Inductively coupled power receiver and method of operation

摘要

A contactless power receiver is provided with a dynamically tuned pick up coil. The power transfer capacity of this power receiver is dynamically tuned using semiconductor devices that are operated in linear mode over part of their operation. The semiconductor devices are driven by a controller that is configured to implement a range of control strategies depending on system requirements. The semiconductor device may be used by itself or in conjunction with reactive elements to dynamically tune the pick up coil. In some implementations the contactless power receiver maybe configured to work with a consumer electronic or a wireless sensor device. The contactless power receiver can be integrated with the energy storage component of the device to provide a retrofit solution for existing products. The device can then be placed in vicinity of a planar magnetic field generated by a charging pad.

主权项

1. A contactless power receiver suitable for use in a near field inductively coupled power transfer system including:
a. a pick up coil; b. a metal-oxide-semiconductor filed-effect transistor (MOSFET) for controlling current flow through the pick up coil; and c. a control circuit which drives the MOSFET in linear mode over at least part of its range of operation to tune the pick up coil based on a voltage output of the contactless power receiver, the control circuit comprising:
an operational amplifier operatively connected to a gate of the MOSFET, the operational amplifier comparing the voltage output of the contactless power receiver to a reference voltage; anda resistive feedback arrangement for establishing dynamic gain of the operational amplifier;wherein driving the MOSFET in linear mode comprises configuring the operational amplifier by the dynamic gain established by the resistive feedback arrangement to drive the MOSFET to switch between OFF and ON-ohmic region by controlling a gate drive voltage of the MOSFET to be in the ohmic region of the MOSFET.