On-chip voltage down converter for low-power digital system

An on-chip differential-amplifier-based DC-to-DC voltage down converter (VDC) is proposed. The converter is a negative feedback-type voltage follower with precise internal reference voltage generator and high current drive capability. VDC converts 5 V to lower voltage so that the internal circuits of the chip are used. In this paper, 3 V is used as a test vehicle. The proposed VDC has characteristics such as output voltage remains 3 V over a large load current range (0-100 mA) and temperature dependency of 3.2 mV//spl deg/C. The VDC chip was fabricated in a 0.8 /spl mu/m single-poly-double-metal CMOS process and layout size is 690/spl times/210 /spl mu/m/sup 2/. The output voltage is stabilized within /spl plusmn/2.8% for supply voltage with /spl plusmn/10% variation achieved.