High-Resolution Time-Interleaved Eight-Channel ADC for Li-Ion Battery Stacks

An analog-to-digital converter (ADC) for monitoring the voltages of a stack of eight Li-ion batteries is presented. The converted voltage range for each battery is 3–4.2 V with a maximum nominal input voltage of 33.6 V. High-voltage (HV) switches and a single HV capacitor make up the HV track and hold. The remaining part of the circuit operates at a nominal 5-V supply. An interleaved extended-range ADC makes up the architecture. It converts the eight channels in 720
$\mu\text{s}$
. The battery monitor has been fabricated in a 0.35-
$\mu\text{m}$
triple-well 5-V HV CMOS process with drain-extended MOS HV devices. The prototype active area is
$1300\times 650\ \mu\text{m}^{2}$
, and the measured total power consumption is 3.64 mW. The measured input-referred noise is 177.9
$\mu\text{V}$
, and the residual offset is 642.5
$\mu\text{V}$
.