Sub-1V Supply CMOS Voltage References Based on Asymmetric Differential Stage

The proposed nonbandgap voltage references are based on asymmetric differential pair. The p-channel transistors of this pair may have different threshold voltages, and different aspect ratios. One gate of this pair is connected to ground, another gate is used as the output reference voltage terminal. The reference voltage is equal to the difference of source-gate voltages in the differential pair. One can find the conditions, when this voltage is equal to the difference of threshold voltages, i.e. practically independent on temperature. The reference circuits are different by methods of tail current division between transistors of the pair, and by methods of tail current generation. The results, achieved at this time in simulations, show that one can obtain the output voltage of about 390 mV plusmn 0.5 mV in the range of temperatures -20 to 120degC. The power supply voltage may change, at the same time, from 1.8 V down to 0.7 V. The circuits can be realized in multi-threshold CMOS technology.