Abstract: A wireless power transmission system has a wireless power receiving device that can be charged using multiple different types of wireless power transmitting devices. The different types of wireless power transmitting devices have power transmitting coils that exhibit different levels of magnetic coupling with the power receiving coil of the wireless power receiving device. The wireless power receiving device may include capacitors, resistors, and/or other loading circuits that can be independently switched into use depending on the level of magnetic coupling that is detected, on a rectified voltage level, on the size of the output load, and/or on information conveyed during handshaking operations to present a desired impedance adjustment at the power receiving coil so that data signal can be properly conveyed between the power receiving device and the power transmitting device.

Abstract: A power system has a wireless power transmitting device and a wireless power receiving device. Coils in the transmitting device may include a circular coil overlapped by first and second rectangular coils at a charging surface. The rectangular coils each include straight segments extending over a central region of the circular coil. Control circuitry can activate the circular coil to transmit wireless power to a first type of wireless power receiving coil using vertical components of the magnetic field generated by the circular coil. The control circuitry can activate the rectangular coils to transmit wireless power to a second type of wireless power receiving coil using horizontal components of the magnetic field generated by the rectangular coils. The circular and rectangular coils wirelessly charge the power receiving device while located at the same position on the charging surface, regardless of the type of wireless power receiving coil that is used.

Abstract: A wireless power transmitting device transmits wireless power signals to a wireless power receiving device using an output circuit that includes a wireless power transmitting coil. Measurement circuitry is coupled to the output circuit to help determine whether the wireless power receiving device is present and ready to accept transmission of wireless power. The measurement circuitry includes a measurement circuit that is coupled to the output circuit and that measures signals while oscillator circuitry supplies the output circuit with signals at a probe frequency. The measurement circuitry also includes a measurement circuit that is coupled to the output circuit and that measures signals while the oscillator circuitry sweeps signals applied to the output circuit between a first frequency and a second frequency to detect sensitive devices such as radio-frequency identification devices. Impulse response circuitry in the measurement circuitry is used to make inductance and Q factor measurements.

Abstract: Disclosed are devices, systems, and methods for reducing common mode noise induced in wireless charging circuits of electronic devices. For an electronic device having an inductive receiving coil near an electric shielding layer, differences in parasitic capacitances of the loops of the inductive receiving coil with an electric shielding layer can induce common mode noise. Common mode noise is reduced by a noise-reduction capacitor from the inductive receiving coil to the electric shielding layer together with a grounding resistor from the electric shielding layer to a common ground of the wireless charging circuit.

Abstract: A wireless power transmission system has a wireless power receiving device that is located on a charging surface of a wireless power transmitting device. The wireless power receiving device has a wireless power receiving coil and the wireless power transmitting device has a wireless power transmitting coil array. Control circuitry in the transmitting device uses inverter circuitry to supply alternating-current signals to coils in the coil array, thereby transmitting wireless power signals. Impulse response measurement circuitry coupled to the coil array is used to make impulse response measurements while the control circuitry uses the inverter circuitry to apply impulse signals to each of the coils. The control circuitry analyzes output from the impulse response measurement circuitry to measure inductances associated with the coils in the coil array.

Abstract: A wireless power transmitting device may have an array of transmitting coils to transmit power wirelessly to a wireless power receiving device having an array of wireless power receiving coils. The receiving device may have a rectifier that receives alternating-current signals from the wireless power receiving coils and provides corresponding rectified direct-current voltage signals to a capacitor and other circuitry. The rectifier circuitry may include bridge circuits each of which is coupled between a respective coil in the array of wireless power receiving coils and the capacitor. The wireless power transmitting coils may be arranged in a hexagonally tiled array. The wireless power receiving coils may include first, second, and third coils that are aligned with respective vertices in an equilateral triangle having sides with lengths equal to half of the center-to-center spacing of the hexagonally tiled transmitting coils.

Abstract: A power system has a wireless power transmitting device and a wireless power receiving device. Coils in the power transmitting and receiving devices are used to transmit and receive wireless power signals. The coils may include pot core coils, figure eight coils, solenoids, and other coils. A solenoid array may extend under a charging surface in a wireless power transmitting device. Solenoids in the array may be separated from each other by small gaps. Solenoids may have rectangular outlines, hexagonal outlines, or other shapes. Pot core coils may have a magnetic material with a circular groove of a groove of other suitable shapes that contains wire windings. Figure eight coils may have first and second adjacent magnetic cores with respective counterclockwise and clockwise wire windings. Magnets and other alignment structures can be used to help align coils in transmitting and receiving devices.

Abstract: A power converter can be implemented with a boosted-output inverter, which integrates the functionality of a voltage converter (e.g., boost converter) and a voltage inverter. In particular, a boosted-output inverter includes a primary tank inductor coupled in series with a secondary tank inductor at a central node. The boosted-output inverter also includes two voltage-controlled switches that respectively define a charging phase and a discharging phase of the primary tank inductor. While the primary tank inductor is charging, the secondary tank inductor is inverted to ground. In this manner, current though the secondary tank inductor alternates at a voltage boosted by the fly-back voltage of the primary tank inductor exhibited when the primary tank inductor transitions from the charging mode to the discharging mode. In many cases, the secondary tank inductor is a transmit coil of a transmitter of a wireless power transfer system.

Abstract: A wireless charging mat and method of operating the same. The wireless charging mat includes a detection system configured to determine a location and an orientation of an electronic device on the wireless charging mat. The location and orientation are determined based on detected locations of one or more structural features of the electronic device. The wireless charging mat is operated according to the detected location and orientation.

Abstract: A wireless power transmission system has a wireless power receiving device that is located on a charging surface. The wireless power transmitting device has an array of wireless power transmitting coils that overlap the charging surface. The wireless power transmitting device uses inductance measurement circuitry that is coupled to the coil array to measure coil inductances for the wireless power transmitting coils. The wireless power receiving device may contain a communications integrated circuit, display circuitry, or other sensitive components. The location and orientation of the wireless receiving device on the charging surface can be determined by analyzing the coil inductances. This information and information on the location of the sensitive component within the wireless power receiving device can be used to select a wireless power transmitting coil to transmit wireless power signals to the wireless power receiving device without exposing the sensitive component to excessive wireless power signals.

Abstract: This disclosure relates to power converters capable of providing multiple output voltage levels. With respect to USB-C adapter design, the converter's output may need to be changed between different voltage levels, e.g., a low voltage (such as 5V, 10V), an intermediate voltage (such as 12V, 20V), or a high voltage (such as 20V, 40V)—based on the charging device's request. By using a tapped-winding transformer, the turns-ratio of a flyback transformer may be intelligently selected for high output voltage ranges, thus enabling the duty cycle to be kept the same for the low and intermediate voltage output levels. The flyback converter would then only need to accommodate the intermediate and high output voltages. For high output voltages, a switch may be activated to put the two windings of the transformer in series; for lower output voltages, the switch may be turned off, such that only one winding is used.

Abstract: A wireless power system may have a wireless power transmitting device and a wireless power receiving device. The wireless power receiving device may have a receive coil that receives wireless power signals from the wireless power transmitting device and may have a rectifier that produces direct-current power from the received wireless power signals. The wireless power transmitting device may have an array of transmit coils. Each transmit coil has a respective magnetic coupling coefficient characterizing its magnetic coupling with the receive coil. The wireless power transmitting device may have control circuitry that uses the magnetic coupling coefficient values in selecting transmit coils to use in transmitting wireless power to the wireless power receiving device.

Abstract: A wireless power system may use a wireless power transmitting device to transmit wireless power to a wireless power receiving device. The wireless power transmitting device may have an array of coils that extend under a wireless charging surface. Control circuitry may supply alternating-current control signals to inverters. The inverters are coupled to resonant circuits. Each resonant circuit includes a capacitor coupled to a respective one of the coils. During operation, wireless power signals are transmitted from the coils to the wireless power receiving device through the charging surface. The capacitor associated with each resonant circuit may potentially be individually selected to enhanced uniformity of the wireless power transmitting device. The array of coils may have multiple layers and the capacitors in each layer may have different respective values.

Abstract: An apparatus for charging a plurality of series connected battery cells, includes a first and second input terminals for providing a charging voltage to the plurality of series connected battery cell. A transformer includes a primary side associated with the charging voltage and a secondary side includes a plurality of portions. Each of the plurality of portions is connected across at least one of the plurality of series connected battery cell. A switch in series between each of the plurality of portions of the secondary side and the at least one of the plurality of series connected battery cells increases an impedance between the portion of the secondary side and the associated one of the plurality of series connected battery cells in a first state and decreases the impedance between the portion of the secondary side and the associated one of the plurality of series connected battery cells in a second state.

Abstract: Disclosed are devices, systems, and methods for reducing common mode noise induced in wireless charging circuits of electronic devices. For an electronic device having an inductive receiving coil near an electric shielding layer, differences in parasitic capacitances of the loops of the inductive receiving coil with an electric shielding layer can induce common mode noise. Common mode noise is reduced by a noise-reduction capacitor from the inductive receiving coil to the electric shielding layer together with a grounding resistor from the electric shielding layer to a common ground of the wireless charging circuit.

Abstract: A power converter can be implemented with a boosted-output inverter, which integrates the functionality of a voltage converter (e.g., boost converter) and a voltage inverter. In particular, a boosted-output inverter includes a primary tank inductor coupled in series with a secondary tank inductor at a central node. The boosted-output inverter also includes two voltage-controlled switches that respectively define a charging phase and a discharging phase of the primary tank inductor. While the primary tank inductor is charging, the secondary tank inductor is inverted to ground. In this manner, current though the secondary tank inductor alternates at a voltage boosted by the fly-back voltage of the primary tank inductor exhibited when the primary tank inductor transitions from the charging mode to the discharging mode. In many cases, the secondary tank inductor is a transmit coil of a transmitter of a wireless power transfer system.

Abstract: This disclosure relates to improved designs for phase-shift power converters, and, in particular, full bridge converters. Phase-shift power converters may lose Zero-Voltage-Switching (ZVS) under some load conditions, e.g., light load conditions—which can result in large switching losses. In order to avoid these losses, additional LC tank circuits may be added into the system to generate an amount of negative current needed to maintain ZVS. However, permanently adding such LC tank circuits into the system will reduce the system's efficiency. By intelligently adjusting the number (and particular combination) of LC tank circuits included in the system at a given time, ZVS may be maintained under all load conditions, while the impact of the additional LC tank circuits on the converter's overall efficiency may be limited, e.g., by employing the minimum number of LC tank circuits for the minimum amount of time needed to maintain ZVS.

Abstract: A wireless power transmission system has a wireless power receiving device that is located on a charging surface. The wireless power transmitting device has an array of wireless power transmitting coils that overlap the charging surface. The wireless power transmitting device uses inductance measurement circuitry that is coupled to the coil array to measure coil inductances for the wireless power transmitting coils. The wireless power receiving device may contain a communications integrated circuit, display circuitry, or other sensitive components. The location and orientation of the wireless receiving device on the charging surface can be determined by analyzing the coil inductances. This information and information on the location of the sensitive component within the wireless power receiving device can be used to select a wireless power transmitting coil to transmit wireless power signals to the wireless power receiving device without exposing the sensitive component to excessive wireless power signals.

Abstract: A wireless power transmitting device transmits wireless power signals to a wireless power receiving device. The wireless power receiving device has a rectifier and a wireless power receiving coil that receives wireless power signals. The rectifier is coupled to an integrated circuit such as a battery charger integrated circuit. One or more capacitors are coupled between input terminals for the rectifier and the wireless power receiving coil. The rectifier has output terminals at which the rectifier provides direct-current output power corresponding to the wireless power signals received with the wireless power receiving coil. Protection circuitry is coupled to one or more nodes located between the wireless power receiving coil and the capacitors. Control circuitry turns on one or more transistors in the protection circuitry in response to measurements made with sensor circuitry coupled to the output terminals.

Abstract: A wireless power transmission system has a wireless power receiving device that is located on a charging surface of a wireless power transmitting device. The wireless power transmitting device uses measurement circuitry such as coil impedance measurement circuitry or impulse-response circuitry that makes coil inductance measurements to monitor the charging surface for the presence of the wireless power receiving device. In response to detecting that the wireless power receiving device is present on the charging surface, the wireless power transmitting device and the wireless power receiving device establish a wireless communications link. The wireless power transmitting device transmits information on wireless power transmission capabilities of the wireless power transmitting device to the wirelessly power receiving device. The receiving device selects desired settings and transmits these to the transmitting device.