A Digitally Calibrated Bandgap Reference With 0.06% Error for Low-Side Current Sensing Application

TLDR: A design of an on-chip precision bandgap reference with a digitally calibrated technique is described and Experimental results show that a maximum of 0.06% variation in the bandgap output for a temperature range of −40 °C–100 °C at a power supply voltage of 3.3 V is achieved.

Abstract: Accurate current and voltage measurements are essential for estimating the state of charge of an automotive battery Typically, circuits are designed to measure low-side current of lead-acid battery These circuits, however, require a precision reference voltage across a temperature range In this paper, a design of an on-chip precision bandgap reference with a digitally calibrated technique is described The bandgap is trimmed for temperature and magnitude and is calibrated digitally Experimental results show that a maximum of 006% variation in the bandgap output for a temperature range of −40 °C–100 °C at a power supply voltage of 33 V is achieved The integrated circuit is fabricated in 035- $\mu \text{m}$ standard CMOS technology and occupies an area of 023 mm2