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

• Published in: IEEE journal of solid-state circuits Vol. 53; no. 10; pp. 2951 - 2957
• Main Authors: Vulligaddala, Veeresh Babu, Adusumalli, RaviKumar, Singamala, Sudhakar, Srinivas, M. B.
• Format: Journal Article
• Language: English
• Published: New York IEEE 01.10.2018; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Bandgap; Batteries; battery management; Calibration; Circuit design; CMOS; Current measurement; Electric potential; Electrical measurement; Energy gap; Error detection; Integrated circuits; Lead acid batteries; Photonic band gap; Power supplies; proportional to absolute temperature (PTAT); Resistors; sigma–delta analog-to-digital converter (SDADC); Temperature measurement; Temperature sensors; Voltage measurement
• ISSN: 0018-9200; 1558-173X
• DOI: 10.1109/JSSC.2018.2859984

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 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. The integrated circuit is fabricated in 0.35-<inline-formula> <tex-math notation="LaTeX">\mu \text{m} </tex-math></inline-formula> standard CMOS technology and occupies an area of 0.23 mm 2 .