Lithium Ion Battery Safety Monitor

AD8280

Rev. C

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FEATURES

Wide supply voltage range: 6.0 V to 30.0 V

Multiple inputs can monitor 3 to 6 cell voltages

and 2 temperatures

Adjustable threshold levels: overvoltage, undervoltage,

overtemperature

Alarm options: separate or shared alarms

Extended temperature range performance

Can be daisy-chained

Internal reference

Powered from battery stack

LDO available to power isolator

Qualified for automotive applications

Extensive self-test feature aids in meeting ASIL/SIL

requirements

APPLICATIONS

Lithium ion battery backup monitor and threshold detection

Electric and hybrid electric vehicle

Industrial vehicle

Uninterruptible power supply

Wind and solar

GENERAL DESCRIPTION

The AD8280 is a hardware-only safety monitor for lithium ion

battery stacks. The part has inputs to monitor six battery cells

and two temperature sensors (either NTC or PTC thermistors).

The part is designed to be daisy-chained with other AD8280

devices to monitor a stack of significantly more than six cells

without the need for numerous isolators. Its output can be con-

figured for an independent or shared alarm state.

The AD8280 functions independently from a primary monitor

and contains its own reference and LDO, both of which are

powered completely from the battery cell stack. The reference, in

conjunction with external resistor dividers, is used to establish

trip points for the overvoltages and undervoltages. Each cell

channel contains programmable deglitching circuitry to prevent

alarms from transient input levels.

The AD8280 also has two digital pins that can be used to select

various combinations of inputs in the case where fewer than six

cells are to be monitored. Most important, it has a self-test feature,

making it suitable for high reliability applications, such as auto-

motive hybrid electric vehicles or higher voltage industrial usage,

such as uninterruptible power supplies. The AD8280 can function

over a temperature range of −40°C to +105°C.

FUNCTIONAL BLOCK DIAGRAM

I/V

CONVERTER

V/I

CONVERTER

VIN6

VIN5

VIN2

VIN1

OT

UV

OV

AIINOV

AIOUTOV

VT1

SEL0

SEL 1

VTOP

VBOT1

C6O

CT2

C1O

C1U

C6U

DE-

GLITCHING

DE-

GLITCHING

DE-

GLITCHING

DE-

GLITCHING

DE-

GLITCHING

DE-

GLITCHING

VIN3

VIN4

AD8280

CT1

VT2

AVOUTOV

ALARM

LOGIC

VIN0

LDO

REF

ENBO

ENBI

TOP

REF

DGT0

DGT1

OT

OT

LDO

TESTO

TESTI

SELF-

TEST

GENERATOR

BOT

LEVEL

SHIFTER

LEVEL

SHIFTER

AIOUTUV

AIOUTOT

AIINUV AIINOT

DGT2

NPTC

ALRMSEL

AVOUTUV

AVOUTOT

VCC

VCCS

GND2

GND1

VBOT1S

VBOT2

VBOT2S

FB

LDOS

VTOPS

LEVEL

SHIFTER

Figure 1.