A Low-Cost RFID Regulator Insensitive to Temperature and Supply Voltage Variations.

A low-cost regulator insensitive to temperature and supply voltage variations for power management units of Radio Frequency Identification (RFID) tag chips and other batteryless devices is proposed in this paper. The commonly used regulator has poor temperature rejection ratio (TRR) and poor voltage rejection ratio (VRR). By using combination resistors and long channel transistors, the bias and regulator circuits are improved over temperature variations. A power supply rejection (PSR) enhancement branch is also added to suppress the supply noise and stabilize the bias current. The regulator is designed and fabricated in the HJTC 0.25 mu m CMOS technology. Simulation results show that this regulator achieves 0.044mV/degrees C TRR when temperature varies from -20 degrees C to 70 degrees C and 1.1mV/V VRR while the supply voltage of the regulator ranges from 4 to 12V. The PSR is nearly -100 dB at DC. The area of this regulator is 0.102mm(2) including the bias circuit. The measurement results meet simulation results well and this regulator is successfully applied in HF passive tag chips within voltage deviations of +/- 5% of 2.5 V.