A Multiphase Resonance-Based Boosting Rectifier With Dual Outputs for Wireless Power Transmission

This paper proposes a multiphase resonance-based rectifier (MPRR), capable of delivering power to multiple loads with large difference in their output voltages. This behavior is particularly useful for wireless sensors and actuators, in which the micromachined transducer/actuator needs a high voltage to operate but the interface circuitry requires only a fraction of that voltage. This is achieved by shorting the receiver (Rx) L
₃
C
₃
-tank to increase its loaded quality factor, Q
_Rx
, over several cycles to accumulate wirelessly transferred energy in the inductor during this period, and then first break the loop in-phase, by connecting the L
₃
C
₃
-tank to the in-phase load (R
_L,I
), to transfer energy at low voltage in a half cycle (in-phase charging), and then transfer energy to the quadrature load (R
_L,Q
) through a diode in a quarter cycle at high voltage (quadrature charging). By optimizing the number of cycles for in-phase charging, N
_I
, and quadrature charging, N
_Q
, through an iterative design procedure, the MPRR can achieve the highest power delivered to the load under a given set of design constraints. Governing equations in the MPRR operation are derived to identify the key specifications for the design procedure. Using an exemplar set of specifications, the optimized MPRR was able to generate 21.5 and 1.84 V across 100 kΩ and 200 Ω loads, respectively, from a class-D power amplifier operating at 15 V, 6.78 MHz sinusoid input in the industrial-scientific-medical band (ISM-band) at a Tx/Rx coil separation of 1.3 cm with N
_I
= 3 cycles, N
_Q
= 6 cycles, and IQRatio = 5.