A Link-and-Load Adaptive IC for Co-optimization of Power Delivery and Energy Storage in Voltage-Mode Resonant Inductive Power Receivers

We present a stand-alone energy-efficient integrated circuit (IC) for adaptive co-optimization of power delivery and energy storage in resonant voltage-mode inductive power receivers. The IC does this by (a) dynamically adjusting the rectifier’s conduction angle to optimize the load seen by the link, thus isolating the link’s efficiency from load variations, and (b) continuously supplying the load while storing/recycling the excess/deficit received energy in/from a storage capacitor. The conduction angle adjustment is done by controlling the current drawn from the LC tank in a voltage-controlled manner, hence is needless of continuous load power monitoring and resonators manipulation (i.e., disrupting resonance). The charging and recycling are done using a buck-boost charger, which is also responsible for isolating the link from the effect of load variations and capacitive charging. Additionally, an automatic calibration circuit is integrated on chip to adapt the receiver’s operation to link variations, such as coil movement or misalignment. The measurement results demonstrate improvements of up to $\mathbf{9 2. 7 0 \%}$ in the overall charging time and $\mathbf{1 2 7 0 \%}$ in stored power, respectively, compared to non-optimized situations.