A Rail-to-Rail Second Generation Voltage Conveyor for Low-Power Applications

In this paper, a second-generation voltage conveyor (VCII), designed for low-voltage low-power applications, is proposed. A Rail-to-Rail feature is obtained through the use of a bipolar charge pump applied on the voltage supply of the output stage. The circuit has been designed in a 0.18 mu m standard CMOS technology operating at a +/- 0.9 V supply voltage, extended by the charge pump to +/- 1.45 V for the output stage. Spice simulations have shown that the output voltage has a 94% and a 100% dynamic range for a 10 k Omega and a 100 k Omega load, respectively. The VCII operates efficiently at relatively low frequencies, within the range of tens of MHz. The average power consumption retrieved from the bipolar voltage sources equals +/- 35 mu W, while the same parameter, retrieved at the outputs of the charge pumps, equals +/- 3.5 mu W.