A digitally corrected bandgap voltage reference with a 3 Sigma temperature coefficient of 3.8 ppm/K
2015 European Conference on Circuit Theory and Design (ECCTD), Trondheim, Norway
Abstract—Bangap voltage references (BGRs) are widely used in today’s circuits as references with a low temperature coefficient. Especially measurement circuits and metering applications demand a very low temperature coefficient to maintain the desired precision over the entire temperature range. Today’s BGR designs use analog circuits to correct for the effects which lead to a temperature drift. In this paper a bandgap reference voltage which uses a digital correction technique is presented. The proposed design includes a temperature sensor to measure the current chip temperature and a bandgap reference which is controllable by a 3-bit digital input. The input to the bandgap block is calculated using a digital correction algorithm. The proposed design was implemented in a 0.35 μm CMOS process and occupies 0.437 mm2 . After calibration, a 3σ temperature coefficient of 3.8 ppm/K is achieved over a temperature range from −40 ◦C to 100 ◦C. With the proposed design, high performance measurements over a large temperature range have become possible. The digital design allows for an easy adaptation to various needs and temperature coefficients.
Index Terms—CMOS integrated circuits, Temperature dependence, Feedback circuits, Photonic band gap