Precision Integrated Analog Front End, Controller,
and PWM for Battery Test and Formation Systems
Data Sheet
AD8452
FEATURES
GENERAL DESCRIPTION
CC and CV battery test and formation modes with
The AD8452 combines a precision analog front-end controller
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)
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 ±±.ꢀ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 ±.4 V/V, respectively),
and stabilize the AD8452 performance across the rated
operating temperature range.
Gain drift: <3 ppm/°C (maximum)
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).
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
The AD8452 simplifies designs by providing excellent
performance, functionality, and overall reliability in a space
saving 48-lead, 7 mm × 7 mm × ꢀ.4 mm LQFP package rated
for operation at temperatures from −4±°C to +85°C.
FUNCTIONAL BLOCK DIAGRAM
LOOP
COMP (×4)
SYSTEM CONTROL
VCL
+DCBUS
VIN
SYNC
SCFG
CC FILTER
AMPLIFIER
VCL
DH
MODE
MOSFET
DRIVER
VBAT
IBAT
DL
SELECT
DIFF IN-AMP
AMP
SS
PWM
×1
CV FILTER
AMPLIFIER
CLVT
DT
ISREFH/
ISREFL
BVREFH/
BVREFL
FREQ
DMAX
VREF
0.4×
BV
66×
AD8452
FAULT
DGND
ISV
Figure 1.
Rev. 0
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