ANALYSIS OF THE RECTIFYING PROPERTIES OF NANOMETER MOS TRANSISTORS IN A DIODE CONNECTION AT ULTRALOW VOLTAGE
Abstract
Advances in microelectronics, especially the development of CMOS technology, have made it possible to create devices with extremely low power consumption. This made it possible to develop autonomous wireless devices that, using radio waves, not only receive, process, and transmit information, but also receive power from the terminals. For wireless and battery-free power supply, harvesting of radio frequency energy from the environment can be used: radiation energy from cellular stations, radio and television stations, microwave ovens, Wi-Fi, Bluetooth, and other sources. To convert radio frequency energy into supply voltage, rectifiers based on nanometer diode-connected MOSFETs are most often used. When wireless powered devices are located far from the terminal or harvest energy from the environment, the power density of the electromagnetic field and therefore the amplitude of the input voltage can be quite small. The urgent task is to develop and study such devices capable of operating at very low input voltages. The purpose of the study is to analyze the rectifying properties of diodes based on nanometer MOSFETs in weak inversion mode at ultra-low input voltages and to develop recommendations for the choice of technology and design of microcircuits with wireless power. Expressions are obtained for estimating the rectification coefficients of diodes in terms of current and power. Calculations using the obtained expressions and modeling using the BSIM4v4.8.2 model of current-voltage characteristics and dependences of diode rectification coefficients for current and power on voltage for a typical 90 nm CMOS technology were performed. The possibility of constructing rectifiers based on MOSFETs at ultralow voltages down to units of mV has been demonstrated. Recommendations are given for justifying technological and design parameters when designing modules for converting and harvesting energy of wireless devices.
