Wireless power system with interference mitigation

Abstract

The present disclosure relates to a wireless power system with interference mitigation. The invention relates to a wireless power system having a wireless power transmission device and a wireless power receiving device. A clock signal can be provided to an inverter circuit in the wireless power transmission circuit at a power transmission frequency. The clock signal can cause transistors in the inverter circuit to turn on and off to generate an AC current signal through the wireless power transmission coil. The clock signal can be processed to mitigate electromagnetic interference in the system.

Description

[0001] This patent application claims priority to U.S. Patent Application No. 17 / 858,228, filed July 6, 2022, and U.S. Provisional Patent Application No. 63 / 233,528, filed August 16, 2021, the entire contents of which are incorporated herein by reference. Technical Field

[0002] This disclosure relates in general to power systems, and more specifically to wireless power systems for charging electronic devices. Background Technology

[0003] In a wireless charging system, a wireless power transmitting device transmits wireless power to a wireless power receiving device. The wireless power transmitting device uses a wireless power transmitting coil to transmit a wireless power signal to the wireless power receiving device. The wireless power receiving device has a coil and a rectifier circuit. The coil of the wireless power receiving device receives the AC wireless power signal from the wireless power transmitting device. The rectifier circuit converts the received signal into DC power. Summary of the Invention

[0004] A wireless power system includes a wireless power transmitting device and a wireless power receiving device. The wireless power transmitting device may include a coil and a wireless power transmitting circuit coupled to the coil. The wireless power transmitting circuit may be configured to transmit a wireless power signal using the coil. The wireless power receiving device may include a coil configured to receive a wireless power signal from the wireless power transmitting device and a rectifier circuit configured to convert the wireless power signal into DC power.

[0005] A clock signal can be provided to the inverter circuit in the wireless power transfer circuit according to the power transfer frequency. This clock signal causes transistors in the inverter circuit to turn on and off, generating an AC current signal (also according to the power transfer frequency) through the wireless power transfer coil. To mitigate electromagnetic interference (EMI) in the system, the clock signal used to control the inverter can be jittered. This effectively jitters the power transfer frequency of the wireless power transfer between the wireless power transfer device and the wireless power receiving device.

[0006] The wireless power transmission device may include jitter circuitry and clock modulation circuitry for implementing spread spectrum clocking technology (sometimes called clock jitter). In spread spectrum clocking, the edges of the clock waveform are intentionally modified so that the signal's spectrum is spread around the target frequency of the clock signal. This reduces EMI associated with the target frequency of the clock signal.

[0007] The jitter circuit in this wireless power transmission device can generate the optimal modulation waveform of the clock signal based on the real-time operating conditions of the wireless power system. This jitter circuit can take into account information such as the power status of the wireless power receiver, maximum frequency jitter constraints, occupied bandwidth constraints, parameters of the wireless power receiver, parameters of the wireless power transmission device, and / or clock waveforms. Attached Figure Description

[0008] Figure 1 This is a schematic diagram of an exemplary wireless power system based on the implementation plan.

[0009] Figure 2 This is a circuit diagram of an exemplary wireless power system based on the implementation plan.

[0010] Figure 3 This is a schematic diagram of an exemplary power transmission device including a jitter circuit, according to the implementation scheme.

[0011] Figure 4 It is a graph showing the power of the power transmission equipment as a function of frequency, according to the implementation plan.

[0012] Figure 5 It is a graph of an exemplary modulation waveform of a clock signal that can be used in a modulated power transmission device according to the implementation scheme.

[0013] Figure 6A It is a graph of an exemplary modulation waveform with a regular step shape according to the implementation scheme.

[0014] Figure 6B It is a graph of an exemplary modulation waveform with an irregular step shape according to the implementation scheme.

[0015] Figure 7 This is a schematic diagram of an exemplary system for testing the performance of different modulation waveforms, according to the implementation scheme.

[0016] Figure 8 This is a schematic diagram of an exemplary system for obtaining data that correlates power transmitter device parameters with power receiver device electrical status values, according to the implementation scheme.

[0017] Figure 9 This is a schematic diagram of an exemplary jitter circuit in a power transmission device for outputting an optimized modulation waveform for frequency jitter, according to an implementation scheme.

[0018] Figure 10 This is a flowchart illustrating the operation of a power transmission device for operating frequency jitter of a clock signal, according to the implementation scheme.

[0019] Figure 11This is a diagram illustrating an exemplary frequency shift keying (FSK) modulation bit coding scheme according to some implementations. Detailed Implementation

[0020] This invention discloses a wireless power system comprising a wireless power transmission device. The wireless power transmission device wirelessly transmits power to a wireless power receiving device. The wireless power transmission device may be a charging puck, charging pad, portable electronic device with power transmission capability, removable battery case with power transmission capability, or other power transmitter. The wireless power receiving device may be a device such as a cellular phone, tablet computer, laptop computer, removable battery case, electronic device accessory, wearable device such as a watch, or other electronic equipment. The wireless power receiving device uses power from the wireless power transmission device to power the receiving device and charge its internal battery.

[0021] Wireless power is transmitted from a wireless power transmitting device to a wireless power receiving device by using an inverter in the wireless power transmitting device to drive current through one or more wireless power transmitting coils. The wireless power receiving device has one or more wireless power receiving coils coupled to a rectifier circuit that converts the received wireless power signal into DC power.

[0022] Figure 1 An exemplary wireless power system (wireless charging system) is shown. For example... Figure 1 As shown, the wireless power system 8 includes wireless power transmission devices (such as wireless power transmission device 12) and wireless power receiving devices (such as wireless power receiving device 24). Wireless power transmission device 12 includes control circuitry 16. Wireless power receiving device 24 includes control circuitry 30. The control circuitry in system 8, such as control circuitry 16 and control circuitry 30, is used to control the operation of system 8. This control circuitry may include processing circuitry associated with a microprocessor, power management unit, baseband processor, digital signal processor, microcontroller, and / or application-specific integrated circuit (ASIC) having processing circuitry. The processing circuitry implements desired control and communication features in devices 12 and 24. For example, the processing circuitry may be used to process user input, process negotiation between devices 12 and 24, transmit and receive in-band and out-of-band data, perform measurements, estimate power loss, determine power transmission levels, and otherwise control the operation of system 8.

[0023] The control circuitry in system 8 can be configured to perform operations within system 8 using hardware (e.g., dedicated hardware or circuitry), firmware, and / or software. Software code and other data used to perform operations within system 8 are stored on a non-transitory computer-readable storage medium (e.g., a tangible computer-readable storage medium) within the control circuitry 8. Software code may sometimes be referred to as software, data, program instructions, commands, or code. The non-transitory computer-readable storage medium may include non-volatile memory such as non-volatile random access memory (NVRAM), one or more hard disk drives (e.g., disk drives or solid-state drives), one or more removable flash drives, or other removable media. Software stored on the non-transitory computer-readable storage medium can be executed on the processing circuitry of control circuitry 16 and / or 30. The processing circuitry may include an application-specific integrated circuit (ASIC) with processing circuitry, one or more microprocessors, a central processing unit (CPU), or other processing circuitry.

[0024] The power transfer device 12 can be a standalone power adapter (e.g., a wireless charging pad or charging stand including power adapter circuitry), a wireless charging pad or stand coupled to a power adapter or other equipment via a cable, a portable device, equipment already integrated into furniture, vehicles or other systems, a removable battery box, or other wireless power transfer equipment.

[0025] The power receiving device 24 may be a portable electronic device, such as a cellular phone, laptop computer, tablet computer, wearable device (such as earphones or a watch), a removable battery case for wireless charging of an electronic device, or other electronic equipment. The power transmitting device 12 may be coupled to a wall-mounted power outlet (e.g., an AC power source), may have a battery for power supply, and / or may have another power source. The power transmitting device 12 may have an AC-DC power converter, such as an AC-DC power converter 14, for converting AC power from the wall outlet or other power source into DC power. The DC power can be used to power the control circuitry 16. During operation, the controller in the control circuitry 16 uses the power transmitting circuitry 52 to transmit wireless power to the power receiving circuitry 54 of the device 24. The power transmitting circuitry 52 may have a switching circuit (e.g., an inverter circuitry 61 formed of transistors) that is turned on or off based on a control signal provided by the control circuitry 16 to form an AC current signal through one or more wireless power transmitting coils, such as the wireless power transmitting coil 36. These coil drive signals cause the coil 36 to transmit wireless power. Multiple coils 36 may be arranged as a planar coil array (e.g., in a configuration where device 12 is a wireless charging pad) or may be arranged to form a coil cluster (e.g., in a configuration where device 12 is a wireless charging stand). In some arrangements, device 12 (e.g., a charging pad, charging stand, portable electronic device such as a cellular phone, etc.) may have only a single coil. In other arrangements, the wireless charging device may have multiple coils (e.g., two or more coils, 2-4 coils, 5-10 coils, at least 10 coils, less than 25 coils, or other suitable number of coils).

[0026] When an AC current passes through one or more coils 36, an alternating electromagnetic (e.g., magnetic) field (wireless power signal 44) is generated. This alternating electromagnetic field is received by one or more corresponding receiver coils, such as one or more coils 48 in a power receiving device 24. Device 24 may have a single coil 48, at least two coils 48, at least three coils 48, at least four coils 48, or other suitable number of coils 48. When the alternating electromagnetic field is received by a coil 48, a corresponding alternating current is induced in the coil 48. The AC signal used to transmit wireless power can have any suitable frequency (e.g., 100-400 kHz, etc.). A rectifier circuit, such as rectifier circuit 50 (which includes rectifier components, such as synchronously rectified metal-oxide-semiconductor transistors arranged in a bridge network), converts the AC signal (the received AC signal associated with the electromagnetic signal 44) received from one or more coils 48 into a DC voltage signal for powering device 24.

[0027] The DC voltage generated by rectifier circuit 50 (sometimes referred to as the rectifier output voltage Vrect) can be used to charge batteries such as battery 58 and to power other components in device 24. For example, device 24 may include input-output device 56. Input-output device 56 may include input devices for acquiring user input and / or performing environmental measurements, and may include output devices for providing output to the user. As an example, input-output device 56 may include a display, speaker, camera, touch sensor, ambient light sensor, and other devices for collecting user input, performing sensor measurements, and / or providing output to the user. Device 12 may include input-output device 69 (e.g., any input-output device described in conjunction with input-output device 56).

[0028] Device 12 and / or device 24 can perform wireless communication using in-band or out-of-band communication. Device 12 may, for example, have a wireless transceiver circuit 40 that uses an antenna to wirelessly transmit out-of-band signals to device 24. The wireless transceiver circuit 40 can be used to wirelessly receive out-of-band signals from device 24 using an antenna. Device 24 may have a wireless transceiver circuit 46 that transmits out-of-band signals to device 12. The receiver circuit in wireless transceiver 46 can use an antenna to receive out-of-band signals from device 12. In-band transmission between devices 12 and 24 can be performed using coils 36 and 48. In one exemplary configuration, frequency shift keying (FSK) is used to transfer in-band data from device 12 to device 24, and amplitude shift keying (ASK) is used to transfer in-band data from device 24 to device 12. During these FSK and ASK transmissions, power can be wirelessly transferred from device 12 to device 24.

[0029] The control circuit 16 has a measurement circuit 41. The measurement circuit 41 may include a voltage measurement circuit (e.g., for measuring one or more voltages in the device 12, such as the coil voltage associated with the wireless power transmission coil) and / or a current measurement circuit (e.g., for measuring one or more currents, such as the wireless power transmission coil current).

[0030] The control circuit system 30 has a measurement circuit system 43. The measurement circuit 43 may include voltage measurement circuitry (e.g., for measuring one or more voltages in the device 24, such as the coil voltage associated with the wireless power transmission coil and / or the rectifier output voltage) and / or current measurement circuitry (e.g., for measuring one or more currents, such as the wireless power receiving coil current and / or the rectifier output current).

[0031] Figure 2 An exemplary wireless power circuit in system 8 is shown in an exemplary case where a wireless power transmitting device and a wireless power receiving device have been paired. Figure 2The wireless power circuitry includes a wireless power transmission circuit 52 in the wireless power transmission device 12 and a wireless power receiving circuit 54 in the wireless power receiving device 24. During operation, the wireless power signal 44 is transmitted by the wireless power transmission circuit 52 and received by the wireless power receiving circuit 54. Figure 2 The configuration includes a single transmitting coil 36 and a single receiving coil 48 (as an example).

[0032] like Figure 2 As shown, the wireless power transfer circuit 52 includes an inverter circuit 61. The inverter circuit (inverter) 61 can be used to provide signals to the coil 36. During wireless power transfer, the control circuit of device 12 provides a signal to the control input 82 of the inverter 61, which causes the inverter 61 to provide an AC drive signal to the coil 36. Figure 2 As shown, circuit components such as capacitor 70 may be coupled in series with coil 36. Measurement circuitry 41 in device 12 can measure the operating current and voltage in device 12. For example, voltage sensor 41A can be used to measure the coil voltage across coil 36, and current sensor 41B can be used to measure the coil current through coil 36. In other embodiments, the voltage across capacitor 70 is measured, and the current through the coil is inferred from this measurement.

[0033] When an AC current signal is supplied to coil 36, a corresponding AC electromagnetic signal (wireless power signal 44) is transmitted to a nearby coil, such as the exemplary coil 48 in the wireless power receiving circuit 54. This induces a corresponding AC current signal in coil 48. A capacitor, such as capacitor 72, may be connected in series with coil 48. Rectifier 50 receives AC current from coil 48 and generates corresponding DC power (e.g., DC voltage Vrect) at output terminal 76. This power can be used to power a load. Measurement circuit 43 in device 24 can measure the operating current and voltage in device 24. For example, voltage sensor 43A can measure Vrect (output voltage of rectifier 50), or a voltage sensor can measure the coil voltage on coil 48. Current sensor 43B can measure the rectifier output current of rectifier 50, or a current sensor can measure the current in coil 48.

[0034] If needed, some devices in the wireless power system 8 may have the ability to transmit and receive wireless power signals. As an example, a cellular phone or other portable electronic device may have a single coil that can be used to receive wireless power signals from a charging dock or other wireless power transmitting device and also to transmit wireless power to another wireless power device (e.g., another cellular phone, accessory, etc.). Devices capable of transmitting and receiving wireless power may have all the components of the wireless power transmitting device 12 and all the components of the wireless power receiving device 24 (e.g., power transmission circuit 52 and power receiving circuit 54 are included in a single device). However, the functions of wireless power transmission and wireless power reception are combined... Figure 1 and Figure 2 The description is the same. Therefore, although the examples in this article will focus on the case where a dedicated wireless power transmission device transfers charge to a dedicated wireless power receiving device, it should be understood that a device that both transmits and receives wireless power can be used instead of one or both devices.

[0035] Figure 3 This is a diagram of an exemplary power transmission device with jitter circuitry. As previously described, power transmission device 12 transmits an AC signal to power receiving device 24 at a power transmission frequency. The power transmission frequency can be between 100kHz and 400kHz or any other desired value. A clock signal can be provided to inverter circuit 61 at the power transmission frequency to cause transistors in the inverter circuit to turn on and off, generating an AC current signal (also at the power transmission frequency) through the wireless power transmission coil.

[0036] Consideration can be given to mitigating electromagnetic interference (EMI) in system 8. One way to mitigate EMI in system 8 is by using clock signal jitter in the inverter 61 of the control wireless power transmission circuit 52. This effectively jitters the power transmission frequency of the wireless power transfer between the power transmission device 12 and the power receiving device 24. For example... Figure 3 As shown, the power transmission device 12 may include a jitter circuit 84 and a clock modulation circuit 86 for performing frequency jitter during wireless power transfer operations. The jitter circuit 84 and the clock modulation circuit 86 may be considered as part of the power transfer frequency 52 and / or control circuit 16 in the device 12.

[0037] The jitter circuit 84 determines the modulation waveform 90 used to modulate the power transfer clock waveform 88. The clock waveform 88 may have the same frequency as the power transfer frequency. To mitigate EMI in system 8, the modulation waveform 90 may be applied to the clock waveform 88 by the clock modulation circuit 86. The clock modulation circuit 86 can use the modulation waveform 90 to frequency modulate the clock waveform 88. The modified clock signal 92 is then provided to the inverter 61 to generate an AC current signal for wireless power transfer.

[0038] In one possible arrangement, the jitter circuit 84 and the clock modulation circuit 86 can be used to implement spread spectrum clocking techniques (sometimes called clock jitter). In spread spectrum clocking, the edges of the clock waveform are intentionally modified so that the spectrum of the signal is spread around the target frequency of the clock signal. This reduces EMI associated with the target frequency of the clock signal.

[0039] Figure 4 This is a graph showing the power as a function of frequency, illustrating the effect of a spread spectrum clock. This can be obtained using a spectrum analyzer. Figure 4 The graph shows the power of a clock signal without a spread-spectrum clock (e.g., a regular square wave or sine wave at a constant frequency) as a function of frequency. As shown, without a spread-spectrum clock, the power peaks occur at each harmonic of the power transmission frequency. Figure 4 The diagram illustrates the Nth harmonic (e.g., the Nth multiple of the power transmission frequency), the (N+1)th harmonic, and the (N+2)th harmonic. At each harmonic, a narrow peak exists. The peak height can decrease slowly with increasing harmonic number.

[0040] Curve 96 illustrates the frequency of a clock signal after spread-spectrum clocking as a function of power. As shown, with a spread-spectrum clock, the power is lower at harmonic frequencies compared to the example without a spread-spectrum clock (e.g., curve 96 is lower than curve 94 at the Nth, N+1th, and N+2th harmonics). Between harmonic frequencies, curve 96 is higher than curve 94. Spread-spectrum clocks essentially distribute power (and corresponding EMI) more evenly across the entire spectrum (e.g., reduced power at harmonic frequencies and increased power at non-harmonic frequencies). Therefore, there is additional EMI at non-harmonic frequencies relative to the unmodulated clock signal (e.g., curve 96 is higher than curve 94 between harmonic frequencies). However, spread-spectrum clocks may ultimately be beneficial due to the reduction in EMI at harmonic frequencies.

[0041] Figure 5 This is a graph illustrating an exemplary modulation waveform that can be used for spread spectrum clocking. The modulation waveform is used to frequency modulate a carrier wave (e.g., the original clock waveform 88). The modulation waveform can have a corresponding frequency f. m And spread spectrum Δf. Frequency f m It is the frequency of the modulating wave at 90°. In other words, the modulating waveform is at a frequency f. m The waveform is scanned between two fixed frequencies, f1 and f2. The difference between frequencies f1 and f2 can sometimes be referred to as the spread spectrum or frequency offset (Δf) of the modulated waveform.

[0042] For example, consider a wireless power system that chooses a power transmission frequency of 140 kHz. The unmodified clock waveform 88 could be a square wave or a sine wave at 140 kHz. The modulation waveform 90 could have a spread spectrum of 10 kHz (Δf) and a frequency (f) of 15 kHz. m In this example, after frequency modulating waveform 88 with modulated waveform 90, the modified clock signal can scan back and forth between 135kHz and 145kHz at a frequency of 15kHz. In this example, the spread spectrum of the modulated waveform is uniformly distributed around the original frequency of 140kHz. This can be referred to as center spread. Alternatively, the frequency modulation can be spread downward (so that the modified clock signal scans back and forth between 130kHz and 140kHz) or spread upward (so that the modified clock signal scans back and forth between 140kHz and 150kHz).

[0043] Modulation waveform frequency f m There are many choices for frequency offset Δf and waveform shape. Frequency f m The frequencies can be greater than 0kHz, greater than 5kHz, greater than 10kHz, greater than 20kHz, greater than 30kHz, greater than 40kHz, greater than 50kHz, greater than 75kHz, greater than 100kHz, greater than 200kHz, less than 5kHz, less than 10kHz, less than 20kHz, less than 30kHz, less than 40kHz, less than 50kHz, less than 75kHz, less than 100kHz, less than 200kHz, etc. The frequency offset Δf can be greater than 0kHz, greater than 1kHz, greater than 3kHz, greater than 5kHz, greater than 10kHz, greater than 20kHz, greater than 30kHz, greater than 40kHz, greater than 50kHz, less than 1kHz, less than 3kHz, less than 5kHz, less than 10kHz, less than 20kHz, less than 30kHz, less than 40kHz, less than 50kHz, etc. Figure 5 In this example, the modulated waveform 90 has a triangular shape. This example is merely illustrative. Typically, the modulated waveform 90 can have any desired shape (e.g., a sine shape, a square shape, a sawtooth shape, a random shape, or a step shape that approximates any of the aforementioned shapes).

[0044] Figure 6A and Figure 6B This is a graph of an exemplary modulation waveform 90 in clock signal jitter that can be used for wireless power transmission. Figure 6A This is an example of a waveform with a step shape that follows a regular pattern (i.e., a regular step shape). Figure 6A In this pattern, the regular step shape approximates a sawtooth shape. The waveform increases with continuous steps between the minimum frequency f1 and the maximum frequency f2. Once f2 is reached, the waveform returns to f1 and repeats the pattern. Figure 6AIn the waveform, six frequencies are used (e.g., f1, f2, and four intermediate frequencies). The duration of the clock signal at each frequency (e.g., the width of each step) can be the same or approximately the same. Alternatively, the duration of the clock signal at each frequency can be varied if desired.

[0045] exist Figure 6B In the waveform 90, the modulation waveform has an irregular step shape. Similar to... Figure 6A , Figure 6B The waveform can have continuous steps between the minimum frequency f1 and the maximum frequency f2. Figure 6B In the waveform, six frequencies are used (e.g., f1, f2, and four intermediate frequencies). However, in Figure 6B In this waveform, the frequencies do not pass through in ascending (or descending) order. These steps occur in a random sequence, so the waveform does not need to increase continuously (e.g., Figure 6A (as shown) or decrease (e.g., with) Figure 6A (The opposite arrangement). This type of irregular waveform can be used to optimize the spread spectrum clock in the power transmission device 12. The random sequence can be repeated in each cycle, or it can be randomized after each cycle.

[0046] Waveforms with a stepped shape (such as...) Figure 6A The rules pattern or such Figure 6B The irregular pattern in the data can include any desired number of steps (e.g., three, four, five, six, seven, eight, more than eight, more than ten, etc.).

[0047] In summary, the modulated waveform can have multiple discrete steps. The order of these frequency steps and the duration of each frequency step can be optimized for EMI attenuation. The frequency steps can be ordered periodically or randomly. The optimal sequence can be found using exhaustive search techniques or optimization techniques using genetic algorithms and / or neural networks.

[0048] Figure 7 This is a diagram of an exemplary system that can be used to test the effectiveness of various jittered clock signals. As shown, the system includes a host device 100. The host device 100 may include computing equipment such as a personal computer, laptop computer, tablet computer, or handheld computing device. The host device 100 may include one or more networked computers. The host device 100 can maintain a results database, can be used to send commands to a clock modulation circuit 86, can be used to send commands to a spectrum analyzer 102, and can receive data from the spectrum analyzer 102, etc.

[0049] exist Figure 7During system operation, host device 100 can send multiple different clock waveforms and modulation waveforms to clock modulation circuit 86. Clock modulation circuit uses the modulation waveform to frequency modulate the clock waveform and outputs the corresponding modified clock signal to spectrum analyzer 102. Spectrum analyzer 102 measures the magnitude of the modified clock signal over a frequency range to measure power at different frequencies. Spectrum analyzer 102 can output data corresponding to a given modified clock signal to host device 100. Host device 100 can maintain a database of test results associated with different clock waveforms and modulation waveforms.

[0050] Figure 7 An example is shown of spectrum analyzer 102 testing a modified clock signal supplied directly from clock modulation circuit 86. This example is merely illustrative. If desired, spectrum analyzer 102 can alternatively test the AC drive signal supplied by inverter 61 to coil 36 based on the modified clock signal received by inverter 61. As yet another example, spectrum analyzer 102 can alternatively test the AC current signal induced in coil 48. Circuit simulation tools can be used to supplement or replace spectrum analyzer 102 to determine the performance of the modulated clock signal.

[0051] The operating parameters of the spectrum analyzer 102 (e.g., center frequency, range, scan time, resolution bandwidth (RBW), video bandwidth (VBW), attenuation / amplification, etc.) can be tuned to obtain the required spectrum data during test operations.

[0052] The host device 100 can perform various tests to optimize the modulation waveform, thereby minimizing EMI (maximum attenuation) at one or more frequencies of interest during wireless power delivery operations. For example, the power delivery device 12 and / or the power receiving device 24 may have design constraints with EMI requirements at certain frequencies. The host device 100 can optimize the modulation waveform to meet all these EMI requirements and minimize EMI as much as possible at the frequencies of interest.

[0053] The host device 100 can test many spread spectrum (Δf) values ​​of the modulated waveform. For example, in a series of tests, when using different spread spectrum values, the shape of the modulated waveform, the characteristics of the clock waveform, and the frequency f of the modulated waveform will change. m Other operating conditions can remain constant. The host device can gradually pass through the spread spectrum at regular intervals (e.g., x, 2x, 3x, 4x, etc.) within the required frequency range, and can test various irregular interval spread spectrums, etc.

[0054] Small changes in Δf can have a significant impact on attenuation at certain frequencies of interest. As an example, when the equation 2*Δf*N / f... clock(where Δf is the spread spectrum, N is the harmonic number of interest, and f) clock When the frequency of the clock signal is equal to or approximately equal to an even number (e.g., within 5%, within 3%, within 1%, etc.), the attenuation at a given Nth harmonic can be improved. clock Taking 360kHz as an example, and considering the need for attenuation at the 85th harmonic (30.6MHz), when Δf equals 8.5kHz (where 2*Δf*N / f) clock ≈4), 12.7kHz (where 2*Δf*N / f) clock ≈6) and 16.9kHz (where 2*Δf*N / f) clock When ≈8), the attenuation can have a local maximum. The learning from the spread spectrum test can be used to optimize the frequency jitter of the clock signal in subsequent operation of the power transmission device 12 (e.g., it can be used to develop the algorithm used by the jitter circuit 84 in the device 12 to produce the optimal modulation waveform for real-time conditions).

[0055] The host device 100 can also test many frequencies (f) of the modulated waveform. m For example, in a series of tests, the shape of the modulation waveform, the characteristics of the clock waveform, the modulation waveform spread spectrum Δf, and other operating conditions can remain constant when using different frequency values. The host device can gradually pass through frequencies at regular intervals (e.g., x, 2x, 3x, 4x, etc.) within the desired frequency range, and can test frequencies at various irregular intervals. In one example, a larger frequency (e.g., 45 kHz) can be compared to a lower frequency (e.g., 5 kHz, 10 kHz, 20 kHz) at a wavelength of interest (e.g., the 85th harmonic of 360 kHz) with more attenuation. The learning from frequency testing can be used to optimize the frequency jitter of the clock signal in subsequent operation of the power transmission device 12 (e.g., it can be used to develop algorithms used by the jitter circuit 84 in device 12 to generate the optimal modulation waveform for real-time conditions).

[0056] The host device 100 may also test many waveform shapes of the modulation waveform. For example, in a series of tests, when different modulation waveform shapes (e.g., sawtooth, triangular, sinusoidal, square, etc.) are used, the characteristics of the clock waveform, the frequency of the modulation waveform, the spread spectrum of the modulation waveform, and other operating conditions may be kept constant. The host device may test each shape to determine the magnitude of attenuation of each shape at one or more wavelengths of interest. In one example, a modulation waveform having a sawtooth shape may have more attenuation at the wavelength of interest (e.g., the 85th harmonic at 360 kHz) as compared to a modulation waveform having a triangular, sinusoidal, or square shape. The lessons learned from the waveform shape test may be used to optimize the frequency jitter of the clock signal in subsequent operations of the power transmission device 12 (e.g., may be used to develop the algorithm used by the jitter circuit 84 in the device 12 to generate the optimal modulation waveform for real-time conditions).

[0057] As described above, the modulation waveform may have multiple frequency steps (e.g., approximating a sawtooth shape or other desired shape or having a random order). For a modulation waveform having multiple frequency steps, the order in which the frequency steps are employed and the duration of each frequency step may be optimized. In one example, the host device 100 may perform an exhaustive search on the frequency step order given a plurality of constraints. For example, the order of the frequency steps may be tested for a constant clock frequency, modulation waveform frequency, number of steps, and spread between each step. Consider a 6-step curve that approximates a sawtooth shape including progressively increasing frequencies f1, f2, f3, f4, f5, and f6 (e.g., f1<f2<f3<f4<f5<f6) (similar to Figure 6A the curve in). The host device may provide the modulation waveform with these frequency steps in every possible permutation. For example, in a first test, the waveform may have frequency steps in the order of f1, f2, f3, f4, f5, and f6. In a second test, the waveform may have frequency steps in the order of f1, f2, f3, f4, f6, and f5. In a third test, the waveform may have frequency steps in the order of f1, f2, f3, f6, f4, and f5. In a fourth test, the waveform may have frequency steps of f1, f2, f3, f6, f5, and f4. This process may be repeated until every permutation of f1-f6 has been tested (e.g., an exhaustive search). The best candidate (e.g., the sequence that produces the most attenuation at one or more frequencies of interest) may be stored for future use in optimizing the frequency jitter of the clock signal in subsequent operations of the power transmission device 12 (e.g., may be used to develop the algorithm used by the jitter circuit 84 in the device 12 to generate the optimal modulation waveform for real-time conditions).

[0058] In summary, any desired characteristics of the modulated waveform (e.g., frequency, spread spectrum, waveform shape, frequency step sequence, frequency step duration, etc.) can be tested to determine their impact on attenuation at the frequency of interest and to find the optimal values ​​for these characteristics. Individual characteristics can be tested separately (as described above). However, this example is merely illustrative, and in general, combinations of characteristics can also be tested to find the optimal set of characteristics.

[0059] The effectiveness of the modulated waveform can also be tested under different operating conditions. During normal operating conditions (in the field), the power transmission device 12 (with clock modulation circuit 86) transmits power to the power receiving device 24, which has different load conditions. The load current of the power receiving device (e.g., the current provided by rectifier 50) can vary depending on the operating state of the power receiving device (e.g., which input-output components in the power receiving device are in use), the power state of the power receiving device, etc.

[0060] The waveform shape of the AC signal used for wireless power transfer can vary when operating under different load conditions. For example, the duty cycle, rise time, fall time, undershoot, and / or overshoot of the AC signal (provided by inverter 61 and coil 36 and / or received by coil 48) can vary depending on the load conditions of the wireless power receiving device. These shape variations can affect frequency jitter operation to mitigate EMI.

[0061] For example, when the state of charge is 20%, the power receiving device 24 can receive wireless power. Under these conditions, the AC signal may have a waveform shape that causes undesirable high EMI at frequency f1. A first jitter mode (optimized for EMI reduction at f1) may be optimal under these conditions. Subsequently, when the state of charge is 80%, the power receiving device 24 can receive wireless power. Under these conditions, the AC signal may have a waveform shape that causes undesirable high EMI at a frequency f2 different from f1. A second jitter mode (optimized for EMI reduction at f2) may be optimal under these conditions.

[0062] Furthermore, given the different waveforms produced by different load conditions under different state of charge, mitigating EMI at a given frequency of interest may require different optimal jitter modes for different state of charge. For example, when the state of charge is 20% and a corresponding first load current is present for the power receiving device, the power receiving device 24 can receive wireless power. The first jitter mode may be optimal for mitigating EMI at frequency f1 under these conditions. At a subsequent time, when the state of charge is 80% and a corresponding second load current is present for the power receiving device, the power receiving device 24 can receive wireless power. A second jitter mode, different from the first jitter mode, may be optimal for mitigating EMI at frequency f1 under these conditions.

[0063] For example, when the state of charge is 20%, the optimal spread spectrum for the modulation waveform used to mitigate EMI under f1 might be 10 kHz, while when the state of charge is 80%, the optimal spread spectrum might be 20 kHz. As another example, when the state of charge is 20%, the optimal modulation waveform for mitigating EMI under f1 could have a sawtooth shape, while when the state of charge is 80%, the optimal modulation waveform for mitigating EMI under f1 could have a triangular shape. These examples are merely illustrative and illustrate how modulation waveforms can have different optimal characteristics under different operating conditions.

[0064] To illustrate these differences, the above tests can also be performed under different operating conditions (e.g., using...). Figure 7 (System). For example, tests can be performed when the power receiving device has different power states, different corresponding load conditions, etc.

[0065] In one possible implementation, host device 100 may test modulation waveform characteristics and optimize the modulation waveform using only the direct test results. Alternatively, host device 100 may include a machine learning classifier that uses the test results to develop a machine learning algorithm to optimize the modulation waveform characteristics. The machine learning algorithm may output an optimized modulation waveform for a given set of constraints. The developed machine learning algorithm can then be used in jitter circuitry 84 in power transmission device 12.

[0066] As described above, the power state of the wireless power receiving device can affect the optimal frequency jitter pattern used for wireless power transmission. Therefore, it is desirable for the wireless power transmitting device 12 to know the power state of the wireless power receiving device 24 during wireless power transfer operations. When the power transmitting device 12 knows the power state of the wireless power receiving device 24, it can take the power state into account when optimizing the frequency jitter pattern.

[0067] In some cases, the wireless power transmitting device 12 may receive power status information directly from the wireless power receiving device 24. The wireless power receiving device 24 may report its power status to the wireless power transmitting device 12 at regular intervals, such as when the power status changes by a certain amount from a previously reported power status. Alternatively, the wireless power transmitting device 12 may intermittently query the wireless power receiving device 24 for its power status. In response to receiving a query, the wireless power receiving device 24 may report its power status to the wireless power transmitting device 12. These types of communication may be performed in-band (e.g., using coils 36 and 48 and simultaneously with power transmission) or out-of-band (e.g., using a separate communication antenna such as a Bluetooth antenna).

[0068] When the wireless power receiving device 24 reports its power status to the wireless power transmitting device 12, the control circuitry within the wireless power transmitting device 12 can decode the data received from the wireless power receiving device. The decoded data can represent the power status value reported by the wireless power receiving device. The wireless power transmitting device 12 can receive the data using a power transmission coil 36 (e.g., using in-band communication) or using an antenna formed separately from the coil (e.g., using out-of-band communication).

[0069] Directly reporting the power status is the most accurate way for the wireless power transmitting device 12 to determine the power status of the wireless power receiving device 24. However, some wireless charging communication protocols may not involve (or allow) reporting the power status from the power receiving device to the power transmitting device. In these cases, the power transmitting device 12 can measure parameters associated with the power transmitting coil 36 and use these measured parameters to estimate the power status of the receiver 24.

[0070] As previously described, the measurement circuit 41 in device 12 can measure the operating current and voltage in device 12. For example, voltage sensor 41A can be used to measure the coil voltage across coil 36, and current sensor 41B can be used to measure the coil current through coil 36 (see [reference]). Figure 2 Coil voltage and coil current can be two parameters used by the wireless power transmission device 12 to estimate the power status of the wireless power receiving device. Additional parameters such as duty cycle (e.g., the duty cycle or the clock signal generated by inverter 61 and the corresponding AC drive signal) can be used to estimate the power status of the wireless power receiving device. In summary, the control circuitry within the power transmission device 12 can determine the operating parameters of the wireless power transmission device 12 (e.g., coil voltage, coil current, etc.) to determine the power status information of the wireless power receiving device.

[0071] While in some implementations it is beneficial for the wireless transceiver to report information such as power status for feedback and power delivery control, the aforementioned technology does not require the transmission of personally identifiable information to function. Out of an abundance of caution, it should be noted that, to some extent, if any specific implementation of this charging technology involves the use of data communication between the wireless power transmitter and receiver, the transmitted information is used to control power delivery, and implementers should adhere to privacy policies and practices generally considered to meet or exceed industry or governmental requirements for protecting user privacy.

[0072] Figure 8 This is a diagram of a system used to determine the correlation between parameters of the power transmission device (such as duty cycle, coil voltage, and / or coil current) and the electrical state of the power receiving device 24. (See diagram for example.) Figure 8 As shown, host device 100 can be connected to wireless power transmission device 12 and wireless power receiving device 24. Host device 100 may include computing devices such as personal computers, laptop computers, tablet computers, or handheld computing devices. Host device 100 may include one or more networked computers. Host device 100 can maintain a results database, can be used to send commands to wireless power transmission device 12 and / or wireless power receiving device 24, and can receive data from wireless power transmission device 12 and / or wireless power receiving device 24, etc.

[0073] When the wireless power receiving device 24 is in various known power states, the host 100 can obtain data about the wireless power transmitting device 12. For example, wireless power transmitting device parameters (e.g., duty cycle, coil current, and coil voltage) can be measured during power transfer when the wireless power receiving device 24 has a first power state (e.g., 25%), when the wireless power receiving device 24 has a second power state different from the first power state (e.g., 50%), and when the wireless power receiving device 24 has a third power state different from the second power state (e.g., 75%). A machine learning classifier can use the test results to develop a machine learning algorithm that estimates the receiver's power state based on transmitter operating parameters. The developed machine learning algorithm can then be used in the jitter circuitry 84 in the power transmitting device 12.

[0074] Therefore, instead of using directly reported power status information, the wireless power transmission device 12 can use proxy information (e.g., transmitter duty cycle, transmitter coil current, transmitter coil voltage) to estimate the receiver's power status. For simplicity, both the directly reported receiver power status information and the proxy information of the receiver power status can be referred to herein as power status information (or receiver power status information). In other words, the power transmission device 12 can determine the receiver power status information using decoded data received directly from the power receiving device 24 (e.g., directly reported data) or using operating parameters of the power transmission device (e.g., proxy information).

[0075] Combination Figure 7 and Figure 8 The described test operation can be used to develop an optimization algorithm, which is used by the dithering circuit 84 to determine the optimal modulation waveform for a given set of conditions and constraints.

[0076] Figure 9 This is a diagram of the dithering circuit 84, showing the various inputs used by the dithering circuit to determine and optimize the modulation waveform. For example... Figure 9 As shown, the jitter circuit 84 can receive receiver power status information. As described above, the receiver power status information may include directly reported receiver power status information (e.g., power status reported by the power receiving device to the power transmitting device using in-band or out-of-band communication) or proxy information of the receiver power status (e.g., duty cycle, current, or voltage of the transmission coil 36 in device 12). Proxy information may include measured / known transmission device parameters and known (e.g., via in-band or out-of-band communication) receiving device parameters. When the jitter circuit 84 receives proxy information of the receiver power status, the jitter circuit 84 can use the proxy information to estimate the receiver power status and use the estimated power status for subsequent determination.

[0077] In addition to receiver battery status information, jitter circuit 84 can receive constraints such as maximum frequency jitter constraints. The maximum frequency jitter constraint can be fixed or can be updated over time (e.g., by control circuit 16).

[0078] The jitter circuit 84 can also consider occupied bandwidth limitations. Occupied bandwidth refers to the frequency range that includes most of the power of the modulated communication signal. Various communication standards impose limitations on the range of occupied bandwidth. These occupied bandwidth constraints can, for example, limit the value of the spread spectrum Δf of the modulated waveform output by the jitter circuit 84.

[0079] The jitter circuit 84 can also receive information about the wireless power receiving device 24 (RX parameters) and the wireless power transmitting device 12 (TX parameters). The receiver parameters received by the jitter circuit 84 may include the output voltage of the rectifier 50 (e.g., measured by the voltage sensor 43A), the voltage of the coil 48 in the power receiving device, and the rectifier output current of the rectifier 50 (e.g., measured by the voltage sensor 43A). Figure 2 The current is measured by the current sensor 43B in the wireless power transmitting device 12 or the current in the coil 48 in the power receiving device. This information can be received from the wireless power receiving device 24 at the wireless power transmitting device 12 using in-band or out-of-band communication. In some cases, the device 12 may also have prior knowledge of certain operating parameters of the device 24 (e.g., device type, coil characteristics, etc.), which the jitter circuit 84 uses to determine the optimized modulation waveform.

[0080] The parameters of the wireless power transmission device may include the voltage of coil 36 (e.g., measured by voltage sensor 41A), the current of coil 36 (e.g., measured by current sensor 41B), the duty cycle of inverter 61, etc.

[0081] The jitter circuit 84 can also receive information about the clock waveform (e.g., the target of the jitter operation). In some wireless charging systems, the power transmission frequency can be negotiated between devices 12 and 24 (e.g., the power transmission frequency is not fixed). As an example, when the first wireless power receiving device is near the power transmitting device, the power transmitting device 12 can transmit a wireless power signal at a frequency of 120 kHz. Subsequently, when the second wireless power receiving device is near the power transmitting device (or when the first wireless power receiving device is removed and placed near the power transmitting device again), the transmitting device 12 can transmit a wireless power signal at a frequency of 180 kHz. Therefore, the frequency (and shape) of the clock signal for a given power transmission session can be provided to the jitter circuit 84.

[0082] The jitter circuit 84 can also have a jitter sequence memory constraint, such as Figure 9 As shown. As an example, memory constraints can lead to a limitation on the number of frequency steps allowed in a stepped waveform shape.

[0083] Based on all these inputs, the jitter circuit 84 outputs an optimized modulation waveform. This optimized modulation waveform is then used by the clock modulation circuit 86 to jitter the clock waveform. The modified (jittered) clock signal is then provided to the inverter 61 to apply an AC drive signal to the coil 36 and transmit wireless power to the coil 48 in the wireless power receiving device 24. In other words, the power transmission frequency is jittered based on the optimized modulation waveform.

[0084] It should be understood that, if necessary, the jitter circuit 84 can provide the clock modulation circuit with characteristics of the modulated waveform. For example, the jitter circuit 84 provides the clock modulation circuit with the frequency, spread spectrum, and waveform shape for modulating the waveform. The clock modulation circuit 86 then uses the received characteristics characterizing the modulated waveform to modulate the clock waveform.

[0085] Figure 10 This is a flowchart illustrating exemplary operations involved in using a wireless power system according to the implementation scheme. As shown, in step 202, a jitter circuit, such as jitter circuit 84 (which can be considered part of control circuit 16 and / or power transmission circuit 52), can collect information. The collected information may include... Figure 9 Any inputs shown include wireless power receiver power status information, maximum frequency jitter constraints, occupied bandwidth constraints, wireless power receiver parameters, wireless power transmitter parameters, and clock waveforms. The received information can be obtained from sensors within the power transmitter 12 (e.g., Figure 2 The voltage sensor 41A or current sensor 41B in the transmission device can be received from the device 24 (e.g., using in-band communication or using out-of-band communication), or from the control circuit 16, or derived based on known information within the transmission device, etc.

[0086] In step 204, the control circuitry within the power transmission device 12 (e.g., jitter circuit 84) can use the collected information to determine the optimal modulation waveform for the current operating conditions. The optimal modulation waveform may have a corresponding frequency, spread spectrum, shape, etc. The jitter circuit 84 can use an algorithm to determine the optimal modulation waveform. If needed, machine learning techniques (e.g., neural networks, genetic algorithms, etc.) can be used to develop this algorithm. In some cases, the optimal waveform shape may be a randomized shape (e.g., having a combination of...). Figure 6A and Figure 6B The frequency step randomization sequence under discussion. The optimized jitter pattern can conform to any constraints received by the jitter circuit (e.g., occupied bandwidth constraints, jitter sequence memory constraints, maximum frequency jitter constraints, etc.).

[0087] As an example, the dithering circuit 84 can calculate the optimal modulation waveform based on current conditions. As another example, the dithering circuit 84 can have multiple modulation waveforms stored in a memory. Each modulation waveform can have a set of associated operating conditions. The dithering circuit 84 can select a modulation waveform from the memory that has associated operating conditions that best match the real-time operating conditions and also satisfy any real-time constraints.

[0088] Finally, in step 206, the optimized jitter mode (e.g., optimized modulation waveform) can be used to modulate the clock waveform (e.g., as shown in the image). Figure 3(As shown). The modified (jittered) clock signal is provided to inverter 61 to generate an AC signal using coil 36.

[0089] As previously described, Frequency Shift Keying (FSK) can be used to transfer in-band data from device 12 to device 24. During these FSK transmissions, power can be wirelessly transferred from device 12 to device 24. Frequency jitter (as described above) can also be performed during FSK transmissions.

[0090] During FSK modulation, the power transmission device 12 can operate at a first operating frequency (e.g., the unmodulated operating frequency f). op ) and the second operating frequency (e.g., the modulated operating frequency f) mod The operating frequency is switched between two frequencies. The difference between the two frequencies has polarity (represented by f). mod and f op The difference between them (whether positive or negative) and depth (representing f) mod and f op The magnitude of the difference between them.

[0091] Using an unmodulated operating frequency and a selected modulation operating frequency, a power transmitter can transmit bits using FSK modulation. The power transmitter can use a bit coding scheme to transmit bits using FSK modulation. In an exemplary example, the power transmitter can use a differential biphase coding scheme to modulate data bits using a power signal. This type of biphase coding scheme... Figure 11 As shown in the image.

[0092] Figure 11 The diagram shows the power signal frequency varying over time during FSK modulation. The power signal frequency is switched between frequencies f1 and f2 to encode bits. Frequencies f1 and f2 can be equal to f as previously described. op and f mod , where f op or f mod It is the higher of the two frequencies. As shown in the figure, in Figure 11 In the encoding scheme, the transition between the two frequencies occurs at the beginning of each bit. To encode a "one" bit, there are two transitions at the power signal frequency. To encode a "zero" bit, there is one transition at the power signal frequency.

[0093] For example, at t1, the operating frequency (power signal frequency) changes from f2 to f1. This indicates the start of encoding one bit. For a given number of power signal cycles (e.g., 256 cycles), the operating frequency can remain at f1, and then change back to f2 at t2. For a given number of cycles, the operating frequency remains at f2. At t3, the encoding of one bit is complete.

[0094] At t3, the operating frequency (power signal frequency) transitions from f2 to f1. This indicates the start of encoding the zero bit. For a given number of cycles (e.g., 512 cycles), the operating frequency can remain at f1, then transition back to f2 at t4. At t4, the encoding of the zero bit is complete.

[0095] In short, within the same time period (e.g., Figure 11 Each bit ("one" or "zero") is transmitted over a duration T2. ​​This time period is sometimes referred to as the bit period. For a zero bit, the operating frequency changes once at the beginning of the bit period and then remains the same throughout the entire bit period (T2). For a single bit, the operating frequency changes once at the beginning of the bit period and again midway through the bit transmission. Therefore, during the encoding of a single bit, the operating frequency remains equal for the same duration T1 at both frequencies f1 and f2, which is half of T2.

[0096] In use Figure 11 In a differential biphase coding scheme, during bit encoding, the frequency remains constant for a duration T2 or T1 before switching to another frequency. T1 is half of T2. These periods of constant frequency are called modulation states. Modulation states are used to transmit bits using a bit encoding scheme.

[0097] To prevent frequency jitter from affecting FSK communication, the jitter mode can be set to equal to... Figure 11 The power signal cycles are repeated after a factor (e.g., an exact divisor) of the number of power cycles in T1 (e.g., the length of the shortest modulation state in the coding scheme). For example, consider the example above, where T1 equals 256 cycles of the power signal. In this case, the total length of the repeated jitter pattern (e.g., Figure 3 , Figure 5 , Figure 6A or Figure 6B The period of the modulated waveform in the FSK communication can be any divisor of 256 periods (e.g., 1 period, 2 periods, 4 periods, 8 periods, 16 periods, 32 periods, 64 periods, 128 periods, or 256 periods). This ensures that the jitter pattern completes within a given modulation state and does not traverse multiple modulation states, which simplifies FSK demodulation for FSK communication receivers (e.g., power receiving device 24).

[0098] The concept of choosing the total length of the repeating jitter pattern as a factor equal to the total length of the shortest modulation state in the FSK coding scheme can be used for FSK communication from a wireless power transmitter to a wireless power receiver or for FSK communication from a wireless power receiver to a wireless power transmitter.

[0099] According to the implementation scheme, a wireless power transmission device configured to provide wireless power to a wireless power receiving device is provided. The wireless power transmission device includes a wireless power transmission circuit having an inverter and a wireless power transmission coil, and a control circuit. The inverter is configured to receive a clock signal and provide a corresponding AC drive signal to the wireless power transmission coil. The control circuit is configured to jitter the clock signal provided to the inverter based at least in part on the power status information of the wireless power receiving device.

[0100] According to another embodiment, frequency jittering of the clock signal includes: determining a modulation waveform based at least in part on the power status information of the wireless power receiving device, and using the modulation waveform to modulate the clock signal.

[0101] According to another embodiment, determining the modulated waveform includes determining the frequency, spread spectrum, and shape of the modulated waveform.

[0102] According to another embodiment, the control circuit is also configured to determine the power status information of the wireless power receiving device by determining the operating parameters of the wireless power transmitting device.

[0103] According to another embodiment, determining the operating parameters includes determining the voltage or current measurement of the wireless power transmission coil.

[0104] According to another embodiment, the control circuit is further configured to determine the power status information of the wireless power receiving device by decoding data received from the wireless power receiving device, the decoded data representing the power status value reported by the wireless power receiving device.

[0105] According to another embodiment, the control circuit uses the wireless power transmission coil to receive the data from the wireless power receiving device.

[0106] According to another embodiment, the wireless power transmission device includes an antenna formed separately from the wireless power transmission coil, and the control circuit uses the antenna to receive the data from the wireless power receiving device.

[0107] According to another embodiment, the control circuit is configured to jitter the clock signal at least in part based on occupied bandwidth constraints.

[0108] According to another embodiment, the control circuit is configured to jitter the clock signal at least in part based on a maximum frequency jitter constraint.

[0109] According to another embodiment, the control circuit is configured to jitter the clock signal at least in part based on the target power transmission frequency of the AC drive signal.

[0110] According to an embodiment, a non-transitory computer-readable storage medium is provided that stores one or more programs configured to be executed by one or more processors of a wireless power transmission device configured to provide wireless power to a wireless power receiving device. The wireless power transmission device includes a wireless power transmission circuit having an inverter and a wireless power transmission coil, and the inverter is configured to receive a clock signal and provide a corresponding AC drive signal to the wireless power transmission coil. The one or more programs include instructions for frequency jittering of the clock signal provided to the inverter, based at least in part on power status information of the wireless power receiving device.

[0111] According to another embodiment, frequency jittering of the clock signal includes: determining a modulation waveform based at least in part on the power status information of the wireless power receiving device, and using the modulation waveform to modulate the clock signal.

[0112] According to another embodiment, determining the modulated waveform includes determining the frequency, spread spectrum, and shape of the modulated waveform.

[0113] According to another embodiment, frequency jittering of the clock signal includes jittering the clock signal at least in part based on occupied bandwidth constraints.

[0114] According to another embodiment, frequency jittering of the clock signal includes jittering the clock signal at least in part based on a maximum frequency jitter constraint.

[0115] According to another embodiment, frequency jittering of the clock signal includes jittering the clock signal at least in part based on the target power transmission frequency of the AC drive signal.

[0116] According to another embodiment, the one or more procedures also include instructions for determining the power status information of the wireless power receiving device by determining the operating parameters of the wireless power transmitting device.

[0117] According to an embodiment, a method is provided for operating a wireless power transmission device configured to provide wireless power to a wireless power receiving device, the wireless power transmission device including a wireless power transmission circuit having an inverter and a wireless power transmission coil, and the inverter being configured to receive a clock signal and provide a corresponding AC drive signal to the wireless power transmission coil, the method including frequency jittering of the clock signal provided to the inverter based at least in part on the power status information of the wireless power receiving device.

[0118] According to another embodiment, frequency jittering of the clock signal includes: determining a modulation waveform based at least in part on the power status information of the wireless power receiving device, and using the modulation waveform to modulate the clock signal.

[0119] The foregoing description is merely illustrative and various modifications can be made to the described implementation scheme. The described implementation scheme can be implemented independently or in any combination.

Claims

1. A wireless power transmission device configured to provide wireless power to a wireless power receiving device, the wireless power transmission device comprising: A wireless power transmission circuit having an inverter and a wireless power transmission coil, wherein the inverter is configured to receive a clock signal and provide a corresponding AC drive signal to the wireless power transmission coil; as well as A control circuit configured to frequency jitter a clock signal provided to the inverter based at least in part on power status information from a wireless power receiving device, wherein frequency jittering of the clock signal includes: The modulation waveform is determined at least in part based on the power status information of the wireless power receiving device; as well as The clock signal is modulated using the modulation waveform.

2. The wireless power transmission device according to claim 1, wherein determining the modulation waveform includes determining the frequency, spread spectrum, and shape of the modulation waveform.

3. The wireless power transmission device according to claim 1, wherein the control circuit is further configured to determine the power status information of the wireless power receiving device by determining the operating parameters of the wireless power transmission device.

4. The wireless power transmission device according to claim 3, wherein determining the operating parameters includes determining the voltage or current measurement value of the wireless power transmission coil.

5. The wireless power transmission device of claim 1, wherein the control circuit is further configured to determine the power status information of the wireless power receiving device by decoding data received from the wireless power receiving device, wherein the decoded data represents a power status value reported by the wireless power receiving device.

6. The wireless power transmission device according to claim 5, wherein the control circuit uses the wireless power transmission coil to receive the data from the wireless power receiving device.

7. The wireless power transmission device according to claim 5, further comprising: An antenna formed separately from the wireless power transmission coil, wherein the control circuit uses the antenna to receive the data from the wireless power receiving device.

8. The wireless power transmission device of claim 1, wherein the control circuitry is configured to jitter the clock signal at least in part based on occupancy bandwidth constraints.

9. The wireless power transmission device of claim 1, wherein the control circuitry is configured to frequency jitter the clock signal at least in part based on a maximum frequency jitter constraint.

10. The wireless power transmission device of claim 1, wherein the control circuitry is configured to jitter the clock signal at least in part based on the target power transmission frequency of the AC drive signal.

11. A non-transitory computer-readable storage medium storing one or more programs configured to be executed by one or more processors of a wireless power transmission device, the wireless power transmission device being configured to provide wireless power to a wireless power receiving device, wherein the wireless power transmission device includes a wireless power transmission circuit having an inverter and a wireless power transmission coil, and wherein the inverter is configured to receive a clock signal and provide a corresponding AC drive signal to the wireless power transmission coil, the one or more programs including instructions for performing the following operations: The clock signal provided to the inverter is frequency jittered based at least in part on the power status information of the wireless power receiving device, wherein frequency jittering of the clock signal includes: The modulation waveform is determined at least in part based on the power status information of the wireless power receiving device; as well as The clock signal is modulated using the modulation waveform.

12. The non-transitory computer-readable storage medium of claim 11, wherein determining the modulated waveform includes determining the frequency, spread spectrum, and shape of the modulated waveform.

13. The non-transitory computer-readable storage medium of claim 11, wherein frequency jittering of the clock signal comprises jittering the clock signal at least in part based on occupied bandwidth constraints.

14. The non-transitory computer-readable storage medium of claim 11, wherein frequency jittering of the clock signal comprises jittering the clock signal at least in part based on a maximum frequency jitter constraint.

15. The non-transitory computer-readable storage medium of claim 11, wherein frequency jittering of the clock signal comprises jittering the clock signal at least in part based on the target power transmission frequency of the AC drive signal.

16. The non-transitory computer-readable storage medium of claim 11, wherein the one or more programs further include instructions for performing the following operations: The power status information of the wireless power receiving device is determined by determining the operating parameters of the wireless power transmission device.

17. A method of operating a wireless power transmission device, the wireless power transmission device being configured to provide wireless power to a wireless power receiving device, wherein the wireless power transmission device includes a wireless power transmission circuit having an inverter and a wireless power transmission coil, and wherein the inverter is configured to receive a clock signal and provide a corresponding AC drive signal to the wireless power transmission coil, the method comprising: The clock signal provided to the inverter is frequency jittered based at least in part on the power status information of the wireless power receiving device, wherein frequency jittering of the clock signal includes: The modulation waveform is determined at least in part based on the power status information of the wireless power receiving device; and The clock signal is modulated using the modulation waveform.

Images