Figure 6. ESD Diode Diagram
Detailed Description
Figure 1 shows the functional diagram; Figure 2 shows
the application circuit diagram for a 12-cell system
while Figure 3 shows the application circuit design for a
10-cell system and Figure 4 for an 8-cell system. Figure
5 is the application schematic for the battery module
system with redundant fault detection and Figure 6 is
the ESD diode diagram.
Architectural Overview
The MAX11080/MAX11081 are battery-pack fault-monitor
ICs capable of monitoring up to 12 Li+ battery cells.
These devices are designed to provide an overvoltage or
undervoltage alarm indicator when any of the cells cross
the user-selectable threshold for longer than the config-
ured decision delay interval. The MAX11080/MAX11081
also incorporates daisy-chain bus for use in high-voltage
stacked-battery operation. The daisy-chain bus relays
shutdown and alarm communication across up to 31
stacked modules without the need for isolation between
each module. This results in a simplified system with
reduced cost. The MAX11080/MAX11081 are ideal as an
ultra-low-power, redundant cell-fault monitor that is the
perfect complement to the MAX11068 high-voltage bat-
tery measurement IC. Both ICs in concert form a powerful
Li+ battery system monitor with redundant overvoltage
and undervoltage fault detection.
Overvoltage and Undervoltage
Fault Detection
Figure 7 summarizes the fault-detection mechanism for
a set of differential cell inputs in the MAX11080/
MAX11081.
First, the differential cell inputs are attenuated by a fac-
tor of four while being level shifted and converted to a
single-ended voltage referenced to AGND. The ground-
referenced voltage is then connected to a set of over-
