Wireless power receiver and method thereof and wireless power transmitter and method thereof

Abstract

A wireless power receiver is disclosed, adapted to: establish wireless power reception from a wireless power transmitter at a first power level during a wireless power transfer session; perform an authentication procedure with the wireless power transmitter; send session attribute information to a memory if the authentication procedure is successfully completed; receive session attribute information from the memory after the wireless power receiver interrupts the wireless power reception at the first power level; and establish wireless power reception from the wireless power transmitter at a second power level higher than the first power level. Since the short authentication procedure is used to determine whether the wireless power receiver meets the requirements or qualifications by checking the session attribute information before switching to the second operating mode, the time required for authentication can be saved, the possibility of changes or interference in the conditions of wireless power transfer during the mode switching can be reduced, and the normal operation of wireless power transfer can be ensured.

Description

Technical Field

[0001] The present invention relates to wireless power transmission, and more particularly to a wireless power receiver and a method for receiving power thereon, and a wireless power transmitter and a method for transmitting power thereon. Background Technology

[0002] Wireless Power Transfer Systems (WPTS) are gaining popularity as a convenient way to provide power without wires or connectors. Currently, WPTSs under development in the industry can be broadly categorized into two types: magnetic induction (MI) systems and magnetic resonance (MR) systems. Both types of systems include a wireless power transmitter and a wireless power receiver. Induction WPTSs typically use frequency variation as a power flow control mechanism, operating within a allocated frequency range of several hundred kilohertz. MR WPTSs typically use input voltage regulation to adjust the output power, thus operating at a single resonant frequency. In some applications, MR WPTSs operate at a frequency of 6.78 MHz. Such systems can be used to power or charge consumer electronic devices such as smartphones, calculators, cameras, and tablets, and can be used in other applications as well.

[0003] In wireless power transmission, there may be at least two power transmission modes, such as one transmitting at a lower power level and the other at a higher power level. These two modes can be switched between each other; however, how to switch safely and whether such switching is even possible are pressing issues that need to be addressed in this field. Summary of the Invention

[0004] In view of this, the present invention provides a wireless power receiver and method thereof, and a wireless power transmitter and method thereof, to solve the above-mentioned problems.

[0005] According to a first aspect of the present invention, a wireless power receiver is disclosed, which is suitable for:

[0006] During a wireless power transmission session, wireless power reception is established from the wireless power transmitter at a first power level.

[0007] Perform the authentication process with the wireless power transmitter;

[0008] If the authentication process is successful, the session attribute information is sent to the storage.

[0009] receiving session attribute information from the memory after the wireless power reception is interrupted at the first power level; and

[0010] establishing wireless power reception from the wireless power transmitter at a second power level higher than the first power level.

[0011] According to a second aspect of the present invention, a method of a wireless power receiver receiving power is disclosed, the method comprising:

[0012] establishing wireless power reception from a wireless power transmitter in a first operating mode;

[0013] performing an authentication procedure with the wireless power transmitter;

[0014] sending session attribute information to a memory, wherein the session attribute information comprises at least information related to the authentication procedure;

[0015] receiving the session attribute information at the wireless power receiver after the wireless power reception at the first operating mode is interrupted; and

[0016] establishing wireless power reception from the wireless power transmitter in a second operating mode after receiving the session attribute information.

[0017] According to a third aspect of the present invention, a wireless power transmitter is disclosed, the wireless power transmitter being adapted to:

[0018] establishing wireless power transmission to a wireless power receiver at a first power level;

[0019] performing an authentication procedure with the wireless power receiver;

[0020] sending session attribute information related to the authentication procedure to a memory;

[0021] performing a foreign object detection procedure for a time period in which the wireless power reception at the first power level is interrupted by the wireless power receiver; and

[0022] transmitting at least a portion of the session attribute information retrieved from the memory to the wireless power receiver before wirelessly transmitting power at a second power level higher than the first power level.

[0023] According to a fourth aspect of the present invention, a method of a wireless power transmitter transmitting power is disclosed, the method comprising:

[0024] establishing wireless power transmission to a wireless power receiver in a first operating mode;

[0025] performing an authentication procedure with the wireless power receiver;

[0026] after the authentication procedure is performed, performing a foreign object detection procedure for a time in which wireless power reception by the wireless power receiver in the first operating mode is interrupted;

[0027] reestablishing wireless power transmission to the wireless power receiver in the first operating mode; and

[0028] after the foreign object detection procedure is performed, establishing wireless power transmission to the wireless power receiver in a second operating mode.

[0029] The wireless power receiver of the present disclosure can save time required for authentication, reduce the possibility of change or interference (e.g., foreign object interference, etc.) in the conditions of wireless power transmission in the process of mode switching, while ensuring the safety of wireless power transmission, determine to maintain a session with the same wireless power transmitter, and ensure the normal operation of wireless power transmission, by determining whether the wireless power receiver meets the conditions or requirements by checking session attribute information before switching to the second operating mode. BRIEF DESCRIPTION OF DRAWINGS

[0030] Figure 1 is a block diagram depiction of a wireless power system including a wireless power transmitter and a wireless power receiver according to some embodiments.

[0031] Figure 2A depicts an example of actions associated with a wireless power transmission method that can be performed by a wireless power transmitter according to some embodiments.

[0032] Figure 2B depicts an example of actions associated with a wireless power transmission method that can be performed by a wireless power transmitter according to some embodiments.

[0033] Figure 3 depicts an example of actions associated with a wireless power transmission method that can be performed by a wireless power receiver according to some embodiments. DETAILED DESCRIPTION

[0034] Wireless power systems can provide a convenient way to provide power from a first device (e.g., a wireless power transmitter) that can function as a charging device to a second device (e.g., a wireless power receiver) that needs power without the need to plug and unplug one or more power chords. In many implementations, the power provided wirelessly can be used to power and / or charge electronic devices. Some wireless power systems can operate in two or more wireless power transmission modes, which can correspond to different levels of wireless power transmission.

[0035] Some wireless power transfer systems are capable of providing power wirelessly at high power levels (e.g., higher than 5 Watts). In some cases, 15 Watts or more can be transferred wirelessly. When operating at high power levels, it is desirable to avoid transferring significant amounts of power to foreign objects that can be located in the wireless power transfer area. In some cases, it is also desirable to ensure that the wireless power receiver and / or the wireless power transmitter are authenticated or qualified for transferring high power levels. Accordingly, authentication and foreign object detection steps can be performed prior to transferring high power levels. In some implementations, the wireless power run can perform authentication and / or foreign object detection steps when the wireless power transmitter and the wireless power receiver change from a first mode of operation (possibly a non-privileged mode that can be used by all such devices) to a second mode of operation (possibly a privileged mode that can be limited to certain authorized devices). Embodiments described herein relate to methods for wireless power transfer at high power levels when foreign objects can be present, and also relate to the transition of wireless power transmitters and wireless power receivers between non-privileged and privileged modes of operation.

[0036] Some embodiments relate to control logic for a wireless power receiver that adapts the wireless power receiver to: establish wireless power reception from a wireless power transmitter at a first power level during a wireless power transfer session; perform an authentication procedure with the wireless power transmitter; send session attribute information to a memory if the authentication procedure is successfully completed; receive the session attribute information from the memory after the wireless power receiver discontinues the wireless power reception at the first power level; and establish wireless power reception from the wireless power transmitter at a second power level that is higher than the first power level.

[0037] Some embodiments relate to a method of wirelessly receiving power by a wireless power receiver during a wireless power transfer session. Such a method can include the following acts: establishing wireless power reception from a wireless power transmitter in a first mode of operation; performing an authentication procedure with the wireless power transmitter; sending session attribute information to a memory, wherein the session attribute information includes at least information related to the authentication procedure; receiving the session attribute information after the wireless power reception is discontinued at the wireless power receiver in the first mode of operation; establishing wireless power reception from the wireless power transmitter in a second mode of operation after the session attribute information is received.

[0038] Some embodiments relate to a controller for a wireless power transmitter adapted to code to establish a wireless power transfer to a wireless power receiver at a first power level; perform an authentication procedure with the wireless power receiver; send session attribute information related to the authentication procedure to a memory; perform a foreign object detection procedure for a time in which the wireless power receiver is interrupted in receiving the wireless power at the first power level; transmit at least some of the session attribute information retrieved from the memory to the wireless power receiver prior to wirelessly transferring power at a second power level higher than the first power level.

[0039] Some embodiments relate to a method of wirelessly transferring power by a wireless power transmitter. Such a method can include the following acts: establishing a wireless power transfer to a wireless power receiver in a first operating mode; performing an authentication procedure with the wireless power receiver; after performing the authentication procedure, performing a foreign object detection procedure for a time in which the wireless power receiver is interrupted in receiving the wireless power in the first operating mode; re-establishing the wireless power transfer to the wireless power receiver in the first operating mode; after performing the foreign object detection procedure, establishing a wireless power transfer to the wireless power receiver in a second operating mode.

[0040] For example, a wireless power system 100 (such as Figure 1 The illustrated wireless power system) can operate in a low-power mode. According to some embodiments, the amount of power transferred in the low-power mode can be 5 Watts or less. In some cases, this mode can be referred to as a "basic power performance" mode, although other names can be used. The power level delivered to a foreign object and a wireless power receiver in the low-power operating mode can not result in high temperature conditions or exceed standard operating conditions for the receiver. Heating can be caused by a foreign object 20 (e.g., a paperclip, a coin, etc.) inadvertently positioned in the wireless power transfer region between the two devices. In the wireless power transfer region, the electromagnetic field can impinge on the foreign object 20 and potentially generate currents in the foreign object, which can radiate heat.

[0041] The foreign object 20 can also adversely affect the efficiency of the wireless power transfer. The wireless power transfer can be reduced due to the presence of a conductive foreign object 20 in the field generated by the wireless power transmitter. Conductive and / or metallic objects can absorb energy due to the induction of currents in the objects. If a metallic object is present, the efficiency of the power transfer can be greatly reduced (e.g., from 90% to 40%). Thus, it can be beneficial to detect a foreign object and calibrate the wireless power system 100 to address the foreign object before wirelessly providing power at any power level for an extended period of time.

[0042] Wireless power system 100 can operate in one or more high power modes. For example, a high power mode can be a mode in which wireless power transfer can occur at power levels exceeding 5 Watts. In some cases, a high power mode can transition power levels from 5 Watts to 15 Watts, or even higher. Such a mode or modes can be referred to as "extended power performance," although other names can be used. It can be appreciated that undesirable power losses and heating conditions increase as power transfer levels increase. Thus, it can be beneficial to further perform foreign-object detection (FOD) and calibration to address foreign objects prior to entering a high power mode, as well as to perform FOD intermittently during operation in a high power mode.

[0043] Certain wireless power receivers 11 can not be configured to handle high level power transfer from wireless power transmitter 1. For example, they can have internal electronic components that are not rated for the higher power levels that wireless power transmitter 1 can provide. For such receivers, an authentication process can be implemented prior to attempting to enter a high power mode of operation. The authentication process can determine, for example, that receiver 11 complies with standards (e.g., Qi standards) that wireless power transmitter 1 also adheres to, and is rated for one or more high power modes of operation.

[0044] The inventors have recognized and appreciated that an authentication process between wireless power transmitter 1 and wireless power receiver 11 can take a considerable amount of time (e.g., greater than 5 seconds, greater than 10 seconds, or greater than 20 seconds in some cases). During such a time interval, conditions related to foreign object 20 can change. For example, if a foreign object is present, during the time interval the foreign object can be moved, or foreign object 20 can be inadvertently placed in the wireless power transfer region. Thus, FOD and calibration performed in a low power mode of operation can no longer be valid when entering a high power mode of operation after performing a lengthy authentication process. If high power operation is allowed, the change in foreign object conditions can result in undesirable operating conditions.

[0045] Before describing methods to avoid undesirable operating conditions when performing an authentication process and transitioning to a high power mode of operation, more details of wireless power transfer system 100 and foreign object detection are briefly described.

[0046] Figure 1 A block diagram of wireless power system 100 including wireless power transmitter 1 and wireless power receiver 11 is shown. Wireless power transmitter 1 has a drive circuit 7, which can include inverter 3 and matching network 6. Inverter 3 can drive transmit coil 10 and impedance match with transmit coil through matching network 6.

[0047] According to some embodiments, the wireless power transmitter 1 can further include a regulated voltage source 2 (e.g., a voltage regulator) that provides a regulated DC voltage to the inverter 3. The regulated voltage source 2 generates a regulated DC output voltage in response to a control stimulus from the controller 5. In some embodiments, the drive circuit 7 can be a class D or E amplifier that converts the DC voltage at the input of the inverter 3 to an AC output voltage to drive the transmit coil 10. The voltage enables wireless power transfer through electromagnetic induction.

[0048] The controller 5 can also control the signal generator 9 to drive the inverter 3 with a signal at a selected wireless power transfer frequency. As an example, the inverter 3 can switch at frequencies between 100 and 205 kHz to transmit power to wireless power receivers designed for receiving wireless electrical power according to the Qi specification for low power Qi receivers and for medium power Qi receivers at 80-300 kHz. The inverter 3 can switch at higher frequencies, such as frequencies greater than 1 MHz, within the ISM band, for example, 6.765 MHz to 6.795 MHz, to transmit power to receivers designed to receive wireless power using MR technology. However, these frequencies are provided by way of example only, as wireless power can be transmitted at various suitable frequencies according to any suitable specification. The controller 5 can be an analog circuit or a digital circuit. The controller 5 can be programmable and can instruct the signal generator 9 to generate a signal at a desired transfer frequency based on stored program instructions, such that the inverter 3 switches at the desired transfer frequency.

[0049] The matching network 6 can include one or more impedance matching networks and facilitates wireless power transfer by presenting an appropriate impedance to the inverter 3. The matching network can have one or more capacitive or inductive elements or any suitable combination of capacitive and inductive elements. Since the transmit coil 10 can have an inductive impedance, in some embodiments, the matching network 6 can include one or more capacitive elements that, when combined with the impedance of the transmit coil 10, present an impedance to the output of the inverter 3 that is suitable for driving the transmit coil 10. For example, the matching network can rotate the input impedance of the transmit coil 10 to approximate the output impedance of the inverter 3, thereby reducing power reflections that would otherwise occur from the transmit coil 10. In some embodiments, the resonant frequency of the matching network 6 and the transmit coil 10 can be adjusted (e.g., through variable capacitors and / or switched-in and switched-out capacitors) during wireless power transfer and can be set to equal or approximately equal the switching frequency of the inverter 3.

[0050] The transmit coil 10 and receive coil 12 can be implemented by any suitable type of conductor. The conductor can be a wire, including a solid, single-core wire or a Litz wire. In some cases, the coils can be formed from patterned conductors, such as patterned conductors of a printed circuit board or an integrated circuit.

[0051] According to Ampere’s law, an alternating current (AC) driven in the transmit coil 10 produces an oscillating magnetic field. According to Faraday’s law, the oscillating magnetic field can induce an alternating current in the nearby receive coil 12 of the wireless power receiver 11 and produce a voltage across it. The alternating voltage induced across the receive coil 12 is provided through the matching network 13 to a rectifier 14, which produces an unregulated DC voltage. The rectifier 14 can be a synchronous rectifier, or can be implemented using diodes and one or more capacitors. The unregulated DC voltage can be regulated using a DC / DC converter 15, the output of which can be filtered and provided as an output voltage Vout to a load. In some alternative embodiments, the DC / DC converter 15 can be replaced by a linear regulator or a battery charger, or omitted altogether.

[0052] According to some embodiments, the wireless power receiver 11 can include a memory 17 and control logic 16. The control logic 16 can include dedicated circuitry, such as dedicated circuitry formed from logic gates and buffers and other circuit components, one or more field-programmable gate arrays, a microcontroller, a microprocessor, or some combination thereof. The memory can include one or both of volatile and non-volatile types of memory. The control logic 16 can be in communication with the memory 17, and can further be in communication with one or both of the rectifier and DC / DC converter or linear regulator or battery charger.

[0053] In some embodiments, the wireless power transmitter 1 may have communication circuitry (e.g., within or connected to the controller 5) for communicating with the wireless power receiver 11. This communication can be in-band or out-of-band. Similarly, the wireless power receiver 11 may have communication circuitry (e.g., within or connected to the control logic 16) for communicating with the wireless power transmitter 1. According to some embodiments, the wireless power receiver 11 may send information to the wireless power transmitter 1 indicating the power required at the wireless power receiver 11, or requesting a change in the power level provided by the wireless power transmitter 1. In response, the wireless power transmitter 1 may increase or decrease its power output accordingly. The wireless power transmitter 1 may control the amount of power transmitted by changing the voltage drive level applied to the transmitting coil 10, the frequency of the oscillation voltage applied to the transmitting coil 10, or both. Any suitable power control technique may be used.

[0054] like Figure 1 As shown, for example, a conductive foreign object 20 can enter the wireless power transmission area, where a field generated by the transmitting coil 10 of the wireless power transmitter 1 exists. If this happens, the wireless power transmission efficiency may be reduced, and / or power may be lost and dissipated in the conductive foreign object 20. Examples of conductive foreign objects 20 include, but are not limited to, coins, paperclips, keys, jewelry, pens, pencils, metallized medical or pharmaceutical items, metal personal care products, etc.

[0055] According to some embodiments, the wireless power transmitter 1 can be configured to perform foreign object detection automatically or semi-automatically before and / or during wireless power transmission. By performing foreign object detection and / or foreign object calibration, the wireless power transmitter 1 can determine whether to perform wireless power transmission to the receiver 11.

[0056] In some implementations, foreign object detection can be performed by measuring the quality factor Q associated with the transmitting coil 10. For example, the wireless power transmitter 1 can excite a resonance in the transmitting coil 10, then allow the stored energy to decay. The observed decay rate depends on the Q of the transmitting coil and the parameters of the circuitry in which it exists, and may also be affected by any foreign objects 20 that interact with the electromagnetic field generated by the transmitting coil 10. Examples of foreign object detection methods are further described in detail in U.S. Patent Application No. 15 / 957,704, filed April 19, 2018, entitled "Detecting Foreign Objects in a Wireless Power Transmission System," the entire contents of which are incorporated herein by reference.

[0057] According to some embodiments, a method called "loss balancing" can alternatively or additionally be used to determine the effect of foreign objects 20 on wireless power transfer. In loss balancing, the power losses associated with the wireless power transmitter 1 and the wireless power receiver 11 are known or predetermined (e.g., determined during device manufacturing). During power transfer, the amount of power received by the receiver 11 can be transmitted to the wireless power transmitter. The difference between the expected amount of power received (based on the power transmitted, transmitter losses, and receiver losses) and the actual power received can be attributed at least in part to power losses associated with one or more foreign objects.

[0058] In some implementations, if the power loss associated with the foreign object(s) exceeds a threshold during the loss balancing calibration, the wireless power transfer will be interrupted so that the foreign object 20 can be removed. Certain standards (e.g., the Qi standard) can have multiple thresholds, depending on the operating mode. For example, the wireless power transfer can be interrupted if the power loss associated with the foreign object exceeds 350 milliwatts in a low power operating mode and 750 milliwatts in a high power operating mode. It should be understood that other thresholds can be used in the Qi standard or other standards, and the present invention is not limited to these example values.

[0059] In Figure 2A , Figure 2B and Figure 3 The actions associated with the methods for wireless power transfer in different operating modes, authentication, and foreign object detection are listed in the flowcharts of Figure 2A and Figure 2B The actions described in Figure 3 The actions described in

[0060] According to some embodiments, the method 200 of wireless power transfer can begin after the wireless power transmitter 1 is turned on and after a wireless power receiver (abbreviated PRX) is detected (action 205) in the wireless power transfer area. In some cases, the wireless power receiver 11 can be detected by the transmitter 1 sending a digital or analog ping that can elicit a response from the wireless power receiver. For example, the wireless power receiver 11 can return identifying information and / or a request for wireless power transfer.

[0061] The wireless power transmitter 1 can then begin a wireless power transfer session with the receiver and perform (act 210) a foreign object detection procedure prior to wirelessly transmitting power to the wireless power receiver 11. As described above, examples of the FOD procedure can include evaluating the quality factor Q of the transmit coil 10. The wireless power transmitter 1 and the wireless power receiver 11 can establish (act 215) a power contract in the first operating mode. The power contract in the first operating mode can include specifications for the oscillation frequency and / or modulation amplitude (e.g., peak-to-peak voltage) at one or both of the transmitter and receiver. In some cases, a power metric can be included in the power contract, such as the average power detected at one or both of the transmitter and receiver. The terms of the power contract can be used to establish wireless power transfer to the wireless power receiver 11 at a first power level associated with the first operating mode.

[0062] Having established the power contract, the wireless power transmitter 1 can perform (act 220) a calibration procedure for wireless power transfer, for which there can or can not be one or more foreign objects present in the wireless power transfer region. The calibration procedure can determine power transfer losses associated with the foreign objects and adjust the wireless power transfer parameters (e.g., frequency and / or voltage level) to reduce such losses. According to some implementations, the power transfer losses can be determined by a loss balancing procedure, as described above.

[0063] In many wireless power transfer sessions, the wireless power receiver 11 can issue a request for wireless power transfer in a second operating mode that involves a higher power level than the first operating mode. In some cases, the request can arise immediately after the wireless power transmitter 1 performs (act 220) the calibration procedure. The request can be received (act 225) by the wireless power transmitter 1. In some wireless power transfer protocols or standards, the higher power level wireless power transfer can not be allowed unless an authentication procedure is successfully performed and completed between the wireless power transmitter 1 and the wireless power receiver 11. The authentication procedure can ostensibly avoid the undesirable operating conditions described above (e.g., attempting to transfer a high power level to a device that has not been registered or authenticated to handle the higher power level). In response to the request for wireless power transfer in the second operating mode, the wireless power transmitter 1 and the wireless power receiver 11 can perform (act 230) an authentication procedure. In some cases, the authentication procedure can involve a lengthy information exchange process through in-band or out-of-band communication between the two devices. In some implementations, the wireless power receiver 11 initiates the authentication procedure. In some cases, the wireless power transmitter 1 can initiate the authentication procedure.

[0064] The authentication procedure can include determining the identity and / or type of the wireless power receiver 11 and determining that the receiver is rated for high power levels. In some cases, the authentication procedure can include making the identity and / or type of the wireless power transmitter 1 known to the receiver 11 and confirming by the receiver 11 that the transmitter was manufactured according to acceptable industry standards and established quality control procedures (e.g., in compliance with industry standards). According to some embodiments, the authentication procedure can include retrieving a secure key or a public key by one or both of the wireless power transmitter 1 and the wireless power receiver 11.

[0065] As noted above, the authentication procedure can take a significant amount of time compared to other wireless power transfer procedures that are performed prior to commencing wireless power transfer at a particular power level. For example, for a wireless power receiver 11 and a wireless power transmitter 1 operating according to the Qi standard, the time associated with actions 205-225 in Figure 2A may take approximately 1.5 seconds. In some cases, performing the identity verification procedure (step 230) can take approximately 20 seconds or more. As noted above, the inventors have recognized and appreciated that such time intervals can allow for changes in foreign object conditions and can result in undesirable operating conditions. Figure 2B The actions of

[0066] According to some embodiments and with reference to Figure 2B After the authentication procedure is completed, the method 200 of wireless power transfer can continue by determining (action 235) whether to allow operation in a second operating mode. For example, if the authentication procedure fails to complete successfully (which can occur if the wireless power transmitter 1 or the wireless power receiver 11 does not comply with the same wireless power transfer standard as the wireless power receiver 11 or the wireless power transmitter 1, respectively, or fails to complete the key decryption procedure), then the wireless power receiver 11 and the wireless power transmitter 1 can operate in the first operating mode for the remainder of the wireless power transfer session (action 240).

[0067] On the other hand, if it is determined (act 235) that operation in the second operating mode is allowed (e.g., authentication is successfully completed), the wireless power transmitter 1 can perform several acts to prepare for power transfer at the higher power level. In some embodiments, the wireless power transmitter 1 can receive (act 245) at least some session attributes from the wireless power receiver 11 and store the session attributes. The session attributes can include information related to the particular wireless power transfer session (e.g., operating information of the wireless power receiver 11 and / or the wireless power transmitter 1). In some cases, the session attributes can include authentication information from the successfully completed authentication process. The authentication information can include information related to the receiver and / or the transmitter successfully completing the authentication process (e.g., information required for the authentication process or information from the authentication process). In some cases, the authentication information can include confirmation information from the receiver that the authentication has been successfully completed. Additionally or alternatively, the session attributes can include other information unique to the current session (e.g., any one or some combination of receiver identification, randomly generated number, encryption key, time, date, power level, oscillation frequency, etc.). The session attributes can be sent to a data storage location (e.g., a volatile or non-volatile memory 4 that is part of and / or in communication with the controller 5 of the transmitter). At a later time, at least some of the session attribute information can be retrieved and used to more quickly transition from the first operating mode to the second operating mode. The session attributes can also include authentication information from the wireless power transmitter 1. In some cases, at least some of the session attribute information can be sent back to the receiver at a later time so that the receiver can use the session attribute information to quickly proceed with wireless power transfer at the second power level. The session attribute information can be generated by one or both of the wireless power transmitter 1 and the wireless power receiver 11.

[0068] According to some embodiments, the method 200 can include sending (act 250) a power-down command to the wireless power receiver 11 that causes the receiver to temporarily interrupt power transfer from its receive coil 12 at the first power level. In some cases, the receiver can be powered down completely. In other cases, the wireless power receiver 11 can disable power draw from its receive coil while still continuing to draw low power from in-device power storage elements such as a large capacitor of a rectifier 14. The charge stored in the large capacitor can be used to reverse bias the rectifier's diodes, thereby substantially preventing current draw from the receive coil 12 for a short period of time. Such a short period of time can allow the wireless power transmitter 1 to again perform (act 255) a foreign object detection (e.g., evaluate the Q-factor) before beginning wireless power transfer in the first operating mode.

[0069] According to some embodiments, instead of sending (act 250) a power-off command to the wireless power receiver 11, the transmitter can temporarily interrupt the wireless power transmission to the receiver 11 at the first power level, so that the power reception at the receiver 11 is temporarily interrupted at the first power level. During the temporary interruption, the wireless power transmitter 1 can perform (act 255) a foreign object detection. Thus, the receiver 11 can initiate the interruption of the wireless power reception at the first power level, or the wireless power transmitter 1 can initiate the interruption of the wireless power transmission from the wireless power transmitter 1 and the interruption of the wireless power reception at the receiver 11 at the first power level.

[0070] When performing (act 255) the foreign object detection, the wireless power transmitter 1 can reduce the power to its transmitting coil 10 (compared to the previous level used for the wireless power transmission during the session), thereby generating a low level of voltage and power at the receiver. Reducing the power of the transmitting coil 10 can make it easier for the receiver 11 to interrupt the received power from its receiving coil 12.

[0071] In some cases, a power-off command can not be sent to the wireless power receiver 11. Instead, the wireless power receiver can automatically power off after the identity verification process and signal to the wireless power transmitter 1 when it is powered off and / or disables its receiving coil 12. Thus, the act of sending a power-off command (act 250) can not be performed by the wireless power transmitter 1 and is not included in the method 200 (as shown in dashed lines). In some cases, the wireless power transmitter 1 can receive a signal from the wireless power receiver 11 that it is powering off and / or disabling its receiving coil 12.

[0072] The method 200 of performing wireless power transmission by a transmitter can include performing (act 255) a foreign object detection and establishing (act 260) a power contract for the wireless power transmission in the first operating mode. These two acts can be substantially the same as acts 210 and 215 described above. After performing the foreign object detection (act 255), the receiver 11 can power up and / or signal that it has powered up or is ready for wireless power transmission. If the wireless power transmitter 1 has received (act 245) the session attributes from the wireless power receiver 11, the wireless power transmitter 1 can send (act 265) the session attributes information back to the wireless power receiver 11 that it has woken up from its power transmission interruption. If no session attributes are received from the receiver, this step can be omitted from the method 200 as shown in dashed outline. The session attributes information sent from the wireless power transmitter 1 to the wireless power receiver 11 or received by the wireless power receiver 11 from its memory 17 can include information that allows the following two acts of wireless power transmission in the second operating mode.

[0073] The wireless power transmitter 1 can then proceed to establish (act 270) a power contract with the wireless power receiver 11 in a second operating mode, which can be a high power mode. After establishing the power contract, the wireless power transmitter 1 can perform a calibration procedure (act 275) during wireless power transmission in the second operating mode, where one or more foreign objects 20 can be present in the wireless power transfer region. The calibration procedure can include the acts of loss balancing. The calibration procedure can occur one or more times while the wireless power transmitter 1 is operating in the second operating mode (act 280).

[0074] In some embodiments, the session attribute can be considered a session key created as a result of successfully completing the authentication procedure (act 230). By exchanging the session attribute, the wireless power transmitter 1 and the wireless power receiver 11 can proceed quickly from the second act of establishing a power contract (act 260) for the first operating mode to operating (act 280) in the second operating mode of wireless power transmission. For example, for transmitters and receivers operating according to the Qi standard, the amount of time after establishing (act 260) a power contract for the first operating mode to operating (act 280) in the second operating mode can be approximately 2.5 seconds. This can be significantly shorter than the delay associated with the authentication procedure occurring between the acts of establishing (act 260) a power contract in the first operating mode and operating (act 280) in the second, higher power mode, and can avoid the longer delays associated with the authentication procedure (e.g., up to 20 seconds or more). Due to the significant reduction in time, for example, the likelihood of conditions changing related to one or more foreign objects 20 between establishing power contracts for the first and second operating modes of operation is much less. In the event that authentication is not successfully completed (e.g., the authentication information is not verified by the wireless power receiver 11 or the wireless power transmitter 1), then the acts of calibration (220, 320) can be repeated after the subsequent act of establishing (260, 360) a power contract in the first operating mode.

[0075] As Figure 3As shown, during the method 300 of performing wireless power transfer, the wireless power receiver 11 can perform corresponding actions. According to some embodiments, the wireless power receiver 11 can initiate (act 305) a charging mode when the wireless power receiver 11 is placed in the wireless power receiver 11. In some cases, the charging mode can be initiated in response to a ping from the transmitter. In some implementations, the receiver 11 can ping the wireless power transmitter 1 to indicate its presence and / or readiness for wireless power reception. The wireless power receiver 11 can participate in establishing (act 315) a power contract in a first operating mode in which the wireless power transmitter 1 participates. As described above, establishing the power contract can involve exchanging information with the wireless power transmitter 1 and establishing the wireless power reception at the receiver. The wireless power receiver 11 can further participate in performing (act 320) a calibration of power transfer during the first operating mode for which one or more foreign objects can exist.

[0076] After completing the calibration process, the wireless power receiver 11 can issue (act 325) a request for wireless power transfer in a second operating mode and then participate in performing (act 330) an authentication process with the wireless power transmitter 1. The method 300 can or can not include determining (act 335) whether to allow operation in the second operating mode based on a result of performing (act 330) the authentication process. For example, one or more acts 335 of determining can be performed entirely by the wireless power transmitter 1. If the second operating mode is not allowed (e.g., the authentication process is not successfully completed), the wireless power receiver 11 can be limited to operating (act 340) in the first operating mode for the remainder of the wireless power transfer session.

[0077] If the authentication process is successfully completed, the wireless power receiver 11 can store (act 345) session attributes. The session attributes can be those described above in connection with act 245. According to some embodiments, the wireless power receiver 11 can store the session attributes locally (e.g., in non-volatile memory) and / or transmit them to the wireless power transmitter 1 for storage by the transmitter. According to some embodiments, transmitting the session attributes to the wireless power transmitter can automatically grant the transmitter permission to proceed with foreign object detection and power transfer at a higher power level.

[0078] The wireless power receiver 11 can further interrupt (act 350) the reception of wireless power from the receive coil 12. In some cases, the interruption of the reception of wireless power can be in response to a command issued by the wireless power transmitter 1. To interrupt the reception of wireless power, as described above, the receiver can disable the power flow from the receive coil 12. The interruption of the reception of wireless power can allow the wireless power transmitter 1 to perform (act 255) a foreign object detection (e.g., by evaluating the Q-factor).

[0079] According to some embodiments, the wireless power receiver 11 can further engage in establishing (act 360) a power contract with the wireless power transmitter 1 for the first operating mode, and then receive (act 365) the session attribute information. The session attribute information can be received from the wireless power transmitter 1 in some cases if it was stored in the session attribute information (act 350) during the interruption of the reception of wireless power. In some implementations, the session attribute information can be retrieved from local storage (e.g., non-volatile or volatile memory) in communication with the receiver 11 or its control logic 16. In some cases, the reception (act 365) of the session attribute information can include the receiver 11 verifying the session attribute information. For example, upon the session attribute information being prepared and sent to the transmitter, the receiver can compare the received session attribute information to the session attribute information it stores in its memory 17 to verify that at least some of the information matches.

[0080] In some embodiments, the reception (act 365) of the session attribute information can effectively restore the authenticated state at the wireless power receiver 11 without requiring the transmitter and receiver to go through the authentication process again. This can allow the wireless power receiver 11 and the wireless power transmitter 1 to quickly proceed to the acts of establishing (acts 370, 270) a power contract, performing calibration (acts 375, 275), and operating (acts 380, 280) in the second operating mode. When establishing (act 370) the power contract in the second operating mode, the wireless power receiver 11 can send at least some of the session attribute information stored with the session attribute to the wireless power transmitter 1.

[0081] In embodiments of the wireless power transfer methods 200, 300, the actions associated with the retrieval and use of the session attribute can be considered an abbreviated authentication or re-authentication procedure performed after the wireless power reception is interrupted (action 350) in the wireless power receiver 11. In some cases, re-authentication can only be checked by one device. For example, only the wireless power transmitter 1 can check the valid session attribute information provided by the wireless power receiver 11 when transitioning to the second operating mode (e.g., when a power contract is established (action 370) in the second operating mode). In other embodiments, both the wireless power receiver 11 and the wireless power transmitter 1 can check the session attribute information when transitioning to the second operating mode. For example, the wireless power receiver 11 can check the retrieved session attribute information (from action 365) to determine that a session is being maintained with the same wireless power transmitter 1.

[0082] The methods 200, 300 described above involve two operating modes, namely a low power mode (e.g., a basic performance mode) and a high power mode (e.g., an extended performance mode). The methods can be applied to more operating modes (e.g., additional high power operating modes). In some cases, the two operating modes can be related to an increase or decrease in power level. For example, whenever the wireless power receiver 11 requests an increase or decrease in power level, the storage and / or exchange of session attributes, interruption of wireless power transfer, foreign object detection, and re-establishment of wireless power transfer can occur. As such, the first operating mode and the second operating mode in the illustrated methods 200, 300 can belong to the high power and low power modes, respectively.

[0083] It can be further understood that the methods 200, 300 can involve a transition from a non-privileged operating mode (similar to a low power mode) to a privileged operating mode (similar to a high power mode). The non-privileged mode can be a basic power transfer mode that is widely used for wireless power receivers and wireless power transmitters. For example, neither the wireless power receiver nor the wireless power transmitter can need authentication or authorization to access the non-privileged operating mode. The privileged operating mode can be a mode that contains higher performance functions (e.g., power saving functions, higher power transfer, device diagnostic functions, etc.). The privileged mode can not require power transfer at a higher power level than the non-privileged mode. As such, the first operating mode and the second operating mode in the illustrated methods 200, 300 can belong to the non-privileged mode and the privileged mode, respectively.

[0084] As an example, a method of wirelessly receiving power by a wireless power receiver during a wireless power transfer session can include the following acts: establishing wireless power reception from a wireless power transmitter in a non-privileged mode of operation; performing an authentication procedure with the wireless power transmitter; sending session attribute information to a memory, wherein the session attribute information includes at least information related to the authentication procedure; receiving the session attribute information at the wireless power receiver after the wireless power reception is interrupted in the non-privileged mode of operation; establishing the wireless power reception from the wireless power transmitter in a privileged mode of operation after receiving the session attribute information. Circuit control logic can be configured to operate in this manner.

[0085] As another example, a method of wirelessly transmitting power by a wireless power transmitter can include the following acts: establishing wireless power transmission to a wireless power receiver in a non-privileged mode of operation; performing an authentication procedure with the wireless power receiver; performing a foreign object detection procedure for a time during which wireless power reception at the wireless power receiver at a first power level is interrupted after performing the authentication procedure; re-establishing the wireless power transmission to the wireless power receiver in the non-privileged mode of operation; establishing the wireless power transmission to the wireless power receiver in a privileged mode of operation after performing the foreign object detection procedure. Circuit control logic can be configured to operate in this manner.

[0086] The methods of wireless power transfer 200, 300 described above in connection with Figures 2A to 3 The methods of wireless power transfer 200, 300 described above include various functions that can be implemented using logic circuitry or a processor and code. Code written in connection with performing such functions can be stored on a non-transitory computer readable medium so that it can be loaded into one or more processors (or configured as logic circuitry) to adapt the one or more processors (or logic circuitry) and related circuitry to perform the functions.

[0087] Accordingly, the wireless power transmitter 1 can be controlled using the controller 5, and the wireless power receiver 11 can be controlled using the control logic 16, which can be implemented by suitable logic circuitry. For example, the controller 5 or the control logic 16 can be implemented using hardware or some combination of hardware, firmware, and code (software). When implemented using code, the suitable code can be executed on a suitable processor (e.g., a microprocessor) or collection of processors. The one or more processors can be implemented in a number of ways, such as with dedicated hardware, or with general purpose hardware (e.g., one or more processors) programmed using code to perform the functions described above.

[0088] In this regard, it should be understood that at least a portion of the embodiments described herein are implemented in an manner that includes at least one computer-readable storage medium (e.g., RAM, ROM, EEPROM, flash memory or other storage technologies, or other tangible, non-transitory computer-readable storage medium encoded with computer code (i.e., a plurality of executable instructions), which, when executed on one or more processors, performs at least some of the functions described in the one or more embodiments above. Furthermore, it should be understood that references to code that performs any of the functions discussed above during execution are not limited to applications running on a host computer. Rather, the terms “code” and “software” are used herein in a general sense to refer to any type of computer code (e.g., application software, firmware, microcode, or any other form of computer instructions) that can be used to program one or more processors and / or logic circuits to implement the functions described herein.

[0089] The various aspects of the apparatus and techniques described herein can be used individually, in combination, or in various arrangements not specifically discussed in the embodiments described in the preceding description; therefore, their application is not limited to the details and arrangements of the component sets shown in the foregoing description or in the accompanying drawings. For example, aspects described in one embodiment may be combined with aspects described in other embodiments.

[0090] The use of ordinal terms such as "first," "second," and "third" in claims to modify claim elements themselves does not indicate any priority, precedence, or order of one claim element relative to another or in time. The order of execution of methods is used, but only as a label to distinguish one claim element with the same name from another element with the same name (but using ordinal terms) to differentiate claim elements.

[0091] Those skilled in the art will readily observe that numerous modifications and alterations can be made to the apparatus and method while maintaining the teachings of this invention. Therefore, the foregoing disclosure should be interpreted as being limited only by the scope and limits of the appended claims.

Claims

1. A wireless power receiver, comprising: The wireless power receiver is adapted to: establish a wireless power reception from a wireless power transmitter at a first power level during a wireless power transfer session; perform an authentication procedure with the wireless power transmitter after establishing the wireless power reception at the first power level; send session attribute information to a memory if the authentication procedure is successfully completed, the wireless power reception established by the wireless power receiver at the first power level being interrupted after sending the session attribute information to the memory; receive the session attribute information from the memory after the wireless power receiver interrupts the wireless power reception at the first power level; and establish a wireless power reception from the wireless power transmitter at a second power level higher than the first power level after receiving the session attribute information from the memory.

2. The wireless power receiver of claim 1, wherein, The wireless power receiver is further adapted to: generate the session attribute information; verify the received session attribute information; and re-establish the wireless power reception from the wireless power transmitter at the first power level before establishing the wireless power reception at the second power level.

3. The wireless power receiver of claim 1, wherein, The memory is located in the wireless power transmitter.

4. The wireless power receiver of claim 1, wherein, The session attribute information comprises at least one component of information specific to the wireless power transfer session.

5. The wireless power receiver of claim 1, wherein, The session attribute information comprises authentication information.

6. The wireless power receiver of claim 1, wherein, The wireless power receiver is adapted to second establish a wireless power reception from the wireless power transmitter at the first power level before the act of receiving the session attribute information.

7. A wireless power receiving method, comprising: The method comprises: establishing a wireless power reception from a wireless power transmitter in a first operating mode; performing an authentication procedure with the wireless power transmitter after establishing the wireless power reception in the first operating mode; sending session attribute information to a memory, wherein the session attribute information comprises at least information related to the authentication procedure, the wireless power reception established by the wireless power receiver in the first operating mode being interrupted after sending the session attribute information to the memory; receiving the session attribute information from the memory at the wireless power receiver after the wireless power reception in the first operating mode is interrupted; and establishing a wireless power reception from the wireless power transmitter in a second operating mode after receiving the session attribute information from the memory.

8. The method of claim 7, wherein, The second operating mode comprises wireless power transfer at a higher power level than the first operating mode.

9. A wireless power transmitter, characterized by The wireless power transmitter is adapted to: establish wireless power transfer to a wireless power receiver at a first power level; perform an authentication procedure with the wireless power receiver after establishing the wireless power reception at the first power level; send session attribute information related to the authentication procedure to a memory if the authentication procedure is successfully completed; perform a foreign object detection procedure for a time period in which the wireless power reception at the first power level is interrupted at the wireless power receiver after sending the session attribute information to the memory; and retrieve at least a portion of the session attribute information from the memory after performing the foreign object detection procedure; transmit the at least a portion of the session attribute information retrieved from the memory to the wireless power receiver; and After transmitting at least a part of the session attribute information retrieved from the memory to the wireless power receiver, the wireless power transmission is established at a second power level higher than the first power level.

10. The wireless power transmitter of claim 9, wherein, The wireless power transmitter is further adapted to: establish the wireless power transmission to the wireless power receiver at the first power level a second time after performing the authentication procedure; and establish the wireless power transmission to the wireless power receiver at the second power level after establishing the wireless power transmission to the wireless power receiver at the first power level a second time.

11. The wireless power transmitter of claim 10, wherein, The wireless power transmitter is further adapted to subsequently perform a calibration procedure of the wireless power transmission with a foreign object present in the wireless power transmission area during the wireless power transmission at the second power level.

12. The wireless power transmitter of claim 9, wherein, The wireless power transmitter is further adapted to receive at least a part of the session attribute information from the wireless power receiver.

13. The wireless power transmitter of claim 9, wherein, Further comprising: sending a command to the wireless power receiver, the command causing the wireless power receiver to interrupt wireless power reception after performing the authentication procedure.

14. The wireless power transmitter of claim 9, wherein, The wireless power transmitter is further adapted to evaluate a Q-factor of a transmitting coil of the wireless power transmitter.

15. A wireless power transmission method, comprising: The method comprises: establishing the wireless power transmission to the wireless power receiver in a first operating mode, wherein the first operating mode comprises a wireless power transmission established at a first power level; performing an authentication procedure with the wireless power receiver after establishing the wireless power transmission at the first power level; sending session attribute information related to the authentication procedure to a memory if the authentication procedure is successfully completed; performing a foreign object detection procedure for a time in which wireless power reception of the wireless power receiver in the first operating mode is interrupted after sending the session attribute information to the memory; retrieving at least a part of the session attribute information from the memory after performing the foreign object detection procedure; transmitting at least a part of the session attribute information retrieved from the memory to the wireless power receiver; and establishing the wireless power transmission to the wireless power receiver in a second operating mode after transmitting at least a part of the session attribute information retrieved from the memory to the wireless power receiver, wherein the second operating mode comprises a wireless power transmission established at a second power level higher than the first power level.

16. The method of claim 15, wherein, Further comprising: sending session attribute information related to the authentication procedure to a memory before performing the foreign object detection procedure; and sending the session attribute information retrieved from the memory to the wireless power receiver after performing the foreign object detection procedure and before establishing the wireless power transmission to the wireless power receiver in the second operating mode.

17. The method of claim 15, wherein, Further comprising: establishing the wireless power transmission to the wireless power receiver at the first power level a second time after performing the authentication procedure.

18. The method of claim 17, wherein, Further comprising: After establishing the wireless power transmission to the wireless power receiver in the first operating mode for the second time, the wireless power transmission to the wireless power receiver is established in the second operating mode, wherein the session attribute information transmitted to the wireless power receiver allows the wireless power transmission to the wireless power receiver to be established in the second operating mode.

19. The method of claim 17, wherein, It is further included that during the wireless power transmission in the second operating mode subsequently, a calibration procedure for the wireless power transmission against foreign objects existing in the wireless power transmission area is performed.

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