ANALYSIS OF THE RECTIFYING PROPERTIES OF NANOMETER MOS TRANSISTORS IN A DIODE CONNECTION AT ULTRALOW VOLTAGE
Keywords:
Internet of Things, wireless transmission, harvesting and conversion of energy, diodes, nanometer MOSFETs, subthreshold mode, rectification coefficientAbstract
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.
