Abstract:
Certain aspects of the present disclosure relate to systems and methods for using electrostatic deflection of tissue to generate ultrasound power signals, such as for powering medical implants. Certain aspects of the present disclosure provide a system for generating ultrasonic pressure waves. The system includes an electrode configured to he positioned near a tissue. The system further includes an AC signal generator coupled to the electrode, wherein the AC signal generator is configured to apply an AC signal to the electrode causing the tissue to vibrate to generate ultrasonic pressure waves directed to an ultrasonic power receiver implanted under the tissue.
Abstract:
Wireless power transfer for integrated cycle drive systems is described. A cycle power system includes a rim that is connected to, and positioned concentrically with, a sealed housing that can rotate about an axis. The cycle power system also includes an integrated drive system disposed within the housing. The integrated drive system includes a battery and a motor for driving a cycle by causing rotational movement of the rim about the axis. Additionally, the cycle power system includes an inductive structure that is disposed within the housing, and that wirelessly charges the battery through induction between the inductive structure and remote a charging station.
Abstract:
Disclosed is a current sensor (600) that senses current flow in a conductor (604) by coupling a first magnetic field generated by the conductor to a sense element (602). The current sensor includes a shield (700) including a first material (702a,702b) that sandwiches the sense element to define a stack and a second material (704a,704b) that sandwiches the stack. The shield is configured to generate a second magnetic field, responsive to a third magnetic field external to the current sensor that opposes the third magnetic field. The shield is further configured to prevent production of a magnetic field that opposes the first magnetic field generated by the flow of current in the conductor.
Abstract:
A device with a noise adaptive power supply may include a noise adaptation unit configured to receive a noise adaptation signal. The noise adaptation unit can provide processing, such as digital filter processing to reduce the effect of power supply noise. A feedback signal may be used to adjust the output voltage of the power supply. The noise adaptation signal can be similar to the feedback signal. The noise adaptation unit can provide the processing in response to the noise adaptation signal.
Abstract:
A multi-level rectifier is presented that is suitable for use at high frequencies, including into MHz range such as in the 6.78 MHz band used for wireless power transfer. Depending on the amplitude of the input waveform, the rectifier can be operated in different modes. For lower input levels, the rectifier acts as a voltage doubler. For higher input levels, the impedance of the rectifier can be varied based on the input level. The rectifier is a synchronous rectifier with a front section and a back section, where the impedance is varied by changing the phase of the control signal of the back section relative to that of the front section.
Abstract:
Resonant rectifier topologies are described for tuning the rectifier so that it performs from an electromagnetic interference (EMI) point of view, while maintaining the voltage regulation at the output that a series tuned rectifier would maintain. Examples include a an inductor of a receive coupler and a rectifier connectable to drive a load, along with first and second filter elements that are each configured to provide an impedance inversion function in a frequency band and that are connected in series between the inductor of a receive coupler and rectifier. In one set of examples, both filter elements are implemented as pair filters, while in other examples the first filter element includes the inductor of a receive coupler in parallel with a capacitance connected to ground.
Abstract:
Methods and apparatus for charging a battery of a portable device are disclosed, including receiving, by a charging component, an amount of voltage on a power bus connectable to an external device, wherein the charging component charges the battery with the amount of voltage received. The methods and apparatus include authenticating, by an authentication component, the portable device with the external device via a plurality of signal lines, wherein the authentication component is configured to transmit one or more authentication signals on one or more of the plurality of signal lines. The methods and apparatus include transmitting, by a configuration component, a modified voltage signal and a modified current signal to the external device via the plurality of signal lines, wherein the modified voltage signal and the modified current signal are operable to cause the external device to modify the amount of voltage transmitted to the power bus.
Abstract:
This disclosure provides systems, methods and apparatus related to touch and gesture recognition with an electronic interactive display. The interactive display has a front surface that includes a viewing area, a planar light guide disposed proximate to and behind the front surface, a light source, and at least one photo sensing element coupled with the first planar light guide. The planar light guide is configured to receive scattered light, the received scattered light resulting from interaction between light emitted by the light source and an object in optical contact with the front surface. The photo sensing element is configured to detect at least some of the received scattered light and to output, to a processor, image data. The processor is configured to recognize, from the image data, one or both of a contact pressure and a rotational orientation of the object.
Abstract:
Certain aspects of the present disclosure relate to methods and apparatus for controlling a power level of wireless power transfer. Certain aspects provide a wireless power receiver. The wireless power receiver includes an antenna and a rectifier. The rectifier includes a first diode and a second diode. The wireless power receiver further includes a resistor in parallel with the first diode. A first terminal of the resistor is coupled to a first terminal of the first diode. A second terminal of the resistor is coupled to a second terminal of the first diode.
Abstract:
A multi-level rectifier is presented that is suitable for use at high frequencies, including into MHz range such as in the 6.78 MHz band used for wireless power transfer. Depending on the amplitude of the input waveform, the rectifier can be operated in different modes. For lower input levels, the rectifier acts as a voltage doubler. For higher input levels, the impedance of the rectifier can be varied based on the input level. The rectifier is a synchronous rectifier with a front section and a back section, where the impedance is varied by changing the phase of the control signal of the back section relative to that of the front section.