Multi-Cell Battery Sensing and Protection IC With Integrated Low-Temperature-Drift Reference for Series Battery Pack Management

The demand for compact battery management systems (BMS) in applications such as two-wheelers and uninterruptible power supplies has driven the development of battery management integrated circuits (BMICs). These BMICs incorporate functions such as battery sensing, fault detection, and protection management. This paper introduces an 18-cell lithium-ion battery sensing and protection BMIC, designed to enable the implementation of a compact BMS. Additionally, a high-order temperature-compensated bandgap reference (BGR) structure, with a temperature coefficient of 5 ppm/°C, is proposed to deliver a high-precision reference for sensing and comparison. The chip also integrates power management circuits capable of handling input voltages up to 90 V, thereby powering low-voltage modules. It features an 18-channel multiplexer for selectively detecting high-voltage, series-connected battery packs and achieving on-chip cell balancing through sequential control. Furthermore, a current-sense amplifier and programmable overcurrent protection circuits are included to reliably detect charging and discharging currents in the battery packs. The proposed BMIC occupies an area of 3 mm <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\times 3.3$ </tex-math></inline-formula> mm and is fabricated using a 180 nm BCD process. The total current consumption of the chip during normal operation is <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$65.1~\mu $ </tex-math></inline-formula>A, which can be reduced to <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$2~\mu $ </tex-math></inline-formula>A in shutdown mode to minimize long-term battery pack losses.