Nonresonant Synchronizing Inductively Coupled CMOS
While the functionality of emerging wireless microsensors, cellular phones, and biomedical implants, to name a few, is on the rise, their dimensions continue to shrink. This is unfortunate because smaller batteries exhaust quicker. Not surprisingly, recharging batteries wirelessly is becoming increasingly popular today. Still, small pickup coils cannot harness much, so induced EMF voltages ${textit{v}}_{_{rm EMF.S}}$ are low. Modern receivers can resonate these low input voltages to rectifiable levels, but only with a finely tuned capacitor that resonates at megahertz when on-chip and at kilohertz when off-chip. In other words, resonant rectifiers are sensitive to frequency and dissipate considerable switching power when integrated on-chip.
Unluckily, excluding the resonant capacitor requires a control signal that synchronizes switching events to the transmitter’s operating frequency. The 0.18- $mu $ m CMOS prototype presented here derives this synchronizing signal from the coupled ${textit{v}}_{_{rm EMF.S}}$ by counting the number of pulses of a higher-frequency clock across a half cycle during a calibration phase and using that number to forecast half-cycle crossings. This way, the prototyped IC switches every half cycle to draw up to 557 $mu $ W from 46.6 to 585-mV $_{rm PK}$ signals with 38%–84% efficiency across 1.0–5.0 cm.
Related Communication System Project Titles:
- Predictive Torque Control Scheme for Three-Phase Four-Switch Inverter-Fed Induction Motor Drives With DC-Link Voltages Offset Suppression.
- Control and Monitoring for Grid-Friendly Wind Turbines: Research Overview and Suggested Approach.
- Speed sensor-less maximum power point tracking and constant output power operation of wind-driven wound rotor induction generators.
- A High Step-Down Multiple Output Converter With Wide Input Voltage Range Based on Quasi Two-Stage Architecture and Dual-Output LLC Resonant Converter.
- Analysis and Suppression of High-Order Mode Oscillation in an S-Band Klystron.
- Automated Demand Response From Home Energy Management System Under Dynamic Pricing and Powerand Comfort Constraints.
- Circulating Current Suppressing Strategy for MMC-HVDC Based on Nonideal Proportional Resonant Controllers Under Unbalanced Grid Conditions.
- Primary-Side Peak Current Measurement Strategy for High-Precision Constant Output Current Control.
- Approach for torque ripple reduction for brushless DC motor based on three-level neutral-point-clamped inverter with DC–DC converter.