Wireless power receiver with programmable power path

摘要

A synchronous rectifier using only n-channel devices in which the low-side switches are effectively cross-coupled using low-side comparators and the high-side switches perform an accurate zero-voltage-switching (ZVS) comparison. The charging path of each bootstrap domain is completed through the low-side switches, which are each always on for every half-cycle independent of loading. This scheme gives rectifier efficiency gain because a) each bootstrap domain receives maximum charging time, and b) the charging occurs through a switch rather than a diode. Both these factors ensure the bootstrap domain is fully charged, thereby reducing conduction losses through the rectifier switches. Furthermore, settings may be adjusted by software to optimize the resistive and capacitive losses of the rectifier. Using data for die temperature and operating frequency, software can create a feedback loop, dynamically adjusting rectifier settings in order to achieve the best possible efficiency.