Minimum Energy Tracking Loop with Embedded DC-DC Converter Delivering Voltages down to 250mV in 65nm CMOS

An energy minimization loop, with on-chip energy sensor circuitry, that can dynamically track the minimum energy operating voltage of a digital circuit with changing workload and operating conditions occupies 0.05mm² in 65nm CMOS. The DC-DC converter that enables this minimum energy operation can deliver load voltages as low as 250mV and achieved an efficiency >80% while delivering load powers of the order of 1 pW and higher from a 1.2V supply