A stackable, 6-cell, Li-ion, battery management IC for electric vehicles with 13, 12-bit ΣΔ ADCs, cell balancing, and direct-connect current-mode communications

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, 5mV accuracy, better than 1.5mV matching) to measure individual cell voltages, cell temperature and battery current. Gate drivers with programmable frequency (5kHz - 2.048MHz), duty cycle and dither for active and passive cell balancing is provided. On chip 3.3V and 5.2V LDOs power the various 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 15uA of quiescent current.