DRIVER FOR WIRELESS POWER TRANSMITTER SENSING REQUIRED TRANSMIT POWER FOR OPTIMUM EFFICIENCY

摘要

An auto-resonant driver for a transmitter inductor drives the inductor at an optimal frequency for maximum efficiency. The transmitter inductor is magnetically coupled, but not physically coupled, to a receiver inductor, and the current generated by the receiver inductor is used to power a load. The system may be used, for example, to remotely charge a battery (as part of the load) or provide power to motors or circuits. A feedback circuit is used to generate the resonant driving frequency. A detector in the transmit side wirelessly detects whether there is sufficient current being generated in the receiver side to achieve regulation by a voltage regulator powering the load. This point is achieved when the transmitter inductor peak voltage suddenly increases as the driving pulse width is ramped up. At that point, the pulse width is held constant for optimal efficiency.

主权项

1. A power transmission system for wirelessly supplying power to a load comprising:
a transmitter inductor; a first switch coupled between a voltage source and the transmitter inductor and controlled to generate a varying current through the transmitter inductor; a receiver inductor magnetically coupled to the transmitter inductor; a voltage regulator receiving power from the receiver inductor to generate a regulator output voltage; a load coupled to an output of the voltage regulator, wherein power in the transmitter inductor is wirelessly coupled to the receiver inductor for being converted to a regulated voltage by the regulator for driving the load; a peak voltage detector coupled to detect a peak voltage on the transmitter inductor, wherein a peak voltage on the transmitter inductor is affected by an ability of the voltage regulator to achieve regulation for driving the load; and a controller for controlling a peak current through the transmitter inductor, the controller being controlled to modulate the peak current through the transmitter inductor so as to modulate a peak current through the receiver inductor, wherein the peak voltage on the transmitter inductor increases during a time when the voltage regulator is able to achieve regulation, wherein the controller is configured to terminate modulating the peak current through the transmitter inductor, based on a change in the peak voltage, so that the voltage regulator is able to achieve regulation.