Patent ID: 8908400

Claim:
An apparatus configured as a wireless energy transfer receiver in an electronic device, the wireless energy receiver operable with a wireless energy transmitter for wireless energy transfer from the transmitter to the electronic device, comprising: an inductive coil configured to receive alternating current (AC) electric energy magnetically coupled into the inductive coil from the wireless energy transmitter; an output circuit including an output capacitor; a resonator circuit including the inductive coil and a resonator capacitor; a synchronous rectification circuit coupled to the inductive coil and the resonator capacitor, and configured to convert the AC energy received at the inductive coil into DC energy supplied to the output circuit including the output capacitor and the electronic device; and the synchronous rectification circuit including four diodes D 1 -D 4 arranged as a diode bridge rectifier, and four transistor switches Q 1 -Q 4 respectively connected across the diodes D 1 -D 4 , the transistor switches controlled such that the synchronous rectification circuit is operable in two modes; a resonant multiplication mode in which transistor switches Q 2 and Q 4 are conducting, short circuiting respective diodes D 2 and D 4 , and transistors Q 1 and Q 3 are non-conducting, such that (i) the resonator circuit operates as a resonant tank storing transferred wireless energy on the resonator capacitor, and (ii) DC energy is supplied to the electronic device from the output capacitor; and a rectification mode in which the transistor switches Q 1 -Q 4 are synchronously controlled such that the diode bridge rectifier supplies rectified energy from the resonator circuit to the output circuit.