An Ultra Low Power Voltage Regulator for RFID Application
Abstract
An ultra low power and low voltage regulator for radio-frequency identification (RFID) passive tags is designed and optimized in this thesis. It consists of a low power sub-1V reference voltage generator with temperature and supply voltage ripple compensation, and a low-dropout voltage (LDO) regulator. The circuits are designed in CMOS 65nm technology. The total quiescent current of 63.8nA at 1.5V supply voltage has been achieved using properly sized transistors operating in the subthreshold region. With the low voltage property of transistors operating in subthreshold region the output regulated voltage can easily achieve 1V with load capacity of 50uA. Self-biased current sources are employed and optimized to eliminate the effect of supply voltage variation and to achieve a line regulation of 4.06mV/V. A PMOS pass device with small output resistance is used to reduce the load regulation to 6.57mV/50uA. By utilizing subthreshold properties, the temperature coefficient is reduced to 12.7 and 31ppm/°C for the reference voltage and regulated voltage, respectively. The circuits can operate well from -30°C to 50°C, a typical temperature range of the environment where RFID tags are widely deployed.