A Stackable, 6-Cell, Li-Ion, Battery Management IC for Electric V ehicles With 13, 12-bit ADCs, Cell Balancing, and Direct-Connect Current-Mode Communications

Abstract

Battery monitoring systems are a critical aspect of electric vehicles. To interface with the high voltages in these systems a stacked IC approach is used. In this work we present an IC suitable for monitoring 6 cells which can be stacked to monitor a total of 192 cells. The IC has 13 parallel ΣΔ ADCs (12 bit, 5 mV accuracy, better than 1.5 mV matc hing) to measure individual cell voltages, cell temperature and battery current. Gate drivers with programmable frequency (5 kH z–2.048 MHz), duty cycle and dither for active and passive cell balancing is provided. On-chip 3.3 V and 5.2 V LDOs power the var ious subsystems. To eliminate external components, the ICs uses current-mode signaling which allows the IC to be directly connected to one another to transmit information about cells from the top of the stack to the host. The IC consumes less than 15 µA of quiescent current.