Low-Power Double-Gate ZnO TFT Active Rectifier

This letter reports a low-power full-wave active rectifier using double-gate ZnO thin-film transistors (TFTs). The active rectifier is designed to operate at low voltage and low power to allow integration with mechanical energy harvesters. Double-gate TFTs allow the TFT threshold voltage to be tuned and enable enhancement/depletion-mode circuits with high gain and low power consumption. The active rectifier is designed to work with input voltage as small as 200-mV peak-to-peak and frequencies up to 4 Hz. The active rectifier circuit includes 12 TFTs and operates with a power consumption <150 nW. The low fabrication temperature for the active rectifier circuit allows direct and distributed integration with micro-electromechanical energy harvesters.