A multi-piecewise curvature-corrected technique for bandgap reference circuits

A systematic design methodology utilizing piecewise curvature correction technique for the purpose of improving the temperature coefficient of bandgap references (BGRs) is presented in this paper. It is shown that the temperature dependency of the drain current of a MOSFET transistor depends on the transistor´s operating region. Using this property, a multi-piecewise compensation technique over wide temperature range is achieved by controlling the operating region of MOSFETs through their gate-source voltages. The technique offers several advantages including simplicity, and providing the designers with flexibility to employ a combination of piecewise currents to achieve maximum temperature stability over the desired temperature range. To demonstrate the capability of this approach, the technique is used to effectively reduce the temperature coefficient of a first-order BGR circuit.