AC power delivery for reduced corrosion

Abstract

The disclosure relates to AC power delivery for reduced corrosion. Electric fields that may cause contact corrosion may be compensated for by embodiments of the invention. For example, the voltage waveform at the contact may be made to have a zero volt average, thus having a zero net electric field. Coupling voltages generated by different metals used by the contacts and the housing may generate an electric field, and current excited by the couple electric field may be blocked by capacitively coupling the contacts to their corresponding circuits.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit of U.S. Provisional Application No. 63 / 541,726, filed on September 29, 2023, entitled “AC Power Delivery for Reduced Corrosion,” and U.S. Non-Provisional Application No. 18 / 896,299, filed on September 25, 2024, entitled “AC Power Delivery for Reduced Corrosion,” which are incorporated by reference in their entirety for all purposes. Background Art

[0003] The amount of data transmitted between electronic devices has grown tremendously in recent years. Large amounts of audio, streaming video, text, and other types of data content are now often transmitted between desktop and portable computers, media devices, handheld media devices, displays, storage devices, and other types of electronic devices.

[0004] Power and data can be provided from one electronic device to another electronic device via a cable, which may include one or more wire conductors, fiber optic cables, or other conductors. Connector inserts may be located at each end of these cables and may be inserted into a connector socket in a communication or power transmission electronic device. Contacts in or on the connector insert may form an electrical connection with corresponding contacts in the connector socket. Other devices may have contacts at the surface of the device. When the devices are attached or positioned adjacent to each other and corresponding contacts are electrically connected to each other, a path for power and data may be formed.

[0005] These various contacts in the connector insert, in the connector socket, or on the device surface may be exposed to the local environment. These contacts may encounter liquids, moisture, or other damaging contaminants. For example, liquid may be splashed on these contacts, or the device may be set down so that the contacts of the device fall into a puddle of liquid. Users may swim or exercise while wearing or holding an electronic device. These activities may place the contacts of the electronic device in a position to be exposed to various contaminants.

[0006] These liquids or other contaminants can corrode and damage these contacts. This corrosion is greatly exacerbated by the presence of an electric field, such as when a constant voltage or DC voltage is applied to the contacts. Therefore, power contacts are particularly susceptible to corrosion.

[0007] Therefore, what are needed are methods, structures, and apparatus that can deliver power through device contacts while minimizing corrosion thereof. Summary of the invention

[0008] Thus, embodiments of the present invention may provide methods, structures, and apparatus that are capable of delivering power through a pair of power contacts while minimizing their corrosion. Exemplary embodiments of the present invention may provide methods, structures, and apparatus that are capable of delivering power through a pair of power contacts while minimizing corrosion by delivering power using a differential AC voltage having an average voltage of zero volts (or close to zero volts). These and other embodiments of the present invention may prevent current flow that may be caused by a galvanic voltage by capacitively coupling power contacts to circuits in an electronic device.

[0009] The contacts on the electronic device may be exposed to corrosive materials and fluids. These corrosive materials and fluids may cause corrosion of the contacts, thereby releasing ions from the contacts. In the presence of a DC electric field, corrosion and the release of ions may be accelerated. By applying an alternating electric field, the net corrosion of the contacts may be reduced. By applying an alternating electric field having a voltage with an average value of zero volts or close to zero volts, the migration of ions from the contacts outward may be at least approximately equal to the migration of ions into the contacts. This symmetrical migration may reduce the corrosion of the contacts. The effectiveness of this situation may be reduced by the galvanic voltage between the first metal forming the contacts and the second metal forming the housing or shell of the electronic device. The galvanic voltage may generate an electric field, which may also cause corrosion. The galvanic voltage may provide a current flow through the contacts, through the circuit in the electronic device to the housing or shell that may be grounded. The flow of electrons in the current may balance the migration of ions in the liquid. The current may be interrupted by capacitively coupling the power contacts to the circuit in the electronic device. That is, the capacitor may act as a direct current (DC) block, which may block the DC component of the current excited by the galvanic voltage, thereby further reducing the corrosion of the power contacts.

[0010] In these and other embodiments of the present invention, various contact structures can be used. A first contact on a first device can be matched with a second contact on a second device. The first contact can be biased by a spring to provide a contact force, while the second contact can be fixed to the device housing and can be acted upon by the contact force of the first contact. The first contact can be biased by a pair of inclined coil springs. The inclined coil spring can be positioned in a housing so that its central axis is orthogonal to the connection direction of the first contact. When the first device is matched with the second device, the first contact can be pushed into the first device in one direction. The first contact can push a plate and a retainer into the inclined coil spring, thereby collapsing or flattening the diameter of the inclined coil spring. The deformed inclined coil spring can then provide a deflection force into the second contact. When the first device and the second device are disconnected, the inclined coil spring can return to its original shape, thereby pushing the first contact away from the first device. The movement of the first contact can be limited by attaching the first contact and a pin to the retainer, wherein the pin can move in a corresponding slot in the housing in the first device. The canted coil spring may be held in place using one or more pins positioned through the central axis of the canted coil spring.

[0011] In these and other embodiments of the present invention, the first contact may be biased by a single canted coil spring. The canted coil spring may be positioned in the housing so that its central axis is orthogonal to the connection direction of the first contact. When the first device is mated with the second device, the first contact may be pushed into the first device in one direction. The first contact may push the plate and the retainer into the canted coil spring, thereby collapsing or flattening the diameter of the canted coil spring. The deformed canted coil spring may then provide a deflection force into the second contact. When the first device is disconnected from the second device, the canted coil spring may return to its original shape, thereby pushing the first contact away from the first device. The movement of the first contact may be limited by attaching a pin to the retainer, wherein the pin may move in a slot in the housing in the first device. The canted coil spring may be held in place using a plurality of slats attached to the frame.

[0012] In these and other embodiments of the present invention, the first contact may be biased by one or more stacks of Belleville washers. The Belleville washers may be placed back to back and then stacked. The stack may be placed on an alignment pin to limit the movement of the Belleville washers. When the first device is mated with the second device, the first contact may be pushed into the first device in a direction. The first contact may push a plate into the Belleville washer. When the plate is pushed into the stack of Belleville washers, the Belleville washer may be compressed, thereby reducing the length of the stack of Belleville washers. The Belleville washers may have the same or different thicknesses so that the Belleville washers provide at least slightly constant force on the deflection of the first contact. When the first device is disconnected from the second device, the Belleville washer may return to its original shape, thereby pushing the first contact away from the first device. The first contact and the plate may be attached to a retainer. The movement of the first contact may be limited by attaching a pin to the retainer, wherein the pin may move in a slot in a housing in the first device.

[0013] In these and other embodiments of the present invention, the second contact can be fixed in the second device, and the first contact can provide a force against the second contact. The second contact can be supported by a housing that is sealed to the housing or shell of the second device by a sealing ring. The contact and the housing can be attached to the flexible member using a pressure sensitive adhesive or other adhesive. The flexible member can be held in place by a cover. The cover can be attached to the flexible member using a pressure sensitive adhesive or other adhesive. The cover can be fixed to the housing or shell of the second device.

[0014] In these and other embodiments of the present invention, various circuits can be used to transmit power. These circuits can be used to transmit power from a first device to a second device, from a second device to a first device, or power can be transmitted bidirectionally or in a back-and-forth manner between a first device and a second device. For example, a first device can receive power from a charger or a power adapter. When the first device is powered, the second device can be connected to the first device. This can allow the first device to provide power to the second device. During device operation, the second device can provide power back to the first device. During device operation, the first device can continue to provide power to the second device as needed.

[0015] These power circuits can be the same or substantially similar in the first device and the second device.In these and other embodiments of the present invention, the first device and the second device can have differences, such as where the power transmission between the first device and the second device is unidirectional or one-way.

[0016] These and other embodiments of the present invention may provide a power transmission circuit with a battery. A first power transmission circuit may be housed in a first device, and a second power transmission circuit may be housed in a second device. A battery may be connected to a power circuit in the first device. The battery may be connected to a switch that may be opened when the first device is disconnected from the second device, and may be closed when power is transmitted. The switch may then be connected to a boost / buck circuit that may be connected to an inverter / rectifier circuit. The inverter / rectifier circuit may provide a capacitively coupled output signal to a pair of first contacts. The capacitively coupled output signal may be received from the pair of first contacts by a pair of second contacts of the second device. A rectifier / inverter circuit that may be the same or similar to the inverter / rectifier circuit of the first device may receive an output signal and provide an output to a buck / boost circuit that may be the same or similar to the boost / buck circuit in the first electronic device. The buck / boost circuit may be coupled to the battery and internal circuit of the second device by a switch.

[0017] Power is transferred from a first device to a second device. In the first power transfer circuit, a switch may connect a battery to a step-up / step-down circuit. The step-up / step-down circuit may act as a step-up circuit to increase a voltage from the battery and provide a high voltage and a low voltage to an inverter / rectifier circuit. The inverter / rectifier circuit may operate as an inverter to provide a differential output signal. The differential output signal may be capacitively coupled to a pair of first contacts of the first device.

[0018] The differential output signal may be received by a pair of second contacts of the second device. The differential output signal may be capacitively coupled to a rectifier / inverter circuit that may convert the differential output signal to a high voltage and a low voltage. The high voltage and the low voltage may be stepped down by a buck / boost circuit that may provide power through a switch to charge a battery of the second device. Although power is described as being transferred from the first device to the second device, power may also be transferred from the second device to the first device.

[0019] Various output differential signals can be provided by the inverter circuit according to the embodiment of the present invention. For example, a sine wave of anti-phase (or 180 degrees out of phase) can be provided on the first contact piece in pairs or the second contact piece in pairs. An anti-phase square wave can be provided on the first contact piece in pairs or the second contact piece in pairs. A square wave that has been filtered to remove high-frequency components and anti-phase can be provided on the first contact piece in pairs or the second contact piece in pairs. A square wave with limited bandwidth and anti-phase can be provided on the first contact piece in pairs or the second contact piece in pairs. Other differential waveforms can be provided on the first contact piece in pairs or the second contact piece in pairs.

[0020] The frequency of the differential output signal can vary. The amplitude of the differential output signal can vary. These parameters can vary with various conditions of the paired first contact members or the paired second contact members. For example, when liquid is detected on one or more of the contacts, the frequency, amplitude, or both of the differential output signal can vary. The differential output signal can be interrupted under some conditions.

[0021] A first contact in the first device may be capacitively coupled to a first power transmission circuit in the first device, and a second contact in the second device may be capacitively coupled to a second power transmission circuit in the second device. The presence of a capacitor for this AC or capacitive coupling may break a DC current path between the first contact, the second contact, the housing of the first device, and the housing of the second device.

[0022] For example, a liquid or fluid may be located above some or all of the first contact, the second contact, the housing of the first device, and the housing of the second device. As part of an electrochemical corrosion process, the fluid may cause corrosion of one or more of the first contact, the second contact, the housing of the first device, or the housing of the second device, thereby releasing ions from the structure into the fluid. The transfer of ions into the fluid may be part of a loop that includes a galvanic voltage that causes electrons to migrate from the contact and through a circuit in the first device or the second device and then to a grounded housing or housing. The input coupling capacitor may block the DC component of this current, thereby breaking the loop and slowing the flow of ions out of the contact and into the fluid.

[0023] In short, the presence of an electric field can cause ions to be transferred from the contact to the liquid. This process can corrode the contact. Therefore, the electric field can be compensated by embodiments of the present invention. For example, the voltage waveform at the contact can be made to have a zero volt average value, and therefore a zero net electric field. Moreover, the galvanic voltage generated by the different metals used for the contact and the housing can generate an electric field, but the current excited by the galvanic electric field can be blocked by capacitively coupling the contact to its corresponding circuit.

[0024] Data can be transmitted between the first device and the second device in various ways. The amplitude of the differential output signal can be modulated with data. The phase of the differential output signal can be modulated with data. The frequency of the differential output signal can be modulated with data. These modulations can be applied by the power and data transmitting device and recovered by the power and data receiving device. In these and other embodiments of the present invention, the power transmitting device can provide a differential output signal. The power receiving device can be a data transmitting device and can modulate the load experienced by the power transmitting device. The load can be modulated by data sent back to the power transmitting device by the power receiving device. The power transmitting device can also be a data receiving device and can recover the data.

[0025] These and other embodiments of the present invention may include additional features that can help prevent or reduce corrosion. For example, electrical impedance spectroscopy circuits may be included. These circuits can provide a voltage waveform to one or more contacts of the device. The resulting voltage, the resulting current, or both can be measured. The resulting current can indicate that current flows through the liquid. The phase shift between the applied voltage waveform and the resulting current or the resulting voltage can indicate the amount or type of liquid. A coupling capacitor can be inserted between the contact and the electrical impedance spectroscopy circuit to prevent corrosion paths.

[0026] Embodiments of the present invention may provide power transmission circuits and apparatus that may be located in various types of devices, such as portable computing devices, tablet computers, desktop computers, laptop computers, all-in-one computers, wearable computing devices, cellular phones, smart phones, media phones, storage devices, portable media players, navigation systems, monitors, power supplies, video delivery systems, adapters, remote control devices, chargers, and other devices.

[0027] The first device and the second device can be various types of devices. Although the first device and the second device can be connected by a cable, they are usually directly matched together. For example, the first device can be an audio device such as a headset or earbuds, and the second device can be a housing for carrying and charging the audio device, or the second device can be an audio device such as a headset or earbuds, and the first device can be a housing for carrying and charging the audio device. The first device can be a tablet computer, and the second device can be a housing and a keyboard, or the second device can be a tablet computer, and the first device can be a housing and a keyboard. The first device can be a watch, and the second device can be a watchband, or the second device can be a watch, and the first device can be a watchband. The first device and the second device can be other types of devices that can be connected to each other by direct matching.

[0028] Various embodiments of the present invention may include one or more of these and other features described herein.The nature and advantages of the present invention may be better understood by referring to the following detailed description and the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 An electronic system according to an embodiment of the present invention is illustrated;

[0030] Figure 2 A spring biased contact assembly according to an embodiment of the present invention is illustrated;

[0031] Figure 3 A spring biased contact assembly according to an embodiment of the present invention is illustrated;

[0032] Figure 4 Shows Figure 3 An exploded view of a contact assembly;

[0033] Figure 5 illustrates a force-deflection curve of a first contact according to an embodiment of the present invention;

[0034] Figure 6 illustrates a variation of a spring biased contact assembly according to an embodiment of the present invention;

[0035] Figure 7 yes Figure 6 An exploded view of a contact assembly;

[0036] Figure 8 is a cross-section of a second contact assembly according to an embodiment of the present invention;

[0037] Fig. 9 yes Figure 8 An exploded view of a contact assembly;

[0038] Fig.10 According to an embodiment of the present invention Figure 1 A block diagram of a charging system for an electronic system;

[0039] Fig.11 According to an embodiment of the present invention Figure 1 Circuit diagram of the contact interface of the electronic system;

[0040] Fig.12 is a simplified circuit diagram of a portion of a power system circuit according to an embodiment of the present invention;

[0041] Fig.13 is an alternative simplified circuit diagram of a portion of a power system circuit according to an embodiment of the present invention;

[0042] Fig.14 is a simplified circuit diagram of portions of two power system circuits for transmitting power according to an embodiment of the present invention;

[0043] Figures 15 to 17 A contact assembly according to an embodiment of the present invention is illustrated;

[0044] 18A to 18D illustrates a cross-sectional view of a contact assembly according to an embodiment of the present invention;

[0045] Fig.19 A contact assembly for a contact interface according to an embodiment of the present invention is illustrated;

[0046] Fig. 20 illustrating further details of a contact assembly according to an embodiment of the present invention;

[0047] Fig.21 A contact assembly for a contact interface according to an embodiment of the present invention is illustrated;

[0048] Fig. 22 is a cross-sectional side view of a contact assembly according to an embodiment of the present invention;

[0049] Fig.23 illustrates galvanic corrosion paths in electronic devices according to embodiments of the present invention;

[0050] Fig.24 illustrates optional DC charging in an electronic device according to an embodiment of the present invention;

[0051] Fig.25 illustrates an AC waveform for power transmission according to an embodiment of the present invention;

[0052] Fig.26 illustrates a charging path through an electronic system according to an embodiment of the present invention;

[0053] Fig. 27 illustrates another charging path through an electronic system according to an embodiment of the present invention;

[0054] Fig.28 illustrates another charging path through an electronic system according to an embodiment of the present invention;

[0055] Fig.29 illustrates data that may be used by a method of determining a type of material for a contact according to an embodiment of the present invention; and

[0056] Fig.30 A method of optimizing a charging waveform according to an embodiment of the present invention is illustrated. DETAILED DESCRIPTION

[0057] Figure 1 An electronic system according to an embodiment of the present invention is illustrated. Figure 1 As such, the drawings are shown for illustrative purposes only and do not limit possible embodiments of the invention or the claims.

[0058] In this example, the electronic system 10 may include a first device 100 that can be connected to a second device 200 to share data, power, or both. A first contact 110, a first contact 112, and a first contact 114 (collectively referred to as the first contact 110) on the first device 100 can be electrically connected to a second contact 210, a second contact 212, and a second contact 214 (collectively referred to as the second contact 210) on the second device 200. The first contact 110 on the first device 100 can be electrically connected to the second contact 210 on the second device 200 using a cable (not shown). In other embodiments of the present invention, the first contact 110 on the first device 100 can be directly electrically connected to the second contact 210 on the second device 200. In various embodiments of the present invention, the first contact 110 and the second contact 210 can be power contacts or other types of contacts. Examples of embodiments of the present invention in which the first contact 110, the first contact 112, the second contact 210, and the second contact 212 are power contacts are shown in the following figures. The first and second contacts 114 , 214 may be ground contacts, data or signal contacts, or other types of contacts.

[0059] Embodiments of the present invention may transfer power from the first device 100 to the second device 200 by providing an AC differential voltage having an average value of zero volts or close to zero volts at the first contact 110 and the first contact 112. Power may be transferred from the second device 200 to the first device 100 by providing an AC differential voltage having an average value of zero volts or close to zero volts at the second contact 210 and the second contact 212. This may provide reduced or low levels of migration of ions into the contacts, thereby reducing corrosion of the first contact 110 and the second contact 210 when the device power contacts are exposed to contaminants. The first contact 110 may be capacitively coupled to the power transmission circuit 120, and the second contact 210 may be capacitively coupled to the power transmission circuit 220. The capacitive coupling may eliminate or reduce currents generated by the galvanic voltage between dissimilar metals used for the first contact 110, the second contact 210, and the housings or casings of the first device 100 and the second device 200.

[0060] The first contact 110 can be coupled to a power transmission circuit 120 in the first device 100. The power transmission circuit 120 can provide power to or draw power from the battery 190. The second contact 210 can be coupled to a power transmission circuit 220 in the second device 200. The power transmission circuit 220 can provide power to or draw power from the battery 290.

[0061] The first device 100 and the second device 200 can be various types of devices. Although the first device 100 and the second device 200 can be connected by a cable, they are usually directly matched together. For example, the first device 100 can be an audio device such as a headset or earplug, and the second device 200 can be a shell for carrying and charging the audio device, or the second device 200 can be an audio device such as a headset or earplug, and the first device 100 can be a shell for carrying and charging the audio device. The first device 100 can be a tablet computer, and the second device 200 can be a shell and a keyboard, or the second device 200 can be a tablet computer, and the first device 100 can be a shell and a keyboard. The first device 100 can be a watch, and the second device 200 can be a watchband, or the second device 200 can be a watch, and the first device 100 can be a watchband. The first device 100 and the second device 200 can be other types of devices that can be connected to each other by direct matching.

[0062] The first contact 110 may be a spring biased contact that may cooperate with the fixed second contact 210. The first contact 110 may be spring biased so that it provides a force against the second contact 210 to provide a good electrical connection. Examples of first contacts are shown in the following figures.

[0063] Figure 2 A spring-biased contact assembly according to an embodiment of the present invention is illustrated. The first contact assembly 20 may include a first contact 110. The first contact 110 may be biased by a pair of inclined coil springs 130. The inclined coil springs 130 may be positioned in the housing 150 so that the central axis of the inclined coil springs 130 is orthogonal to the connection direction of the first contact 110. When the first device 100 and the second device 200 (both Figure 1 150 ), the first contact 110 can be pushed into the first device 100 in a direction when mated with the plate 170 and the retainer 160. The first contact 110 can push the plate 170 and the retainer 160 into the canted coil spring 130, thereby causing the canted coil spring 130 to collapse or flatten in the diameter direction thereof. When the first device 100 and the second device 200 are disconnected, the canted coil spring 130 can return to its original shape, thereby pushing the first contact 110, the plate 170 and the retainer 160 away from the first device 100. The movement of the first contact 110 can be limited by attaching the first contact and a pin 162 to the retainer 160, wherein the pin 162 can move in a slot 152 in the housing 150 in the first device 100. The canted coil spring 130 can be held in place using one or more pins 140 positioned through the central axis of the canted coil spring 130. The wire 180 can couple the first contact 110 to a coupling capacitor, such as Fig.11 The coupling capacitor C1 in.

[0064] Figure 3 A spring-biased contact assembly according to an embodiment of the present invention is illustrated. In these and other embodiments of the present invention, the first contact 110 can be biased by a single canted coil spring 230. The first contact assembly 30 can include a canted coil spring 230. The canted coil spring 230 can be positioned in the housing 250 so that the central axis of the canted coil spring is orthogonal to the connection direction of the first contact 110. When the first device 100 and the second device 200 (both Figure 1 200), the first contact 110 can be pushed into the first device 100 in a direction. The first contact 110 can push the plate 270 and the retainer 260 into the canted coil spring 230, causing the canted coil spring 230 to collapse or flatten in its diameter direction. When the first device 100 and the second device 200 are disconnected, the canted coil spring 230 can return to its original shape, pushing the first contact 110, the plate 270 and the retainer 260 away from the first device 100. The movement of the first contact 110 can be limited by attaching the first contact 110 and the pin 262 to the retainer 260, wherein the pin 262 can move in a slot 252 in the housing 250 in the first device 100. The canted coil spring 130 can be held in place using a plurality of slats 242 attached to the frame 240. The wire 280 can couple the first contact 110 to a coupling capacitor, such as Fig.11 The coupling capacitor C1 in.

[0065] Figure 4 Shows Figure 3 Exploded view of a contact assembly of . The first contact assembly 30 may include an inclined coil spring 230. The inclined coil spring 230 may be held in place by a slat 242 extending from the frame 240. The plate 270 may further restrain the inclined coil spring 230. The plate 270 may be attached to the bottom of the retainer 260. The retainer 620 may hold the first contact 110 in the slot 264. The plate 270 may be attached to the underside of the retainer 260. The wire 280 may route voltage and current from the first contact 110 to the power transmission circuit 120 in the first device 100. The retainer 260 may slide within a range defined by the pin 262 in the slot 252 in the housing 250 (e.g., Figure 3 When the first device 100 and the second device 200 (both at Figure 1100). When the first device 100 and the second device 200 are mated, the first contact 110 can be pushed into the first device 100 in a direction. The first contact 110 can push the plate 170 and the retainer 160 into the inclined coil spring 130, thereby causing the inclined coil spring 130 to collapse or flatten in a diameter direction thereof. When the first device 100 and the second device 200 are disconnected, the inclined coil spring 130 can return to its original shape, thereby pushing the plate 270, the retainer 260 and the first contact 110 away from the first device 100.

[0066] Figure 5 5. The force-deflection curve of the first contact according to an embodiment of the present invention is illustrated. The graph 500 illustrates a force-deflection curve 530, which is plotted as a first contact 110 (eg, Figure 1 The contact force 510 provided by the first contact 110 varies with the deflection 520 of the first contact member when the first device is mated with the second device. The amount by which the first contact member 110 can deflect can be within a range 540. Due to manufacturing tolerances in the formation of the first device 100, the second device 200, the first contact member 110, the second contact member 210, and the manner in which they mate, the deflection can vary within this range. Therefore, it is expected that the contact force is independent of the displacement. That is, it is expected that the force-deflection curve 530 is at least relatively flat within the range 540. This can be used Figure 2 and Figure 3 The example of the canted coil spring 130 and the canted coil spring 230 is implemented. The force-deflection curve 530 can be given a flat portion in the range 540 using other structures. An example is shown in the following figure.

[0067] Figure 6 A variation of a spring-biased contact assembly according to an embodiment of the present invention is illustrated. In the contact assembly 30, the first contact 110 may be biased by one or more stacks of Belleville washers 630. The Belleville washers 630 may be placed back to back and then stacked. The stack of Belleville washers 630 may be placed on an alignment pin 644 to limit the movement of the Belleville washers 630. When the first device 100 is aligned with the second device 200 (both are aligned with each other), the first contact 110 may be biased by one or more stacks of Belleville washers 630. The Belleville washers 630 may be placed back to back and then stacked. The stack of Belleville washers 630 may be placed on an alignment pin 644 to limit the movement of the Belleville washers 630. Figure 1660 and the plate 670 are mated. When the plate 270 is mated with the second device 100 (shown in ), the first contact 110 can be pushed into the first device 100 in a direction. The first contact 110 can push the plate 670 into the Belleville washer 630. When the plate 270 is pushed into the stack of Belleville washers 630, the Belleville washers 630 can begin to compress, thereby reducing the length of the stack of Belleville washers 630. The Belleville washers 630 can have the same or different thicknesses so that the Belleville washers 630 can provide at least a slightly constant force on the deflection of the first contact 110. When the first device 100 and the second device 200 are disconnected, the Belleville washer 630 can return to its original shape, thereby pushing the first contact 110, the retainer 660 and the plate 670 away from the first device 100. The wire 680 can route voltage and current from the first contact 110 to the power transmission circuit 120 (all in Figure 1 ). An insulating member 682 may be disposed around the conductive line 680.

[0068] Figure 7 yes Figure 6 640. The stack of Belleville washers 630 can be placed on the alignment pins 644 in the contact assembly 30. The Belleville washers 630 can be held between the frame 640 and the plate 670. The strips 642 can extend from the frame 640. The wires 680 can route voltage and current from the first contact 110 to the power transmission circuit 120 in the first device 100 (all in Figure 1 ). The retainer 660 may support the pin 662 (eg, Figure 6 ), the first contact 110 and the plate 670. The retainer 660 is movable within a range defined by a pin 662 in an opening (not shown) in the housing 650.

[0069] Figure 8 is a cross-section of a second contact assembly according to an embodiment of the present invention. In these and other embodiments of the present invention, the second contact 210 in the second contact assembly 80 can be fixed in the second device 200 (such as Figure 1 850 ). The first contact 110 may provide a force against the second contact 210. The second contact 210 may be supported by a housing 810 that is sealed to a housing or shell 890 of the second device 200 by a sealing ring 820. The second contact 210 may be attached to the flexible circuit board 830 using a pressure sensitive adhesive 840 or other adhesive. The flexible circuit board 830 may be held in place by a cover 850. The cover 850 may be attached to the flexible circuit board 830 using a pressure sensitive adhesive 860 or other adhesive. The cover 850 may be fastened to the housing or shell 890 of the second device 200 by fasteners 892.

[0070] Fig. 9 yes Figure 8 The second contact 210 in the second contact assembly 80 can be supported by a housing 810. The housing 810 can be sealed to the second device 200 (such as Figure 2 ) of a housing or shell 890 (as shown) Figure 8 The second contact member 210 may contact the pad 832 on the flexible circuit board 830. The flexible circuit board 830 may include a pad 834 that may be connected to the pad 832 to electrically connect to the power transmission circuit 220 in the second device 200 (as shown). Figure 1 840 or other adhesive can be used to attach the housing 810 to the flexible circuit board 830. The flexible circuit board 830 can be held in place by the cover 850. The cover 850 can be attached to the flexible circuit board 830 using a pressure sensitive adhesive 860 or other adhesive. The cover 850 can be fastened to the housing or shell 890 of the second device 200 by passing a fastener 892 through the opening 852 and inserting the fastener 892 into a corresponding hole in the housing or shell 890 of the second device 200.

[0071] In these and other embodiments of the present invention, various circuits can be used to transmit power. These circuits can be used to transmit power from a first device to a second device, from a second device to a first device, or power can be transmitted bidirectionally or in a back-and-forth manner between a first device and a second device. For example, a first device can receive power from a charger or a power adapter. When the first device is powered, the second device can be connected to the first device. This can allow the first device to provide power to the second device. During device operation, the second device can provide power back to the first device. During device operation, the first device can continue to provide power to the second device as needed.

[0072] These power circuits may be identical or substantially similar in the first device and the second device. In these and other embodiments of the invention, the first device and the second device may have differences, such as where the power transmission between the first device and the second device is unidirectional or one-way. The following figure shows an example.

[0073] Fig.10 According to an embodiment of the present invention Figure 1 The first power transmission circuit 120 may be housed in a first device 100 (eg, Figure 1 ), and the second power transmission circuit 220 can be accommodated in the second device 200 (as shown Figure 1100). The first power transmission circuit 120 can share power with the second power transmission circuit 220. For example, the power transmission circuit 120 can transmit power to the second power transmission circuit 220. The battery 190 can be connected to a switch 1010, which can be opened when the first device is disconnected from the second device 200, and the switch can be closed when power is transmitted. The switch 1010 can then be connected to a boost / buck circuit 1020, which can be connected to an inverter / rectifier circuit 1030. The inverter / rectifier circuit 1030 can provide a capacitively coupled output signal to a pair of first contacts including a first contact 110 and a first contact 112 through capacitors C1 and C2. The capacitively coupled output signal can be received from the pair of first contacts 110 through a pair of second contacts 210 including a second contact 210 and a second contact 212 of the second device. The signal on the second contact 210 and the second contact 212 may be capacitively coupled to the rectifier / inverter circuit 1040 through capacitors C3 and C4. The rectifier / inverter circuit 1040, which may be the same or similar to the inverter / rectifier circuit 1030 of the first power transmission circuit 120, may provide an output to the buck / boost circuit 1050, which may be the same or similar to the boost / buck circuit 1020 in the first power transmission circuit 120. The buck / boost circuit 1050 may be coupled to the battery 290 and the internal circuitry of the second device 200 through the switch 1060.

[0074] Power can be transmitted from the first device 100 to the second device 200. In the first power transmission circuit 120, the switch 1010 can connect the battery 190 to the boost / buck circuit 1020. The boost / buck circuit 1020 can act as a boost circuit to increase the voltage from the battery 190 and provide a high voltage and a low voltage to the inverter / rectifier circuit 1030. The inverter / rectifier circuit 1030 can operate as an inverter to provide a differential output signal. The differential output signal can be capacitively coupled to the first contact 110 through the capacitor C1, and capacitively coupled to the first contact 112 through the capacitor C2.

[0075] The differential output signal can be received by the second contact 210 and the second contact 212 of the second device 200. The differential output signal can be capacitively coupled to the rectifier / inverter circuit 1040 through capacitors C3 and C4, which can convert the differential output signal into a high voltage and a low voltage. The high voltage and the low voltage can be stepped down by the buck / boost circuit 1050, which can provide power to charge the battery 290 of the second device 200 through the switch 1060. Although power is described as being transmitted from the first device 100 to the second device 200, power can also be transmitted from the second device 200 to the first device 100.

[0076] According to an embodiment of the present invention, various output differential signals can be provided by the inverter of the inverter / rectifier circuit 1030 and the rectifier / inverter circuit 1040. For example, a sine wave of anti-phase (or 180 degrees out of phase with each other) can be provided on the first contact piece in pairs or the second contact piece in pairs. An anti-phase square wave can be provided on the first contact piece in pairs or the second contact piece in pairs. A square wave that has been filtered to remove high-frequency components and anti-phase can be provided on the first contact piece in pairs or the second contact piece in pairs. A square wave with limited bandwidth and anti-phase can be provided on the first contact piece in pairs or the second contact piece in pairs. Other differential waveforms can be provided on the first contact piece in pairs or the second contact piece in pairs.

[0077] The frequency of the differential output signal can vary. The amplitude of the differential output signal can vary. These parameters can vary with various conditions of the paired first contact members or the paired second contact members. For example, when liquid is detected on one or more of the contacts, the frequency, amplitude, or both of the differential output signal can vary. The differential output signal can be interrupted under some conditions.

[0078] Data can be transmitted between the first device 100 and the second device 200 in a variety of ways. The amplitude of the differential output signal can be modulated with data. The phase of the differential output signal can be modulated with data. The frequency of the differential output signal can be modulated with data. These modulations can be applied by a power and data transmitting device and recovered by a power and data receiving device. In these and other embodiments of the present invention, the power transmitting device can provide a differential output signal. The power receiving device can be a data transmitting device and can modulate the load experienced by the power transmitting device. The load can be modulated by data sent back to the power transmitting device by the power receiving device. The power transmitting device can also be a data receiving device and can recover the data. Instead of using a differential output signal, the first contact 114 of the first device 100 and the second contact 214 of the second device 200 (all in Figure 1 ) to transmit data.

[0079] The first contact 110 and the first contact 112 in the first device 100 can be capacitively coupled to the first power transmission circuit 120 in the first device 100 using capacitors C1 and C2, and the second contact 210 and the second contact 212 in the second device 200 can be capacitively coupled to the second power transmission circuit 220 in the second device 200 using capacitors C3 and C4. The presence of capacitors for this AC or capacitive coupling can disconnect the first contact 110, the second contact 210, the device housing 1110 (such as the first device 100) from the first device 100. Fig.11 ) and the device housing 1120 of the second device 200 (as shown in Fig.11The DC current path between the

[0080] For example, the fluid or liquid may be located on some or all of the first contact 110, the second contact 210, the device housing 1110 of the first device 100, and the device housing 1120 of the second device 200. As part of the electrochemical corrosion process, the fluid may cause corrosion and induce ions to move out of one or more of the first contact 110, the second contact 210, the device housing 1110 of the first device 100, and the device housing 1120 of the second device 200 and into the fluid. The transfer of ions from the contact to the fluid may be part of a loop that includes current moving from the contact and passing through a circuit in the first device or the second device and then grounding. The input coupling capacitor may block the DC component of the current, thereby disconnecting the loop and slowing down the flow of ions out of the contact and into the fluid. The following figure shows more details.

[0081] Fig.11 According to an embodiment of the present invention Figure 1 Circuit diagram of a contact interface of an electronic system of FIG. The first contact 110 may be coupled to an electrostatic discharge diode D1. The electrostatic discharge diode D1 may be a high impedance, low leakage diode. The first contact 110 may be coupled to a capacitor C1, which in turn may be coupled to an inductor L1. The inductor L1 may be included to reduce bursts of current through the capacitor C1 when the first power transmission circuit 120 provides power to the second power transmission circuit 220. The capacitor C1 may be selected to be large enough to provide a low impedance for the differential output signal, but small enough to be physically reasonable. The inductor L1 may be selected so that the tuned frequency of the inductor L1 and the capacitor C1 has a period that is shorter than the period of the differential output signal.

[0082] The liquid or fluid may be present on one or more of the first contact 110, the first contact 112, the device housing 1110, the second contact 210, the second contact 212, and the device housing 1120. As part of the electrochemical corrosion process, the fluid may cause corrosion and induce ions to move out of one or more of the first contact 110, the second contact 210, the device housing 1110, and the device housing 1210 and into the fluid. The transfer of ions may be facilitated by an electric current flowing from one of the first contact 110 or the second contact 210 and through a circuit in the first device 100 or the second device 200 and then flowing to one of the device housing 1110 or the device housing 1120, which may be grounded. The current flow may be driven by, for example, a galvanic voltage that occurs between the first contact 110 and the device housing 1110. For example, the first contact may be plated with gold or other conductive material, and the device housing 1110 may be steel, aluminum, or other material. These different materials may form a galvanic voltage between the first contacts 110 and the device housing 1110. The input coupling capacitors C1 and C2 may block the DC component of the current from one of the first contacts 110 to the device housing 1110. The input coupling capacitors C3 and C4 may block the DC component of the current from one of the second contacts 210 to the device housing 1120.

[0083] In this example, capacitor C2 can be coupled to first contact 112, electrostatic discharge diode D2, and inductor L2. Inductor L1 and inductor L2 can be coupled to inverter / rectifier circuit 1030. Diodes D1 and D2 can be the same or similar. Inductors L1 and L2 can be the same or similar. Coupling capacitor C3 can be coupled to second contact 210, electrostatic discharge diode D3, and inductor L3. Diodes D1 and D3 can be the same or similar. Inductors L1 and L3 can be the same or similar. Coupling capacitor C4 can be coupled to second contact 212, electrostatic discharge diode D4, and inductor L4. Diodes D1 and D4 can be the same or similar. Inductors L1 and L4 can be the same or similar. Inductor L3 and inductor L4 can be coupled to rectifier / inverter circuit 1040. The stray impedance between the first contact 110, the second contact 210, the device housing 1110 of the first device 100, and the device housing 1120 of the second device 200 may be modeled as resistors R1 to R7. Capacitors C1, C2, C3, and C4 may be the same or similar.

[0084] Various circuits may be used to implement the power transmission circuit 120 and the power transmission circuit 220. The following figure shows an example.

[0085] Fig.121 is a simplified circuit diagram of a portion of a power system circuit according to an embodiment of the present invention. In this example, a transistor P1 can be used to implement switch 1010 (and switch 1060). Transistor P1 can connect battery 190 (or battery 290) to boost / buck circuit 1020 (or buck / boost circuit 1050). Transistor P1 is shown as a P-MOS transistor, although transistor P1 can be implemented in various ways, such as by an N-MOS transistor, by two parallel transistors (wherein a resistor is connected in series with one of the two transistors), or by other devices or circuits. Boost / buck circuit 1020 (and buck / boost circuit 1050) can be implemented using a single-input multiple-output (SIMO) type architecture including inductor L1, transistor N1, transistor N2, transistor N3, and transistor N4. Boost / buck circuit 1020 (or buck / boost circuit 1050) can be coupled to inverter / rectifier circuit 1030 (or rectifier / inverter circuit 1040). The boost / buck circuit 1020 (and the buck / boost circuit 1050 ) may have a full-bridge architecture, which may include transistor N5 , transistor N6 , transistor N7 , and transistor N8 .

[0086] Fig.13 is an alternative simplified circuit diagram of a portion of a power system circuit according to an embodiment of the present invention. In these and other embodiments of the present invention, such as Fig.12 As shown, switch 1010 (and switch 1060) can be replaced by a circuit (not shown) that is a voltage and current limiter when receiving power and a current limiter when sending data. The boost / buck circuit 1020 (and buck / boost circuit 1050) can be implemented using a SEPIC-Cuk DC to DC converter including three inductors (inductor L1, inductor L2, and inductor L3). Transistor P1, transistor N1, and transistor N2 can be included, as well as capacitor C1, capacitor C2, capacitor C3, capacitor C4, and capacitor C5. The boost / buck circuit 1020 (and buck / boost circuit 1050) can again have a full-bridge architecture, which can include transistor N5, transistor N6, transistor N7, and transistor N8.

[0087] These and other embodiments of the present invention may include additional features that can help prevent or reduce corrosion. For example, electrical impedance spectroscopy circuits may be included. These circuits can provide a voltage waveform to one or more contacts of the device. The resulting voltage, the resulting current, or both can be measured. The resulting current can indicate that current is flowing through the liquid. The phase shift between the applied voltage waveform and the resulting current or the resulting voltage can indicate the amount or type of liquid. A coupling capacitor can be inserted between the contact and the electrical impedance spectroscopy circuit to prevent corrosion paths. Examples are shown in the following figure.

[0088] Fig.14 14 is a simplified circuit diagram of portions of two power system circuits for transmitting power according to an embodiment of the present invention. The inverter / rectifier circuit 1030 may act as an inverter and provide a differential output signal to the first contact 110 through the switch 1420 and the coupling capacitor 1430. The coupling capacitor 1430 may include a Fig.11 The capacitors C1 and C2 of the contact interface of the second device 200 can be connected to the power factor correction controller 1450. The second contact 210 can receive the differential output signal and provide it to the rectifier / inverter circuit 1040, which can act as a rectifier and provide high and low voltages to the power factor correction controller 1450. The power factor correction controller 1450 can pass the output to the power management controller 1460 that can charge the battery 290. The power management controller 1460 can control the voltage and current experienced by the battery 290 during charging. In the case where the second device 200 can charge the first device 100, the path can be reversed.

[0089] An electrochemical impedance spectroscopy (EIS) circuit 1470 may be included. The EIS circuit 1470 may provide a voltage waveform or a current waveform, but in this example a voltage waveform may be provided. The voltage waveform may be a sine wave, a square wave, or other voltage waveform. The EIS circuit 1470 may be coupled to the first contact 110 via a coupling capacitor 1430. When liquid is present at one or more first contacts 110, the EIS circuit 1470 may be used to detect a current or voltage. The current, voltage, or both may indicate changes in capacitance and resistance experienced at the first contact 110. The EIS circuit 1470 may detect the magnitude of the current and voltage and any phase shift compared to the applied voltage, and thereby determine changes in capacitance and resistance experienced at the first contact 110. Based on changes in capacitance and resistance, the presence of liquid and information about the type of liquid present may be determined. More details on this may be found in U.S. Patent No. 11,658,443, filed May 23, 2023, entitled “LIQUID DETECTION AND CORROSION MITIGATION,” which is incorporated by reference. Sources source1 and source2 may be used as voltage signals in the EIS circuit 1470 .

[0090] Other types of circuits may be included in or associated with either or both of the power transmission circuit 120 and the power transmission circuit 220. For example, connection detection may be used to disconnect the battery 190 or the battery 290 when the opposing devices are not mated. The connection detection may include sending occasional voltage pings at the first contact 110. The voltage ping should have the property that the average of the ping or the average of a group of pings should be zero volts.

[0091] Figures 15 to 17 A contact assembly according to an embodiment of the present invention is illustrated. Fig.15 , the contact assembly 1500 may include a contact 110 and a housing 1530. The insulator 1520 may form a seal between the contact 110 and the housing 1530 to prevent leakage into the interior of a device in which the contact assembly 1500 is incorporated.

[0092] The contact 110 may be formed of a block or substrate 1510. An optional plating layer 1512 may be formed on the bottom or inner surface of the contact 110. Other optional plating layers may be formed along the sides of the block or substrate 1510. The block or substrate 1510 may be formed of stainless steel, titanium, tantalum, chrome-nickel-inconel, nickel-aluminum bronze, copper, copper alloy, or other materials. The use of these materials may provide a contact that is easy to manufacture and can save valuable resources compared to contacts that may use foreign materials. These materials may provide good durability and corrosion resistance. The optional plating layer 1512 may be formed of gold or other conductive materials, for example, the optional plating layer 1512 may be contact plating. The optional plating layer 1512 may form a surface that can be soldered to a flexible circuit board or other suitable substrate.

[0093] In these and other embodiments of the invention, the voltage waveform delivered by the contact 110 may be an AC waveform. Thus, much of the current through the contact 110 may be delivered at the surface of the contact 110. Thus, embodiments of the invention may provide electroplating on some of all sides 1514 of the block or substrate 1510. The electroplating may be gold, diamond-like carbon (which has been formed to be conductive), titanium nitride, tin-silver, nickel-gold, or other materials. In these and other embodiments of the invention, the electroplating may extend along the top and some or all sides of the block or substrate 1510. Examples are shown in the following figures.

[0094] exist Fig.16 , the contact assembly 1600 may include a contact 110, a housing 1530, and an insulator 1520, which may form a seal between the contact 110 and the housing 1530. The contact 110 may include a block or substrate 1510 and an optional plating layer 1512, which may be plated with a finish layer 1610. The finish layer 1610 may be formed of diamond-like carbon (which has been formed to be conductive), tin, tin-silver, nickel-gold, or other materials.

[0095] exist Fig.17In the embodiment of the present invention, the contact assembly 1700 may include a contact 110, a housing 1530 and an insulator 1520, which may form a seal between the contact 110 and the housing 1530. The contact 110 may include a block or substrate 1510, an optional plating layer 1512 and a finishing layer 1610, and an intermediate layer 1710. By adding the intermediate layer 1710, the need for the block or substrate 1510 to conduct the AC waveform is reduced. This can allow the use of poorly conductive or non-conductive materials (such as plastics, ceramics, ceramic plastics, aluminum, stainless steel, or other materials) as the block or substrate 1510. The intermediate layer 1710 can be gold, copper, nickel, or a combination of these or other conductive metals. Due to the skin effect, the current generated by the AC waveform received by the contact 110 can be transmitted near the surface of the contact 110. Therefore, the intermediate layer can be relatively thin, for example, 10 to 100 microns, depending on the desired frequency range of the AC waveform. This thickness can allow good conductivity of the AC waveform.

[0096] The materials and various layers that make up the contact 110 can provide at least three functions. They can provide an interface function for mating with another contact, they can provide a conductive function for delivering the charging AC waveform, and they can provide a mechanical function that provides structure to the contact. Fig.15 In the embodiment of the present invention, the block or substrate 1510 can provide a durable interface for mating with contacts on a second device. The conductivity of the block or substrate 1510 can be improved by adding optional plating layers 1512 on the bottom and sides of the block or substrate 1510. The block or substrate 1510 can provide mechanical functions. In the embodiment of the present invention, the block or substrate 1510 can provide a durable interface for mating with contacts on a second device. The conductivity of the block or substrate 1510 can be improved by adding optional plating layers 1512 on the bottom and sides of the block or substrate 1510. Fig.16 In the embodiment, the interface function can be improved by adding a finishing layer 1610. The finishing layer 1610 can provide a surface with improved hardness and corrosion resistance. Fig.17 In the embodiment of the present invention, adding the intermediate layer 1710 provides an opportunity to improve the conductive function of the contact 110 by including a conductive material layer. Likewise, adding the intermediate layer 1710 can eliminate the necessity to provide conductivity to the bulk or substrate 1510. This can allow the bulk or substrate 1510 to be formed of a low conductivity or non-conductive material.

[0097] In different embodiments of the present invention, these functions can be allocated between these layers in different ways. Fig.16 In the embodiment of the present invention, the finish layer 1610 may have a lower conductivity, while the bulk or substrate 1510 may have a higher conductivity. In these and other embodiments of the present invention, more than two layers may be plated or otherwise formed on the bulk or substrate 1510.

[0098] Using an AC waveform may allow for the use of the skin effect. That is, the skin effect may allow for charge conduction to rely on the conductivity of the facing layer 1610 and the intermediate layer 1710. This reliance on the facing layer 1610 and the intermediate layer 1710 may not be possible when using conventional DC voltage and current to transmit power.

[0099] Unfortunately, the use of these plating layers promotes corrosion of these contacts 110. When using the contacts 110 for connection, the plating layers (such as the finish layer 1610 and the intermediate layer 1710) and the substrate (such as the block or substrate 1510) may be damaged, for example, they may be scratched. Then, a galvanic voltage may appear on the scratches. Then, the presence of the electrolyte may cause corrosion of the contacts 110.

[0100] Embodiments of the present invention may include various features to reduce galvanic corrosion that may be caused by scratches on the contact 110. For example, the materials used for the plating and substrate may be selected to reduce any galvanic voltage. For example, the plating of the contact may be gold plated, with a galvanic voltage range of 0.07V to 0.2V, while the bulk or substrate may be titanium, with a galvanic voltage range of -0.12V to 0.04V. Alternatively, the bulk or substrate may be a non-conductive material such as ceramic, plastic, or a combination of these or other materials.

[0101] Along with reducing the galvanic voltage at the scratches, embodiments of the present invention may be directed to contact assemblies that may minimize the chances of such scratches and other types of damage occurring. An example is shown in the following figure.

[0102] 18A to 18D A cross-sectional view of a contact assembly according to an embodiment of the present invention is illustrated. Fig.18A , a first device may include a contact assembly 1810, which may include a contact 1812 surrounded by an adjacent insulator 1814 and a housing 1816. A second device may include a contact assembly 1820, which may include a contact 1822 surrounded by an adjacent insulator 1824 and a housing 1826. In this example, the contact 1812, the insulator 1814, and the housing 1816 are flush with each other, while the contact 1822 and the insulator 1824 are flush with each other and can move relative to the housing 1826.

[0103] The contact 1822 and the insulator 1824 can move relative to the housing 1826 so that the contact 1822 can engage the contact 1812. The contact assembly 1820 can mate with the contact assembly 1810 in a contact direction that is orthogonal or perpendicular to the surface of the contact 1822. Alternatively, the contact assembly 1820 can slide laterally across the contact assembly 1810 (or the contact assembly 1810 can slide laterally across the contact assembly 1820) until the contact 1822 is aligned with the contact 1812, at which point the contact 1822 and the insulator 1824 can move toward the contact assembly 1810 so that the contact 1822 mates with the contact 1812.

[0104] In the case where the contact assembly 1810 and the contact assembly 1820 are engaged in the vertical direction, the contact 1812 and the contact 1822 may encounter little damage. However, when the contact assembly 1820 moves laterally across the contact assembly 1810 (or the contact assembly 1810 slides laterally across the contact assembly 1820), the contact 1822 may interact with the housing 1816 and the contact 1812, thereby being damaged. Similarly, the contact 1812 may interact with the housing 1826, thereby being damaged. This damage may cause scratches. These scratches may expose the galvanic connection and galvanic voltage between the various plating layers and the substrate of the contact 1812 and 1822. In the presence of an electrolyte, these galvanic voltages may cause corrosion at the surface of the contact 1812 and 1822.

[0105] exist Fig.18B , a first device may include a contact assembly 1830, which may include a contact 1832 surrounded by an adjacent insulator 1834 and a housing 1836. A second device may include a contact assembly 1840, which may include a contact 1842 surrounded by an adjacent insulator 1844 and a housing 1846. In this example, the contact 1832, the insulator 1834, and the housing 1836 are flush with each other, and the contact 1842 may include an extension 1848 protruding from the insulator 1844. The contact 1842 and the insulator 1844 may move relative to the housing 1846.

[0106] The contact 1842 and the insulator 1844 can move relative to the housing 1846 so that the contact 1842 can engage the contact 1832. The contact assembly 1840 can mate with the contact assembly 1830 in a contact direction that is orthogonal or perpendicular to the surface of the contact 1842. Alternatively, the contact assembly 1840 can slide laterally across the contact assembly 1830 until the contact 1842 is aligned with the contact 1832, at which point the contact 1842 and the insulator 1844 can move toward the contact assembly 1830 so that the contact 1842 mates with the contact 1832.

[0107] In the case where the contact assembly 1830 and the contact assembly 1840 are engaged in the vertical direction, the contact 1832 and the contact 1842 may encounter little damage. However, when the contact assembly 1840 moves laterally across the contact assembly 1830 (or the contact assembly 1830 slides laterally across the contact assembly 1840), the contact 1842 extension 1848 may interact with the housing 1836 and the contact 1832, thereby being damaged. Similarly, the contact 1832 may interact with the housing 1846, thereby being damaged. This damage may cause scratches. These scratches may expose the galvanic connection and galvanic voltage between the various plating layers and the substrate of the contact 1832 and 1842. In the presence of an electrolyte, these galvanic voltages may cause corrosion at the surface of the contact 1832 and 1842.

[0108] exist Fig. 18C , a first device may include a contact assembly 1850, which may include a contact 1852 surrounded by an adjacent insulator 1854 and a housing 1856. A second device may include a contact assembly 1860, which may include a contact 1862 surrounded by an adjacent insulator 1864 and a housing 1866. In this example, the contact 1852 may be recessed relative to the housing 1856, and the insulator 1854 may be further recessed relative to the housing 1856. The contact 1862 may include an extension 1868 protruding from the housing 1866, and the insulator 1864 may include an extension 1869 protruding from the housing 1866 and the contact 1862. The contact 1862 and the insulator 1864 may move relative to the housing 1866.

[0109] The contact 1862 and the insulator 1864 can move relative to the housing 1866 so that the contact 1862 can engage the contact 1852. The contact assembly 1860 can mate with the contact assembly 1850 in a contact direction that is orthogonal or perpendicular to the surface of the contact 1862. Alternatively, the contact assembly 1860 can slide laterally across the contact assembly 1850 until the contact 1862 is aligned with the contact 1852, at which point the contact 1862 and the insulator 1864 can move toward the contact assembly 1850 so that the contact 1862 mates with the contact 1852.

[0110] In the case where the contact assembly 1850 and the contact assembly 1860 are engaged in a vertical direction, the contact 1852 and the contact 1862 may experience little damage. When the contact assembly 1860 moves laterally across the contact assembly 1850 (or the contact assembly 1850 slides laterally across the contact assembly 1860), the contact 1852 extension 1858 may interact with the insulator 1864 extension 1869, which may not cause significant damage. The contact 1862 extension 1868 can be protected by the insulator 1864 extension 1869, thereby reducing any damage to the contact 1862.

[0111] exist Fig.18D , a first device may include a contact assembly 1870 that may include a contact 1872 surrounded by an adjacent insulator 1874 and a housing 1876. A second device may include a contact assembly 1880 that may include a contact 1882 surrounded by an adjacent insulator 1884 and a housing 1886. In this example, the contact 1872 may be recessed relative to the housing 1876, and the insulator 1874 may be further recessed relative to the housing 1876. The contact 1882 may be flush with the insulator 1884, and both may be recessed relative to the housing 1886. The contact 1882 and the insulator 1884 may move relative to the housing 1886.

[0112] The contact 1882 and the insulator 1884 can move relative to the housing 1886 so that the contact 1882 can engage the contact 1872. The contact assembly 1880 can mate with the contact assembly 1870 in a contact direction that is orthogonal or perpendicular to the surface of the contact 1882. Alternatively, the contact assembly 1880 can slide laterally across the contact assembly 1870 until the contact 1882 is aligned with the contact 1872, at which point the contact 1882 and the insulator 1884 can move toward the contact assembly 1870 so that the contact 1882 mates with the contact 1872. The magnets 1879 in the contact assembly 1870 and the magnets 1889 in the contact assembly 1880 can facilitate this movement.

[0113] In the case where the contact assembly 1870 and the contact assembly 1880 are engaged in a vertical direction, the contact 1872 and the contact 1882 may experience less damage. When the contact assembly 1880 moves laterally across the contact assembly 1870 (or the contact assembly 1870 slides laterally across the contact assembly 1880), the contact 1872 extension 1878 may not interact with the contact assembly 1880 and may avoid being damaged. The contact 1882 may be recessed and protected by the insulator 1884 to avoid damage.

[0114] Fig.19A contact assembly for a contact interface according to an embodiment of the present invention is illustrated. A first electronic device 1902 and a second electronic device 1904 may form an electronic system 1900. The first electronic device 1902 may include a contact assembly including a contact 1910 supported by an insulating member 1930. The contact 1910 and the insulating member 1930 may be located in a recess 1942 in a housing 1940 of the first electronic device 1902.

[0115] The second electronic device 1904 may include a contact assembly including a contact 1950 supported by an insulating member 1960. The contact 1950 and the insulating member 1960 may be located in an opening 1972 in a housing 1970 of the second electronic device 1904. When the contact 1950 in the first electronic device mates with the contact 1950 in the second electronic device 1904, the contact 1910 and the insulating member 1960 may move to be positioned in a recess 1942 of the housing 1940 of the first electronic device 1902.

[0116] Fig. 20 2000 may include two contacts 1950, each supported by an insulator 1960. The insulator 1960 may be supported by a beam 2010. The beam 2010 may be driven by a spring 2030 so that the contact 1950 may engage the contact 1910 (at Fig.19 ). The beam 2010 may be pressed down by the alignment portion 2020. The alignment portion 2020 may be aligned with the recessed portion in the first electronic device 1902 (in Fig.19 ), thereby allowing spring 2030 to push contact 1950 into engagement with contact 1910.

[0117] Fig.21 A contact assembly for a contact interface according to an embodiment of the present invention is illustrated. A first electronic device 2102 and a second electronic device 2104 may form an electronic system 2100. The first electronic device 2102 may include a contact assembly including a contact 2110 supported by an insulating member 2130. The contact 2110 and the insulating member 2130 may be located in a recess 2142 in a housing 2140 of the first electronic device 2102.

[0118] The second electronic device 2104 may include a contact assembly including a contact 2150 supported by an insulating member 2160. The contact 2150 and the insulating member 2160 may be located in an opening 2172 in a housing 2170 of the second electronic device 2104. When the contact 2150 in the first electronic device mates with the contact 1950 in the second electronic device 1904, the contact 1910 and the insulating member 2160 may move to be positioned in a recess 2142 of the housing 2140 of the first electronic device 2102.

[0119] The contact 2150 may include two contact portions separated by an insulating portion 2162. The insulating portion 2162 may be a surface that may be exposed to wear in order to protect the exposed area of ​​the contact 2150. Similar to the insulator 1864 extension 1869 (in Fig. 18C ), the insulating portion 2162 can engage the housing 2140 and the contacts 2110 of the first electronic device 2102 when the first electronic device 2102 and the second electronic device 2104 move laterally across each other during mating.

[0120] Fig. 22 2 is a cross-sectional side view of a contact assembly according to an embodiment of the present invention. The contact assembly 2200 may include a contact 2150, which may be supported by an insulator 2160. The contact 2150 and the insulator 2160 may be positioned in an opening 2172 of a housing 2170. The housing 2170 may be above a housing 2230. The housing 2230 may include a hole 2232 for a spring 2210. When the first electronic device 2102 and the second electronic device 2104 (both in Fig.21 2140 ), the spring 2210 may be compressed when the contact member 2150 and the insulator 2160 are aligned with the recess 2142 of the housing 2140 (both at Fig.21 ), the spring 2210 can push the contact 2150 into the contact 2110. The signal received and provided on the contact 2150 can be transmitted by the conductor 2220. The conductor 2220 can be insulated by the insulator 2222.

[0121] Embodiments of the present invention may incorporate various features to limit or reduce galvanic corrosion of contacts of electronic devices. For example, the materials used on the contacts and housing may be selected to avoid differences in their galvanic voltages. Other DC voltages (such as DC offsets in AC waveforms used to transmit power) may be avoided or adjusted to eliminate galvanic voltages between the materials used. DC conduction paths may also be blocked to limit electrochemical reactions that may lead to corrosion. The following figure shows an example.

[0122] Fig.23The galvanic corrosion path in the electronic device according to the embodiment of the present invention is illustrated. The electronic system 2300 may include a first electronic device 2302 and a second electronic device 2304. The first electronic device 2302 may be provided with AC power through capacitors C1 and C2 and a contact 2310. The contact 2310 may be insulated by an insulator 2320 and supported by a housing 2330.

[0123] In this example, an ion path may exist between the contacts 2310 and the housing 2330. For example, an ion path 2380 may exist between the contacts 2310. An ion path 2385 may exist between each contact 2310 and the housing 2330. The AC nature of the waveform transmitted on the contacts 2310 may alternate quickly enough to limit any electrochemical reactions. However, the presence of any DC current, whether based on a galvanic voltage, an offset in the AC waveform, or otherwise, may cause an electrochemical reaction that may lead to corrosion.

[0124] Therefore, as mentioned above Fig.10 As shown in , DC blocking capacitors C1 and C2 may be placed in series between the internal circuit of the first electronic device 2302 and the contact 2310. Capacitors C1 and C2 may block DC current that would otherwise cause an electrochemical reaction that would lead to corrosion.

[0125] These and other embodiments of the present invention can further limit corrosion by further reducing the electric field between the contact 2310 and the housing 2330. For example, the materials selected for the contact 2310 (including the materials used for any plating and the housing 2330) can be selected to reduce any galvanic voltage. For example, the contact 2310 can be plated with gold, having a galvanic voltage range of 0.07 to 0.2V, while the housing can be titanium, having a galvanic voltage range of -0.12V to 0.04V.

[0126] These and other embodiments of the present invention can further reduce the galvanic voltage difference by selecting a non-conductive material for the housing. For example, the second electronic device 2304 may include a contact 2340 supported by a housing 2360. The contact 2340 may be a metal area formed or plated on the housing 2360. The housing 2360 may be a non-conductive material such as plastic, ceramic, or a combination of these or other materials.

[0127] Selecting a non-conductive material for housing 2360 reduces the ionic pathway between contacts 2340 to pathway 2380. Thus, only one capacitor (shown here as capacitor C3) may be needed to block DC current flowing through pathway 2380. It may be more likely that one capacitor would be used in the power receiving device, where the asymmetry caused by the lack of a second capacitor in the power delivering device is not relevant.

[0128] In these and other embodiments of the present invention, it may be desirable that the capacitors used (such as capacitor C1, capacitor C2, and capacitor C3) fail in an open circuit state to prevent a DC current path from being formed. Therefore, a "Y" type capacitor that fails to open may be used as capacitor C1, capacitor C2, and capacitor C3.

[0129] Electrolytes are not always present in these and other types of electronic systems. Typically, contacts 2310 or other contacts are dry and do not contain liquid or other electrolytes. In this case, power can be saved by transmitting power in a DC manner. For example, inverter / rectifier circuit 1030 and inverter / rectifier circuit 1040 (both in Fig.10 An example is shown in the figure below.

[0130] Fig.24 Optional DC charging in an electronic device according to an embodiment of the present invention is illustrated. The electronic system 2400 may include a first electronic device 2402 and a second electronic device 2404. In the first electronic device 2402, the contact 2410 may be insulated by an insulating member 2420 and supported by a housing 2430. In the second electronic device 2404, the contact 2440 may be supported by a non-conductive housing 2460 or plated on the non-conductive housing.

[0131] The first electronic device 2402 may provide AC power through capacitors C1 and C2 and contact 2310. The first electronic device 2402 may provide DC power through a closed switch S1 (which may bypass capacitor C1) and through a closed switch S2 (which may bypass capacitor C2), thereby connecting contact 2410 to a DC source. Similarly, the second electronic device 2404 may receive power through capacitor C3 and may receive DC power by bypassing capacitor C3 with switch S3.

[0132] It may be desirable for switches S1, S2, and S3 to have very high open circuit impedance to prevent DC leakage in the presence of electrolyte at contacts 2410 and 2440. Thus, embodiments of the present invention may use micro-relays, micro-mechanical switches, or other types of switches. It should also be noted that many of the design considerations described herein may not provide contacts optimized for DC power transmission, and further compromises may need to be made.

[0133] The switches S1, S2, and S3 may each be controlled by the first electronic device 2402 or the second electronic device 2404. The switches S1 and S2 may be controlled by the first electronic device 2402, and the switch S3 may be controlled by the second electronic device 2404, or the switches may be controlled by other circuits. For example, the first electronic device 2402 may determine that the contact 2410 and the contact 2440 are not exposed to the electrolyte, and may close the switches S1, S2, and S3 before delivering the DC power. The second electronic device 2404 may determine that the contact 2410 and the contact 2440 are not exposed to the electrolyte, and may close the switches S1, S2, and S3 before requesting the DC power from the first electronic device 2402.

[0134] Likewise, embodiments of the present invention may take steps to reduce or eliminate the DC electric field or DC voltage at the contacts of the electronic device. These steps may reduce the galvanic voltage as described above. They may also involve reducing the DC offset of the AC waveform used to transmit data. They may also involve using the DC offset of the AC waveform to eliminate the remaining galvanic voltage. They may also involve using the DC offset of the AC waveform that has been found empirically or otherwise to provide reduced corrosion. Examples of such waveforms are shown in the following figure.

[0135] Fig.25 A differential AC waveform for power transmission according to an embodiment of the present invention is illustrated. The waveform 2500 may have a low voltage V2, a high voltage V1, and an average voltage V0. The waveform 2500 may have a rise time Tr1 from V0 to V1 and may remain at V1 for a time T1. The waveform 2500 may have a fall time Tf1 from V1 to V0 and a fall time Tf2 from V0 to V2. The waveform 2500 may remain at V2 for a time T2. The waveform 2500 may have a rise time Tr2 from V2 to V0. The waveform 2500 may have a positive pulse width Tp1 and a negative pulse width Tp2. Filtering may be used to reduce the amount of harmonics present in the AC waveform 2500.

[0136] Some or all of these rise times, fall times, high and low levels, and other parameters may be adjustable. For example, the average voltage V0 may be varied. The average voltage V0 may be adjusted to be close to zero to reduce any DC voltage generated by the differential AC waveform 2500. The average voltage V0 may alternatively be adjusted to a level to offset or compensate for the galvanic voltage present at the power transmission contact. The average voltage V0 may alternatively be adjusted to a level that has been found empirically or otherwise to provide reduced corrosion at the power transmission contact. Examples of circuits and methods that may be used are shown in the following figures.

[0137] Fig.262604 in the second electronic device 2604. The DC to DC converter 2610 may receive a DC input voltage DCIN, which may be a battery or other voltage. The DC to DC converter 2610 may set a high voltage V1 and a low voltage V2 (at 100V) of an AC waveform to be provided from an inverter 2620 in the first electronic device 2602 to a rectifier 2630 in the second electronic device 2604. Fig.25 ). Rectifier 2630 may provide an output to a DC to DC converter 2640, which may provide an output voltage DCOUT.

[0138] In this example, voltages V1 and V2 may be programmable. Voltages V1 and V2 may be programmed so that the average voltage V0 (at Fig.25 ) is close to zero to reduce any DC voltage generated by the differential AC waveform 2500. V1 and V2 may alternatively be programmed so that the average voltage V0 can be adjusted to a level to cancel or compensate for the galvanic voltage present at the power transmission contacts. V1 and V2 may alternatively be programmed to provide an average voltage V0 that has been found empirically or otherwise to minimize corrosion.

[0139] In this example, voltage V1 and voltage V2 may be provided in an open loop manner. In these and other embodiments of the invention, voltage V1 and voltage V2 may be provided in a closed loop manner. The following figure shows an example.

[0140] Fig. 27 Another charging path through an electronic system according to an embodiment of the present invention is illustrated. In this example, a first electronic device 2602 can provide power to a second electronic device 2604 in the electronic system 2600. A DC to DC converter 2610 can receive a DC input voltage DCIN, which can be a battery or other voltage. The DC to DC converter 2610 can set a high voltage V1 and a low voltage V2 (at the AC waveform to be provided from an inverter 2620 in the first electronic device 2602 to a rectifier 2630 in the second electronic device 2604) Fig.25 ). Rectifier 2630 may provide an output to a DC to DC converter 2640, which may provide an output voltage DCOUT.

[0141] In this example, the voltage V1 and the voltage V2 may be adjusted by a feedback path including a correction circuit 2710 in the first electronic device 2602. The voltage V1 and the voltage V2 at the power transmission contact of the inverter 2620 may be detected and provided to the correction circuit 2710. The voltages V1 and V2 may be adjusted by the correction circuit 2710 so that the average voltage V0 (at Fig.25 27) to near zero to reduce any DC voltage generated by the differential AC waveform 2500. V1 and V2 may alternatively be adjusted by the correction circuit 2710 so that the average voltage V0 may be adjusted to a level to cancel or compensate for the galvanic voltage present at the power transmission contact. V1 and V2 may alternatively be adjusted by the correction circuit 2710 to provide an average voltage V0 that has been found empirically or otherwise to minimize corrosion. The correction circuit 2710 may be used to integrate the positive and negative pulses of the waveform 2500 to adjust the average voltage V0.

[0142] Fig.28 Another charging path through an electronic system according to an embodiment of the present invention is illustrated. In this example, a first electronic device 2602 can provide power to a second electronic device 2604 in the electronic system 2600. A DC to DC converter 2610 can receive a DC input voltage DCIN, which can be a battery or other voltage. The DC to DC converter 2610 can set a high voltage V1 and a low voltage V2 (at the AC waveform to be provided from an inverter 2620 in the first electronic device 2602 to a rectifier 2630 in the second electronic device 2604) Fig.25 ). Rectifier 2630 may provide an output to a DC to DC converter 2640, which may provide an output voltage DCOUT.

[0143] In this example, the voltage V1 and the voltage V2 can be adjusted by a feedback path including a receiving detection circuit 2810 in the second electronic device 2604 and an adjustment circuit 2820 in the first electronic device 2602. This can be achieved in various ways. In one example, the voltage V1 and the voltage V2 at the power receiving contact of the rectifier 2630 can be detected by the receiving detection circuit 2810. This information can be transmitted to the adjustment circuit 2820. The voltages V1 and V2 can be adjusted by the adjustment circuit 2820 so that the average voltage V0 (at Fig.25 ) is close to zero to reduce the difference AC waveform 2500 (in Fig.252500). For another example, the receive detection circuit 2810 may determine the adjustments to be made and may provide this information to the adjustment circuit 2820. V1 and V2 may alternatively be adjusted by the adjustment circuit 2820 so that the average voltage V0 may be adjusted to a level to offset or compensate for the galvanic voltage present at the power transmission contact. V1 and V2 may alternatively be adjusted by the adjustment circuit 2820 to provide an average voltage V0 that has been found empirically or otherwise to minimize corrosion. The receive detection circuit 2810 may communicate with the adjustment circuit 2820 through the power transmission contact by sending an AC signal at a different frequency than the AC waveform 2500. The receive detection circuit 2810 may communicate with the adjustment circuit 2820 through other wired, wireless, or other types of communication channels.

[0144] In these and other embodiments of the present invention, known patterns, which may be referred to as training patterns, may be provided by the first electronic device 2602 to the second electronic device 2604. These known patterns may be used by the receive detection circuit 2810 in the second electronic device 2604 and the adjustment circuit 2820 in the first electronic device 2602 to adjust the AC waveform provided by the first electronic device 2602 to the second electronic device 2604.

[0145] The AC waveform may be used to transmit data between the first electronic device 2602 and the second electronic device 2604. The frequency, phase, amplitude, or other characteristics of the AC waveform may be modulated to transmit data. Other signals at other frequencies may be combined with the AC waveform using a duplexer, common mode choke, or other circuit. Data may be transmitted in the same direction as power transmission, or power and data may be transmitted in different directions.

[0146] Various aspects of the differential AC waveform 2500 may vary or adjust based on the material of the contact, the material of the housing, the presence or absence of electrolyte, and the type of any electrolyte present. An example of a method of determining the type of material to use for a contact is shown in the following figure.

[0147] Fig.29 Data that can be used by a method for determining the type of material used for a contact according to an embodiment of the present invention is illustrated. In this example, electrochemical impedance spectroscopy (EIS) curves of different materials are generated in advance in the absence of an electrolyte. When an electrolyte may not be present, the electronic device may make similar measurements shortly after the connection between two electronic devices. These measurements can be made at these times and other times when it has been determined that an electrolyte is not present.

[0148] The EIS curve measured by the electronic device may reflect the parallel combination of the contact at the measuring device and the contact of the mating device. The contact at the measuring device may be known during manufacturing and stored. Using the measured EIS curve and the known measuring device material, the contribution of the parallel mating device contacts to the EIS curve may be extrapolated. The extrapolated EIS curve of the mating device contacts may be compared with a pre-measured curve (such as the curve in the figure). Thus, the material used for the contacts of the mating device may be determined. These and other embodiments of the present invention may not generate a complete curve. Instead, data points at several specific frequencies may be used.

[0149] Fig.30 A method for optimizing a charging waveform according to an embodiment of the present invention is illustrated. In act 3010 of method 3000, when a connection is made, the first device may use EIS to determine the contact material of the second device. Such a method is described above. Fig.29 As outlined in . Instead of using EIS, in act 3020, the first device can receive information about the contact material directly from the second device. The first device can collect other information during use. The information can include environmental and other information. For example, in act 3030, the first device can receive EIS updates, depth, and other information from other sensors. In act 3040, an optimized charging waveform can be determined. In act 3050, the charging waveform is provided to the contacts of the first device for receipt by the contacts of the second device.

[0150] Embodiments of the present invention may provide power transmission circuits and apparatus that may be located in various types of devices, such as portable computing devices, tablet computers, desktop computers, laptop computers, all-in-one computers, wearable computing devices, cellular phones, smart phones, media phones, storage devices, portable media players, navigation systems, monitors, power supplies, video delivery systems, adapters, remote control devices, chargers, and other devices.

[0151] Reference numerals are used in a consistent manner throughout the drawings.

[0152] It is understood that the use of personally identifiable information should be subject to privacy policies and practices that are generally recognized to meet or exceed industry or government requirements for maintaining user privacy. Specifically, personally identifiable information data should be managed and processed to minimize the risk of unintentional or unauthorized access or use, and the nature of the authorized use should be clearly stated to users.

[0153] For the purpose of illustration and description, the above description of the embodiment of the present invention is presented. It is not intended to be exhaustive, nor is it intended to limit the present invention to the precise form, and many modifications and variations are possible according to the above teachings. This embodiment is selected and described to fully illustrate the principle of the present invention and its practical application, so that other technical personnel in the field can make full use of the present invention in various embodiments and in the case of various modifications suitable for the specific purpose envisioned. Therefore, it should be understood that the present invention is intended to cover all modifications and equivalents within the scope of the following claims.

Claims

1. A method for delivering power from a first electronic device to a second electronic device, the method comprising: Determining one or more environmental parameters using the first electronic device; optimizing an AC charging waveform using the one or more environmental parameters; as well as The optimized AC charging waveform is provided to the second electronic device.

2. The method of claim 1, wherein the one or more environmental parameters include the presence of an electrolyte.

3. The method of claim 2, wherein the AC charging waveform is optimized in part by adjusting an average value of the AC charging waveform to compensate for a galvanic voltage of the first electronic device. 4 . The method of claim 3 , wherein the AC charging waveform comprises one of: two bandwidth limited anti-phase square waves, two anti-phase square waves, and two anti-phase sine waves.

5. A power transmission circuit, comprising: Battery; a switch coupled to the battery; a step-up / step-down circuit coupled to the switch; an inverter / rectifier circuit coupled to the step-up / step-down circuit; a first capacitor coupled to a first output of the inverter / rectifier circuit; and a second capacitor coupled to a second output of the inverter / rectifier circuit; a first contact coupled to the first capacitor; and A second contact is coupled to the second capacitor. 6 . The power transmission circuit of claim 5 , wherein the first contact and the second contact are spring biased contacts. 7 . The power transmission circuit of claim 6 , wherein the first contact and the second contact each include a canted coil spring.

8. The power transmission circuit of claim 6, wherein the first contact and the second contact each comprise a stack of Belleville washers.

9. The power transmission circuit of claim 6, wherein the first contact and the second contact each comprise two stacks of Belleville washers. 10 . The power transmission circuit according to claim 5 , wherein the first contact and the second contact are fixed contacts.

11. The power transmission circuit of claim 5, wherein the switch is configured to disconnect the battery from the step-up / step-down circuit when the power transmission circuit is not transmitting or receiving power. 12 . The power transmission circuit according to claim 11 , wherein the step-up / step-down circuit increases the voltage from the battery and provides a high voltage and a low voltage when the power transmission circuit is transmitting power.

13. The power transmission circuit according to claim 12, wherein when the power transmission circuit is receiving power, the step-up / step-down circuit steps down a voltage from an inverter / rectifier and provides a charging voltage for the battery.

14. The power transmission circuit of claim 13, wherein the inverter / rectifier circuit converts the high voltage and the low voltage from the step-up / step-down circuit into a differential output signal when the power transmission circuit is transmitting power.

15. The power transmission circuit of claim 14, wherein the inverter / rectifier circuit rectifies the differential output signal when the power transmission circuit is receiving power.

16. The power transmission circuit of claim 15, wherein the differential output signal comprises two anti-phase sinusoidal waves.

17. The power transmission circuit of claim 15, wherein the differential output signal comprises two anti-phase square waves.

18. The power transmission circuit of claim 15, wherein the differential output signal comprises two bandwidth limited anti-phase square waves.

19. A power transmission circuit for generating a differential output signal, the power transmission circuit comprising: a first capacitor coupled to receive a first side of the differential output signal; a second capacitor coupled to receive a second side of the differential output signal; a first contact coupled to the first capacitor; and A second contact is coupled to the second capacitor.

20. The power transmission circuit of claim 19, wherein the differential output signal comprises one of: two bandwidth limited anti-phase square waves, two anti-phase square waves, and two anti-phase sine waves.

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