Isolating switch amplifier system

Abstract

The switching amplifier system includes an amplifier printed circuit board (PCB); a filter PCB coupled to the amplifier PCB and configured to receive an amplified signal from the amplifier PCB; and a resonant capacitor PCB coupled to the filter PCB and one or more antennas. The resonant capacitor PCB is physically separated from the amplifier PCB and the filter PCB by a distance of at least 10 mm. The filter PCB is also physically separated from the amplifier PCB by a distance of at least 10 mm.

Description

[0001] Cross-references to related applications

[0002] This patent document claims priority and benefit to U.S. Provisional Patent Application No. 62 / 985,692, entitled “ISOLATED SWITCHING AMPLIFIER SYSTEM,” filed March 5, 2020, which is incorporated herein by reference in its entirety. Technical Field

[0003] This document relates to circuits, and in particular to electric power amplifiers. Background Technology

[0004] In recent years, products that allow wireless charging of electronic devices have become increasingly common. The future trend could be that virtually any device operating on battery power could be wirelessly charged. Summary of the Invention

[0005] Various designs for isolating switch amplifier systems are described. These designs can be incorporated into wireless power charging devices.

[0006] In one exemplary aspect, the disclosed technology provides a system and method for isolating components of a radio frequency (RF) amplifier system (e.g., a system based on switched Class D and Class E amplifiers) to achieve operational and thermal stability, including techniques for isolating amplifier printed circuit boards (PCBs) from one or more filter PCBs, resonant capacitor PCBs, and antennas to reduce hysteresis losses, switching losses, and / or thermal losses.

[0007] In one example aspect, a switching amplifier system is described. The system includes: an amplifier printed circuit board (PCB); a filter PCB coupled to the amplifier PCB and configured to receive an amplified signal from the amplifier PCB, wherein the filter PCB is physically separated from the amplifier PCB by a distance of at least 10 mm; a resonant capacitor PCB coupled to the filter PCB and one or more antennas, wherein the resonant capacitor PCB is physically separated from the amplifier PCB and the filter PCB by a distance of at least 10 mm, wherein the resonant capacitor PCB is configured to receive a filtered signal from the filter PCB and drive the filtered signal to one or more antennas, and wherein the filtered signal is generated by filtering the amplified signal via a radio frequency (RF) filter in the filter PCB, and wherein the physical separation distance between the filter PCB, the amplifier PCB, the resonant capacitor PCB, and the one or more antennas is selected to reduce at least one of hysteresis loss, switching loss, or thermal loss in the switching amplifier system.

[0008] In another example, a method for manufacturing a wireless charging system is disclosed. The method includes: attaching an amplifier printed circuit board (PCB) to a first region of a non-conductive support structure; attaching a filter PCB to a second region of the support structure, wherein the filter PCB is electrically connected to the amplifier PCB and configured to receive an amplified signal from the amplifier PCB; and attaching a resonant capacitor PCB to a third region of the support structure, wherein the resonant capacitor PCB is electrically connected to the filter PCB and one or more antenna coils, and configured to receive a filtered signal from the filter PCB and drive the filtered signal to one or more antenna coils, wherein the first, second, and third regions of the support structure are selected to maintain physical separation between the amplifier PCB, the resonant capacitor PCB, the filter PCB, and the one or more antenna coils, and wherein the distance of physical separation between the filter PCB and the amplifier PCB, and the distance of physical separation between the filter PCB and the resonant capacitor PCB, are at least 10 mm.

[0009] In another aspect, a different method for manufacturing a wireless charging system is disclosed. The method includes: attaching an amplifier printed circuit board (PCB) to a first region of a first support structure, wherein the first support structure is non-conductive; attaching a first filter PCB to a second region of the first support structure, wherein the first filter PCB is electrically connected to the amplifier PCB and configured to receive an amplified signal from the amplifier PCB, and wherein the first and second regions of the first support structure are selected to maintain a physical separation distance of at least 10 mm between the amplifier PCB and the first filter PCB; attaching a resonant capacitor PCB to a second support structure, wherein the second support structure is separate from the first support structure, wherein the resonant capacitor PCB is electrically connected to the first filter PCB and one or more antenna coils, and wherein the physical separation distance between the resonant capacitor PCB and the first filter PCB is at least 10 mm.

[0010] These and other aspects are disclosed throughout the document. Attached Figure Description

[0011] Figure 1 This is a representative block diagram of an isolating switch amplifier system.

[0012] Figure 2 This is a representative schematic diagram of a parallel-tuned Class E amplifier.

[0013] Figure 3 This is a representative layout for isolated switch amplifier systems with packaging constraints.

[0014] Figure 4 This is a representative schematic diagram of a filter circuit.

[0015] Figure 5 This is a representative layout for the PCBs of filters, amplifiers, and DC jacks used in isolated switch amplifier systems.

[0016] Figure 6 A flowchart illustrating a method for manufacturing a wireless charging system.

[0017] Figure 7 A flowchart illustrating a method for manufacturing a wireless charging system. Detailed Implementation

[0018] In power amplifier design, thermal analysis of individual components and board layout is crucial for system stability. This is especially true in the design of switching power amplifiers, including Class D and Class E amplifiers, for at least two reasons. First, the input signal is amplified at radio frequency (RF), not line frequency, which can generate significant thermal stress on the switching components. Second, any impedance mismatch or unintended frequency shift will lead to significant system losses. Therefore, how the RF amplifier is designed and laid out determines its thermal and operational stability, particularly for switching amplifiers such as Class D and Class E amplifiers.

[0019] This application describes systems and methods for designing radio frequency (RF) amplifiers to achieve thermal and operational stability. The disclosed techniques are particularly applicable to switching amplifiers, including Class D and Class E amplifiers.

[0020] Various embodiments will now be described. The following description provides specific details for a thorough understanding and advantageous description of these embodiments. However, those skilled in the art will understand that the disclosed techniques can be practiced without many of these details. Additionally, some well-known structures or functions may not be shown or described in detail to avoid unnecessarily obscuring the relevant descriptions of the various embodiments. The terminology used in the description presented below is intended to be interpreted in its broadest and most reasonable manner, even when used in conjunction with the detailed description of certain specific embodiments of the invention.

[0021] Figure 1This is a representative system 100 of an isolated switch amplifier system. System 100 depicts the isolation of amplifier components according to one embodiment of the disclosed technology. For example, system 100 depicts the physical separation of a DC power supply 110, an amplifier PCB 120, a filter PCB 130, a resonant capacitor PCB 140, and one or more transmitter coils 150. In some embodiments, a PCB may be present between the DC power supply, AC / DC charger, or rechargeable battery and the amplifier PCB to provide various different voltages to properly drive the system, such as logic circuits, switching circuits, and fans for active cooling. That is, power PCBs with different voltages required to apply to the amplifier may be used, and the amplifier may have a DC jack for an AC / DC charger. In some embodiments using a differential topology, two separate filter PCBs 130 may be used, one filter PCB 130 for each differential line. This physical separation reduces thermal stress in the components of system 100, such as the amplifier PCB 120, due to the lower connection of high voltage spikes across the passive components in system 100. The isolation provided by physical separation also reduces hysteresis losses in the inductive components of the RF signal. This is particularly important for wireless charging systems employing these amplifier topologies, as magnetic fields from the transmitter antenna can cause hysteresis losses in these inductive components. In some embodiments, the physical separation distance between the filter PCB 130 and the amplifier PCB 120 is at least 10 mm, and the distance between the filter PCB 130 and the resonant capacitor PCB 140 or the antenna (transmitter coil) 150 is at least 10 mm. The separation distance is chosen to reduce hysteresis losses, switching losses, and / or heat losses in the isolated switching amplifier system 100. System 100 can be used in loosely coupled wireless charging systems configured to provide wireless power to electronic devices such as cellular phones or tablets. In some embodiments, the separation distance is nominally about 10 mm, but not less than about 5 mm.

[0022] In some implementations, the degree of isolation can be determined during the manufacture of the isolated switch amplifier system 100 by monitoring the temperature across the components of the switch amplifier system. The aforementioned losses can be thermally visualized using the components and the additional current drawn from the DC power supply 110. The physical isolation or spacing between components can then be determined based on the available clearance in the package and the minimum spacing required to maintain the lowest possible thermal properties (e.g., increasing isolation to reduce temperature until a target temperature is met or until constrained by package limitations). For example, in the case of a filter within an antenna less than 1 inch in diameter, a parallel inductor outputs approximately 20 watts at approximately ~230°F. If the separation distance is increased to more than 1 inch, losses can be significantly reduced (e.g., in situations where...). Figure 5In the system depicted, for vehicle applications, there is more space to physically isolate components. In such a system, for the same 20W output, the temperature can be as low as approximately 100°F or even at room temperature. The isolation distance required for a low thermal gradient depends particularly on the output power and antenna configuration (which determines the magnetic field strength). Increasing the output from 20W to 25W may require increasing the isolation spacing to maintain the thermal gradient. The antenna arrangement also affects the thermal gradient (e.g., due to cross-coupling). Isolation achieved by physically separating the circuit boards also significantly reduces losses. Switching circuits (such as transistors in amplifiers) can also have their operating temperatures reduced from 150°F or higher to ambient temperature by physically separating them from the filters.

[0023] Figure 2 This is a representative schematic diagram of a single-ended Class E amplifier 200 with a parallel tuned resonant network. Figure 2 In this circuit, the oscillator and gate driver integrated circuit (Vosc2) 202 can generate a signal (e.g., a square wave) at a desired resonant frequency. This signal is applied to the gate of transistor 210. In some embodiments, the signal can be generated by the gate driver and oscillator integrated circuit and can be used with a dead-time circuit (…). Figure 2 (Such as diodes and resistors, not shown) are used to adjust and regulate the current and voltage waveforms of amplifier 200 for zero-voltage switching (ZVS). Amplifier 200 may also include a choke inductor (Lchoke2) 208, a parallel capacitor (Csh2) 220, and an additional series inductor (Le2) 230 for protecting DC power supply 204.

[0024] The Vosc 202 signal generator circuit generates a periodic signal that is boosted or amplified by the Class E amplifier 200. The amplifier 200 has a series capacitor (CS2) 222 used to tune the inductive reactance of an additional inductor (Le2) 230 at the desired resonant frequency of the signal generated by the Vosc 202. The series capacitor (CS2) 222, together with Le2 230, acts as a series resonant filter, making the design more robust by reducing harmonics. The amplifier 200 also includes a parallel capacitor (Cparallel) 226, which is placed in parallel with the transmitter antenna (e.g., transmitter coil), represented by the inductor Ltxcoil 224 and the parasitic resistance Rtxparasitic 225. Because the parallel capacitor (Cparallel) 226 excites the transmitter antenna, the transmitter device containing the amplifier 200 operates independently of the actual impedance reflected by the receiver device.

[0025] The load network for amplifier 200, consisting of a parallel capacitor (Csh2) 220, an RF choke (Lchoke2) 208, and an additional inductor (Le2) 230, is tuned such that the current and voltage waveforms are out of phase, resulting in zero-voltage switching (ZVS) of transistor 210. This significantly reduces the power consumed across transistor 210. When the load network is properly tuned, the voltage across transistor 210 is minimized when the switch is "closed," and the current across transistor 210 is minimized when the switch is "open." This can increase the power efficiency of amplifier 200 to over 90%, making this Class E amplifier topology suitable for other applications where wireless power delivery and system efficiency are important design criteria. However, in practice, achieving this efficiency can be difficult due to switching losses, hysteresis losses in passive components, and other heat losses in the system. This applies to... Figure 2 The single-ended parallel-tuned resonant Class E system shown herein, as well as any other efficient switching topologies using transistors as the main switching component, include differential parallel-tuned systems, single-ended and differential Class E series resonant and non-resonant systems, and Class D non-resonant and resonant systems. That is, it will be understood that the parallel-tuned single-ended amplifier described herein is merely a representative implementation, and the same isolation techniques disclosed in the art can be used in other amplifier topologies (including other Class D or Class E topologies and series-tuned amplifier topologies).

[0026] Figure 3 This is a representative system layout 300 for an isolated switch amplifier system with packaging constraints. The main PCB (amplifier PCB) 330 drives the signal to filter PCBs (e.g., filter PCBs 320 and 340) connected to a resonant capacitor PCB 310. Filter PCBs 320 and 340 receive amplified signals from the amplifier PCB 330, and the resonant capacitor PCB 310 receives filtered signals from the filter PCBs. The resonant capacitor PCB 310 is connected to multiple antennas, such as transmitting antenna coils 352 and 354 (for convenience, in...). Figure 3 Only two antennas are depicted in this diagram. Physical isolation of each subsystem (e.g., each PCB in system layout 300) allows for a more efficient amplifier system and less loss due to heat. This is particularly important due to the potential cross-coupling between inductors or passive components in the filter PCBs and the antennas used for wireless charging applications. Due to the differential output from the main PCB 330 / amplifier PCB 330, in the presence of two filter PCBs (e.g., ... Figure 3 In the case shown in the figure, physical separation of each subsystem is particularly advantageous.

[0027] In one implementation, each radio frequency (RF) filter in filter PCBs 320 and 340 may have Figure 4The topology of filter 400 includes a series inductor-capacitor network (LC) 420, which is connected to a parallel LC network 430, and then to a series LC network 440 to form a bandpass filter. The input (input node 410) of filter 400 can be connected to the main PCB 330 (in...). Figure 3 (in the middle), and the output of filter 400 (output node 450) can be connected to resonant capacitor PCB 310 (in Figure 3 (in Chinese). This will be understood. Figure 4 The filter configuration shown is merely representative, and other filter topologies can be used in filter PCBs 320 and 340. That is, in some implementations, filter 400 can be configured differently depending on the required attenuation of the system's harmonics. For example, in addition to a bandpass filter configuration, filter 400 can be configured similar to... Figure 2 The circuit diagram shows a series resonant filter. In one embodiment, the filters in filter PCB 320 and filter PCB 340 can be differentially connected.

[0028] Back Figure 3 In one embodiment of the disclosed technology, the RF filter (e.g., in filter PCBs 320 and 340) is physically separated from the switching components on the amplifier PCB (e.g., in the main PCB 330). Physically isolating the RF filter from the switching components on the amplifier PCB reduces thermal stress on the switching components. This... Figure 3 The examples are particularly important, in Figure 3 In this example, due to packaging limitations, there is no significant physical clearance between the filter PCB and the transmitter antenna. This close proximity would result in higher hysteresis losses, and consequently, heat losses within the filter PCB. By physically isolating these filter PCBs from the amplifier PCB, this allows the amplifier PCB to operate with minimal thermal impact due to temperature rises within the filter PCB assembly. In this exemplary embodiment, the filter PCB can be as high as 230 degrees Celsius, while the switching components can be as low as near ambient temperature.

[0029] The switching components of an amplifier include, for example, the amplifier's switching transistors (e.g., Figure 2 Transistor 210 in the middle), and the parallel capacitor of the switching transistor (e.g., Figure 2 The capacitors (Csh2 220), RF chokes (e.g., choke inductors Lchoke2 208), and digital circuitry driving the switching transistors (e.g., Figure 2This is depicted as the Vosc2 202, an oscillator and gate driver integrated circuit (IC). This switching component is more sensitive to heat than passive components (e.g., high-voltage capacitors and high-power rated inductors used in various output filters and resonant capacitors). This sensitivity further emphasizes the importance of physical isolation between the amplifier PCB and the filter PCB. Additionally, this switching component is more sensitive to unexpected impedance and resonant frequency shifts.

[0030] In addition to isolating the RF filter from the switching components, the representative layout 300 also describes isolating the antenna resonant capacitor (e.g., resonant capacitor PCB 310) from the switching components (e.g., in the main PCB 330) and from the RF filter components (in the filter PCBs 320 and 340). This provides better isolation of high-voltage spikes across the antenna's resonant capacitor.

[0031] Configuring the amplifier as multiple isolated subsystems, rather than using a single PCB for the amplifier assembly—a traditional approach—results in better operational stability and improved performance. The disclosed techniques are particularly advantageous for parallel-tuned resonant amplifiers (e.g., Figure 2 Amplifier 200), which is used to establish a zero-voltage switching waveform (e.g., Figure 2 The additional series inductors in Le2 230 (in the amplifier) ​​also serve as filters to reduce first and second harmonics. These inductors can experience large hysteresis losses, significantly increasing the operating temperature (e.g., above 60 degrees Celsius). Since the signal from the amplifier drives one or more antennas, and the radiated signal from the antennas can be coupled to inductors on the amplifier PCB (e.g., main PCB 330) and filter PCBs 320 and 340 (e.g., coupled to inductors 320, 324, 340, and 344), the structure of the wireless charging device can exacerbate these hysteresis losses.

[0032] The disclosed isolation subsystem allows for greater design flexibility and improved performance by physically separating the amplifier PCB further away from the filter and the amplifier-driven antenna in the wireless charging system. For example, in system layout 300, the amplifier PCB in the main PCB 330 is physically separated from the antenna coils 352 and 354.

[0033] In one embodiment, the antenna coils (e.g., coils 352 and 354) are surface spiral coils made of a continuous conductor (without interruptions or radio frequency discontinuities). This conductor may be wound at an angle around the dielectric material to reduce proximity effects at the operating frequency of the wireless charging transmitter device and to maintain the high intrinsic quality factor (“Q”) of the surface spiral coil at the operating frequency. The continuous conductor may have a thickness of approximately 40 μm.

[0034] In one embodiment, coil 352 may be arranged on a first plane (e.g., the y-axis plane), and coil 354 may be arranged on a second vertical plane (e.g., the x-axis plane), such that coil 352 and coil 354 are perpendicular to each other. Figure 3 The third coil (not shown) can be in a z-axis plane perpendicular to the first and second planes. The first and second planes can define four quadrants. To maximize the use of the space on the non-conductive support structure where different PCBs are attached, the amplifier PCB 330 can be attached to the support structure in the first quadrant of the four quadrants, the first filter PCB 320 can be attached to the support structure in the second quadrant of the four quadrants, the resonant capacitor PCB 310 can be attached in the third quadrant, and the second filter PCB 340 can be attached in the fourth quadrant. These PCBs are spaced apart from each other and from the antenna coil to improve system performance.

[0035] In some implementations, to create an isolated wireless charging system, the main PCB 330 or amplifier PCB 330 is attached to a first region of a non-conductive support structure (e.g., a first quadrant defined by an intersecting plane in which antenna coils are arranged); a first filter PCB 320 is attached to a second region of the support structure (e.g., a second quadrant); a resonant capacitor PCB 310 is attached to a third region (e.g., a third quadrant); and a second filter PCB 340 is attached to a fourth region of the support structure (e.g., a fourth quadrant). The first, second, third, and fourth regions of the support structure are selected to maintain physical separation between the amplifier PCB 330, the resonant capacitor PCB 310, the filter PCBs 320 and 340, and the coils 352 and 354. It will be understood that the above description is merely a representative example, and other techniques can be used to optimize the arrangement of various PCBs within physically constrained areas (e.g., when the wireless charging system is integrated into a small form factor device). For example, for three PCBs placed circumferentially around an approximately circular device, optimal spacing can be achieved using different component placements (the optimal placement is where the aggregate radiative and conducted cross-coupling between components is minimized). For example, it may not be optimal to place components 120 degrees apart, and adjustments may be needed to place them in the best possible position. For instance, the first and second PCBs can be placed 90 degrees apart clockwise, and the third PCB can be placed another 150 degrees (or 135 degrees or 180 degrees) apart clockwise from the second PCB.

[0036] For parallel tuned amplifier designs (e.g., Figure 2For amplifiers (200), it is generally advantageous to use high intrinsic quality “Q” antennas and apply high oscillating voltages across these high “Q” antennas for wireless power transmission. For example, the high voltage can be hundreds of volts and can even exceed 1000 volts. In conventional systems where the resonant capacitor is placed on the same PCB as the filter or switching components, it can be difficult to isolate high oscillating voltages to prevent them from causing additional stress on the switching or filter components. Furthermore, residual heat from passive components (such as inductors and filter capacitors) can increase switching losses in the switching components. This is particularly difficult in systems where the amplifier drives multiple antennas in a wireless charging system. The design flexibility of the isolation subsystem in the disclosed technology makes it easy to isolate high oscillating voltages, preventing voltage coupling to other components and preventing increased thermal stress on those components. This results in improved system performance. However, if high voltage spikes across the capacitor used for a particular application do not pose substantial design challenges, the resonant capacitor can also be placed on the same PCB as the filter.

[0037] It will be understood that system layout 300 is merely representative. That is, the component layout (including the physical arrangement of the described filter PCBs 320 and 340, main PCB 330, resonant PCB 310, and coils 352 and 354) is merely representative, and other implementations may have different spacing distances. Considering the form factor constraints of the system, the maximum physical separation between components (such as the maximum physical separation between the antenna coil and the filter PCB) is preferably, for example, 1 inch or greater. Furthermore, although system layout 300 depicts an example differential system, the systems and methods of the disclosed technology are equally applicable to single-ended amplifier implementations. Additionally, to further minimize cross-coupling and hysteresis losses, shielding material may be inserted at both ends of each subsystem. This is for implementations such as... Figure 3 The physical constraint system shown is particularly significant because if these components were placed on a single PCB instead of the isolation method described here, it would be difficult to simultaneously shield the passive components of the filter and actively cool them (e.g., by a fan with switching components for the amplifier). Figure 3 An exemplary implementation is shown, in which isolation substantially improves the thermal response and operation of the system, which is challenging because the physical proximity of the filter PCB to the transmitter antenna causes the filter temperature to be higher than the ambient temperature inside the housing rather than the ambient temperature outside the housing.

[0038] Figure 5 This is a representative system layout 500 for filters, amplifiers, and DC jack PCBs used in isolated switch amplifier systems. For example, when... Figure 3 Compared to the implementation method, Figure 5The system can represent an application of an isolated switching amplifier topology where there are no stringent packaging requirements (e.g., more physical space for component placement). Layout 500 includes filter PCBs 502 and 504, amplifier PCB 510, and a separate power PCB or DC jack PCB 520. The DC jack PCB 520 is a separate PCB that receives the input of a DC power supply (e.g., the output of an AC-to-DC charger) and provides all the voltage levels required by amplifier PCB 510, such as all the logic and power voltages for logic circuitry or power circuitry (e.g., the amplifier). Figure 3 Compared to the implementation method, Figure 5 A representative implementation may include greater spacing between the filter, amplifier, and DC jack PCBs. In this implementation, there is more available physical space in the product to create greater separation between the PCBs. The additional separation distance further improves the overall system performance. Additionally, unlike... Figure 3 Positioning the filter PCB toward (multiple) transmitter antennas in the same way as described above further improves performance by reducing cross-coupling and hysteresis loss.

[0039] Arrows 503 and 505 in layout 500 indicate that the filters in filter PCBs 502 and 504 are electrically connected to separate resonant capacitor PCBs and antennas. Figure 5 (Not shown in the image). That is, in this representative embodiment, the non-conductive housing for the electronic components does not include the antenna and resonant capacitor PCB. This is because, if... Figure 5 As shown, having more available physical space in the product is more advantageous for physically isolating the main PCB (e.g., amplifier PCB 510), filter PCBs (e.g., filter PCBs 502 and 504), and power PCB (e.g., DC jack PCB 520) from the antenna and its resonant capacitor. The resonant capacitor PCB is also physically separated from the main PCB, filter PCB, and power PCB because for high intrinsic "Q" antenna applications, it is beneficial to physically bring the antenna's resonant capacitor close to the antenna. Bringing the resonant capacitor close to the antenna results in shorter lead runs and therefore lower resistance between the antenna and its corresponding resonant capacitor.

[0040] U.S. Patent Application No. 15 / 759,473 (Publication No. US2018 / 0262050) (incorporated herein by reference in its entirety) describes some example coil configurations that can be used with the isolation techniques and manufacturing methods described herein.

[0041] The following terms may be used to describe a list of schemes preferably implemented by some embodiments.

[0042] Clause 1. A switching amplifier system comprising: an amplifier printed circuit board (PCB); a filter PCB coupled to the amplifier PCB and configured to receive an amplified signal from the amplifier PCB, wherein the filter PCB is physically separated from the amplifier PCB by a distance of at least 10 mm; a resonant capacitor PCB coupled to the filter PCB and one or more antennas, wherein the resonant capacitor PCB is physically separated from the amplifier PCB and the filter PCB by a distance of at least 10 mm, wherein the resonant capacitor PCB is configured to receive a filtered signal from the filter PCB and drive the filtered signal onto the one or more antennas, and wherein the filtered signal is generated by filtering the amplified signal via a radio frequency (RF) filter in the filter PCB, and wherein the physical separation distance between the filter PCB, the amplifier PCB, the resonant capacitor PCB, and the one or more antennas is selected to reduce at least one of hysteresis loss, switching loss, or thermal loss of the switching amplifier system. Reference Figures 1 to 5 This section describes some example implementations of the system.

[0043] Clause 2. The switching amplifier system according to Clause 1, wherein the amplifier PCB includes a parallel-tuned Class E amplifier configured to amplify a periodic signal generated by a signal generator circuit.

[0044] Clause 3. The switching amplifier system according to Clause 1, wherein the amplifier PCB includes a Class D amplifier or a Class E amplifier configured to amplify a periodic signal generated by a signal generator circuit.

[0045] Clause 4. The switching amplifier system according to Clause 1, wherein the amplifier PCB is electrically connected to a separate power PCB, and the separate power PCB is connected to a DC power supply or an AC-to-DC (AC / DC) charger output, wherein the separate power PCB is configured to provide power to logic and power circuits.

[0046] Clause 5. The switching amplifier system according to Clause 1, wherein the one or more antennas include at least one coil, the at least one coil being configured as a surface spiral coil, the surface spiral coil including a continuous conductor without interruption or radio frequency discontinuity, the continuous conductor being wound at an angle around a dielectric material to reduce proximity effects at the operating frequency of the switching amplifier system and to maintain a high intrinsic quality factor (Q) of the surface spiral coil at the operating frequency.

[0047] Clause 6. The switching amplifier system according to Clause 5, wherein at least two coils include a first surface spiral coil arranged on a first plane and a second surface spiral coil arranged on a second plane perpendicular to the first plane.

[0048] Clause 7. The switching amplifier system according to Clause 6, wherein the first plane and the second plane intersect to define four quadrants, wherein the amplifier PCB is arranged in the first quadrant of the four quadrants, the filter PCB is arranged in the second quadrant of the four quadrants, and the resonant capacitor PCB is arranged in the third quadrant of the four quadrants.

[0049] Clause 8. The switching amplifier system according to Clause 7 further includes a second filter PCB arranged in the fourth quadrant of the four quadrants, wherein the second filter PCB is coupled to the resonant capacitor PCB and the amplifier PCB, and wherein the second filter PCB is physically isolated from the amplifier PCB, the filter PCB, the resonant capacitor PCB and the at least two coils.

[0050] Clause 9. The switching amplifier system according to Clause 1, further comprising: a differential amplifier contained in the amplifier PCB; and an additional filter PCB coupled to the amplifier PCB and configured to receive an amplified signal from the amplifier PCB.

[0051] Clause 10. A method for manufacturing a wireless charging system (e.g., Figure 6 The method described herein includes: attaching an amplifier printed circuit board (PCB) to a first region (610) of a non-conductive support structure; attaching a filter PCB to a second region of the support structure, wherein the filter PCB is electrically connected to the amplifier PCB and configured to receive an amplified signal from the amplifier PCB (620); attaching a resonant capacitor PCB to a third region (630) of the support structure, wherein the resonant capacitor PCB is electrically connected to the filter PCB and one or more antenna coils, and configured to receive a filtered signal from the filter PCB and drive the filtered signal to the one or more antenna coils, wherein the first, second, and third regions of the support structure are selected to maintain physical separation between the amplifier PCB, the resonant capacitor PCB, the filter PCB, and the one or more antenna coils; and wherein the distance of the physical separation between the filter PCB and the amplifier PCB and the distance of the physical separation between the filter PCB and the resonant capacitor PCB are at least 10 mm.

[0052] Clause 11. The method according to Clause 10, wherein the wireless charging system includes a Class D amplifier or a Class E amplifier configured to amplify a periodic signal generated by a signal generator circuit.

[0053] Clause 12. The method according to Clause 10, wherein the wireless charging system is configured to provide wireless power to an electronic device.

[0054] Clause 13. A method for manufacturing a wireless charging system (e.g., as...) Figure 7 The method described herein includes: attaching an amplifier printed circuit board (PCB) to a first region of a first support structure, wherein the first support structure is non-conductive (710); attaching a first filter PCB to a second region of the first support structure (720), wherein the first filter PCB is electrically connected to the amplifier PCB and configured to receive an amplified signal from the amplifier PCB, and wherein the first region and the second region of the first support structure are selected to maintain a physical separation distance of at least 10 mm between the amplifier PCB and the first filter PCB; attaching a resonant capacitor PCB to a second support structure (730), wherein the second support structure is separate from the first support structure, wherein the resonant capacitor PCB is electrically connected to the first filter PCB and one or more antenna coils; and wherein the physical separation distance between the resonant capacitor PCB and the first filter PCB is at least 10 mm.

[0055] Clause 14. The method according to Clause 13 further includes attaching the second filter PCB to a third region of the first support structure, wherein the first region, the second region, and the third region of the first support structure are selected to maintain a physical separation distance of at least 10 mm between the amplifier PCB, the first filter PCB, and the second filter PCB.

[0056] Clause 15. The method according to Clause 13 further includes attaching a power PCB to a fourth region of the first support structure, wherein the amplifier PCB is electrically connected to the power PCB, and the power PCB is connected to a direct current (DC) power supply or an AC-to-DC (AC / DC) charger output.

[0057] Clause 16. The method according to Clause 13, wherein the wireless charging system includes a Class D amplifier or a Class E amplifier configured to amplify a periodic signal generated by a signal generator circuit.

[0058] Clause 17. The method according to Clause 13, wherein the wireless charging system is configured to provide wireless power to the electronic device.

[0059] Comment

[0060] The accompanying drawings and the foregoing description provide a brief, general description of suitable environments in which the invention may be implemented. The above detailed description of examples of the invention is not intended to be exhaustive or to limit the invention to the precise forms disclosed above. While specific examples of the invention have been described above for illustrative purposes, those skilled in the art will recognize that various equivalent modifications are possible within the scope of the invention. For example, while processes or blocks are presented in a given order, alternative implementations may execute routines with steps / blocks, or employ systems with blocks in a different order, and some processes or blocks may be deleted, moved, added, subdivided, combined, or modified to provide alternatives or sub-combinations. Each of these processes or blocks can be implemented in various different ways. Moreover, while processes or blocks are sometimes shown as being executed serially, these processes or blocks may alternatively be executed or implemented in parallel, or may be executed at different times. Furthermore, any specific figures mentioned herein are merely examples: alternative implementations may employ different values ​​or ranges. For example, in practice, the disclosed embodiments may be implemented using operating tolerances of up to ±10%.

[0061] In light of the above detailed description, these and other changes can be made to the claimed invention. While the foregoing description describes certain examples of the claimed invention and depicts the intended best mode, the invention can be implemented in a variety of ways, regardless of how the foregoing detailed description appears in the text. The details of the system can vary considerably in its specific implementation, but are still covered by the embodiments disclosed herein. As noted above, when describing certain features or aspects of the invention, the terminology used should not be construed as meaning that the term is redefined herein to be limited to any particular characteristic, feature, or aspect of the invention associated with that term. Generally, the terminology used in the following claims should not be construed as limiting the invention to the specific examples disclosed in the specification, unless these terms are expressly defined in the foregoing detailed description. Therefore, the actual scope of the invention includes not only the disclosed examples but also all equivalent ways of practicing or implementing the invention under the claims.

Claims

1. A switching amplifier system, comprising: Amplifier printed circuit board (PCB); A filter PCB is connected to the amplifier PCB and configured to receive amplified signals from the amplifier PCB; The resonant capacitor PCB is connected to the filter PCB and one or more antennas. The resonant capacitor PCB is physically separated from the amplifier PCB and the filter PCB by a distance of at least 10 mm. The resonant capacitor PCB is configured to receive a filtered signal from the filter PCB and drive the filtered signal onto the one or more antennas. The filtered signal is generated by filtering the amplified signal via a radio frequency (RF) filter in the filter PCB. Specifically, the physical separation distance between the amplifier PCB, the resonant capacitor PCB, and the one or more antennas is selected to reduce at least one of the hysteresis loss, switching loss, or thermal loss of the switching amplifier system.

2. The switching amplifier system according to claim 1, wherein, The amplifier PCB includes a parallel-tuned Class E amplifier configured to amplify a periodic signal generated by a signal generator circuit.

3. The switching amplifier system according to claim 1, wherein, The amplifier PCB includes a Class D amplifier or a Class E amplifier, which is configured to amplify a periodic signal generated by a signal generator circuit.

4. The switching amplifier system according to claim 1, wherein, The amplifier PCB is electrically connected to a separate power PCB, and the separate power PCB is connected to a DC power supply or an AC-to-DC charger output, wherein the separate power PCB is configured to provide power to the logic and power circuits.

5. The switching amplifier system according to claim 1, wherein, The one or more antennas include at least one coil configured as a surface spiral coil, the surface spiral coil including a continuous conductor without interruption or radio frequency discontinuity, the continuous conductor being wound at an angle around a dielectric material to reduce proximity effects at the operating frequency of the switching amplifier system and to maintain a high intrinsic quality factor (Q) of the surface spiral coil at the operating frequency.

6. The switching amplifier system according to claim 5, wherein, The at least two coils include a first surface spiral coil arranged on a first plane and a second surface spiral coil arranged on a second plane perpendicular to the first plane.

7. The switching amplifier system according to claim 6, wherein, The first plane and the second plane intersect to define four quadrants, wherein the amplifier PCB is arranged in the first quadrant of the four quadrants, the filter PCB is arranged in the second quadrant of the four quadrants, and the resonant capacitor PCB is arranged in the third quadrant of the four quadrants.

8. The switching amplifier system of claim 7, further comprising a second filter PCB arranged in the fourth quadrant of the four quadrants, wherein, The second filter PCB is connected to the resonant capacitor PCB and the amplifier PCB, and wherein the second filter PCB is physically isolated from the amplifier PCB, the filter PCB, the resonant capacitor PCB and the at least two coils.

9. The switching amplifier system according to claim 1, wherein, Also includes: A differential amplifier is included in the amplifier PCB; as well as An additional filter PCB is connected to the amplifier PCB and configured to receive amplified signals from the amplifier PCB.

10. A method for manufacturing a wireless charging system, the method comprising: The amplifier printed circuit board (PCB) is attached to the first region of a non-conductive support structure; The filter PCB is attached to a second region of the support structure, wherein the filter PCB is electrically connected to the amplifier PCB and configured to receive amplified signals from the amplifier PCB; The resonant capacitor PCB is attached to the third region of the support structure. The resonant capacitor PCB is electrically connected to the filter PCB and one or more antenna coils, and is configured to receive a filtered signal from the filter PCB and drive the filtered signal to the one or more antenna coils. Specifically, the first, second, and third regions of the support structure are selected to maintain physical separation between the amplifier PCB, the resonant capacitor PCB, the filter PCB, and the one or more antenna coils; and The physical separation distance between the filter PCB and the resonant capacitor PCB is at least 10 mm.

11. The method according to claim 10, wherein, The wireless charging system includes a Class D amplifier or a Class E amplifier, which is configured to amplify a periodic signal generated by a signal generator circuit.

12. The method according to claim 10, wherein, The wireless charging system is configured to provide wireless power to electronic devices.

13. A method for manufacturing a wireless charging system, the method comprising: An amplifier printed circuit board (PCB) is attached to a first region of a first support structure, wherein the first support structure is non-conductive; The first filter PCB is attached to a second region of the first support structure, wherein the first filter PCB is electrically connected to the amplifier PCB and configured to receive an amplified signal from the amplifier PCB; The resonant capacitor PCB is attached to the second support structure. The second support structure is separate from the first support structure. Wherein, the resonant capacitor PCB is electrically connected to the first filter PCB and one or more antenna coils; and The physical separation distance between the resonant capacitor PCB and the first filter PCB is at least 10 mm.

14. The method of claim 13, further comprising attaching the second filter PCB to a third region of the first support structure, wherein, The first, second, and third regions of the first support structure are selected to maintain a physical separation distance of at least 10 mm between the amplifier PCB, the first filter PCB, and the second filter PCB.

15. The method of claim 13, further comprising attaching the power PCB to a fourth region of the first support structure, wherein, The amplifier PCB is electrically connected to the power PCB, and the power PCB is connected to a DC power supply or an AC-to-DC charger output.

16. The method according to claim 13, wherein, The wireless charging system includes a Class D amplifier or a Class E amplifier, which is configured to amplify a periodic signal generated by a signal generator circuit.

17. The method according to claim 13, wherein, The wireless charging system is configured to provide wireless power to electronic devices.

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