Apple Inc.
Asymmetric duty control of a half bridge power converter

Abstract:

A half bridge power converter can be coupled to, or included in, a wireless transmitter device. The half bridge power converter includes an upper switching element connected between a direct current supply voltage and a lower switching element. A duty controller is coupled to the upper and the lower switching elements and is configured to asymmetrically control the duty cycles of the upper and lower switching elements based on a voltage level of the direct current supply voltage. In general, the duty cycle of the lower switching element is different than the duty cycle of the upper switching element. Additionally or alternatively, the duty controller is configured to determine and control the duty cycles of the upper and lower switching elements to adjust a direct current gain of a wireless energy transfer system that includes the wireless transmitter device.