor 754. Transistor 730 acts as a switch, which controls whether the reference current IREF is mirrored through transistor 754 based on the output from comparator 710. Transistors 754 and 760 form an output branch of the HVR module 700.

[0061] In operation, VRECT is applied to resistor divider 702, which generates a divided voltage 703 based on the relative sizes of resistors R1 and R2. Divided voltage 703 is applied to the gate of PFET 712, while reference voltage VREF is applied to the gate of PFET 714, where HVR=VREF*(1+R1 / R2). Note that VREF can be generated by a bandgap voltage generator or other suitable circuitry that accurately generates a substantially constant voltage level.

[0062] When VRECT is below HVR, the gate of NFET 730 is driven low, turning off NFET 730 and ensuring that reference current IREF is not mirrored through NFET 754. However, when VRECT is above HVR, the gate of NFET 730 is driven high, turning on NFET 730 and enabling reference current IREF to be mirrored through NFET 754, thereby drawing a sink current ISINK from node VRECT and suppressing an increase in the voltage level of VRECT. The sink current ISINK from VRECT to ground is limited to IREF*K, where K is the total gain of current mirrors 740 and 750, which can be precisely trimmed. Note that appropriate DC bias voltages are applied to the gates of PFET 704 and NFET 760 to ensure that they are always on. Therefore, when VRECT is above HVR, HVR module 700 suppresses an increase in VRECT.

[0063] Although the present invention has been described in terms of a separate regulation module that monitors VRECT and takes the discussed actions depending on the value of VRECT, the system may include a process for monitoring VRECT and using software (or firmware) to take the described actions. Furthermore, although the present invention has been described in the context of a wireless charging system in which the power transfer path and the communication path between TX and RX share the same inductive interface, the present invention may also be implemented in the context of a wireless charging system having separate wireless interfaces for power transfer and communication.

[0064] Although the present invention is described herein with reference to specific embodiments, various modifications and changes may be made without departing from the scope of the present invention as set forth in the following claims. Therefore, the description and drawings should be regarded as illustrative rather than restrictive, and all such modifications are intended to be included within the scope of the present invention. Any benefits, advantages, or solutions to problems described herein with respect to specific embodiments are not intended to be construed as key, required, or essential features or elements of any or all claims.

[0065] It should be understood that the steps of the exemplary methods set forth herein do not necessarily need to be performed in the order described, and the order of the steps of these methods should be understood to be merely exemplary. Likewise, in methods consistent with various embodiments of the present invention, additional steps may be included in these methods, and certain steps may be omitted or combined.

[0066] Even though elements in the following method claims, if any, are recited in a specific sequence with corresponding labels, these elements are not necessarily intended to be limited to being implemented in that specific sequence unless the claim recitation otherwise implies a specific sequence for implementing some or all of these elements.

[0067] Also for the purposes of this specification, the terms "couple", "coupled to", "coupled", "connected", "connected to", or "connected" refer to any means known or later developed in the art that allows energy to be transferred between two or more elements and the insertion of one or more additional elements is contemplated but not required. In contrast, the terms "directly coupled", "directly connected", etc. imply that there are no such additional elements.

[0068] A signal and a corresponding terminal, node, port, or path may be represented by the same name and are interchangeable herein.

[0069] For illustrative purposes, transistors are generally shown as single devices. However, those skilled in the art will appreciate that transistors will have various dimensions (e.g., gate width and length) and characteristics (e.g., threshold voltage, gain, etc.), and may include multiple transistors coupled in parallel to obtain desired electrical characteristics from the combination. Furthermore, the transistors shown may be composite transistors.

[0070] As used in this specification and claims, the term "channel node" generally refers to the source or drain of a metal oxide semiconductor (MOS) transistor device (also known as a MOSFET), the term "channel" refers to the path through the device between the source and the drain, and the term "control node" generally refers to the gate of a MOSFET. Similarly, as used in the claims, the terms "source", "drain" and "gate" should be understood to refer to the source, drain and gate of a MOSFET, respectively, or the emitter, collector and base of a bipolar device, respectively, if an embodiment of the present invention is implemented using bipolar transistor technology. In addition, the terms source, drain and gate mean the same as "source terminal", "drain terminal" and "gate terminal", respectively, and can be used interchangeably.

[0071] References herein to "one embodiment" or "an embodiment" mean that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment of the present invention. The phrase "in one embodiment" appearing in various places in the specification does not necessarily refer to the same embodiment, nor are separate or alternative embodiments necessarily mutually exclusive of other embodiments. The same applies to the term "implementation".

Claims

1. A power receiver RX for a wireless charging system including a power transmitter TX that wirelessly transmits an AC power signal to the RX, the RX comprising: a rectifier configured to rectify the AC power signal into a DC power signal; and a plurality of regulation modules configured to monitor the DC power signal in a plurality of voltage regions, the plurality of voltage regions comprising two or more different high voltage regions and two or more different low voltage regions, wherein each regulation module is configured to affect the operation of the wireless charging system in a different manner; A first region includes a voltage higher than an overvoltage protection OVP voltage level; a second region including voltages lower than the OVP voltage level and higher than a high voltage regulation HVR voltage level; A third region includes a voltage lower than the HVR voltage level and higher than the overvoltage warning OVW voltage level; a fourth region including a voltage lower than the OVW voltage level and higher than a low voltage regulation LVR voltage level; a fifth region including a voltage lower than the LVR voltage level and higher than an under-voltage monitoring UVLO voltage level; and a sixth region including voltages lower than the UVLO voltage level; When the OVP module determines that the DC power signal is higher than the OVP voltage level, the OVP module turns off rectification of the rectifier, and the RX instructs the TX to reduce the power transmission level; When the HVR module determines that the DC power signal is higher than the HVR voltage level, the HVR module inhibits the DC power signal from increasing, and the RX instructs the TX to reduce the power transmission level; When the OVW module determines that the DC power signal is higher than the OVW voltage level, the RX instructs the TX to reduce the power transmission level; When the LVR module determines that the DC power signal is lower than the LVR voltage level, the LVR module reduces the load current of the RX, and the RX instructs the TX to increase the power transmission level; and When the UVLO module determines that the DC power signal is below the UVLO voltage level, the UVLO module shuts down one or more other modules in the RX, and the RX instructs the TX to increase the power transmission level.

2. The RX according to claim 1, wherein the plurality of adjustment modules include: An OVP module, monitoring whether the voltage of the DC power signal is higher than the OVP voltage level; an HVR module, monitoring whether the voltage of the DC power signal is higher than the HVR voltage level; An OVW module, monitoring whether the voltage of the DC power signal is higher than the OVW voltage level; an LVR module, monitoring whether the voltage of the DC power signal is lower than the LVR voltage level; and The UVLO module monitors whether the voltage of the DC power signal is lower than the UVLO voltage level.

3. The RX according to claim 2, wherein the HVR module comprises: a comparator that compares an input voltage signal based on the DC power signal with a reference voltage signal based on the HVR voltage level; as well as A current master and one or more current mirrors are configured to generate a mirror current sink signal when the input voltage signal is higher than the reference voltage signal, wherein the mirror current sink signal is applied to the DC power signal.

4. The RX according to claim 2, wherein the LVR module comprises: a first error amplifier that generates a first error signal based on a difference between (i) an input voltage signal based on the DC power signal and (ii) a reference voltage signal based on the LVR voltage level; a first voltage-to-current V2I converter, converting the first error signal into a first current signal; a second error amplifier that generates a second error signal based on a difference between (i) the reference voltage signal and (ii) a feedback voltage signal based on a voltage at an output node of the RX; a second V2I converter, converting the second error signal into a second current signal; a current mirror to generate a third current signal based on a current flowing through an output branch of the LVR module; a current adder, generating a sink current signal based on a sum of the first current signal, the second current signal and the third current signal; A charge pump, generating a source current signal; a current-to-voltage (I2V) converter, generating a gate voltage signal based on the sum of the source current signal and the sink current signal; and a power transistor located in an output branch of the LVR module and controlled by the gate voltage signal, wherein: When the DC power signal is higher than the LVR voltage level, the first error signal is zero, the first current signal is a zero current signal, and the current in the output branch of the LVR module is at a first level; and When the DC power signal is below the LVR voltage level, then the first error signal is positive, the first current signal is a non-zero current signal, and the current in the output branch of the LVR module is at a second level below the first level.

5. A wireless charging system, comprising: Power transmitter TX; and A power receiver RX, wherein the RX comprises: a rectifier configured to rectify an AC power signal wirelessly received from the TX into a DC power signal; and a plurality of regulation modules configured to monitor the DC power signal in a plurality of voltage regions, the plurality of voltage regions including one or more different high voltage regions and one or more different low voltage regions, wherein each regulation module is configured to affect the operation of the wireless charging system in a different manner; The multiple voltage regions include: A first region includes a voltage higher than an overvoltage protection OVP voltage level; a second region including voltages lower than the OVP voltage level and higher than a high voltage regulation HVR voltage level; A third region includes a voltage lower than the HVR voltage level and higher than the overvoltage warning OVW voltage level; a fourth region including a voltage lower than the OVW voltage level and higher than a low voltage regulation LVR voltage level; a fifth region including a voltage lower than the LVR voltage level and higher than an under-voltage monitoring UVLO voltage level; and a sixth region including voltages lower than the UVLO voltage level; When the OVP module determines that the DC power signal is higher than the OVP voltage level, the OVP module turns off rectification of the rectifier, and the RX instructs the TX to reduce the power transmission level; When the HVR module determines that the DC power signal is higher than the HVR voltage level, the HVR module inhibits the DC power signal from increasing, and the RX instructs the TX to reduce the power transmission level; When the OVW module determines that the DC power signal is higher than the OVW voltage level, the RX instructs the TX to reduce the power transmission level; When the LVR module determines that the DC power signal is lower than the LVR voltage level, the LVR module reduces the load current of the RX, and the RX instructs the TX to increase the power transmission level; and When the UVLO module determines that the DC power signal is below the UVLO voltage level, the UVLO module shuts down one or more other modules in the RX, and the RX instructs the TX to increase the power transmission level.

6. The wireless charging system according to claim 5, wherein the plurality of adjustment modules include: An OVP module, monitoring whether the voltage of the DC power signal is higher than the OVP voltage level; an HVR module, monitoring whether the voltage of the DC power signal is higher than the HVR voltage level; An OVW module, monitoring whether the voltage of the DC power signal is higher than the OVW voltage level; an LVR module, monitoring whether the voltage of the DC power signal is lower than the LVR voltage level; and The UVLO module monitors whether the voltage of the DC power signal is lower than the UVLO voltage level.

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