Communication method for wireless power transmission system

Abstract

A method of communicating between a receiver of a wireless power transfer system and a transmitter of the wireless power transfer system is provided. The receiver includes a synchronous rectifier. The method includes modifying operation of a synchronous rectifier of a receiver of the wireless power transfer system. The method also includes detecting a parameter change at a transmitter of the wireless power transfer system based on the modification of the operation of the synchronous rectifier. The method further includes determining data transmitted from the receiver to the transmitter based on the parameter change.

Description

Technical Field

[0001] The present disclosure relates generally to wireless power transfer, and more particularly to methods and controllers for communicating between a receiver and a transmitter of a wireless power transfer system, the receiver including a synchronous rectifier. Background Art

[0002] Wireless power transfer systems, such as wireless charging, are becoming increasingly important technologies to support next-generation devices. More and more manufacturers and companies are investing in this technology, as the potential benefits and advantages it offers are evident.

[0003] Various wireless power transmission systems are known. A typical wireless power transmission system includes a power source electrically connected to a wireless power transmitter, and a wireless power receiver electrically connected to a load.

[0004] In a magnetic induction system, a transmitter has a transmitter coil with a certain inductance that transfers electrical energy from a power source to a receiver, which has a receiver coil with a certain inductance. Power transfer occurs due to magnetic field coupling between the transmitter and receiver coils or inductors. These magnetic induction systems have a limited range, and the transmitter and receiver coils or inductors must be tightly coupled—with a coupling factor above 0.5—and in optimal alignment for efficient power transfer.

[0005] Magnetic resonance systems also exist, in which power is transferred due to magnetic field coupling between transmitter and receiver coils or inductors. The transmitter and receiver inductors can be loosely coupled, i.e., have a coupling factor below 0.5. However, in magnetic resonance systems, the inductors resonate with at least one capacitor. Furthermore, in magnetic resonance systems, the transmitter and receiver are self-resonant. The power transfer range in magnetic resonance systems is increased compared to that of magnetic induction systems, and alignment issues are corrected. Although electromagnetic energy is generated in magnetic induction and magnetic resonance systems, most power transfer occurs via magnetic fields. Little, if any, power is transferred via electric induction or resonant electric induction.

[0006] In capacitive systems, the transmitter and receiver have capacitive electrodes. Power transfer occurs due to electric field coupling between the capacitive electrodes of the transmitter and receiver. Similar to magnetic resonance systems, there are electric resonance systems, in which the capacitive electrodes of the transmitter and receiver resonate using at least one inductor. The inductor can be a coil. In electric resonance systems, the transmitter and receiver are self-resonant. Compared to electric induction systems, electric resonance systems increase the power transfer range and correct for alignment issues. Although electromagnetic energy is generated in electric induction and electric resonance systems, the majority of power transfer occurs via electric fields. Little, if any, power is transferred via magnetic induction or resonant magnetic induction.

[0007] While some wireless power transfer systems are known, improvements are needed. For example, in a wireless power transfer system, it may be desirable to transmit data from the system's receiver to the transmitter. Typically, data is transmitted from the receiver to the transmitter, so the system's source of power, the transmitter, receives relevant data from the receiver. This can occur before the wireless power transfer system is initialized, for example, to detect a suitable receiver to transmit power to. For example, the transmitter can receive a rectified voltage at the receiver to regulate the DC voltage of the transmitter's inverter during initialization of the wireless power transfer system. Alternatively or additionally, data can be transmitted during operation of the wireless power transfer system to transmit relevant data regarding the receiver's operating status, such as DC voltage, current, temperature, and battery level. The transmitter can then use this data to make decisions regarding system authentication, protection, and operation. Additionally, customer data can be sent from the receiver to the transmitter, which can then be transmitted to the end user using common communication methods such as Wi-Fi, Ethernet, Bluetooth, or USB.

[0008] While some communication methods in wireless power systems are known, improvements and / or alternatives are needed. Therefore, it is an object of the present invention to provide novel methods, devices, systems, apparatus, apparatus, and / or non-transitory computer-readable media for communication from a receiver to a transmitter in a wireless power transfer system.

[0009] This background technology is intended only to set the scene so that those skilled in the art can better understand the following description. Therefore, the above discussion should not be construed as an admission that it is part of the state of the art or common general knowledge. One or more aspects / embodiments of the present disclosure may or may not address one or more of the background technology issues. Summary of the Invention

[0010] One aspect of the present disclosure provides a method and controller for communicating between a receiver and a transmitter in a wireless power transfer system. Compared to existing communication methods, such a method and controller can reduce power consumption, thereby improving efficiency. Compared to existing communication methods, such a method and system can increase the symbol or data rate—the speed at which data is transmitted between the receiver and the transmitter—and achieve increased bandwidth compared to existing communication methods.

[0011] Thus, in one aspect, a method of communicating between a receiver of a wireless power transfer system and a transmitter of the wireless power transfer system is provided, the receiver including a synchronous rectifier.

[0012] The wireless power transmission system can be a high-frequency wireless power system as described in the applicant's U.S. provisional application No. 17 / 018328, a resonant capacitive coupling wireless power transmission system as described in the applicant's own U.S. patent No. 9653948B2, or a bidirectional wireless power transmission system as described in the applicant's own U.S. patent application No. 17 / 899711, relevant parts of which are incorporated herein.

[0013] The method may include:

[0014] modifying the operation of a synchronous rectifier of a receiver of a wireless power transfer system;

[0015] detecting a parameter change at a transmitter of a wireless power transfer system based on a modification of the operation of a synchronous rectifier; and

[0016] Data transmitted from the receiver to the transmitter is determined based on the parameter change.

[0017] Modifying the operation of the synchronous rectifiers can result in a detectable parameter change at the transmitter. Detection of this parameter change at the transmitter can be used to determine data transmitted from the receiver to the transmitter. Transmitting data from the receiver to the transmitter based on modifying the operation of the synchronous rectifiers can be more energy-efficient and allow for greater throughput than conventional communication methods.

[0018] Modifying the operation of a synchronous rectifier may include:

[0019] The synchronous rectifier is switched between synchronous and non-synchronous operation.

[0020] Modifying the operation of a synchronous rectifier may include:

[0021] Selectively enables and disables the synchronous rectifiers.

[0022] Selectively enabling and disabling the synchronous rectifiers may include enabling and disabling synchronous operation of the synchronous rectifiers. Modifying the operation of the synchronous rectifiers may include switching operations of the synchronous operation. The timing between the selective enabling / disabling or switching operations may be varied to transfer data from the receiver to the transmitter.

[0023] Selectively enabling and disabling the synchronous rectifier may include selectively enabling and disabling a portion of the synchronous rectifier. Additionally, selectively enabling and disabling the synchronous rectifier may include enabling and / or disabling one side of the synchronous rectifier in a push-pull configuration.

[0024] Synchronous rectifiers can include two-phase systems, or have a push-pull configuration. One side (or phase) of the synchronous rectifier can be synchronous, while the other side can be asynchronous.

[0025] Selectively enabling and disabling the synchronous rectifiers may include selectively enabling and disabling one side (or phase) of the synchronous rectifiers.

[0026] The synchronous rectifier may include at least one field effect transistor (FET).

[0027] The synchronous rectifier may include at least one of the following:

[0028] Rectifier components for rectifying power signals into direct current (DC);

[0029] trigger circuit; and

[0030] A gate driver electrically connected to the trigger circuit and the rectifier element.

[0031] The gate driver may be used to control the operation of the rectifier element via a trigger signal output by the trigger circuit.The gate driver may output a gate drive voltage or gate signal that is in phase with an input voltage received at the rectifier element.

[0032] The trigger circuit can ensure proper timing of the gate drive voltage or gate signal output by the gate driver.

[0033] The rectifier element may include an amplifier. The rectifier element may include a FET. The rectifier element may include a load-independent class E rectifier. The class E rectifier design may be suitable for converting an input radio frequency (RF) power signal to DC. The operating or switching frequency of the rectifier element may be, for example, 13.56 MHz and 27.12 MHz.

[0034] The gate driver can output a gate drive voltage or a gate signal to control the operation of the rectifier element. Specifically, the gate signal can control the operation of the amplifier by controlling the operation of the FET.

[0035] The trigger circuit may include:

[0036] The sampling circuit samples the input signal.

[0037] The sampling circuit may be a voltage divider.

[0038] The trigger circuit may include:

[0039] A delay line is used to delay the output of the sampling circuit so that the gate signal is synchronized with the input signal received at the drain element.

[0040] The trigger circuit may include:

[0041] A comparator generates a clock signal by comparing a delayed signal output from the delay line with a DC voltage level.

[0042] The trigger circuit may include:

[0043] The RC delay circuit is used to delay the output of the sampling circuit so that the gate signal is synchronized with the input signal received at the drain element.

[0044] The RC delay circuit may include at least one resistor electrically connected to at least one capacitor.

[0045] The trigger circuit may include:

[0046] The comparator generates a clock signal by comparing the delayed signal output by the RC delay circuit with a DC voltage level.

[0047] The synchronous rectifier may further include an auxiliary DC / DC converter for powering at least one of the trigger circuit and the gate driver. In other words, the synchronous rectifier may include a power supply for powering at least one of the trigger circuit and the gate driver. The power supply may be powered by power received at the receiver (e.g., power received from the transmitter via wireless power transmission).

[0048] The auxiliary DC / DC converter may be electrically connected to a low dropout (LDO) regulator.

[0049] Modifying the operation of a synchronous rectifier may include:

[0050] Controlling the operation of at least one of the trigger circuit, the gate driver, and the auxiliary DC / DC converter. Modifying the operation of the synchronous rectifier may include controlling the operation of all of the trigger circuit, the gate driver, and the auxiliary DC / DC converter.

[0051] Controlling the operation of the trigger circuit may include:

[0052] Controlling operation of a comparator of the trigger circuit. Controlling operation of the comparator may include selectively enabling and disabling the comparator. The comparator may include comparator circuitry. The comparator may include an enable pin. Controlling operation of the trigger circuit may include selectively enabling the comparator via the enable pin.

[0053] Controlling the operation of the auxiliary DC / DC converter may include:

[0054] The auxiliary DC / DC converter can be selectively enabled and disabled to selectively power the trigger circuit and the gate driver. The auxiliary DC / DC converter can include controlling power supplied to the auxiliary DC / DC converter. The auxiliary DC / DC converter can include an enable pin. The auxiliary DC / DC converter can include selectively enabling the auxiliary DC / DC converter via the enable pin.

[0055] Detecting parameter changes can include:

[0056] Detecting the voltage or current waveform at the transmitter. The voltage or current waveform can be detected at certain nodes of the transmitter. The voltage waveform can be detected at the output stage of the transmitter. The current waveform can be detected at the input of the transmitter's inverter.

[0057] The data determined to be transmitted may include:

[0058] The detected voltage or current waveform is processed to determine the transmitted data.

[0059] Processing the detected voltage or current waveform may include:

[0060] Filtering voltage or current waveforms;

[0061] generating logic levels based on the filtered voltage or current waveform; and

[0062] The data is decoded based on the generated logic levels.

[0063] Logic levels can reflect changes in voltage or current waveforms. For example, a change from high voltage to low voltage can represent a 1-to-0 data transmission, and a change from low voltage to high voltage can represent a 0-to-1 data transmission.

[0064] Decoding the data involves:

[0065] determining the time intervals between logic levels; and

[0066] Decodes data based on time intervals.

[0067] In another aspect, a method of communicating between a receiver of a wireless power transfer system and a transmitter of the wireless power transfer system is provided, the receiver including a synchronous rectifier, the method being performed by the receiver.

[0068] The method performed by the receiver may include:

[0069] Operation of a synchronous rectifier of a receiver of a wireless power transfer system is modified based on input data to change parameters at a transmitter.

[0070] Modifying the operation of a synchronous rectifier may include:

[0071] The synchronous rectifier is switched between synchronous and non-synchronous operation.

[0072] Modifying the operation of the synchronous rectifiers can result in a detectable parameter change at the transmitter. Detection of this parameter change at the transmitter can be used to determine data transmitted from the receiver to the transmitter. Transmitting data from the receiver to the transmitter based on modifying the operation of the synchronous rectifiers can be more energy-efficient and allow for greater throughput than conventional communication methods.

[0073] Modifying the operation of a synchronous rectifier may include:

[0074] Selectively enables and disables the synchronous rectifiers.

[0075] Selectively enabling and disabling the synchronous rectifiers may include enabling and disabling synchronous operation of the synchronous rectifiers. Modifying the operation of the synchronous rectifiers may include switching operations of the synchronous operation. The timing between the selective enabling / disabling or switching operations may be varied to transfer data from the receiver to the transmitter.

[0076] The synchronous rectifier may include at least one field effect transistor (FET).

[0077] The synchronous rectifier may include at least one of the following:

[0078] Rectifier components for rectifying power signals into direct current (DC);

[0079] trigger circuit; and

[0080] A gate driver electrically connected to the trigger circuit and the rectifier element.

[0081] The gate driver can be used to control the operation of the rectifier element through a trigger signal output by the trigger circuit. The gate driver can output a gate drive voltage or gate signal that is in phase with the input voltage received at the rectifier element.

[0082] The trigger circuit can ensure proper timing of the gate drive voltage or gate signal output by the gate driver.

[0083] The rectifier element may include an amplifier. The rectifier element may include a FET. The rectifier element may include a load-independent class E rectifier. The class E rectifier design may be suitable for converting an input radio frequency (RF) power signal to DC. The operating or switching frequency of the rectifier element may be, for example, 13.56 MHz and 27.12 MHz.

[0084] The gate driver can output a gate drive voltage or a gate signal to control the operation of the rectifier element. Specifically, the gate signal can control the operation of the amplifier by controlling the operation of the FET.

[0085] The trigger circuit may include:

[0086] The sampling circuit samples the input signal.

[0087] The sampling circuit may be a voltage divider.

[0088] The trigger circuit may include:

[0089] A delay line is used to delay the output of the sampling circuit so that the gate signal is synchronized with the input signal received at the drain element.

[0090] The trigger circuit may include:

[0091] A comparator generates a clock signal by comparing a delayed signal output from the delay line with a DC voltage level.

[0092] The trigger circuit may include:

[0093] The RC delay circuit is used to delay the output of the sampling circuit so that the gate signal is synchronized with the input signal received at the drain element.

[0094] The RC delay circuit may include at least one resistor electrically connected to at least one capacitor.

[0095] The trigger circuit may include:

[0096] The comparator generates a clock signal by comparing the delayed signal output by the RC delay circuit with a DC voltage level.

[0097] The synchronous rectifier may further include an auxiliary DC / DC converter for powering at least one of the trigger circuit and the gate driver. In other words, the synchronous rectifier may include a power supply for powering at least one of the trigger circuit and the gate driver. The power supply may be powered by power received at the receiver (e.g., power received from the transmitter via wireless power transmission).

[0098] The auxiliary DC / DC converter may be electrically connected to the LDO regulator.

[0099] An auxiliary DC / DC converter may be electrically connected to the LDO regulator.

[0100] Modifying the operation of a synchronous rectifier may include:

[0101] Controlling the operation of at least one of a trigger circuit, a gate driver, and an auxiliary DC / DC converter. Modifying the operation of the synchronous rectifier may include controlling the operation of all of the trigger circuits, the gate driver, and the auxiliary DC / DC converter. Each of the trigger circuit, the gate driver, and the auxiliary DC / DC converter may include an enable pin. Controlling the operation of at least one of the trigger circuit, the gate driver, and the auxiliary DC / DC converter may include controlling the operation of at least one of the trigger circuit, the gate driver, and the auxiliary DC / DC converter via their respective enable pins.

[0102] Controlling the operation of the trigger circuit may include:

[0103] Controlling operation of a comparator of the trigger circuit. Controlling operation of the comparator may include selectively enabling power to the comparator. The comparator may include a comparator circuit.

[0104] Controlling the operation of the auxiliary DC / DC converter may include:

[0105] The operation of the auxiliary DC / DC converter is selectively enabled and disabled to selectively power at least one of the trigger circuit and the gate driver. Selectively enabling / disabling the auxiliary DC / DC converter may include controlling power supplied to the auxiliary DC / DC converter.

[0106] According to yet another aspect, a controller for transmitting signals between a receiver of a wireless power transmission system and a transmitter of the wireless power transmission system is provided, the receiver including a synchronous rectifier.

[0107] The controller may be adapted to modify the operation of the synchronous rectifier to change a parameter detectable at the transmitter.

[0108] The controller may be adapted to switch the synchronous rectifier between synchronous operation and non-synchronous operation.

[0109] The controller may be adapted to selectively enable and disable the synchronous rectifier.

[0110] Selectively enabling and disabling the synchronous rectifiers may include enabling and disabling synchronous operation of the synchronous rectifiers. Modifying the operation of the synchronous rectifiers may include switching the operation of the synchronous operation. The time between selectively enabling / disabling or switching operations may be varied to transfer data from the receiver to the transmitter.

[0111] A controller may be electrically connected to the synchronous rectifier.

[0112] The controller may be electrically connected to at least one of:

[0113] a trigger circuit for a synchronous rectifier; and

[0114] A gate driver for the synchronous rectifier is electrically connected to the trigger circuit and the rectifier element of the synchronous rectifier.

[0115] The controller may be adapted to control the operation of a comparator of the trigger circuit. Controlling the operation of the comparator may include selectively enabling power to the comparator. The comparator may include a comparator circuit.

[0116] The controller can be electrically connected to:

[0117] An auxiliary DC / DC converter of the synchronous rectifier is used to power at least one of the trigger circuit and the gate driver.

[0118] The controller may be adapted to selectively enable and disable operation of the auxiliary DC / DC converter to selectively power at least one of the trigger circuit and the gate driver. Selectively enabling / disabling the auxiliary DC / DC converter may include controlling power supplied to the auxiliary DC / DC converter.

[0119] The controller may further include a power supply for supplying power to the controller. The power supply may supply power to at least one of the trigger circuit and the gate driver. The power supply may be powered by power received at the receiver (e.g., power received from the transmitter via wireless power transmission).

[0120] The power supply may include an auxiliary DC / DC converter.

[0121] The controller can be powered by an LDO regulator.

[0122] According to yet another aspect, the present invention provides a method of communicating between a receiver of a wireless power transmission system and a transmitter of the wireless power transmission system, the receiver including a synchronous rectifier, the method being performed by the transmitter.

[0123] The method performed by the transmitter may include:

[0124] A parameter change at the transmitter is detected based on a modification to the operation of a synchronous rectifier of the receiver.

[0125] The method may further include:

[0126] Data transmitted from the receiver to the transmitter is determined based on the parameter change.

[0127] Modification of the operation of the synchronous rectifier at the receiver can result in a detectable parameter change at the transmitter. Based on the change in the parameter, data can be determined to be transmitted from the receiver to the transmitter.

[0128] Detecting parameter changes can include:

[0129] Detect the voltage or current waveform at the transmitter.

[0130] Determining the data being transferred may include:

[0131] The detected voltage or current waveform is processed to determine the transmitted data.

[0132] Processing the detected voltage or current waveform may include:

[0133] Filtering voltage or current waveforms;

[0134] generating a logic level based on the filtered voltage or current waveform; and

[0135] The data is decoded based on the generated logic levels.

[0136] Decoding the data involves:

[0137] determining the time intervals between logic levels; and

[0138] Decodes data based on time intervals.

[0139] According to yet another aspect, a controller for transmitting signals between a receiver of a wireless power transmission system and a transmitter of the wireless power transmission system is provided, the receiver including a synchronous rectifier.

[0140] The controller may be adapted to detect parameter changes at the transmitter based on modifications to the operation of the synchronous rectifiers of the receiver.

[0141] The controller may also be adapted to determine data to be transmitted from the receiver to the transmitter based on the parameter change.

[0142] The controller may also include:

[0143] A detector is used to detect the voltage and / or current waveform at the transmitter.

[0144] The detector may also include:

[0145] A demodulator is adapted to demodulate the voltage and / or current waveform at the transmitter.

[0146] Detectors may include:

[0147] A filter is adapted to filter the demodulated voltage and / or current.

[0148] The detector can be adapted to:

[0149] generating logic levels based on the filtered voltage and / or current; and

[0150] The data is decoded based on the generated logic levels.

[0151] The detector can be adapted to:

[0152] determining the time intervals between logic levels; and

[0153] The data is decoded based on the time interval.

[0154] The controller may also include a power supply to provide power to the controller.

[0155] The power supply may include an auxiliary DC / DC converter.

[0156] The controller can be powered by an LDO regulator.

[0157] The controller may also include:

[0158] Scaling units are used to reduce the amplitude of detected voltage or current waveforms. Reducing the waveform amplitude can simplify waveform processing.

[0159] The controller may also include:

[0160] A peak detector is used to detect peak values ​​in the sensed voltage or current waveform.

[0161] The controller may also include:

[0162] Signal conditioner.

[0163] The signal conditioner may be adapted to amplify the detected voltage or current waveform.

[0164] The signal conditioner may be adapted to compare the detected voltage or current waveform with a reference level (eg, a reference voltage or current level).The signal conditioner may be adapted to output a logic level signal, such as a 0 or a 1, based on the comparison.

[0165] The signal conditioner may comprise a comparator. The comparator may be adapted to perform the described comparison.

[0166] The controller may also include:

[0167] An encoder receives data and encodes the data into a time sequence. Thus, the data to be transmitted from the receiver to the transmitter can be encoded into a time sequence for synchronous and asynchronous operation of the synchronous rectifier. The data can be binary data.

[0168] The synchronous rectifier can switch between synchronous and non-synchronous operation based on a time sequence encoded by the encoder. Switching the synchronous rectifier according to the time sequence can cause a detectable parameter change at the transmitter, which can be demodulated or decoded into data, thereby transmitting the data from the receiver to the transmitter.

[0169] The features and / or aspects of the controller described may be implemented in one or more microcontrollers (MCUs). For example, the detector may be implemented in a microcontroller at the transmitter. Additionally or alternatively, the encoder may be implemented in a separate and distinct microcontroller at the receiver.

[0170] The microcontroller at the receiver can be adapted to encode the received data (e.g., binary data) into a time sequence. The microcontroller can also be adapted to switch the synchronous rectifier at the receiver between synchronous operation and asynchronous operation based on the time sequence (e.g., based on the time sequence encoded by the received data).

[0171] A microcontroller at the transmitter may be adapted to receive a detected parameter change, for example, a parameter change detected at the transmitter. The parameter change may be a voltage and / or current waveform that varies over time. The microcontroller may be adapted to demodulate the parameter change into separate logic levels. The microcontroller may be adapted to convert the logic levels into data based on the time between the logic levels. The data may be binary data.

[0172] According to yet another aspect, there is provided a computer readable medium comprising instructions which, when executed by a processor, perform any of the described methods.

[0173] Computer-readable media can be non-transitory. Computer-readable media can include storage media that do not contain propagating signals. Computer-readable media can include any suitable memory or storage device, such as random access memory (RAM), static RAM (SRAM), dynamic RAM (DRAM), non-volatile RAM (NVRAM), read-only memory (ROM), or flash memory.

[0174] The processor may have a single core processor or a multi-core processor constructed from a variety of materials such as silicon, polysilicon, high-K dielectric, copper, and the like.

[0175] According to yet another aspect, there is provided a computer program comprising instructions which, when executed by a processor, perform any of the described methods.

[0176] The present invention includes one or more corresponding aspects, embodiments or features that can exist alone or in various combinations, whether or not specifically described in combination or alone (including in the claims). It should be understood that features associated with a particular exemplary embodiment relating to a system can also be applicable to features specifically relating to an embodiment of a method of operation or use, and vice versa.

[0177] The foregoing summary is intended to be illustrative only and not limiting. BRIEF DESCRIPTION OF THE DRAWINGS

[0178] These and other aspects of the present disclosure will now be described, by way of example only, with reference to the accompanying drawings, in which:

[0179] Figure 1 is a block diagram of a wireless power transfer system;

[0180] Figure 2 is another block diagram of a wireless power transfer system;

[0181] Figure 3 yes Figure 2 A block diagram of a receiver for a wireless power transmission system;

[0182] Figure 4 yes Figure 3A block diagram of a circuit portion of a receiver;

[0183] Figure 5 yes Figure 3 A schematic diagram of a circuit portion of a receiver;

[0184] Figure 6 is a block diagram of a receiver of a wireless power transmission system according to one aspect of the present disclosure;

[0185] Figure 7 is a block diagram of a transmitter of a wireless power transmission system according to one aspect of the present disclosure;

[0186] Figure 8 yes Figure 7 a schematic diagram of a portion of a transmitter;

[0187] Figure 9 yes Figure 7 A block diagram of a detector of a transmitter;

[0188] Figure 10 is a flow chart of a method for communicating between a receiver and a transmitter of a wireless power transfer system according to one aspect of the present disclosure;

[0189] Figure 11 is a graph of voltage and current waveforms of a transmitter according to one aspect of the present disclosure;

[0190] Figure 12 is a graph of voltage rise time of a transmitter according to one aspect of the present disclosure;

[0191] Figure 13 is a graph of voltage fall time of a transmitter according to one aspect of the present disclosure;

[0192] Figure 14 is a graph of current rise time of a transmitter according to one aspect of the present disclosure;

[0193] Figure 15 is a graph of current fall time of a transmitter according to one aspect of the present disclosure;

[0194] Figure 16 is a schematic diagram of a portion of a transmitter according to one aspect of the present disclosure; and

[0195] Figure 17 yes Figure 16 Block diagram of the transmitter's current demodulator. DETAILED DESCRIPTION

[0196] The foregoing summary of the invention and the detailed description of certain embodiments below will be better understood by reading in conjunction with the accompanying drawings. It should be understood that throughout the specification and the accompanying drawings, the same reference numerals are used to refer to the same elements. As used herein, elements or features cited in the singular and preceded by the word "one" or "an" should be understood to not necessarily exclude multiple elements or features. In addition, reference to "an example" or "an embodiment" is not intended to be interpreted as excluding the existence of other examples or embodiments that also include elements or features cited by this example or embodiment. In addition, unless explicitly stated otherwise, examples or embodiments that "include," "have," or "contain" one or more elements or features with a specific property may also include other elements or features that do not have this specific property. In addition, it should be understood that the terms "include," "have," and "contain" mean "including but not limited to," and the terms "include," "have," and "contain" have equivalent meanings.

[0197] As used herein, the term "and / or" may include any and all combinations of the associated one or more listed elements or features.

[0198] It should be understood that when an element or feature is referred to as being “on (another element or feature),” “attached” to another element or feature, “connected” to another element or feature, “coupled” to another element or feature, “contacting” another element or feature, etc., the element or feature can be directly on, directly attached to, directly connected to, directly coupled to, or directly contacting another element or feature, or intervening elements may also be present. In contrast, when an element or feature is referred to as, for example, being “directly on (another element or feature),” “directly attached” to, “directly connected” to, “directly coupled” to, or “directly contacting” another element or feature, there are no intervening elements or features present.

[0199] It should be understood that spatially relative terms, such as "below," "beneath," "lower," "above," "upper," "front," and "rear," may be used herein to facilitate describing the relationship of an element or feature depicted in the drawings to another element or feature. However, the spatially relative terms may refer to different orientations in use or operation in addition to the orientation depicted in the drawings.

[0200] Reference herein to an "example" means that one or more features, structures, elements, components, characteristics, and / or operational steps described in connection with the example are included in at least one embodiment and / or implementation of the subject matter of the present disclosure. Thus, throughout this disclosure, the phrases "an example," "another example," and similar language may, but do not necessarily, refer to the same example. Furthermore, subject matter representing any one example may, but does not necessarily, include subject matter representing any other example.

[0201] References herein to "configured" refer to the actual state of configuration that substantially relates the physical characteristics of an element or feature to the element or feature preceding the phrase "configured to."

[0202] Unless otherwise indicated, the terms "first," "second," etc. are used herein merely as labels and are not intended to impose ordinal, positional, or hierarchical requirements on the items to which these terms refer. Furthermore, reference to a "second" item does not require or preclude the presence of lower-numbered items (e.g., a "first" item) and / or higher-numbered items (e.g., a "third" item).

[0203] As used herein, the terms "approximately" and "about" mean close to a specified amount and still perform a desired function or achieve a desired result. For example, the terms "approximately" and "about" may refer to a quantity being within less than 10%, less than 5%, less than 1%, less than 0.1%, or less than 0.01% of a specified amount.

[0204] Now go to Figure 1 , a wireless power transfer system, generally designated by the reference numeral 100, is shown. The wireless power transfer system 100 includes a transmitter 110 (including a power source 112 electrically connected to a transmitting element 116) and a receiver 120 (including a receiving element 124 electrically connected to a load 128). Power is transferred from the power source 112 to the transmitting element 116. Power is then transferred from the transmitting element 116 to the receiving element 124 via resonant or non-resonant electric or magnetic field coupling. Power is then transferred from the receiving element 124 to the load 128. The exemplary wireless power transfer system 100 includes a high-frequency inductive wireless power transfer system as described in applicant's U.S. Provisional Application No. 62 / 899,165, or a resonant capacitive coupling wireless power transfer system as described in applicant's U.S. Patent No. 9,653,948 B2, relevant portions of which are incorporated herein.

[0205] In the wireless power transfer system 100, power is transferred from the transmitting element 116 to the receiving element 124. It may be desirable to be able to transfer power to and from each respective element, ie, from the receiving element 124 to the transmitting element 116.

[0206] Now go to Figure 2, another embodiment of a wireless power transfer system is shown, generally designated by the reference numeral 200 .

[0207] Wireless power transmission system 200 includes power supply 212, DC / DC converter 214, circuit 216, and transmitting element 222. Power supply 212 is electrically connected to DC / DC converter 214. DC / DC converter 214 is electrically connected to circuit 216. Circuit 216 is electrically connected to transmitting element 222.

[0208] The power supply 212 is configured to generate an input power signal for transmitting power. In this embodiment, the input power signal is a direct current (DC) power signal.

[0209] The DC / DC converter 214 is used to convert the received DC voltage signal to a desired voltage level. The received DC voltage can come from the power supply 212. The system 200 shown includes the DC / DC converter 214, and those skilled in the art will appreciate that other configurations are possible. In another embodiment, there is no DC / DC converter.

[0210] In the arrangement shown, circuit 216 includes an inverter and an output stage. The output stage matches the output impedance of circuit 216 to the optimal impedance of wireless link 230 between the transmitter and receiver. The output stage also filters high-frequency harmonic components of the inverter.

[0211] The transmitting element 222 includes one or more capacitive electrodes and an inductive element, i.e., an inductor. The capacitive electrodes can be laterally spaced, elongated electrodes; however, those skilled in the art will appreciate that other configurations are possible, including but not limited to concentric, coplanar, circular, elliptical, disk-shaped, and the like electrodes. Other suitable electrode configurations are described in the applicant's U.S. Patent No. 9,979,206B2, the relevant portions of which are incorporated herein by reference. The inductive element can include one or more coils. The coil can include a boost or shield coil as described in the applicant's U.S. Patent Application No. 17 / 193,539, the relevant portions of which are incorporated herein by reference.

[0212] Power supply 212 provides a DC input power signal to DC / DC converter 214, which converts the signal to a desired voltage level. The inverter of circuit 216 receives the converted DC power signal and inverts it to generate a magnetic field and / or electric field at transceiver element 222, thereby transmitting power via electric or magnetic field coupling. Specifically, transmitting element 222 generates a magnetic / electric field to transmit power to a receiver via magnetic / electric field coupling. Power supply 212, DC / DC converter 214, circuit 216, and transmitting element 222 may collectively form transmitter 210. As previously described, DC / DC converter 214 may not be present in transmitter 210.

[0213] Wireless power transmission system 200 further includes a load 228, a DC / DC converter 226, a circuit 224, and a receiving element 229. Load 228 is electrically connected to DC / DC converter 226. DC / DC converter 226 is electrically connected to circuit 224. Circuit 224 is electrically connected to receiving element 229.

[0214] In the arrangement shown, the load 228 is a DC load. The load 228 may be static or variable.

[0215] The DC / DC converter 226 is used to convert the received DC voltage signal to a desired voltage level. The received DC voltage can come from the circuit 224. Although the system 200 includes the DC / DC converter 226, it will be understood by those skilled in the art that other configurations are also possible. In another embodiment, there is no DC / DC converter 226.

[0216] Circuit 224 includes an input stage and a synchronous rectifier. The input stage is configured to ensure that the optimal impedance is presented to the receiving element 229 when the wireless power transmission system 200 is in full power. The input stage also maintains the quasi-voltage source characteristic of the receiving element 229, so that the output of the rectifier presents a stable DC voltage from no-load to full-load conditions.

[0217] The receiving element 229 includes one or more capacitive electrodes and an inductive element, i.e., an inductor. The capacitive electrodes can be laterally spaced, elongated electrodes; however, those skilled in the art will appreciate that other configurations are possible, including but not limited to concentric, coplanar, circular, elliptical, disc-shaped, and the like electrodes. Other suitable electrode configurations are described in the applicant's U.S. Patent No. 9,979,206B2, the relevant portions of which are incorporated herein by reference. The inductive element can include one or more coils. The coil can include a boost or shield coil as described in the applicant's U.S. Patent Application No. 17 / 193,539, the relevant portions of which are incorporated herein by reference.

[0218] Transmitting element 222 and receiving element 229 of system 200 form a wireless link 230. Elements 222 and 229 are separated by a wireless gap. The wireless gap can be formed by the atmosphere (i.e., air) or by a physical medium (e.g., a wall, glass, liquid, wood, an insulator, etc.). Power is transferred from one element to another across wireless link 230 via resonant or non-resonant magnetic and / or electric field coupling (i.e., electrical or magnetic induction).

[0219] During operation, receiving element 229 extracts power from the magnetic and / or electric fields generated by transmitting element 222. Circuit 224 functions as a synchronous rectifier and rectifies the received power signal. DC / DC converter 226 converts the rectified power signal to the desired power level for reception by load 228. In this manner, receiving element 229 extracts power transmitted by transmitting element 222 (transmitter 210), transferring the power to load 228 via magnetic / electric field coupling. Load 228, DC / DC converter 226, circuit 224, and receiving element 229 may collectively form receiver 220. As previously mentioned, DC / DC converter 226 may not be present in receiver 220.

[0220] Now go to Figure 3 , which shows the receiver 220 of the system 200 in more detail. Figure 3 As shown, circuit 224 includes an input stage 250 , a trigger circuit 252 , a rectifier element 254 , a gate driver 256 , and an auxiliary DC / DC converter 258 .

[0221] Receiver element 229 is electrically connected to input stage 250 and trigger circuit 252. Receiver element 229 is configured to receive power from a transmitter (e.g., transmitter 210) using resonant or non-resonant electric or magnetic field coupling. Receiver element 229 can extract power from the transmitter via non-resonant or resonant magnetic or electric field coupling. Therefore, receiver element 229 includes one or more receive coils (i.e., inductors) or one or more capacitive electrodes. The corresponding transmitters each include a corresponding transmit coil (i.e., inductor) or capacitive electrode.

[0222] The receiving element 229 extracts power from the transmitter and thus outputs an input voltage or signal Vin corresponding to the extracted power or signal.

[0223] Input stage 250 is electrically connected to rectifier element 254, receiving element 229, and trigger circuit 252. Input stage 250 is adapted to perform any combination of three functions. In particular, input stage 250 is used to transform the impedance presented by rectifier element 254 under nominal load into an optimal load impedance for receiving element 229. Input stage 250 is used to reduce the harmonic content generated by the nonlinear behavior of rectifier element 254, enabling receiver 220, and thus the wireless power system of which receiver 220 forms a part, to meet international product requirements related to electromagnetic compatibility (EMC). Input stage 250 is used to ensure that the current input to rectifier element 254 is approximately sinusoidal.

[0224] In this embodiment, the input stage 250 includes a matching network or circuit. A variety of matching networks are possible. In this embodiment, the matching network takes the form of a two-stage impedance inverter. The two-stage impedance inverter is electrically connected to the receiving element 229. The input stage 250 may also include additional filtering in series with the rectifier element 254. The use of a two-stage impedance inverter topology can advantageously ensure that the rectifier element 254 is driven by a quasi-constant voltage source. Although a two-stage impedance inverter is described, it will be understood by those skilled in the art that the matching network may take the form of a single-stage impedance inverter.

[0225] The input stage 250 is configured to ensure that the optimal impedance is presented to the receiving element 229 in the full power state of the wireless power transmission system 200. The input stage can also maintain the quasi-voltage source characteristic of the receiving element 229, so that the output of the rectifier presents a stable DC voltage from no-load to full-load conditions.

[0226] Rectifier element 254 is electrically connected to input stage 254 , main DC / DC converter 226 (ie, the main DC / DC converter), and auxiliary DC / DC converter 258 .

[0227] Rectifier element 254 includes an amplifier. The amplifier is a Class E amplifier. The amplifier includes a gate driver 258 and a main switch. Gate driver 258 drives the amplifier's main switch. In this embodiment, the main switch includes an n-type MOSFET 260. Although an n-type MOSFET 260 is shown, those skilled in the art will appreciate that other FETs and switching devices may be used.

[0228] DC / DC converter 226 is electrically connected to rectifier element 254, auxiliary DC / DC converter 258, and load 228, such as a DC load. Main DC / DC converter 226 receives a DC power signal Vrect output from rectifier element 254. DC / DC converter 226 connects rectifier element 254 to load 228. DC / DC converter 226 converts the received DC power signal. The converted DC power signal is output from DC / DC converter 226 to load 228.

[0229] An auxiliary DC / DC converter 258 is also electrically connected to the main DC / DC converter 226. The auxiliary DC / DC converter 258 is electrically connected to the DC / DC converter 226, the trigger circuit 252, and the gate driver 258 of the rectifier element 254. The auxiliary DC / DC converter 258 is configured to convert the Vrect output by the rectifier element 254 to an auxiliary voltage Vaux range, for example, in the 5V range, to power the trigger circuit 252 and the gate driver 258. The auxiliary supply voltage or signal Vaux powers the trigger circuit 252 and the gate driver 258. Until the auxiliary DC / DC converter 258 can regulate, the FET 260 of the rectifier element 254 is turned off, and the rectifier element 254 functions as a passive (diode) rectifier. In this embodiment, the auxiliary DC / DC converter 258 comprises a low-power buck converter.

[0230] The gate driver 258 is electrically connected to the rectifier element 254, the auxiliary DC / DC converter 258, and the trigger circuit 252. The gate driver 258 is powered by a signal (e.g., Vaux) from the auxiliary DC / DC converter 258. The gate driver 258 outputs a signal to switch the FET 260 of the rectifier element 254. In particular, the gate driver 258 outputs a gate drive voltage or gate signal Vgate to control the operation of the rectifier element 254, such as controlling the switching of the FET 260 of the rectifier element 254.

[0231] The trigger circuit 252 is electrically connected to the rectifier element 254. The trigger circuit 252 is used to synchronize wireless power transmission. The trigger circuit 252 is also electrically connected to the receiving element 229 and the input stage 250. To address the challenge of non-negligible propagation delay from the gate driver 258 and the trigger circuit 252, the trigger circuit 252 is designed so that the trigger circuit 252 further delays the output signal Vtrig to ensure that Vgate is synchronized with Vin.

[0232] The load 228 is electrically connected to the DC / DC converter 226. The load 228 receives the signal Vout output by the DC / DC converter 226. The load 228 can be variable. As will be understood by those skilled in the art, if DC conversion is not required, the load 228 can be directly connected to the rectifier element 254 and receive Vrect.

[0233] Although receiver 220 has been described as including input stage 250 and DC / DC converter 226 , those skilled in the art will appreciate that other configurations are possible. In particular, receiver 220 may not include one or both of input stage 250 and DC / DC converter 226 .

[0234] The gate signal Vgate controls the operation of the current between the source and drain of FET 260, thereby controlling the input signal Vin received at the receiving element 229. When the gate signal is in phase with the input signal, FET 260 operates as a class E inverter. Class E inverters generally operate at high efficiency, resulting in a high efficiency rectifier.

[0235] Now go to Figure 4 , a block diagram of a portion of circuit 224. Specifically, a block diagram of trigger circuit 252 and gate driver 258 is shown. Figure 4 As shown, the input voltage or signal Vin is sampled by sampling circuit 260 and fed to delay line 262. In this embodiment, sampling circuit 260 is a voltage divider, and delay line 262 is a lumped element delay line circuit. The output of delay line 262 is fed to comparator circuit 264. Comparator circuit 264 generates a clock signal by comparing the delayed signal (Vd) output by delay line 262 with a DC level.

[0236] The resulting trigger voltage (Vtrig) is fed to gate driver 258. Gate driver 258 converts the trigger voltage into a suitable waveform (Vgate) for driving FET 260 of rectifier element 254. Both comparator circuit 264 and gate driver 258 have propagation delays in the nanosecond range, which is significant when dealing with switching cycles of approximately 73.7ns (for an operating frequency of 13.56 MHz) or 36.9ns (for an operating frequency of 27.12 MHz). Sampling circuit 260, delay line 262, and comparator circuit 264 form trigger circuit 252. These components are designed to ensure that Vgate is synchronized with Vin.

[0237] Now go to Figure 5 , shows a schematic diagram of another portion of the circuit 224. The schematic diagram shows an exemplary arrangement of the comparator circuit 264 and the gate driver 258. As previously described, the comparator circuit 264 generates the clock signal by comparing the delayed signal (Vd) output by the delay line 262 with the DC level.

[0238] like Figure 5 As shown, comparator circuit 264 includes a comparator 280 (A1) powered by an auxiliary supply having an auxiliary supply voltage (Vaux). The input of comparator 280 is biased to approximately half of Vaux. For the positive comparator input (V+), this is achieved using two equal-valued resistors 282 and 284, each having a resistance of R2. The negative comparator input (V-) is achieved using two equal-valued resistors 286 and 288, each having a resistance of R1.

[0239] The delayed voltage signal (Vd) output by delay line 262 is coupled to the negative comparator input (V-) via a DC blocking capacitor 290 having a capacitance (Cb). This causes the trigger voltage (Vtrig) to be inverted (180° out of phase) relative to the delayed voltage signal (Vd). This effectively accounts for half of the switching period in terms of the total delay required to ensure that Vgate is in phase with Vin, thereby reducing the burden on delay line 262.

[0240] While the system 200 described can transfer power wirelessly, it may be desirable to send data from the receiver 220 to the transmitter 210. For example, it may be desirable to send data during operation of the wireless power transfer system 200 to transmit relevant data regarding the operating conditions of the receiver 220, such as DC voltage, current, temperature, and battery level. The transmitter 210 can then use this data to make decisions regarding the authentication, protection, and operation of the system 200. Additionally, customer data can be sent from the receiver 220 to the transmitter 210, which can then be transmitted to the end user using common communication methods such as Wi-Fi, Ethernet, Bluetooth, or USB.

[0241] To transmit data from a receiver to a transmitter in some wireless power transfer systems, a dummy load is introduced at the receiver to change the load conditions. The dummy load (e.g., a resistor) is connected in series via a switch at the output of the receiver's rectifier element. By turning the switch on and off, the system's load conditions are altered, and this change can be detected and demodulated at the transmitter to receive data from the receiver.

[0242] This approach has several drawbacks. For example, the baud rate (i.e., transmission rate) of data transmitted from the receiver to the transmitter is limited by the value of the dummy load and the total DC capacitance at the output of the rectifier element. Using a smaller dummy load can increase the baud rate, however, this increases power dissipation in the dummy load resistor, causing component heating. Furthermore, reducing the value of the capacitor at the output of the rectifier element (i.e., the input capacitor of the receiver's DC / DC converter) can lead to unstable operation of the wireless power transmission system.

[0243] Other wireless power transfer systems incorporate capacitors at the switching nodes of the rectifier elements, rather than a pseudo-resistive load at the output of the rectifier elements. This technique can be effective for passive rectifier elements, but for synchronous rectifier elements, such as those described in circuit 226, turning off the capacitors can detune the zero voltage switching (ZVS) of the rectifier elements. Detuning the ZVS can reduce the efficiency of the rectifier elements, resulting in an overall reduction in the system's power transfer.

[0244] The present disclosure provides a method and controller for communicating between a receiver of a wireless power transmission system and a transmitter of the wireless power transmission system, wherein the receiver includes a synchronous rectifier. Figure 6 , shows a receiver 300 according to one aspect of the present disclosure.

[0245] Receiver 300 includes a receiving element 302 , an input stage 304 , a trigger circuit 306 , a rectifier element 308 having a gate driver 310 and a FET 312 , an auxiliary DC / DC converter 314 , a DC / DC converter 316 (i.e., a main DC / DC converter), a low dropout (LDO) regulator 318 , a microcontroller 320 , and a load 322 .

[0246] Receiver element 302 is electrically connected to input stage 304 and trigger circuit 306. Unless otherwise specified, receiver element 302 is identical to receiver element 229. Receiver element 302 extracts wireless power from the field generated by the transmitter of the wireless power transfer system. The extracted or received voltage is represented by Vin.

[0247] Input stage 304 is electrically connected to rectifier element 308, trigger circuit 306, and receiving element 302. Input stage 304 is identical to input stage 250 unless otherwise noted.

[0248] The rectifier element 308 is electrically connected to the input stage 304, the trigger circuit 306, the auxiliary DC / DC converter 314, the DC / DC converter 316, the LDO regulator 318, and the microcontroller 320. Unless otherwise noted, the rectifier element 308 is identical to the rectifier element 254. In the arrangement shown, the gate driver 310 of the rectifier element 308 is electrically connected to the microcontroller 320 so that the microcontroller 320 can control the operation of the gate driver 310, as will be described.

[0249] The trigger circuit 306 is electrically connected to the rectifier element 308, the input stage 304, the receiving element 302, the auxiliary DC / DC converter 314, and the microcontroller 320. Unless otherwise noted, the trigger circuit 306 is identical to the trigger circuit 252. In the arrangement shown, the microcontroller 320 can control the operation of the trigger circuit 306, as will be described.

[0250] Auxiliary DC / DC converter 314 is electrically connected to trigger circuit 306, gate driver 310, LDO regulator 318, rectifier element 308, DC / DC converter 316, and microcontroller 320. Unless otherwise noted, auxiliary DC / DC converter 258 is identical to auxiliary DC / DC converter 258. In the arrangement shown, microcontroller 320 can control the operation of auxiliary DC / DC converter 314, as will be described.

[0251] DC / DC converter 316 is electrically connected to LDO regulator 318, auxiliary DC / DC converter 314, and rectifier element 308. DC converter 316 is identical to DC / DC converter 226 unless otherwise noted.

[0252] Load 322 is electrically connected to DC / DC converter 316. Load 322 is identical to load 228 unless otherwise noted.

[0253] An LDO regulator 318 is electrically connected to the DC / DC converter 316, the rectifier element 308, and the auxiliary DC / DC converter 314. The LDO regulator 318 is adapted to provide power to the microcontroller 320.

[0254] The microcontroller 320 is adapted to selectively modify the operation of elements of the receiver 300. Specifically, the microcontroller 320 is adapted to modify the operation of the synchronous rectifiers (e.g., the rectifier element 308, the trigger circuit 306, and the auxiliary DC / DC converter 314) of the receiver 300. The microcontroller 320 is adapted to selectively enable and disable the synchronous rectifiers to achieve a parameter detectable at the transmitter. The parameter change can be detected and demodulated to determine data transmitted from the receiver 300 to the wireless power transfer transmitter that transmits power to the receiver 300.

[0255] Microcontroller 320 receives input data for transmission to the transmitter. Alternatively, microcontroller 320 may generate its own data for transmission to the transmitter. For example, microcontroller 320 may include a timer. Microcontroller 320 may be adapted to transmit data (i.e., timer data) from the timer to the transmitter. Thus, a reference to data transmitted to the transmitter may include data received by microcontroller 320 for transmission and / or data generated by microcontroller 320 for transmission.

[0256] The microcontroller 320 is adapted to control the operation of the rectifier element 308, the trigger circuit 306, and the auxiliary DC / DC converter 314 based on input data. Specifically, the microcontroller 320 controls the amount of time the synchronous rectifiers are enabled and disabled, thereby encoding data for transmission.

[0257] In the arrangement shown, the microcontroller 320 includes a plurality of outputs (e.g., general purpose inputs / outputs that control the operation of the auxiliary DC / DC converter 314 that provides power to the gate driver 310 and the trigger circuit 306), a comparator (e.g., comparator circuit 264) of the trigger circuit 306, and the gate driver 310. Those skilled in the art will appreciate that the microcontroller 320 may be electrically connected to only one of these components in order to switch the operation of the synchronous rectifier.

[0258] Microcontroller 320 is adapted to disable the operation of any of these components, thereby placing the synchronous rectifier in an unloaded state. Due to the junction capacitance of the diode in parallel with the main switch of the Class E synchronous rectifier of rectifier element 308, the impedance presented to receiving element 302 will be different, and the duty cycle of the diode at the switch node of rectifier element 308 will approach 100%. This causes a sharp change in the impedance seen by receiving element 302, and therefore a sharp change in the impedance seen by the transmitter wirelessly transmitting power to receiver 300. This sharp change in the transmitter output impedance causes an immediate change in the waveform at the transmitter, which can be decoded to determine the data sent from receiver 300 to the transmitter.

[0259] Now turn Figure 7 , shows an embodiment of a transmitter 330 according to one aspect of the present disclosure. The transmitter 330 is suitable for use with the receiver 300 described.

[0260] Transmitter 330 includes a power supply 332, a DC / DC converter 334, a circuit 336 including an inverter 338 and an output stage 340, and a transmitting element 342. Power supply 332 is electrically connected to DC / DC converter 334. Power supply 332 is adapted to provide a power signal to DC / DC converter 334. Power supply 332 is adapted to provide a DC power signal to DC / DC converter 334.

[0261] The DC / DC converter 334 (i.e., the main DC / DC converter) is electrically connected to the power source 332 and the circuit 336. Specifically, the DC / DC converter 334 is electrically connected to the inverter 338 of the circuit 336. The DC / DC converter 334 is adapted to convert the power signal received from the power source 332 to a desired voltage level.

[0262] Circuit 336 is electrically connected to transmitting element 342 and DC / DC converter 334. Specifically, inverter 338 is electrically connected to DC / DC converter 334, and output stage 340 is electrically connected to transmitting element 342. Inverter 338 is adapted to convert the converted DC power signal from DC / DC converter 334 into an alternating current (AC) signal. Inverter 338 may include a high-frequency power inverter. Output stage 340 is adapted to match the output impedance of inverter 338 to the optimal impedance of the wireless power link between transmitting element 342 and a corresponding receiving element (e.g., receiving element 229). Output stage 340 is additionally or alternatively adapted to filter high-frequency harmonic components of inverter 338. The output stage is additionally or alternatively adapted to establish a quasi-current source characteristic at the connection point of the wireless link.

[0263] Transmitting element 342 is electrically connected to circuit 336. Specifically, transmitting element 342 is electrically connected to output stage 340. Transmitting element 342 includes one or more capacitive electrodes and an inductive element, i.e., an inductor. The capacitive electrodes can be laterally spaced, elongated electrodes; however, those skilled in the art will appreciate that other configurations are possible, including but not limited to concentric, coplanar, circular, elliptical, disc-shaped electrodes. Other suitable electrode configurations are described in applicant's U.S. Patent No. 9,979,206 B2, the relevant portions of which are incorporated herein by reference. The inductive element can include one or more coils. The coils can include boosted or shielded coils as described in applicant's U.S. Patent Application No. 17 / 193,539, the relevant portions of which are incorporated herein by reference. Transmitting element 342 can generally correspond to receiving elements (e.g., receiving elements 229, 302) to enable wireless power transfer from transmitter 330 to receivers (e.g., receivers 220, 300).

[0264] According to one aspect of the present disclosure, the circuit 336 further includes an LDO regulator 344, a microcontroller 346, and a detector 348. The LDO regulator 344 is electrically connected to the DC / DC converter 344, the inverter 336, and the microcontroller 346. The LDO regulator 344 is adapted to supply power to the microcontroller 346.

[0265] The microcontroller 346 is electrically connected to the LDO regulator 344 and the detector 348. The microcontroller 346 is adapted to decode data sent by the receiver to the transmitter 330 based on parameter changes detected by the detector 348. The microcontroller 346 may include a microcontroller.

[0266] The detector 348 is electrically connected to the output stage 340, or the DC / DC converter 334 and the inverter 338. The detector is adapted to detect parameter changes at the transmitter 330, as will be described.

[0267] Will refer to Figure 8 The microcontroller 346 and the detector 348 are described in more detail. Figure 8 , shows a portion of an embodiment of transmitter 330 in more detail. In the arrangement shown, LDO regulator 344 is powered by DC / DC converter 336 and also powers microcontroller 346. Microcontroller 346 receives a signal from detector 348. Detector 348 outputs a logic level signal (i.e., a logic level), which microcontroller 346 decodes into data to be sent by the receiver to transmitter 330.

[0268] In the illustrated arrangement, detector 348 detects a voltage waveform, i.e., detector 348 is a voltage detector. Detector 348 detects the voltage waveform based on changes in voltage at two nodes, for example, V1 at the midpoint of output stage 340 and Vres-tx at the output of output stage 340. Although detector 348 is described as detecting a voltage waveform based on changes in voltage at two nodes, those skilled in the art will appreciate that detector 348 can be connected to only a single node. For example, detector 348 can detect a voltage waveform based on changes in voltage Vres-tx at the output of output stage 340.

[0269] In the illustrated arrangement, inverter 338 includes a capacitor 350, an inductor 352, a gate driver 354, a clock generator 356, a main switch 358, a diode 360, a capacitor 362, a capacitor 364, and an inductor 366. Capacitor 350, having capacitance C3, is connected in parallel to DC / DC converter 336 and to inductor 352, having inductance LZVS-t. Capacitor 350 is connected in parallel to main switch 358, designated Q1-t. In the illustrated arrangement, main switch 358 comprises an n-type MOSFET. While an n-type MOSFET is illustrated, those skilled in the art will appreciate that other FETs and switching devices may be used.

[0270] The main switch 358 is electrically connected to a gate driver 354, which is electrically connected to a clock generator 356. The gate driver 354 drives the main switch 358 of the inverter 338. The clock generator 356 is electrically connected to the gate driver 354. The clock generator 356 includes an oscillator. Those skilled in the art will understand that the clock generator 356 can include any signal generator.

[0271] The clock generator 356 is configured to generate a clock signal to control the gate driver 354 connected to the main switch 358 to invert the input power signal from the power supply 332 (via the DC / DC converter 334 ) into an RF or AC signal.

[0272] Inverter 338 also includes a diode 360, designated D1-t, electrically connected in parallel with main switch 358, and a capacitor 362 having a capacitance CZVS-t electrically connected in parallel with diode 360. Capacitor 362 is electrically connected to capacitor 364 having a capacitance CZVS-t, which is electrically connected in series with inductor 366 having an inductance Lf-t+La-t. Main switch 358, diode 360, and capacitor 362 are connected in parallel between inductor 352 and capacitor 364.

[0273] In the illustrated arrangement, the output stage 340 includes an inductor 370 having an inductance L1 -tx electrically connected in series to an inductor 372 having an inductance L1 -tx, and a capacitor 374 having a capacitance C1 -tx electrically connected in parallel between the inductors 370 , 372 .

[0274] As described, the detector 348 detects a voltage waveform based on a change in voltage at at least one of two nodes, for example, V1 at the midpoint of the output stage 340 and Vres-tx at the output of the output stage 340. The detector 348 outputs a logic level signal (i.e., a logic level), and the microcontroller 346 decodes the logic level signal into data sent by the receiver to the transmitter 330.

[0275] Now go to Figure 9 , showing detector 348 in more detail. Detector 348 demodulates the voltage waveform detected at the transmitter. In other words, detector 348 comprises a voltage demodulator. Detector 348 includes scaling circuit 380, peak detector 382, ​​filter 384, and signal conditioner and comparator 386.

[0276] In operation, scaling circuit 380 receives detected waveforms, such as V1 and Vres-tx. Scaling circuit 380 reduces the amplitude of the detected waveform to facilitate waveform processing. The reduced-amplitude waveform is then fed to peak detector 382, ​​which converts the signal into a DC voltage. When a sudden change in the RF signal input to peak detector 382 occurs due to the switching operation of the receiver's synchronous rectifiers, the signal output from peak detector 382 changes proportionally. Filter 384 (i.e., the input filtering stage) filters this output. For example, filter 384 filters the change while blocking unwanted signal components such as high-frequency noise and DC offset. The filtered signal then passes through signal conditioner and comparator 386. Signal conditioner and comparator 386 amplifies the signal and then compares the amplified voltage level to a reference voltage. Signal conditioner and comparator 386 may include a comparator. Whenever a sufficiently large modulation occurs in the RF input voltage signal, signal conditioner and comparator 386 outputs a logic-level signal.

[0277] The output logic level signal is then provided to the microcontroller 346 for decoding. The microcontroller 346 determines the time between the modulated pulses to decode / demodulate the logic level signal with a binary sequence representing the data sent from the receiver to the transmitter 330.

[0278] This is similar to the process performed at the receive microcontroller 320 that receives or generates data for transmission to a transmitter, such as transmitter 330. Similar to the transmit microcontroller 346, the receive microcontroller 320 encodes the data to be transmitted into a time sequence of synchronous and non-synchronous operation of the synchronous rectifiers, which results in changes in the waveform detected at the transmitter.

[0279] Now go to Figure 10 , a flow chart of a method 400 for communicating between a receiver (e.g., receiver 300) and a transmitter (e.g., transmitter 330) is shown. Method 400 includes modifying 402 the operation of a synchronous rectifier of the receiver. For example, modifying 402 the operation may include selectively enabling and / or disabling the operation of gate driver 310, trigger circuit 306, and / or auxiliary DC / DC converter 314. This selective switching of components of the synchronous rectifier is performed based on data to be transmitted, such that parameter changes generated at transmitter 330 indicate the data to be transmitted from receiver 300 to transmitter 330.

[0280] Switching the synchronous rectifier between synchronous and non-synchronous operation by selectively enabling and / or disabling the gate driver 310, the trigger circuit 306, and / or the auxiliary DC / DC converter 314 is performed based on a time sequence generated by the receiving microcontroller 320 based on the data to be transmitted. In this manner, data (e.g., binary data) is converted from a binary sequence into a time sequence of switching operations. Thus, the method 400 may include, before the modifying 402 step, a step of encoding the data to be transmitted into a modified time sequence of operations for the synchronous rectifier.

[0281] Method 400 also includes detecting 404 a parameter change at transmitter 330 based on the modification of the operation of the synchronous rectifier. As depicted, detector 348 detects a voltage waveform at transmitter 330 based on the modification of the operation of the synchronous rectifier.

[0282] The method 400 also includes determining 406 data to be transmitted from the receiver 300 to the transmitter 330 based on the parameter change (i.e., the detected parameter change). As described above, the detector 348 processes the detected waveform and compares the processed waveform to a level to generate a logic level signal that is decoded into the data transmitted from the receiver 300 to the transmitter 330.

[0283] This method of transmitting data can be more efficient than existing methods while allowing for higher data transfer rates. In addition, this method can operate with a receiver including a synchronous rectifier by selectively switching the operation of the synchronous rectifier to transmit data to a transmitter from which the receiver draws power.

[0284] An experimental setup of receiver 300 and transmitter 330 was tested to evaluate performance. To simulate a fixed-coupled wireless link between transmitter 330 and receiver 300, an equivalent T-network was used to connect transmitter 330 and receiver 300. To switch receiver 300 between synchronous and asynchronous operation, a function generator was used to enable / disable the receiver 300's auxiliary DC / DC converter 314, which powers the synchronous rectifier's gate driver 310. All tests were conducted with receiver 300 under no-load conditions. Operation of receiver 300 and transmitter 330 could be performed under load conditions, with receiver 300 under load. The experimental setup primarily used magnetic field coupling to transfer power from transmitter 330 to receiver 300. Furthermore, the experimental setup had an operating frequency of 13.56 MHz.

[0285] The transmitter RF voltage V1 and transmitter current Iin were measured while the synchronous rectifier was modulated between synchronous and non-synchronous operation. The results of this test are given in Figures 11 to 15 Shown in. Figure 11 is a graph of the voltage and current waveforms of the transmitter 330 .

[0286] Figure 11 The response of these voltage and current waveforms when the receiver 300 is modulated at a frequency of 1700 Hz is shown. As shown, the voltage waveform ranges from +18 V to -18 V, with peaks at +18 V and -18 V and valleys at +6 V and -6 V. The current waveform ranges from almost 1000 mA to a steady state of approximately 112-117 mA.

[0287] Figure 12 is a graph of the voltage rise time of the transmitter 330 for an exemplary period of the voltage waveform. Figure 12 As shown, during the rise time of 1.777 μs, the waveform exhibits a sharp increase in voltage of 2.612 V.

[0288] Figure 13 is a graph of the voltage fall time of the transmitter 330 for an exemplary period of the voltage waveform. Figure 13 As shown, during the falling time of 2.228 μs, the waveform shows a sharp decrease in voltage of 4.939 V.

[0289] Figure 14 is a graph of the current rise time of transmitter 330 for an exemplary period of the current waveform. Figure 14 As shown, during the rise time of 31.247 μs, the waveform exhibits a current increase of 548.984 mA.

[0290] Figure 15 is a graph of the current fall time of the transmitter 330 for an exemplary period of the current waveform. Figure 15 As shown, during the fall time of 46.633 μs, the waveform shows a sharp decrease in the current of 612.376 mA.

[0291] These graphs illustrate changes in detectable voltage and current waveforms based on changes in the operation of the synchronous rectifiers to transmit data from the receiver to the transmitter.

[0292] Although a particular transmitter 330 is described, those skilled in the art will appreciate that other configurations are possible. Figure 16 , shows another embodiment of a portion of a transmitter. In this embodiment, the transmitter includes the same components as transmitter 330, with the same elements having reference numbers increased by 100. LDO regulator 444 is powered by DC / DC converter 446, which also powers controller 46. Controller 446 receives a signal from detector 448. Detector 448 outputs a logic level signal (i.e., a logic level), which controller 446 decodes into data to be sent by the receiver to the transmitter.

[0293] In the arrangement shown, the detector 448 detects one or more current waveforms, ie, the detector 448 is a current detector. The detector 448 detects a current waveform based on changes in current at a single node (eg, Iin at the output of the DC / DC converter 446).

[0294] Since the transmitter's input DC current changes depending on the impedance it sees, this signal (i.e., Iin) can alternatively or additionally be used as a source for a detector 448 (e.g., a current demodulator), which filters the detected DC current and generates a logic level message reflecting the change in the transmitter's DC current level. This signal is then transmitted to a controller 446, such as a microcontroller.

[0295] Now go to Figure 17 , shows detector 448, i.e., a current detector, in more detail. Detector 448 demodulates the current waveform detected at the transmitter, as will be described. In other words, detector 448 comprises a current demodulator. Detector 448 includes current sensing circuit 480, filter 482, and signal conditioner and comparator 484.

[0296] In operation, the current sensing circuit 480 detects a current signal, such as the input current Iin. The current sensing circuit 480 also scales the sensed current to a smaller amplitude. The current sensing circuit 480 also converts the sensed current (e.g., the scaled sensed current) into a voltage signal proportional to the sensed current. The filter 428 (i.e., the input filtering stage) filters the output (i.e., the converted voltage). For example, the filter 428 filters the variation while blocking unwanted signal components such as high-frequency noise and DC offset. The filtered signal then passes through the signal conditioner and comparator 484. The signal conditioner and comparator 484 amplifies the signal and then compares the amplified level to a reference level. The signal conditioner and comparator 484 may include a comparator. Whenever a sufficiently large modulation occurs in the input current Iin signal, the signal conditioner and comparator 484 outputs a logic level signal.

[0297] The output logic level signal is then provided to the controller 446 for decoding. The controller 446 determines the time between the modulated pulses to decode / demodulate the logic level signal with a binary sequence representing the data sent from the receiver to the transmitter.

[0298] It should be understood that the examples provided are merely examples of the present disclosure and that various modifications may be made thereto.

Claims

1. A method for communicating between a receiver of a wireless power transfer system and a transmitter of the wireless power transfer system, wherein the receiver includes a synchronous rectifier, the method comprising: modifying the operation of a synchronous rectifier of a receiver of a wireless power transfer system; detecting a parameter change at a transmitter of the wireless power transfer system based on the modification of the operation of the synchronous rectifier; as well as Data transmitted from the receiver to the transmitter is determined based on the parameter change.

2. The method according to claim 1, wherein Modifying the operation of the synchronous rectifier includes: The synchronous rectifier is switched between synchronous operation and non-synchronous operation.

3. The method according to claim 1 or 2, wherein: Modifying the operation of the synchronous rectifier includes: The synchronous rectifier is selectively enabled and disabled.

4. A method according to any preceding claim, wherein: The synchronous rectifier comprises: Rectifier components for rectifying power signals into direct current (DC); trigger circuit; and A gate driver is electrically connected to the trigger circuit and the rectifier element, the gate driver controlling the operation of the rectifier element via a trigger signal output by the trigger circuit.

5. The method according to claim 4, wherein The synchronous rectifier further includes an auxiliary DC / DC converter for powering at least one of the trigger circuit and the gate driver.

6. The method according to claim 4 or 5, wherein: Modifying the operation of the synchronous rectifier includes: The operation of at least one of the trigger circuit, the gate driver, and the auxiliary DC / DC converter is controlled.

7. The method according to claim 6, wherein: Controlling the operation of the trigger circuit includes: Controls the operation of the comparator of the trigger circuit.

8. The method according to claim 6 or 7, wherein: Controlling the operation of the auxiliary DC / DC converter includes: Operation of the auxiliary DC / DC converter is selectively enabled and disabled to selectively power at least one of the trigger circuit and the gate driver.

9. A method according to any one of the preceding claims, wherein Detecting the parameter change includes: A voltage or current waveform at the transmitter is detected.

10. The method according to claim 9, wherein: The data to be transmitted include: The detected voltage or current waveform is processed to determine the transmitted data.

11. The method according to claim 10, wherein: Processing the detected voltage or current waveform includes: filtering the voltage or current waveform; generating a logic level based on the filtered voltage or current waveform; and Data is decoded based on the generated logic levels.

12. The method according to claim 11, wherein Decoding the data involves: determining a time interval between the logic levels; and Data is decoded based on the time interval.

13. A method of communicating between a receiver of a wireless power transfer system and a transmitter of the wireless power transfer system, the receiver comprising a synchronous rectifier, the method performed by the receiver comprising: Operation of the synchronous rectifier of the receiver of the wireless power transfer system is modified based on input data to change parameters at the transmitter.

14. The method according to claim 13, wherein Modification operations include: Synchronous operation of the synchronous rectifier is enabled and disabled based on the input data.

15. A controller for transmitting signals between a receiver of a wireless power transmission system and a transmitter of the wireless power transmission system, the receiver comprising a synchronous rectifier, The controller is adapted to modify operation of the synchronous rectifier to change a parameter detectable at the transmitter.

16. The controller according to claim 15, wherein: The controller is adapted to selectively enable and disable the synchronous rectifier.

17. The controller according to claim 15 or 16, wherein: The controller is electrically connected to the synchronous rectifier.

18. The controller according to claim 17, wherein: The controller is electrically connected to at least one of the following: a trigger circuit of the synchronous rectifier; and A gate driver for the synchronous rectifier is electrically connected to the trigger circuit and a rectifier element of the synchronous rectifier.

19. The controller according to claim 18, wherein: The controller is adapted to control the operation of the comparator of the trigger circuit.

20. The controller according to any one of claims 17 to 19, wherein: The controller is electrically connected to: An auxiliary DC / DC converter of the synchronous rectifier is used to power at least one of the trigger circuit and the gate driver.

21. The controller according to claim 20, wherein: The controller is adapted to selectively enable and disable operation of the auxiliary DC / DC converter to selectively power at least one of the trigger circuit and the gate driver.

22. A controller according to any one of claims 20 to 21, further comprising a power supply for supplying power to the controller.

23. A method of communicating between a receiver of a wireless power transfer system and a transmitter of the wireless power transfer system, the receiver comprising a synchronous rectifier, the method performed by the transmitter comprising: detecting a parameter change at the transmitter based on a modification of the operation of the synchronous rectifier of the receiver; as well as Data transmitted from the receiver to the transmitter is determined based on the parameter change.

24. The method according to claim 18, wherein Detecting the parameter change includes: A voltage or current waveform at the transmitter is detected.

25. The method according to claim 24, wherein Make sure the data being transferred includes: The detected voltage or current waveform is processed to determine the transmitted data.

26. The method according to claim 25, wherein Processing the detected voltage or current waveform includes: filtering the voltage or current waveform; generating a logic level based on the filtered voltage or current waveform; and Data is decoded based on the generated logic levels.

27. The method according to claim 26, wherein Decoding the data involves: determining a time interval between the logic levels; and Data is decoded based on the time interval.

28. A controller for transmitting signals between a receiver of a wireless power transmission system and a transmitter of the wireless power transmission system, the receiver comprising a synchronous rectifier, The controller is adapted to detect a parameter change at the transmitter based on a modification of the operation of the synchronous rectifier of the receiver.

29. The controller of claim 28, further adapted to determine data to be transmitted from the receiver to the transmitter based on the parameter change.

30. The controller according to claim 28 or 29, further comprising: A detector for detecting a voltage and / or current waveform at the transmitter.

31. The controller according to claim 30, wherein: The detector comprises: A demodulator adapted to demodulate the voltage and / or current waveform at the transmitter.

32. The controller according to claim 31, wherein The detector comprises: A filter adapted to filter the demodulated voltage and / or current.

33. The controller according to claim 32, wherein: The detector is suitable for: generating a logic level based on the filtered voltage and / or current; as well as Data is decoded based on the generated logic levels.

34. The controller according to claim 33, wherein: The detector is suitable for: determining a time interval between the logic levels; and Decode the data based on the time interval The controller according to any one of claims 28 to 34, further comprising a power supply for supplying power to the controller.

35. A non-transitory computer readable medium having program code stored thereon, the program code being executable by a processor to perform the method of any one of claims 1 to 9 and 19 to 27.

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