An input-powered active AC/DC converter with zero standby power for energy harvesting applications

AC/DC converters in energy harvesting systems are typically powered from either external power supplies or load-side energy storage elements. This paper presents an active AC/DC converter that is directly powered by the input AC signal generated from the energy harvester. This approach eliminates the need for external power supplies, reduces the pin count, and avoids standby power consumption when the input amplitude is too low for energy harvesting. For demonstration, the circuitry is realized in AMI 3M-2P 0.5 μm CMOS process. The measured input amplitude range is from 0.65 V to 2.5 V, and the operating frequency range is from 1 Hz to 100 kHz. A maximum efficiency of 82% is achieved. When the input voltage amplitude drops below 0.6 V, the converter automatically enters standby mode with no standby power consumption. The circuit also functions properly in tests with an electrodynamic vibrational energy harvester.