Google Inc.

Srikanth Lakshmikanthan

Liang Jia

Eduardo Marcelo Lipiansky

Udaya Kiran Ammu

Qi Tian

Liyu Yang

Veera Venkata Siva Nagesh Polu

Srenik Suresh Mehta

Honggang Sheng

Cornelius Bendict O'Sullivan

Rahul A Apte

Jae-Won Hwang

Li Wang

Eklavya Singh

Enrique Romero Pintado

Douglas Osterhout

William Riis Hamburgen

Aaron Leiba

Shuo Wang

Yiming Li

Stefano Saggini

Brandon Baxter Harris

Christopher Thomas Lyon

Jinal Dalal

Tressa Christie Scott

Frank Hislop

Tracy Van Dyk

Maire Mahony

Mario Ursino

Chao Fei

Chris Lyon

Tracy Jane Van Dyk

Robert Thomas Shone

YungChih Chen

Ruben Specogna

The present disclosure provides for a wearable device having a wireless power receiving system that may inductively receive or transmit power. The wireless power receiving system includes a receiver coil having a profile that follows a contour of a bottom cover of the wearable device. A transmitter coil from a wireless charging device has a complementary profile that mates with the profile defined by the receiver coil. In one example, the wireless power receiving system includes a shielding, and a receiver coil attached to the shielding. The receiver coil further includes an inner wall and an outer wall connected by a top surface of a coil body. The inner wall defines a center opening in the receiver coil, wherein the receiver coil is conical in shape.

Wireless charging coil in wearable devices

Shielded electrical transformers and power converters using those transformers are disclosed. In some implementations, a shielded electrical transformer includes a magnetic core, a primary winding, a first secondary winding, and a second secondary winding. The transformer includes a first shielding winding that has a same voltage potential direction as the primary winding and is connected in series with the primary winding to carry current that passes through the primary winding. The transformer also includes a second shielding winding that has a voltage potential direction opposite the primary winding and is connected from primary ground to a floating terminal. The first secondary winding, the second secondary winding, the first shielding winding, and the second shielding winding can each have an approximately equal number of turns.

Shielded electrical transformer

An example active stylus includes a core comprising: a main cylinder having a first end, a second end; a first supplemental cylinder disposed at the first end of the main cylinder and having a diameter that is larger than a diameter of the main cylinder; a second supplemental cylinder disposed between the first supplemental cylinder and the second end of the main cylinder and having a diameter that is larger than the diameter of the main cylinder; and a wireless charging receive coil configured to transduce flux of a magnetic field generated by a wireless charging transmit coil into electrical current, wherein the wireless charging receive coil is positioned around a longitudinal axis of the main cylinder of the core and between the first supplemental cylinder and the second supplemental cylinder.

Active stylus with wireless charging

This document describes a passive adapter for wireless charging of an electronic device and associated methods and systems. The described passive adapter includes two coils connected by a capacitor and separated by a core material that prevents mutual coupling between the coils. These two coils may have differing sizes, such that one coil can size-match to a transmitter coil of an existing wireless charger and the second coil can size-match to a smaller (or larger) receiver coil in a wireless-power receiver to charge a battery of the wireless-power receiver. In aspects, these two coils may be separated by a distance that enables the passive adapter to act as a passive repeater by bridging a space between the transmitter coil and the receiver coil.

Passive adapter for magnetic inductive wireless charging

In general, techniques are described that are directed to a device that includes a power storage device, an electrical load, and a first regulated power converter including components configured to generate, during a first time period and using electrical energy received from a power source external to the device, a first power signal to charge the power storage device. A second regulated power converter includes components configured to determine a charging current at which to charge the power storage device, determine a total amount of current flowing to the power storage device that includes current sourced by the second power converter less current sinked by the electrical load, and generate, during a second time period that is non-overlapping with the first time period, using electrical energy from the power source and based on determined the total amount of current, a second power signal to charge the power storage device.

Parallel charger circuit with battery feedback control

Methods, systems, and apparatus, including computer programs encoded on computer-storage media, for wireless charging using time-division multiplexing. In some implementations, a wireless charger is configured to concurrently charge multiple devices by providing power wirelessly to individual devices in different time periods. The wireless charger can perform time-division multiplexing by selectively directing the output of a single driver circuit to different power transfer coil segments at different times. The wireless charging sessions of multiple devices can be maintained by repeating a pattern of activating different power transfer coil segments one by one in successive time periods.

Wireless charging using time-division multiplexing

This document describes techniques and apparatuses directed at reducing inductive-charging power loss. In aspects, a mobile device includes a multi-layer flexible printed circuit board (FPCB) coil that forms a receiver coil having a Litz-wire structure. The FPCB coil includes a multi-trace bundle, having traces systematically routed throughout the different layers of the FPCB coil to reduce eddy current losses.

Techniques and apparatuses to reduce inductive charging power loss

Methods, systems, and techniques for safely controlling wireless charging in the presence of a foreign object are presented. A method includes determining a power difference between a power transmitted by a wireless charger and a power received by an electronic device, determining a level of misalignment of the electronic device with respect to the wireless charger; estimating an amount of power difference due to the level of misalignment of the electronic device with respect to the wireless charger, adjusting a power difference threshold for the wireless charger based on the estimated amount of power difference, and controlling operation of the wireless charger based on the power difference and the adjusted power difference threshold.

Controlling wireless charging

Methods, systems, and apparatus, including computer programs encoded on computer-storage media, for improving wireless charging. In some implementations, an electronic device determines a power demand of the electronic device. The electronic device includes a wireless power receiver including a wireless power receiving coil configured to receive power through inductive coupling with a wireless charge. The electronic device determines an operating voltage or operating frequency for the wireless charger based on the power demand of the electronic device. The electronic device sends, to the wireless charger, data indicating the operating voltage or operating frequency for the wireless charger.

Wireless charging efficiency

Methods, systems, and devices, including machine-readable media, for dynamic battery power management are disclosed. In some implementations, an electronic device that is powered by a battery senses a voltage provided by the battery and an electric current provided by the battery. The electronic device determines a present state of the battery. The electronic device determines a current limit for the electronic device based on the sensed voltage and electric current and the determined present state of the battery. The electronic device manages power use of the electronic device to maintain electric current draw from the battery at or below the electric current limit.

Dynamic battery power management

A computing device is associated with a circuit for sharing and distributing backup power. During normal operating conditions, a main bus bar provides power to each computing device in a rack via a main power bus of the corresponding circuit. In the event of an AC power outage, the main power bus is deactivated and a backup power path of the circuit is activated. Backup power is provided to the device from a battery of the circuit via the backup power path. A shared power path is also activated in the circuit such that backup power may be provided from the battery to the main bus bar. By providing backup power to the main bus bar, the other computing devices in the rack that do not have sufficient backup power may receive backup power from the main bus bar until AC power is restored.

Backup power architecture for rack system

In some implementations, a programmable power adapter includes a first set of switches, a resonant circuit, a transformer, and a second set of switches. The power adapter includes control circuitry configured to provide control signals that change the voltage conversion ratios of the first set of switches and the second set of switches. The control circuitry can provide control signals causing the first set of switches to operate in one of multiple operating modes that each correspond to a different voltage conversion ratio, and the control circuitry can provide control signals causing the second set of switches to operate in one of multiple operating modes that each correspond to a different voltage conversion ratio.

Programmable power adapter

This specification describes a device that includes a voltage-regulated DC-DC converter comprising a switching network, a resonant circuit, and control circuitry, wherein the switching network has a switching frequency. The DC-DC converter has an output impedance and the control circuity uses a control loop to control the DC-DC converter. The control circuitry implements the control loop using: an output voltage sensor configured to sense an output voltage of the DC-DC converter; and a compensator configured to adjust operation of the DC-DC converter based on the output voltage sensed by the output voltage sensor. The DC-DC converter comprises an output impedance suppression mechanism configured to at least partially suppress increases in the output impedance of the DC-DC converter.

Growing community of inventors

Milpitas, CA, United States of America

Srikanth Lakshmikanthan