Free-boost Class E amplifier

Abstract

Systems, methods, and apparatus for wireless charging are disclosed. The charging device includes an amplifier stage, a power switching stage, and a controller. The amplifier stage includes a choke receiving current from an input of the amplifier stage, a resonant network coupled to an output of the choke and providing an output current to a load, and a first switch configured to short the output of the choke to circuit ground when activated. The power switching stage can include a second switch configured to couple a power source to the input of the amplifier stage and operable to couple the input of the amplifier stage to circuit ground when activated. The controller can be configured to control operation of the first switch and the second switch according to a timing sequence that defines a period of the output current.

Description

[Technical Field]

[0001] Priority Claim This application claims priority and benefit from U.S. Provisional Patent Application No. 63 / 111,618, filed with the U.S.P.T. Office on 9 November 2020, U.S. Provisional Patent Application No. 63 / 252,871, filed with the U.S.P.T. Office on 6 October 2021, and U.S. Utility Patent Application No. 17 / 519,471, filed with the U.S.P.T. Office on 4 November 2021, the entire contents of these applications being incorporated herein by reference in whole and for all applicable purposes as fully described below.

[0002] The present invention relates to wireless charging of batteries, including batteries for mobile computing devices in general, and more specifically to the control of power transmitted to a rechargeable device. [Background technology]

[0003] Wireless charging systems have been developed to allow certain types of devices to charge their internal batteries without using physical charging connections. Devices that can utilize wireless charging include mobile devices and / or communication devices. Standards such as the Qi standard set by the Wireless Power Consortium allow devices manufactured by a first supplier to be wirelessly charged with a charger manufactured by a second supplier. Wireless charging standards tend to be optimized for devices with relatively simple configurations and provide basic charging functionality.

[0004] Improvements to wireless charging capabilities are necessary to accommodate increasingly complex mobile devices and evolving form factors. For example, improvements in power control in wireless power transmission are required. [Brief explanation of the drawing]

[0005] [Figure 1]Figure 1 shows an example of a charging cell that may be employed to provide a charging surface according to a particular embodiment disclosed herein. [Figure 2] Figure 2 shows the arrangement of power transmission areas provided on the charging surface of a wireless charging device configured according to a specific embodiment disclosed herein. [Figure 3] Figure 3 shows a wireless transmitter that may be provided on a charger base station according to a particular embodiment disclosed herein. [Figure 4] Figure 4 shows an example of a Class E amplifier. [Figure 5] Figure 5 shows a charging system comprising a power source constructed or configured according to a particular aspect of this disclosure. [Figure 6] Figure 6 is a timing diagram showing an example of the operation of the power supply shown in Figure 5. [Figure 7] Figure 7 is a timing diagram showing the second mode of operation of the power supply shown in Figure 5. [Figure 8] Figure 8 shows the low-power and high-power outputs of a power supply controlled using a pulse-width modulated signal according to a particular aspect of this disclosure. [Figure 9] Figure 9 shows a charging system comprising a power supply constructed or configured such that its operation does not involve a freewheeling phase, according to a particular aspect of the present disclosure. [Figure 10] Figure 10 is a timing diagram illustrating the operation of the power supply shown in Figure 9. [Figure 11] Figure 11 shows a charging system comprising a power supply configured with a switch-mode power supply and a differential Class E amplifier, according to a particular aspect of the present disclosure. [Figure 12] Figure 12 is a timing diagram illustrating the operation of the power supply shown in Figure 11. [Figure 13] Figure 13 shows a charging system including a tunable power supply built or configured according to a particular aspect of this disclosure. [Figure 14]Figure 14 shows an example of an apparatus employing a processing circuit that may be adapted according to a particular embodiment disclosed herein. [Figure 15] Figure 15 shows a power amplification method for a charging device according to a particular aspect of the present disclosure. [Modes for carrying out the invention]

[0006] The detailed descriptions provided below in relation to the attached drawings are intended to illustrate various configurations and are not intended to show only the configurations in which the concepts described herein can be implemented. The detailed descriptions include specific details to provide a complete understanding of the various concepts. However, it will be apparent to those skilled in the art that these concepts can be implemented without specific details. Sometimes, well-known structures and components are shown in block diagram form to avoid obscuring such concepts.

[0007] Next, specific embodiments of wireless charging systems are presented with reference to various devices and methods. These devices and methods are described in the following detailed description and are illustrated in the accompanying drawings by various blocks, modules, components, circuits, steps, processes, algorithms, etc. (collectively referred to as “elements”). These elements can be implemented using electronic hardware, computer software, or any combination thereof. Whether such elements are implemented as hardware or software depends on the specific application and the design constraints imposed on the overall system.

[0008] For example, an element, any part of an element, or any combination of elements may be implemented in a “processing system” comprising one or more processors. Examples of processors include microprocessors, microcontrollers, digital signal processors (DSPs), field-programmable gate arrays (FPGAs), programmable logic devices (PLDs), state machines, gate logic, discrete hardware circuits, and other suitable hardware configured to perform the various functions described throughout this disclosure. One or more processors in a processing system may execute software. Software is broadly interpreted to mean instructions, instruction sets, code, code segments, program code, programs, subprograms, software modules, applications, software applications, software packages, routines, subroutines, objects, executable files, execution threads, procedures, functions, etc., whether they are called software, firmware, middleware, microcode, or hardware description languages, etc. Software may reside in a processor-readable storage medium. Processor-readable storage media, also referred to herein as computer-readable media, may include, for example, magnetic storage devices (e.g., hard disks, floppy disks, magnetic strips), optical discs (e.g., compact discs (CDs), digital-purpose discs (DVDs)), smart cards, flash memory devices (e.g., cards, sticks, key drives), near-field wireless communication (NFC) tokens, random-access memory (RAM), read-only memory (ROM), programmable ROM (PROM), erasable PROM (EPROM), electrically erasable PROM (EEPROM), registers, removable disks, carriers, transmission lines, and any other media suitable for storing or transmitting software. Computer-readable media may reside within a processing system, be outside of a processing system, or be distributed across multiple entities including a processing system. Computer-readable media may also be embodied in computer program products.As an example, a computer program product may include computer-readable media within the packaging material. Those skilled in the art will recognize the best way to implement the functions described throughout this disclosure, depending on the specific application and the overall design constraints imposed on the entire system.

[0009] overview Certain aspects of this disclosure relate to systems, apparatus, and methods applicable to wireless charging devices. A charging cell may be configured by providing one or more induction coils on the surface of the charging device, and this charging cell may be excited to wirelessly charge one or more devices. The location of the device being charged can be detected by sensing techniques that correlate the location of the device with changes in physical properties centered on known locations on the surface of the charging device. Location sensing can be implemented using capacitive, resistive, inductive, contact, pressure, load, strain, and / or other suitable types of sensing.

[0010] In one embodiment of the present disclosure, the device comprises a battery charging power supply and at least one transmission coil.

[0011] In another aspect of this disclosure, the device comprises a battery charging power source and a plurality of charging cells arranged in a matrix, each of which may include one or more coils surrounding a power transmission area. The plurality of charging cells may also be arranged adjacent to each other on the surface of the device such that the power transmission areas of the charging cells in the plurality of charging cells do not overlap. Devices placed on the surface may receive power transmitted wirelessly through one or more charging cells. In some cases, the device may simply be referred to as a charging surface. Power can be transmitted wirelessly to powered devices placed anywhere on the surface of the device. Devices may have any defined size and / or shape and may be arranged regardless of any individual arrangements pre-specified or pre-enabled for charging. Multiple devices can be charged simultaneously on a single surface. The device can track the movement of one or more devices across the surface.

[0012] Certain embodiments disclosed herein relate to improved wireless charging technology. In various embodiments of this disclosure, a wireless charging device may comprise a switched-mode power supply and a Class E amplifier for amplifying power transmitted through one or more transmission coils. A method for amplifying power in a charging device includes the steps of: configuring a choke in an amplification stage to receive current from the input of the amplification stage; configuring a resonant network coupled to the output of the choke to supply output current to a load of the power amplifier; configuring a first switch to short-circuit the output of the choke to ground when turned on; configuring a power switching stage to couple a power supply to the input of the amplification stage; configuring a second switch in the power switching stage to couple the input of the amplification stage to ground when turned on; and controlling the operation of the first and second switches according to a timing sequence that defines the period of the output current. Control of the first switch may include configuring the first switch to be on during a first stage of a cycle, on during a second stage of a cycle following the first stage of the cycle, and off during a third stage of a cycle following the second stage of the cycle. Control of the second switch may include configuring the second switch to be off during the first stage of the cycle, on during the second stage of the cycle, and on during the third stage of the cycle.

[0013] Specific embodiments disclosed herein relate to circuits and methods for tuning a switched-mode power supply and a Class E amplifier of a wireless charger to accommodate load changes. Load changes result from, for example, changes in the number or arrangement of power transmission coils, or changes in the physical location of a powered device that affects electromagnetic coupling. In a first embodiment, a tunable power amplifier includes a first tuning element having a first tunable capacitor and a first tunable switch configured to couple the first tunable capacitor between circuit ground and the output of a choke. A controller may be configured to control the operation of the first tunable switch based on a feedback signal representing the inductance measured in the resonant network. In a second embodiment, a tunable power amplifier includes a second tuning element having a second tunable capacitor and a second tunable switch configured to connect the second tunable capacitor in parallel with the capacitance in the resonant network. A controller may be configured to control the operation of the second tunable switch based on a feedback signal representing the inductance measured in the resonant network.

[0014] rechargeable cell According to certain embodiments disclosed herein, a charging device is provided using charging cells arranged adjacent to the surface of the charging device. In one example, the charging cells are arranged or deployed according to a honeycomb package configuration. The charging cells can be implemented using one or more coils, each capable of inducing a magnetic field along an axis substantially orthogonal to the surface of the charging device and adjacent to the coil. In this specification, charging cell means a component having one or more coils configured to generate an electromagnetic field in which each coil is additive to the fields generated by other coils in the charging cell and is oriented along or adjacent to a common axis.

[0015] In some implementations, a charging cell includes coils stacked along a common axis and / or overlapping to contribute to an induced magnetic field substantially orthogonal to the surface of the charging device. In some embodiments, a charging cell includes coils positioned within a defined portion of the charging surface, and these coils contribute to an induced magnetic field substantially orthogonal to the portion of the charging surface corresponding to the charging cell. In some implementations, a charging cell may be configured by supplying an activation current to coils contained within a dynamically defined charging cell. For example, a charging device may include a stack of multiple coils positioned across the surface of the charging device, and this charging device may detect the position of the device to be charged and select several combinations of the coil stacks to provide charging cells adjacent to the device to be charged. In some embodiments, a charging cell may include a single coil or be characterized as a single coil. However, it should be understood that a charging cell may include multiple stacked coils and / or multiple adjacent coils or stacks of coils.

[0016] Figure 1 shows an example of a charging cell 100 that may be deployed or configured within or near the charging surface of a charging device. In this example, the charging cell 100 has a substantially hexagonal shape surrounding one or more coils 102 constructed with conductors, wires, or circuit board traces capable of receiving a current sufficient to generate an electromagnetic field in the power transfer region 104. In some embodiments, one or more coils 102 may have a substantially polygonal shape, including the hexagonal charging cell 100 illustrated in Figure 1. In some examples, the coils 102 may have other shapes. The shape of the coils 102 may be determined at least in part by the capabilities or limitations of the manufacturing technology, or to optimize the layout of the charging cell on a substrate 106 such as a printed circuit board. Each coil 102 may be mounted using wires, printed circuit board traces, and / or other connectors arranged in a spiral configuration. Each charging cell 100 may span two or more layers separated by an insulator or substrate 106 such that the coils 102 of different layers have a common axis 108.

[0017] Figure 2 shows an example of the arrangement of power transfer areas provided across the charging surface 200 of a charging device. Here, the charging device employs multiple layers of charging cells to provide a charging surface 200 which may be configured or operated according to specific embodiments disclosed herein. The charging surface 200 may consist of four layers of charging cells 202, 204, 206, and 208. In Figure 2, each power transfer area provided by the charging cells of the first layer charging cell 202 is labeled "L1", each power transfer area provided by the charging cells of the second layer charging cell 204 is labeled "L2", each power transfer area provided by the charging cells of the third layer charging cell 206 is labeled "L3", and each power transfer area provided by the charging cells of the fourth layer charging cell 208 is labeled "L4".

[0018] Figure 3 shows a wireless transmitter 300 that may be provided on a charger base station. In some embodiments, a controller 302 may receive a feedback signal that has been filtered by a filter circuit 308 or otherwise processed. The controller 302 may control the operation of a driver circuit 304 that supplies an alternating current (AC) signal to a resonant circuit 306 which includes a capacitor 312 and an inductor 314. The resonant circuit 306 is also referred herein as a tank circuit, an LC tank circuit, and / or an LC tank, and the voltage 316 measured at the LC node 310 of the resonant circuit 306 is also referred to as the tank voltage.

[0019] The wireless transmitter 300 can be used by a charging device to determine whether a compatible device has been placed on the surface of the charging device. For example, the charging device may determine that a compatible device has been placed on the surface of the charging device by transmitting an intermittent test signal (active ping) via the wireless transmitter 300, where the resonant circuit 306 can receive an encoded signal if the compatible device responds to the test signal. The charging device may be configured to excite one or more coils in at least one charging cell upon receiving a response signal specified by a standard, convention, manufacturer, or application. In some examples, the compatible device may respond to the ping by communicating a measured or estimated received signal strength so that the charging device can find the optimal charging cell to use for charging the compatible device.

[0020] Passive ping technology can use voltages or currents measured or observed at the LC node 310 to identify the presence of a receiving coil adjacent to the charging pad of a device adapted according to a specific embodiment disclosed herein. Many conventional wireless charger transmitters include circuits to measure voltages at the LC node 310 or currents in the network. These voltages and currents may be monitored for power regulation purposes or to support communication between devices. In the example shown in Figure 3, the voltage at the LC node 310 is monitored, but it is intended that currents may be monitored additionally or alternatively to support passive ping. The response of the resonant circuit 306 to passive ping (initial voltage V0) is the voltage (V) at the LC node 310. LC ) can be expressed as follows: TIFF0007837571000001.tif13170

[0021] According to certain embodiments disclosed herein, coils in one or more charging cells can be selectively excited to provide an optimal electromagnetic field for charging a compatible device. In some embodiments, coils are assigned to charging cells, and some charging cells may overlap with others. In the latter case, the optimal charging setting can be selected on a per-charging-cell basis. In other embodiments, the charging cells may be defined based on the placement of the device to be charged on the surface of the charging device. In such other embodiments, the combination of coils excited in each charging event may differ. In some implementation examples, the charging device may include a driver circuit that can select one or more cells and / or one or more predetermined charging cells to be excited during a charging event.

[0022] Power amplification in charging devices One aspect of this disclosure relates to the use of a Class E amplifier in a driver circuit that supplies charging current to a transmission coil of a wireless charging device. The Class E amplifier operates as a tunable switching power amplifier and is characterized by high-efficiency operation. Figure 4 shows an example of a Class E amplifier 400. A transistor switch is coupled to a load 410 via a resonant network 406. In one embodiment, the transistor switch may be implemented using a metal-oxide-semiconductor field-effect transistor (MOSFET), such as an N-channel MOSFET (NFET) 402 shown in Figure 4. In the illustrated example, the drain of the NFET 402 is coupled to a DC power supply via a choke 404. The choke 404 may be implemented using an inductor and may be configured to allow DC and low-frequency alternating current (AC) to pass through but to block high-frequency currents. The NFET 402 is switched at an operating frequency corresponding to the resonant frequency of the resonant network 406. The choke 404 may be selected based on its ability to block current cycles at the operating frequency. When NFET402 is turned on, it provides a low-impedance path to ground for the input to the resonant network 406. When NFET402 is turned off, the input to the resonant circuit receives current from the DC power supply via the choke 404.

[0023] Timing diagram 420 shows the operation of the Class E amplifier 400 at the resonant frequency of the resonant network 406. The resonant frequency of the resonant network 406 may be affected or modified by the drain capacitance 408 of the NFET 402. A control signal 418 supplied to the gate of the NFET 402 switches at a frequency corresponding to the resonant frequency of the resonant network 406. When the NFET 402 is switched on, current 416 flows through the drain of the NFET 402. When the NFET 402 is switched off, no current 416 flows through the drain of the NFET 402, or only a very low leakage current flows. When the NFET 402 is switched off, the drain voltage 414 begins to rise at a rate determined by the reactive component of the amplifier. Subsequently, the drain voltage 414 decreases from the peak voltage, and the NFET 402 is switched on at time 422 when the drain voltage 414 approaches zero volts. The output voltage 412 oscillates at the fundamental frequency corresponding to the resonant frequency of the resonant network 406. The Class E amplifier 400 achieves high operating efficiency by turning on the NFET 402 when the current is zero and turning off the NFET 402 when the voltage is zero, thereby minimizing power loss in the switch.

[0024] Wireless chargers are intended to charge various rechargeable devices, and the impedance to the wireless transmitter may vary depending on the location and other factors of each rechargeable device. Wireless chargers may need to adjust their output power level to accommodate the operating conditions of the rechargeable devices, such as the battery temperature. Controlling the output power level of a charger typically requires additional control loops and filter components. Output control of a Class E amplifier may be provided as a buck / boost circuit for front-end DC power supply control. A buck / boost circuit can operate as a DC-DC converter that can provide an output voltage that is increased or decreased in magnitude relative to the input voltage. A buck / boost circuit operates as a buck converter when it obtains an output voltage by decreasing the input voltage. A buck / boost circuit operates as a boost converter when it obtains an output voltage by increasing the input voltage.

[0025] Many systems use a pre-regulating switched-mode power supply (SMPS) to supply DC power to the wireless transmitter. The SMPS and associated power control circuit typically operate at frequencies much higher than the resonant frequency of the Class E amplifier. High-frequency SMPS operation can degrade the efficiency of wireless chargers and introduce or increase unwanted harmonic components in magnetic components. Furthermore, SMPS can operate at frequencies four to ten times the fundamental frequency of the power amplifier's transmission output, and the difference in operating frequencies between the SMPS and the amplifier necessitates the use of more complex and costly power control circuits.

[0026] Certain aspects of this disclosure provide a power supply topology and architecture comprising a switched-mode power supply and a Class-E amplifier configured to provide output power control with low harmonics at the output load. When incorporated into a wireless charging device, the power supply topology may be referred to as a free-boost topology.

[0027] Figure 5 shows a charging system 500 comprising a power supply unit 510 constructed or configured according to a particular aspect of the present disclosure. The power supply 510 comprises a switched-mode power supply (SMPS 504) coupled to a power supply 502 and a Class E amplifier 506. The power supply 510 is shown in Figure 5. C The peak current of the choke, indicated as 518, can be controlled synchronously. Controller 530 controls the half-bridge switch (SW) in SMPS504. H 512, SW L Control signals 522 and 524 are supplied to 514), and the Class E switch (SW) in the Class E amplifier 506 is supplied. E A control signal 526 is provided to 516). As an example, SW H 512, SW L 514, SW E516 is implemented using an NFET. Control signals 522, 524, 526 can be synchronized so that SMPS 504 can operate at the same switching frequency as class-E amplifier 506. One or more duty cycles of control signals 522, 524, 526 can be selected to control buck or boost operation at power supply 510.

[0028] The configurations of SMPS 504 and class-E amplifier 506 can maintain the high-efficiency levels associated with class-E amplifier 506, and C inductors (L T 528) in 518 and resonant output network 520 can remove or limit high-frequency harmonics. In one example, L T 528 includes a transmission coil used to transmit power to a rechargeable device, and load 508 of power supply 510 incorporates or corresponds to a reflected load presented by the rechargeable device. Reduction of high-frequency harmonics can improve the effectiveness of charging system 500 and limit electromagnetic interference. Power supply 510 can be implemented with fewer components than an equivalent conventional power control type power supply.

[0029] Controller 530 can be implemented using a state machine, sequencer, or delay loop configured to generate a repeating sequence of pulses. The configurations of SMPS 504 and class-E amplifier 506 enable linear control of the output power and simplify the control of SMPS 504 and class-E amplifier 506. In some embodiments, controller 530 can be configured to control the output power on a per-cycle basis.

[0030] Figure 6 is a timing diagram 600 showing a first operating mode of the power supply 510 shown in Figure 5. Three phases 604, 606, and 608 can be defined within each cycle 602 of the output current 538. The three phases 604, 606, and 608 correspond to three stages of power generation. In this first example, cycle 602 includes a “freewheel” phase. In some examples, one or more stages of power generation may correspond to the angular phase of cycle 602 of the output current 538, but such correspondence is not expected or required. In some embodiments, the output current 538 represents power transmission to the load 508.

[0031] In the first phase 604, power supply 510 is L C Current 536 is constructed in 518. Controller 530, in the first phase 604, SW H 512 and SW E Turn on 516, SW L Configure control signals 522, 524, and 526 to turn off 514. Switching in this configuration will result in L C The current flowing through 518, 536, is Vin532 and L C It increases at a rate proportional to the ratio of 518. C The rate of increase of the current 536 from 518 can be expressed as follows: TIFF0007837571000002.tif12170 Here, k represents the scaling factor, which may not be 1.

[0032] In the second phase 606, the controller 530 switches L 514 and SW E Turn on 516, SW H Configure control signals 522, 524, and 526 to turn off 512. C Current 536 for 518 is SW L 514 and SW E It starts freewheeling through 516.

[0033] The third phase 608 can be called the power supply phase. Controller 530 switches LTurn on 514, SW H Turn 512 off, SW E Configure control signals 522, 524, and 526 to turn off 516. C The current 536 in 518 begins to decrease as it starts to flow into the resonant output network 520 that provides the output of the power supply 510. E 516 voltage (V SWE 534) rises to a peak that is a multiple of Vin532, and then transitions smoothly back to zero.

[0034] V SWE When 534 returns to zero volts or crosses a threshold close to zero volts, cycle 602 is repeated to begin a new first phase 614. A charging system 500 configured according to a particular aspect of this disclosure can provide a flow of pure sinusoidal output current 538 through a load 508, and high-frequency harmonics are transmitted to the L of the resonant output network 520. C 518 core and / or inductor (L T It may be limited or eliminated in 528).

[0035] The switching frequency of the charging system 500 may be configured or defined based on the output AC load requirements. E The on-time of 516 may be defined by the resonant output network 520 or tuned using any suitable Class E tuning technique. H 512 and SW L The ON time of 514 may be configured based on the level of output power required by the load. In one example, the level of output power required by the load is determined from the charging settings used to wirelessly charge a rechargeable device. The charging settings may be defined by a protocol or negotiation between the rechargeable device and the charging system 500. In one example, the charging system 500 may be a multi-device or multi-coil charger, and the charging settings may specify the level of output power supplied to one or more transmission coils. H 512 and SW LAs the duty cycle of the control signals 522 and 524 supplied to operate 514 increases toward 100%, the output power supplied to the load increases. In some embodiments, SW H The control signal 522 provided to 512 is SW L The control signal 524 provided to 514 may be the reverse of this.

[0036] SW H 512 and SW L The low duty cycle of the control signals 522, 524 provided to operate 514 is when power supply 510 is in the first phase 604. C Limit the peak current of 518. L when transitioning to the third phase 608. C By lowering the peak current of the 518, the total power transmitted to the load can be limited. Duty cycle control allows for output power control without changing the Class E switching time.

[0037] Figure 7 is a timing diagram 700 showing a second operating mode of the power supply unit 510 shown in Figure 5. Three phases 704, 706, and 708 can be defined within each cycle 702 of the output current 538. The three phases 704, 706, and 708 define three stages of power generation and do not include a "freewheel" phase. In some examples, one or more stages or phases of power generation may correspond to the angular phase of one cycle 702 of the output current 538, but such correspondence is not expected or required. In one example, the output current 538 represents power transmission to the load 508. In this operating mode, SW H The ON switching of 512 is delayed for a predetermined or set time before the power supply phase. This delay time can be used to control the output power. If the delay time is long, L C The current stored in 518 decreases.

[0038] In the first phase 704, power supply 510 is L C Current 536 is constructed in 518. Controller 530 is SW H 512 and SWE Turn on 516, SW L Configure control signals 522, 524, and 526 to turn off 514. Switching in this configuration will result in L C The current flowing through 518, 536, is Vin532 and L C It increases at a rate proportional to the ratio of 518.

[0039] The second phase 706 can be called the power supply phase. Controller 530 switches L Turn on 514, SW H Turn 512 off, SW E Configure control signals 522, 524, and 526 to turn off 516. C The current 536 in 518 begins to decrease as it starts to flow into the resonant output network 520 that provides the output of the power supply 510. E 516 voltage (V SWE 534) rises to a peak that is a multiple of Vin532, and then transitions smoothly back to zero.

[0040] In a third phase 708, which can be called a delay phase, the controller 530 performs SW L 514 and SW E Turn on 516, SW H Configure control signals 522, 524, and 526 to turn off 512. The switch configuration is maintained for the duration of the delay.

[0041] The switching frequency of the charging system 500 may be configured or defined based on the output AC load requirements. E The ON time of 516 may be defined by the resonant output network 520 or may be tuned using any suitable Class E tuning technique. The duration of the delay of the third phase 708 and / or SW HThe ON time of 512 may be set based on the level of output power required to be supplied to the load 508. In one example, the level of output power required to be supplied to the load 508 is determined from the charging configuration used to wirelessly charge a rechargeable device. The charging setting may be defined by a protocol or negotiation between the rechargeable device and the charging system 500. In one example, the charging system 500 may be a multi-device charger, and the charging setting may specify the level of output power supplied to one or more transmission coils. H 512 and SW L As the duty cycle of the control signals 522, 524 supplied to operate 514 increases toward 100%, the output power supplied to the load 508 increases. In some embodiments, SW H The control signal 522 provided to 512 is SW L The control signal 524 provided to 514 may be the reverse of this.

[0042] SW H 512 and SW L The low duty cycle of the control signals 522, 524 provided to operate 514 is when power supply 510 is in the first phase 704. C Limit the peak current of 518. L when transitioning to the third phase 708. C By lowering the peak current of 518, the total power transmitted to load 508 can be limited. Duty cycle control allows for output power control without changing the Class E switching time.

[0043] A charging system 500 configured without a freewheeling phase according to a particular aspect of this disclosure can reduce or eliminate losses due to the equivalent series resistance (ESR) of Lc518. ESR represents the series resistance of a non-ideal capacitor or inductor and may be measured or defined with respect to the expected operating frequency of the circuit containing the capacitor or inductor. By eliminating the freewheeling phase, when operating in discontinuous mode, SW L514 is optional and SW when operating in continuous mode. L 514 can be replaced with a diode in some cases.

[0044] One aspect of this disclosure relates to the control of power output in a charging system using a switched-mode power supply and a Class E amplifier. For ease of explanation, the charging system 500 in Figure 5, which includes an SMPS 504 and a Class E amplifier 506, is referenced. In one aspect, the charging system 500 may be adapted, configured, or controlled to have a high dynamic control range of output power. In another aspect, the charging system 500 includes a half-bridge switch (SW H 512 and SW L 514) and Class E switches (SW E 516) can be adapted, configured, or controlled to maintain zero-voltage switching (ZVS) operation. In ZVS operation, the voltage drop across the transistor switch is zero before the transistor turns on or off. ZVS can reduce losses by preventing voltage and current overlap during switching.

[0045] The power output of the charging system 500 operating in accordance with a particular aspect of this disclosure is a half-bridge switch (SW H 512 and SW L This can be achieved by controlling or configuring the duty cycle for 514). H 512 and SW L By pulse width modulating the control signals 522 and 524 that control the switching of 514, SW H 512 and SW L It can control a duty cycle of 514.

[0046] As an example, SW at 100% of the cycle L Turn on 514 and switch at 100% of the cycle. H Turning off 512 gives a 0% duty cycle that commands the minimum output. In another example, SW at 100% of the cycle. L Turn off 514 and switch at 100% of the cycle. HWhen 512 is turned on, a 100% duty cycle commanding the maximum output is obtained. Even if the control signals 522, 524 are pulse-width modulated, the duty cycle of SW E 516 (class-E switch) may remain unchanged.

[0047] According to a particular aspect, the phases of the pulse-width modulation control signals 522, 524 may be aligned with the phase of the control signal 526 supplied to the class-E switch (SW E 516) within the class-E amplifier 506. As an example, by centering the off-time of the PWM signal on the control signal 526 supplied to SW E 516, zero-voltage switching (ZVS) operation can be maintained for the half-bridge switches (SW H 512 and SW L 514).

[0048] FIG. 8 shows a timing diagram 800 at low power output and a timing diagram 810 at high power output when the control signals 522, 524 are pulse-width modulated. In the first timing diagram 800, the control signal 522 coupled to SW H 512 is shown. For the purposes of this description, it may be assumed that the control signal 524 coupled to SW L 514 is the inversion of the control signal 522. In this first timing diagram 800, the control signals 522, 524 turn SW H 512 off for a longer percentage than turning it on in each cycle, and further turn SW L 514 on for a longer percentage than turning it off in each cycle. The centers 802, 804 of each half-cycle of the control signal 526 supplied to the class-E switch (SW E 516) are aligned with the centers of the corresponding half-cycles of the control signals 522, 524.

[0049] In the second timing diagram 800, the control signal 522 coupled to SW H 512 is shown. For the purposes of this description, it may be assumed that the control signal 524 coupled to SW L 514 is the inversion of the control signal 522. In this second timing diagram 800, the control signals 522, 524...H Turn 512 off for a shorter period than it is turned on in each cycle, and further SW L Turn on 514 for a shorter period than it is turned off in each cycle. Class E switch (SW E The centers 812 and 814 of each half-cycle of the control signal 526 supplied to 516) are aligned with the centers of the corresponding half-cycles of the control signals 522 and 524.

[0050] The phase of pulse-width modulated control signals 522 and 524, and the Class E switch (SW) of Class E amplifier 506. E By matching the phase of the control signal 526 supplied to 516), it is possible to ensure that the switching transition of the half-bridge occurs with the appropriate current polarity. When the pulse width modulated control signals 522 and 524 are centered, L C It is guaranteed that the transition will occur around the zero crossing of current 518 and 536. The switch output voltage measured at the half-bridge switch node 540 ( VSW The falling edge of ) is L C The current 536 in 518 is positive and occurs when it flows out from the half-bridge switch node 540 in the direction of the load. The rising edge of Vsw is L C The current 536 in 518 is negative and occurs when it flows into the half-bridge switch node 540. C The new cycle of 518 current 536 is V SWE It starts with a peak at (534).

[0051] A charging system 500 constructed or configured in accordance with a particular aspect of this disclosure includes an E-class switch (SW E 516) may include a Class E amplifier 506 that can be controlled using a pulse-width modulated control signal 526. The phase of the control signal 526 is controlled by a half-bridge switch (SW H 512 and SW LThe pulse width modulated control signals 522, 524 coupled to 514) can be phase-aligned or locked. The Class E section control signal 526 may often be configured with a 50% duty cycle. Several variations in the duty cycle may be provided to accommodate various configurations of the resonant output network 520. Different configurations may be associated with different charge settings that vary the number of power transmission coils.

[0052] Under nominal or ideal operating conditions, V SWE When 534 becomes zero, SW E 516 turns ON. In some embodiments, the OFF time is overestimated, SW E If it is beneficial to allow 516 to be off for a longer period than required or specified, SWE 534 does not need to be used to directly control the transition. For example, SW E One or more FETs included in 516 are SW E 516 early (V SWE When 534 turns on (before it drops to zero), it is hard-switched and the voltage from drain to source can be short-circuited to the FET. In another example, SW E When the FET in the 516 turns off with a delay, conduction losses increase, and the FET's body diode begins to conduct until the FET turns back on. The FET continues to operate in ZVS mode, but slightly higher conduction losses occur during the period when the diode needs to carry the load current. This condition results in reduced overall losses and electromagnetic compatibility.

[0053] E-class switch (SW) E The pulse-width modulated control signal 526 provided to control 516) may be configured using feedback or via a lookup table. In one example, the controller may be configured to use voltage sensing or current sensing to determine the configuration of the resonant output network 520 and to adjust the pulse-width modulation applied to the control signal 526 to obtain a desired or optimal performance level. Voltage or current sensing is L TIt can be used to provide a feedback signal representing a voltage in the resonant output network 520, such as a voltage measured across 528, or a current flowing through the resonant output network 520, equivalent to or so represented by the output current 538. In some examples, if voltage or current sensing is unavailable, the controller may use a lookup table to find the pulse width modulation to be applied to the control signal 526 for the currently operating charge setting. In one example, the lookup table can cross-reference the Class E duty cycle with the inductance and capacitance of the resonant output network 520. The inductance may be calculated or defined based on the amount and / or type of transmission coil used to transmit power to the rechargeable device. The type of transmission coil may be related to the location and manufacturing method of the transmission coil.

[0054] Figure 9 shows a charging system 900 comprising a power supply 910 constructed or configured such that its operation does not involve a freewheeling phase, according to a particular aspect of the present disclosure. The power supply 910 comprises a switched-mode power supply (SMPS904) coupled to a power supply 902 and a Class E amplifier 906. The power supply 910 is shown in Figure 9. C The peak current of the choke, indicated as 918, can be controlled synchronously. Controller 930 controls the half-bridge switch (SW) within SMPS904. H A control signal 922 is supplied to 912), and the Class E switch (SW) in the Class E amplifier 906 is supplied. E The control signal 926 is supplied to 916). Control signals 922 and 926 can be synchronized so that the SMPS 904 operates at the same switching frequency as the Class E amplifier 906. Diode 914 supplies the control signal 926 to the second switch (i.e., SW) of the power supply unit 510 shown in Figure 5. L It replaces 514).

[0055] The configuration of the SMPS904 and the Class E amplifier 906 allows for the maintenance of the high efficiency level associated with the Class E amplifier 906, L C Inductor (L) of 918 and resonant output network 920 THigh-frequency harmonics in 928) can be removed or limited. For example, L T 928 includes a transmission coil used to transmit power to the rechargeable device. The load 908 of the power supply 910 corresponds to or incorporates the reflective load provided by the rechargeable device. Reduction of high-frequency harmonics improves the effectiveness of the charging system 900 and limits electromagnetic interference. The power supply 910 can be implemented with fewer components than comparable conventional power-controlled power supplies.

[0056] The controller 930 may be implemented using a state machine, sequencer, or delay loop configured to generate a repeating sequence of pulses. The configuration of the SMPS 904 and the Class E amplifier 906 allows for linear control of the output power and simplifies the control of the SMPS 904 and the Class E amplifier 906. In some embodiments, the controller 930 may be configured to control the output power on a cycle-by-cycle basis.

[0057] Figure 10 is a timing diagram 1000 illustrating the operation of the power supply 910 shown in Figure 9. Three phases 1004, 1006, and 1008 can be defined within each cycle 1002 of the output current 938. The three phases 1004, 1006, and 1008 define three stages of power generation and do not include a "freewheel" phase. In some examples, one or more stages of power generation may correspond to the angular phase of cycle 1002 of the output current 938, but such correspondence is not expected or required. In one example, the output current 938 represents power transmission to the load 908. In this operating mode, SW H The 912's ON switching is delayed for a predetermined or set time before the power supply phase. This delay time can be used to control the output power. If the delay time is long, L C The current stored in 918 decreases.

[0058] In the first phase 1004, power supply 910 is L C Current 936 is constructed in 918. Controller 930 configures control signals 922, 926, SW H912 and SW E Turn on 916. Switching in this configuration allows L C The current 936 flowing through 918 is Vin932 and L C It increases at a rate proportional to the ratio of 918.

[0059] The second phase 1006 can be called the power supply phase. Controller 930 switches H Turn off 912, SW E Configure control signals 922 and 926 to turn off 916. H 912 is SW E It may be turned off at a different point in phase 1006 than 916. C The current 936 in 918 begins to decrease as it starts to flow into the resonant output network 920 that provides the output. E 916 voltage V SWE 934 increases to a peak that is a multiple of Vin932, and then smoothly transitions back to zero, 1010.

[0060] In the third phase 1008, which can be called the delay phase, the controller 930 SW E Turn on 916, SW H Configure control signals 922 and 926 to turn off 912. The switch configuration is maintained for the duration of the delay.

[0061] The switching frequency of the charging system 900 may be configured or defined based on the output AC load requirements. E The ON time of 916 may be defined by the resonant output network 920 or may be tuned using any suitable Class E tuning technique. The duration of the delay of the third phase 1008 and / or SW HThe ON time of 912 may be set based on the level of output power required to be supplied to the load 908. In one example, the level of output power supplied to the load 908 is determined from the charging settings used to wirelessly charge a rechargeable device. The charging settings may be defined by a protocol or negotiation between the rechargeable device and the charging system 900. In one example, the charging system 900 may be a multi-device charger, and the charging settings may specify the level of output power supplied to one or more transmission coils. H As the duty cycle of the control signal 922 supplied to operate 912 increases toward 100%, the output power supplied to the load 908 increases. H By using the duty cycle control of the control signal 922 provided to operate 912, output power control can be performed without changing the Class E switching time.

[0062] Certain aspects of this disclosure are applicable to charging systems, including wireless charging systems, and various configurations of SMPS or amplifiers in power supplies. For example, in some applications, a differential Class E amplifier may be used. Figure 11 shows a charging system 1100 comprising a power supply 1110 configured with a switch-mode power supply (SMPS 1104) coupled to a power supply 1102 and a differential Class E amplifier 1106, according to a particular aspect of this disclosure. Figure 12 is a timing diagram 1200 illustrating the operation of the power supply 1110 shown in Figure 11. The differential Class E amplifier 1106 comprises two sections, each receiving the current I output by the power supply 1110. Load 1130 supplies half cycles 1142, 1144. Each section operates as a Class E amplifier and uses a choke (L CK1 1118, L CK2 1138) and switch (SW E1 1116, SW E2 1136) and is equipped with. The peak current is L CK1 1118 and L CK2 1138 can be controlled synchronously. Controller 1140 controls the switches (SW) in SMPS1104. H1112, SW L Control signals 1122 and 1124 are supplied to 1114). Controller 1140 switches the differential Class E amplifier 1106. E1 The control signal 1132 is sent to 1116, SW E2 A control signal 1134 is supplied to 1136. In the illustrated example, SW E1 Control signals 1132 and SW supplied to 1116 E2 A 180° phase shift exists between the control signal 1134 supplied to 1136. In another example, SW E1 Control signals 1132 and SW provided to 1116 E2 The phase difference of the control signal 1134 provided to 1136 may be 180° or more, or less.

[0063] Control signals 1122, 1124, 1132, and 1134 can be synchronized so that the SMPS 1104 operates at the same switching frequency as the differential Class E amplifier 1106. Power control can be achieved by controlling the duty cycle or by the duration of the delay phase of the power cycle.

[0064] The configuration of the SMPS1104 and differential Class E amplifier 1106 maintains the high efficiency level associated with the differential Class E amplifier 1106, L CK1 1118 and L CK2 Inductor (L) of 1138 and the resonant output network 1120 T High-frequency harmonics in ) can be removed or limited. For example, L T It includes a transmission coil used to transmit power to a rechargeable device, and the load 1146 of the power supply 1110 corresponds to or incorporates a reflective load presented by the rechargeable device. By reducing high-frequency harmonics, the effectiveness of the charging system 1100 can be improved and electromagnetic interference can be limited.

[0065] The controller 1140 can be implemented using a state machine, sequencer, or delay loop configured to generate a repeating sequence of pulses. The configuration of the SMPS 1104 and the differential Class E amplifier 1106 allows for linear control of the output power and simplifies the control of the SMPS 1104 and the differential Class E amplifier 1106. In some embodiments, the controller 1140 may be configured to control the output power on a cycle-by-cycle basis.

[0066] Figure 13 shows a charging system 1300 including a tunable power supply 1310 constructed or configured according to a particular aspect of the present disclosure. This charging system 1300 may correspond in some respects to the charging system 500. The tunable power supply 1310 comprises a switched-mode power supply (SMPS 1304) coupled to a power supply 1302 and a Class E amplifier 1306. The tunable power supply 1310 is shown in Figure 13. C The peak current in the choke, designated as 1318, can be controlled synchronously, and fluctuations in the inductance of the resonant output network 1320 can be accommodated.

[0067] Controller 1330 controls the half-bridge switch (SW) of SMPS1304. H 1312, SW L Control signals 1322 and 1324 are supplied to 1314), and the Class E switch 1316 (SW) of the Class E amplifier 1306 is supplied. E ) supplies control signal 1326. In one example, SW H 1312, SW L The Class E switch 1316 is implemented using NFETs. The control signals 1322, 1324, and 1326 can be synchronized so that the SMPS 1304 operates at the same switching frequency as the Class E amplifier 1306. One or more duty cycles of the control signals 1322, 1324, and 1326 can be selected to control the step-down or step-up operation of the tunable power supply 1310.

[0068] The configuration of SMPS1304 and Class E amplifier 1306 allows for the maintenance of the high efficiency level associated with Class E amplifier 1306, LC Inductor (L) of 1318 and resonant output network 1320 T High-frequency harmonics in 1328) can be removed or limited. For example, L T 1328 includes one or more transmission coils used to transmit power to a rechargeable device, and the load 1308 of the tunable power supply 1310 incorporates or corresponds to the reflected load presented by the rechargeable device. Reduction of high-frequency harmonics improves the effectiveness of the charging system 1300 and can limit electromagnetic interference. The tunable power supply 1310 can be implemented with fewer components than comparable conventional power-controlled power supplies.

[0069] The controller 1330 can be implemented using a state machine, sequencer, or delay loop configured to generate a repeating sequence of pulses. The configuration of the SMPS 1304 and the Class E amplifier 1306 allows for linear control of the output power and simplifies the control of the SMPS 1304 and the Class E amplifier 1306. In some embodiments, the controller 1330 may be configured to control the output power on a cycle-by-cycle basis.

[0070] The inductance of the resonant output network 1320 can change dynamically in the wireless charging system. T 1328) represents the net inductance, including contributions from the fixed inductor and one or more wireless transmission coils in the wireless charger, and the load transfer effect or reflected load from the powered device. The inductance of the resonant output network 1320 may vary depending on the type of powered device, the circuit configuration within the powered device, and the electromagnetic coupling between the wireless charger and the powered device. Variations in inductance may affect the operation of the SMPS 1304 and the Class E amplifier 1306 and adversely impact the system gain.

[0071] According to certain aspects of this disclosure, a half-bridge switch (SW H 1312 and SW LThe ZVS operation and system gain of 1314) are determined from when a change in load is detected or expected to switch capacitance 1342(C S ) and tank capacity 1348 (C T ) can be controlled or maintained by readjusting. The switch capacitance 1342 and tank capacitance 1348 may have nominal values ​​provided by physical capacitors, which can be adjusted by connecting additional capacitances in parallel.

[0072] The switch capacitance 1342 can be tuned using one or more tuning elements 1350. The switch capacitance 1342 is coupled in parallel with the Class E switch 1316. In the illustrated example, each tuning element 1350 includes a tuning capacitor 1352 configured to be coupled in parallel with the Class E switch 1316 when the associated switch 1354 is closed. In some examples, the switch 1354 is controlled by a control signal 1356 provided by the controller 1330. In other examples, the controller 1330 may write a control word to a decoder (not shown) that provides control signals to the switch 1354 in a selected set of tuning elements 1350. The control word may indicate the number of tuning elements 1350 to be activated. In some examples, the control word may indicate the type of tuning elements 1350 to be activated. For example, the controller 1330 may instruct the number of each of several types of tuning elements 1350 to be activated in order to obtain a desired tuning capacitance value to be added to the switch capacitance 1342. In some examples, different types of tuning elements 1350 may correspond to different capacitance values.

[0073] The tank capacitance 1348 can be tuned using one or more tuning elements 1360. The tank capacitance 1348 is included in the resonant output network 1320. In the illustrated example, each tuning element 1360 includes a tuning capacitor 1362 configured to be coupled in parallel with the tank capacitance 1348 when the associated switch 1364 is closed. In some examples, the switch 1364 is controlled by a control signal 1366 provided by the controller 1330. In other examples, the controller 1330 may write a control word to a decoder (not shown) that provides a control signal to the switch 1364 in the set of tuning elements 1360. The control word may indicate the number of tuning elements 1360 to be activated. In some examples, the control word may indicate the type of tuning elements 1360 to be activated. For example, the controller 1330 may instruct the number of each of several types of tuning elements 1360 to be activated in order to obtain a desired tuning capacitance to be added to the tank capacitance 1348. In some examples, different types of tuning elements 1360 may correspond to different capacitance values.

[0074] In the illustrated example, tuning elements 1350 and 1360 are controlled or set by controller 1330. In some examples, tuning elements 1350 and 1360 may be controlled by a finite state machine or another type of controller. In some examples, tuning elements 1350 and 1360 may be automatically controlled by a feedback circuit. The feedback circuit can provide feedback signals used to control or configure tuning elements 1350 and 1360 using voltage or current sensing. The feedback signals can be used to represent, calculate, or estimate the inductance of the resonant network. Voltage or current sensing may be used to provide feedback signals representing the voltage of the resonant output network 1320, or feedback signals representing the current flowing through the resonant output network 1320. In one example, L TA feedback signal can be generated based on the voltage measured across 1328. In another example, the voltage measured across the Class E switch 1316 (V SWE A feedback signal may be generated based on 1334). In the latter example, V SWE If 1334 does not drop to zero, the switch capacity is 1342(C S ) or tank capacity 1348 (C T ) may be retuned. In another example, the feedback signal may be generated based on the current flowing through the resonant output network 1320, which is equivalent to or can be represented by the output current 1338. In another example, L C A feedback signal may be generated based on the current 1336 flowing through 1318.

[0075] In some examples, voltage or current sensing may not be available, and the controller may use a lookup table or algorithm to control or configure tuning elements 1350, 1360. In some examples, the lookup table or algorithm may be used when a known load change occurs. A known load change is, for example, a change in the charging setting, L T This can occur when the number of transmission coils included in 1328 changes. The lookup table can identify the number or combination of tuning elements 1350, 1360 that are enabled for a selected combination of transmission coils. For each possible combination of transmission coils, the lookup table L T The number or combination of tuning elements 1350, 1360 that are effective for the expected or defined inductance value of 1328 can be identified. The combination of transmission coils is L T 1328 may include a transmission coil that gives different inductance values. Switch capacitance 1342(C) under different load conditions or in response to changes in load conditions. S ) and tank capacity 1348 (C TAn algorithm may be used to calculate the capacitance value used to adjust the ). The calculated capacitance value may relate to the capacitance to be provided by tuning elements 1350, 1360, or to the total capacitance to be achieved using tuning elements 1350, 1360.

[0076] Example of a processing circuit Figure 14 shows an example of a hardware implementation of device 1400, which can be incorporated into a charging or receiving device that enables wireless charging of a battery. In some examples, device 1400 can perform one or more of the functions disclosed herein. According to various aspects of this disclosure, elements, any part of elements, or any combination of elements disclosed herein can be implemented using a processing circuit 1402. The processing circuit 1402 may include one or more processors 1404 controlled by some combination of hardware modules and software modules. Examples of processors 1404 include microprocessors, microcontrollers, digital signal processors (DSPs), SoCs, ASICs, field-programmable gate arrays (FPGAs), programmable logic devices (PLDs), state machines, sequencers, gate logic, discrete hardware circuits, and other suitable hardware configured to perform the various functions described throughout this disclosure. One or more processors 1404 may include dedicated processors that perform specific functions and may be configured, enhanced, or controlled by one of the software modules 1416. One or more processors 1404 may be configured through a combination of software modules 1416 that are loaded during initialization, and may be further configured by loading or unloading one or more software modules 1416 during operation.

[0077] In the illustrated example, the processing circuit 1402 may be implemented in a bus architecture generally represented by bus 1410. Bus 1410 may include any number of interconnection buses and bridges depending on the specific application and overall design constraints of the processing circuit 1402. Bus 1410 links various circuits, including one or more processors 1404 and storage 1406. Storage 1406 may include memory devices and mass storage devices, also referred to herein as computer-readable media and / or processor-readable media. Storage 1406 may include temporary storage media and / or non-temporary storage media.

[0078] Bus 1410 may link various other circuits, such as timing sources, timers, peripherals, voltage regulators, and power management circuits. Bus interface 1408 can provide an interface between bus 1410 and one or more transceivers 1412. For example, transceivers 1412 may be provided to enable device 1400 to communicate with a charging device or powered device according to a standard protocol. Depending on the nature of device 1400, a user interface 1418 (e.g., keypad, display, speaker, microphone, joystick) may also be provided and can be connected to bus 1410 directly or via bus interface 1408 for communication.

[0079] The processor 1404 can be responsible for managing the bus 1410 and for overall processing, including the execution of software stored on a computer-readable medium, including the storage 1406. In this regard, the processing circuit 1402, including the processor 1404, can be used to implement any of the methods, functions, and techniques disclosed herein. The storage 1406 can be used to store data manipulated by the processor 1404 when the software is executed, and the software can be configured to perform any one of the methods disclosed herein.

[0080] One or more processors 1404 of the processing circuit 1402 can execute software. Software is broadly interpreted to mean instructions, instruction sets, code, code segments, program code, programs, subprograms, software modules, applications, software applications, software packages, routines, subroutines, objects, executable files, execution threads, procedures, functions, algorithms, etc., regardless of whether they are called software, firmware, middleware, microcode, or hardware description languages. The software may reside in storage 1406 in a computer-readable format or on external computer-readable media. External computer-readable media and / or storage 1406 may include non-temporary computer-readable media. Non-temporary computer-readable media may include, for example, magnetic storage devices (e.g., hard disks, floppy disks, magnetic strips), optical discs (e.g., compact discs (CDs), digital multipurpose discs (DVDs)), smart cards, flash memory devices (e.g., "flash drives", cards, sticks, key drives), RAM, ROM, programmable read-only memory (PROM), erasable PROM (EPROM) including EEPROM, registers, removable disks, and any other suitable media for storing software and / or instructions that a computer can access and read. The computer-readable media and / or storage 1406 may also include, for example, carriers, transmission lines, and any other suitable media for transmitting software and / or instructions that a computer can access and read. The computer-readable media and / or storage 1406 may reside in the processing circuit 1402, reside in the processor 1404, be outside the processing circuit 1402, or be distributed across multiple entities including the processing circuit 1402. The computer-readable medium and / or storage 1406 may be embodied in a computer program product.As an example, a computer program product may include computer-readable media within the packaging material. Those skilled in the art will recognize the best way to implement the functions described throughout this disclosure, depending on the specific application and the overall design constraints imposed on the entire system.

[0081] Storage 1406 can maintain and / or organize software such as loadable code segments, modules, applications, and programs, also referred to herein as software modules 1416. Each software module 1416 may contain instructions and data that, when installed or loaded into processing circuit 1402 and executed by one or more processors 1404, contribute to a runtime image 1414 that controls the operation of one or more processors 1404. Certain instructions, when executed, can cause processing circuit 1402 to perform a function according to certain methods, algorithms, and processes described herein.

[0082] Some of the software modules 1416 may be loaded during the initialization of the processing circuit 1402, and these software modules 1416 can configure the processing circuit 1402 to enable the execution of various functions disclosed herein. For example, some software modules 1416 can configure the internal devices and / or logic circuits 1422 of the processor 1404 and manage access to external devices such as transceivers 1412, bus interfaces 1408, user interfaces 1418, timers, and numerical coprocessors. The software modules 1416 may include control programs and / or operating systems that interact with interrupt handlers and device drivers and control access to various resources provided by the processing circuit 1402. Resources may include memory, processing time, access to transceivers 1412, user interfaces 1418, and so on.

[0083] One or more processors 1404 of the processing circuit 1402 are multifunctional, thereby loading several software modules 1416 and configuring them to execute different functions or different instances of the same function. Furthermore, one or more processors 1404 may be adapted to manage background tasks initiated in response to inputs from, for example, the user interface 1418, the transceiver 1412, and device drivers. To support the execution of multiple functions, one or more processors 1404 may be configured to provide a multitasking environment, thereby implementing each of the multiple functions as a set of tasks provided by one or more processors 1404 as needed. In one example, the multitasking environment may be implemented using a time-sharing program 1420 that transfers control of the processor 1404 between different tasks, thereby returning control of one or more processors 1404 to the time-sharing program 1420 in response to the completion of any outstanding operations and / or inputs such as interrupts. When a task has control of one or more processors 1404, the processing circuit is effectively specialized for the purposes addressed by the functions associated with the controlled task. The time-sharing program 1420 may include an operating system, a main loop that transfers control in a round-robin manner, a function that assigns control of one or more processors 1404 according to function priority, and / or an interrupt-operated main loop that responds to external events by providing control of one or more processors 1404 to processing functions.

[0084] In one embodiment, the device 1400 includes or operates as a wireless charging device having a battery charging power supply coupled to a charging circuit, a plurality of charging cells, and a controller which may be included in one or more processors 1404. The plurality of charging cells may be configured to provide a charging surface. Each charging cell may include at least one transmission coil configured to guide an electromagnetic field through the charge transmission region of the charging cell. The device 1400 may also include a power amplifier having an amplification stage, a power switching stage, and a controller.

[0085] This power amplifier may be configured to operate as a Class E amplifier. The amplification stage may comprise a choke configured to receive current from the input of the amplification stage, a resonant network coupled to the output of the choke and configured to supply the output current to the load of the power amplifier, and a first switch configured to short-circuit the output of the choke to ground when turned on.

[0086] The power switching stage is configured to couple a power supply to the input of the amplification stage and may include a second switch that, when turned on, is operable to couple the input of the amplification stage to ground. The controller may be configured to control the operation of the first and second switches according to a timing sequence that defines the period of the output current. In one example, the first switch is on during the first stage of a cycle, on during the second stage of the cycle following the first stage of the cycle, and off during the third stage of the cycle following the second stage of the cycle, while the second switch is off during the first stage of a cycle, on during the second stage of the cycle, and on during the third stage of the cycle.

[0087] In one embodiment, the duration of the timing sequence corresponds to the cycle period of the output current. In one embodiment, the power switching stage includes a diode coupled to the output of the power supply and the input of the amplification stage. A diode may be provided instead of a second switch. In another embodiment, the power switching stage includes a third switch that, when turned on, provides coupling between the power supply and the input of the amplification stage. A controller may be further configured to control the operation of the third switch. The third switch may be on during the first stage of the cycle and off during the second and third stages of the cycle. The third switch may be on when the second switch is off. The controller may be further configured to control the power level supplied to the output of the power amplifier. The power level may be controlled using a variable duty cycle of control signals provided to control the operation of the second and third switches. The duty cycle of each control signal may be configured based on a feedback signal representing the inductance measured in the resonant network.

[0088] In one example, the output of a power amplifier is coupled to the transmission coil of a wireless charger. In the latter and other examples, the load of the power amplifier may include one or more transmission coils of a multi-device wireless charger.

[0089] In some examples, the power amplifier may have a second amplification stage, which may be configured to operate as a differential Class E amplifier. The second amplification stage may have a second choke configured to receive current from the input of the amplification stage. The switch of the second amplification stage may be configured to short-circuit the output of the second choke to ground when turned on. The controller may be configured to control the operation of a fourth switch according to a timing sequence that defines the period of the output current. The controller may be configured to supply a control signal to the fourth switch that is 180° out of phase with the control signal supplied to the first switch.

[0090] In some embodiments, the storage 1406 holds instructions and information, and these instructions are configured to cause one or more processors 1404 to configure a first switch to cause a choke of an amplification stage to receive current from the input of the amplification stage, to supply output current to a power amplifier load to a resonant network coupled to the output of the choke, and to short-circuit the output of the choke to circuit ground when turned on, to configure a power switching stage to couple a power supply to the input of the amplification stage, and to configure a second switch of the power switching stage to couple the input of the amplification stage to circuit ground when turned on, and to control the operation of the first and second switches according to a timing sequence that defines the period of the output current. The control of the operation of the first switch may include configuring the first switch to be on during the first stage of a cycle, on during the second stage of the cycle following the first stage of the cycle, and off during the third stage of the cycle following the second stage of the cycle. Controlling the operation of the second switch may include configuring the second switch to be off during the first stage of the cycle, on during the second stage of the cycle, and on during the third stage of the cycle.

[0091] In some examples, the duration of the timing sequence corresponds to the cycle period of the output current. Instructions may be configured to cause one or more processors 1404 to configure diodes in a power switching stage to provide coupling between a power supply and the input of an amplification stage. Instructions may be configured to cause one or more processors 1404 to configure a third switch in the power switching stage to provide coupling between a power supply and the input of an amplification stage, and to control the operation of the third switch according to a timing sequence. Instructions may be configured to cause one or more processors 1404 to configure the third switch to be on during the first stage of a cycle and off during the second and third stages of a cycle. Instructions may be configured to cause one or more processors 1404 to configure the third switch to be on when the second switch is turned off. Instructions may be configured to cause one or more processors 1404 to configure a charger to control the power level supplied to the output of the power amplifier. The power level is controlled by the duty cycle of control signals supplied to control the operation of the second and third switches.

[0092] In one example, the instruction causes one or more processors 1404 to configure a second choke located on a second amplification stage to receive current from the input of the amplification stage, to configure a fourth switch to short-circuit the output of the second choke to ground when turned on, to configure a power switching stage to couple a power supply to the input of the second amplification stage, and to control the operation of the fourth switch according to a timing sequence that defines the period of the output current. The operation of the fourth switch may be controlled by supplying a first signal to the gate of the first switch and a second signal to the gate of the fourth switch. In one example, the second signal is 180° out of phase with the first signal. In other examples, the phase difference between the first signal and the second signal may be greater than or less than 180°.

[0093] In one example, the output of a power amplifier is coupled to the transmission coil of a wireless charger. In the latter and other examples, the load of the power amplifier may include one or more transmission coils of a multi-device wireless charger.

[0094] Figure 15 is a flowchart 1500 illustrating a method for supplying amplified current, voltage, or power to a charging device according to a particular aspect of the present disclosure. This method can be performed by a controller within the charging device. In block 1502, the controller may configure a choke in the amplification stage to receive current from the input of the amplification stage. In block 1504, the controller may configure a resonant network coupled to the output of the choke to supply output current to the load of the charging device. In block 1506, the controller may configure a first switch to short-circuit the output of the choke to ground when turned on. In block 1508, the controller may configure a power supply switching stage to couple a power supply to the input of the amplification stage. In block 1510, the controller may configure a second switch in the power switching stage to couple the input of the amplification stage to ground when turned on. In block 1512, the controller may control the operation of the first and second switches according to a timing sequence that defines the cycle of the output current. Controlling the operation of the first switch may include configuring the first switch to be on during the first stage of a cycle, off during the second stage of the cycle following the first stage of the cycle, and off during the third stage of the cycle following the second stage of the cycle. Controlling the operation of the second switch may include configuring the second switch to be off during the first stage of the cycle, on during the second stage of the cycle, and on during the third stage of the cycle. In one example, the duration of the timing sequence corresponds to the cycle duration of the output current.

[0095] In one embodiment, the controller may configure a diode in the power supply switching stage to provide coupling between the power supply and the input of the amplification stage. In another embodiment, the controller may configure a third switch in the power supply switching stage to provide coupling between the power supply and the input of the amplification stage. The controller may control the operation of the third switch according to a timing sequence. The controller may configure the third switch to be on during the first stage of a cycle, off during the second stage of a cycle, and off during the third stage of a cycle. The controller may configure the third switch to be on when the second switch is turned off. The controller may configure the charger to control the power level supplied to the output of the charger. The power level can be controlled using a variable duty cycle of control signals provided to control the operation of the second and third switches. For example, power can be increased by adjusting the duty cycle toward 100%. In some examples, the duty cycle of each control signal may be dynamically configured based on a feedback signal representing the inductance measured in the resonant network.

[0096] In one example, the controller configures a second choke on a second amplification stage to receive current from the input of the amplification stage, a fourth switch to short-circuit the output of the second choke to ground when turned on, a power switching stage to couple the power supply to the input of the second amplification stage, and controls the operation of the fourth switch according to a timing sequence that defines the period of the output current. The operation of the fourth switch can be controlled by supplying a first signal to the gate of the first switch and a second signal to the gate of the fourth switch. In one example, the second signal is 180° out of phase with the first signal. In other examples, the phase difference between the first and second signals may be greater than or less than 180°.

[0097] In various examples, the output of a power amplifier is coupled to the transmission coil of a wireless charger. In the latter and other examples, the load of the power amplifier may include one or more transmission coils of a multi-device wireless charger.

[0098] In a particular example, this method involves determining a first set of tuning capacitors from a plurality of capacitors configured to be coupled in parallel with a first capacitor, and tuning the first capacitor coupled in parallel with the first switch by closing a switch connected in series with each tuning capacitor in the first set of tuning capacitors. The first set of tuning capacitors may be configured based on the inductive load of a charging device.

[0099] In a particular example, this method involves determining a second set of tuning capacitors from a plurality of capacitors configured to be coupled in parallel with a second capacitor, and tuning the second capacitor of the resonant network by closing a switch connected in series with each of the first tuning capacitors in the second set of tuning capacitors. The second set of tuning capacitors may be configured based on the inductive load of a charging device.

[0100] Several examples are described in the following numbered sections. 1. A power amplifier comprising: an amplification stage comprising: a choke configured to receive current from the input of the amplification stage; a resonant network coupled to the output of the choke and configured to supply output current to the load of the power amplifier; and a first switch configured to short-circuit the output of the choke to ground when turned on; a power switching stage comprising: a second switch configured to couple a power supply to the input of the amplification stage and operable to couple the input of the amplification stage to ground when turned on; and a controller configured to control the operation of the first switch and the second switch according to a timing sequence defining the cycle of the output current, wherein the first switch is on during the first stage of the cycle, on during the second stage of the cycle following the first stage of the cycle, and off during the third stage of the cycle following the second stage of the cycle, and the second switch is off during the first stage of the cycle, on during the second stage of the cycle, and on during the third stage of the cycle.

[0101] 2. The duration of the timing sequence corresponds to the period of the output current cycle, as described in item 1 for the power amplifier.

[0102] 3. The power amplifier according to item 1 or item 2, wherein the power switching stage further comprises a diode that provides coupling between the power supply and the input of the amplification stage.

[0103] 4. The power amplifier according to any one of items 1 to 3, wherein the power switching stage further comprises a third switch that provides coupling between the power supply and the input of the amplification stage when turned on, and the controller is further configured to control the operation of the third switch.

[0104] 5. The power amplifier as described in item 4, wherein the third switch is on during the first stage of the cycle and off during the second and third stages of the cycle.

[0105] 6. The power amplifier as described in item 4, wherein the third switch is on during the first stage of the cycle and off during the second and third stages of the cycle.

[0106] 7. The power amplifier according to item 6, wherein the controller is further configured to control the power level supplied to the output of the power amplifier, the power level being controlled using a variable duty cycle of control signals supplied to control the operation of the second and third switches.

[0107] 8. The power amplifier described in item 7, wherein each duty cycle of the control signal is set based on a feedback signal representing the inductance measured in the resonant network.

[0108] 9. The power amplifier according to any one of items 1 to 8, wherein the controller is further configured to pulse-width modulate the control signal supplied to the first switch based on the amount and type of one or more transmission coils included in the load of the power amplifier.

[0109] 10. The power amplifier load is a power amplifier according to any one of items 1 to 9, which includes one or more transmission coils of a multi-device wireless charging device.

[0110] 11. A power amplifier according to any one of items 1 to 10, further comprising a second amplification stage having a second choke configured to receive current from the input of the amplification stage, and a fourth switch configured to short-circuit the output of the second choke to ground when turned on, wherein the controller is configured to control the operation of the fourth switch according to a timing sequence that defines the cycle of the output current, and the controller is configured to supply the fourth switch with a control signal that is 180° out of phase with the control signal supplied to the first switch.

[0111] 12. A power amplifier according to any one of items 1 to 11, further comprising a first tuning element having a first tuning capacitor and a first tuning switch configured to couple the first tuning capacitor between circuit ground and the output of the choke, wherein the controller is configured to control the operation of the first tuning switch based on a feedback signal representing the inductance measured in the resonant network.

[0112] 13. A power amplifier according to any one of items 1 to 12, further comprising a second tuning element having a second tuning capacitor and a second tuning switch configured to connect the second tuning capacitor in parallel with the capacitance of the resonant network, wherein the controller is configured to control the operation of the second tuning switch based on a feedback signal representing the inductance measured in the resonant network.

[0113] 14. A method for amplifying power in a charging device, comprising the steps of: configuring a choke in an amplification stage to receive current from the input of the amplification stage; configuring a resonant network coupled to the output of the choke to supply output current to the load of the power amplifier; configuring a first switch to short-circuit the output of the choke to circuit ground when turned on; configuring a power switching stage to couple a power supply to the input of the amplification stage; configuring a second switch in the power switching stage that is operable to couple the input of the amplification stage to circuit ground when turned on; and controlling the operation of the first switch and the second switch according to a timing sequence defining the cycle of the output current, wherein the first switch is turned on during the first stage of the cycle, turned on during the second stage of the cycle following the first stage of the cycle, and turned off during the third stage of the cycle following the second stage of the cycle, and the second switch is turned off during the first stage of the cycle, turned on during the second stage of the cycle, and turned on during the third stage of the cycle.

[0114] 15. The duration of the timing sequence is as described in item 14, corresponding to the period of the cycle of the output current.

[0115] 16. The method of item 14 or item 15, further comprising the step of configuring a diode in the power switching stage to provide coupling between the power supply and the input of the amplification stage.

[0116] 17. The method according to any one of items 14 to 16, further comprising the steps of configuring a third switch of the power switching stage to provide coupling between the power supply and the input of the amplification stage, and controlling the operation of the third switch according to the timing sequence.

[0117] 18. The method of item 17, further comprising the step of configuring the third switch to be on during the first stage of the cycle, off during the second stage of the cycle, and off during the third stage of the cycle.

[0118] 19. The method according to item 17 or item 18, further comprising the step of configuring the third switch to turn on when the second switch is turned off.

[0119] 20. The method according to item 19, further comprising the step of configuring the charging device to control the power level supplied to the output of the charging device, wherein the power level is controlled using a variable duty cycle of control signals supplied to control the operation of the second switch and the third switch.

[0120] 21. The method according to item 19 or item 20, further comprising the step of setting the duty cycle of each of the control signals based on a feedback signal representing the inductance measured in the resonant network. 22. The method according to any one of items 14 to 21, further comprising the step of pulse-width modulating a control signal supplied to the first switch based on the quantity and type of one or more transmission coils included in the load of the charging device.

[0121] 23. The method according to any one of items 14 to 22, wherein the load of the charging device includes one or more transmission coils of a multi-device wireless charging device.

[0122] 24. The method according to any one of items 14 to 23, further comprising the steps of: configuring a second choke provided in a second amplification stage to receive current from the input of the amplification stage; configuring a fourth switch to short-circuit the output of the second choke to circuit ground when turned on; configuring a power switching stage to couple a power supply to the input of the second amplification stage; and controlling the operation of the fourth switch according to a timing sequence defining the cycle of the output current, the steps of supplying a first signal to the gate of the first switch and supplying a second signal to the gate of the fourth switch that is 180° out of phase with the first signal.

[0123] 25. The method according to any one of items 14 to 24, further comprising the steps of determining a first set of tuning capacitors from among a plurality of capacitors configured to be coupled in parallel with a first capacitor, and tuning the first capacitor coupled in parallel with the first switch by closing a switch connected in series with each tuning capacitor in the first set of tuning capacitors.

[0124] 26. The method according to item 25, wherein the first set of tuning capacitors is configured based on the inductive load of the charging device.

[0125] 27. The method according to any one of items 14 to 26, further comprising the steps of determining a second set of tuning capacitors from a plurality of capacitors configured to be coupled in parallel with the second capacitor, and tuning the second capacitor of the resonant network by closing a switch connected in series with each of the first tuning capacitors in the second set of tuning capacitors.

[0126] 28. The method according to item 27, wherein the second set of tuning capacitors is configured based on the inductive load of the charging device.

[0127] The above-mentioned descriptions are provided to enable a person skilled in the art to carry out the various embodiments described herein. Various modifications to these embodiments will be obvious to a person skilled in the art, and the general principles set forth herein can be applied to other embodiments. For this reason, the claims are not intended to be limited to the embodiments shown herein, but the entire scope consistent with the language of the claims is recognized, and references to singular elements mean "one or more" and not "only" unless otherwise specified. Unless otherwise specified, the term "several" means one or more. All structural and functional equivalents to elements of the various embodiments described throughout this disclosure, known to a person skilled in the art, or to become known to a person skilled in the art, are expressly incorporated herein by reference and are intended to be included in the claims. Furthermore, nothing disclosed herein is intended to be made available to the public, whether such disclosure is expressly contained in the claims or not. No element of a claim should be construed under the provisions of 35 U.S. SC § 112, Chapter 6 unless that element is expressly contained in the phrase "means for" or, in the case of a method claim, in the phrase "step for".

Claims

1. In a power amplifier, This is an amplification stage, A choke configured to receive current from the input of the amplification stage, A resonant network coupled to the output of the choke and configured to supply output current to the load of the power amplifier, An amplification stage comprising: a first switch configured to short-circuit the output of the choke to ground when turned on; A power switching stage including a second switch configured to couple a power supply to the input of the amplification stage and operable to couple the input of the amplification stage to circuit ground when turned on, The system comprises a controller configured to control the operation of the first switch and the second switch according to a timing sequence that defines the cycle of the output current, The first switch is turned on during the first stage of the cycle, turned on during the second stage of the cycle following the first stage of the cycle, and turned off during the third stage of the cycle following the second stage of the cycle. A power amplifier characterized in that the second switch is off during the first stage of the cycle, on during the second stage of the cycle, and on during the third stage of the cycle.

2. The power amplifier according to claim 1, wherein the duration of the timing sequence corresponds to the period of the output current cycle.

3. The power amplifier according to claim 1, wherein the power switching stage further comprises a third switch that, when turned on, provides coupling between the power supply and the input of the amplification stage, and the controller is further configured to control the operation of the third switch.

4. The power amplifier according to claim 3, wherein the third switch is on during the first stage of the cycle and off during the second and third stages of the cycle.

5. The power amplifier according to claim 3, wherein the third switch is turned on when the second switch is off.

6. The power amplifier according to claim 5, wherein the controller is further configured to control the power level supplied to the output of the power amplifier, the power level being controlled using a variable duty cycle of control signals supplied to control the operation of the second and third switches.

7. The power amplifier according to claim 1, wherein the output of the power amplifier is connected to the transmission coil of a wireless charging device.

8. The power amplifier according to claim 1, wherein the load of the power amplifier includes one or more transmission coils of a multi-device wireless charging device.

9. Furthermore, the second amplification stage, A second choke configured to receive current from the input of the amplification stage, The second amplification stage comprises a fourth switch configured to short-circuit the output of the second choke to ground when it is turned on, The controller is configured to control the operation of the fourth switch according to a timing sequence that defines the cycle of the output current. The power amplifier according to claim 1, wherein the controller is configured to supply to the fourth switch a control signal that is 180° out of phase with the control signal provided to the first switch.

10. A method for amplifying power in a charging device, The steps include configuring a choke in the amplification stage so that it receives current from the input of the amplification stage, The steps include configuring a resonant network that is coupled to the output of the choke and supplies output current to the load of the charging device, The steps include configuring a first switch such that when it is turned on, it short-circuits the output of the choke to the circuit ground, The steps include configuring a power switching stage so as to couple the power supply to the input of the amplification stage, The steps include configuring a second switch in the power switching stage that is operable to couple the input of the amplification stage to the circuit ground when it is turned on, A step of controlling the operation of the first switch and the second switch in accordance with a timing sequence that defines the cycle of the output current, The first switch is configured to be on during the first stage of the cycle, on during the second stage of the cycle following the first stage of the cycle, and off during the third stage of the cycle following the second stage of the cycle. A method characterized by comprising the step of configuring the second switch to be off during the first stage of the cycle, on during the second stage of the cycle, and on during the third stage of the cycle.

11. The method according to claim 10, wherein the duration of the timing sequence corresponds to the period of the cycle of the output current.

12. Furthermore, the step of configuring a third switch of the power switching stage to provide coupling between the power supply and the input of the amplification stage, The method according to claim 10, further comprising the step of controlling the operation of the third switch in accordance with the timing sequence.

13. The method according to claim 12, further comprising the step of configuring the third switch to be on during the first stage of the cycle, off during the second stage of the cycle, and off during the third stage of the cycle.

14. The method according to claim 12, further comprising the step of configuring the third switch to turn on when the second switch is turned off.

15. The method according to claim 14, further comprising the step of configuring the charging device to control the power level supplied to the output of the charging device, wherein the power level is controlled using a variable duty cycle of control signals supplied to control the operation of the second switch and the third switch.

16. The method according to claim 10, wherein the output of the charging device is connected to the transmission coil of a wireless charging device.

17. The method according to claim 10, wherein the load of the charging device includes one or more transmission coils of a multi-device wireless charging device.

18. Furthermore, the step of configuring a second choke provided in the second amplification stage so as to receive current from the input of the amplification stage, The steps include configuring a fourth switch such that when it is turned on, it short-circuits the output of the second choke to the circuit ground, The steps include configuring a power switching stage so as to couple a power supply to the input of the second amplification stage, The method according to claim 10, comprising the steps of controlling the operation of the fourth switch in accordance with a timing sequence defining the cycle of the output current, the steps of supplying a first signal to the gate of the first switch and supplying a second signal to the gate of the fourth switch that is 180° out of phase with the first signal.

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