Precision Integrated Analog Front End, Controller,

and PWM for Battery Test and Formation Systems

Data Sheet

AD8452

Rev. 0

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FEATURES

CC and CV battery test and formation modes with

transparent and automatic switchover, for systems of

20 Ah or less

Precise measurement of voltage and current

Independent feedback control blocks

Highly accurate, factory trimmed instrumentation and

differential amplifiers

In-amp for current sense gain: 66 V/V

Difference amplifier for voltage sense gain: 0.4 V/V

Stable over temperature: offset voltage drift <0.6 μV/°C

(maximum)

Gain drift: <3 ppm/°C (maximum)

Current sense CMRR: 120 dB minimum

Popular SMPS control for charge/discharge

High PWM linearity with internal ramp voltage

50 kHz to 300 kHz user controlled switching frequency

Synchronization output or input with adjustable phase shift

Programmable soft start

APPLICATIONS

Battery formation and testing

High efficiency battery test systems with recycle capability

Battery conditioning (charging and discharging) systems

GENERAL DESCRIPTION

The AD8452 combines a precision analog front-end controller

and switch mode power supply (SMPS), pulse-width modulator

(PWM) driver into a single silicon platform for high volume

battery testing and formation manufacturing. A precision

instrumentation amplifier (in-amp) measures the battery charge/

discharge current to better than ±0.1% accuracy, while an equally

accurate difference amplifier measures the battery voltage.

Internal laser trimmed resistor networks establish the in-amp

and difference amplifier gains (66 V/V and 0.4 V/V, respectively),

and stabilize the AD8452 performance across the rated

operating temperature range.

Desired battery cycling current and voltage levels are established

by applying precise control voltages to the ISET and VSET

inputs. Actual charge and discharge current levels are sensed

(usually by a high power, highly accurate shunt resistor) whose

value is carefully selected according to system parameters.

Switching between constant current (CC) and constant voltage

(CV) loop integration is instantaneous, automatic, and completely

transparent to the observer. A logic high at the MODE input

selects the charge or discharge mode (high for charge, low for

discharge).

The AD8452 simplifies designs by providing excellent

performance, functionality, and overall reliability in a space

saving 48-lead, 7 mm × 7 mm × 1.4 mm LQFP package rated

for operation at temperatures from −40°C to +85°C.

FUNCTIONAL BLOCK DIAGRAM

IBAT

IN-AMP

VBAT

DIFF

AMP

FAULT

×1

AD8452

BVREFH/

BVREFL

ISREFH/

ISREFL

VREF

0.4×

66×

CV FILTER

AMPLIFIER

SYSTEM CONTROL

SYNC

VIN

DT

DH

DL

SCFG

DMAX

FREQ

DGND

+DCBUS

VCL

VCL

ISV

BV

SS

CLVT

PWM

LOOP

COMP (×4)

MODE

SELECT

CC FILTER

AMPLIFIER

MOSFET

DRIVER

Figure 1.