Conductance modulation techniques in switched-capacitor DC-DC converter for maximum-efficiency tracking and ripple mitigation in 22nm Tri-gate CMOS

摘要

Active conduction modulation techniques are demonstrated in a fully integrated multi-ratio switched-capacitor voltage regulator with hysteretic control, implemented in 22nm tri-gate CMOS with high-density MIM capacitor. We present (i) an adaptive switching frequency and switch-size scaling scheme for maximum efficiency tracking across a wide range voltages and currents, governed by a frequency-based control law that is experimentally validated across multiple dies and temperatures, and (ii) a simple active ripple mitigation technique to modulate gate drive of select MOSFET switches effectively in all conversion modes. Efficiency boosts upto 15% at light loads are measured under light load conditions. Load-independent output ripple of <50mV is achieved, enabling fewer interleaving. Testchip implementations and measurements demonstrate ease of integration in SoC designs, power efficiency benefits and EMI/RFI improvements.