The AD8450 is a precision analog front end for testing and
monitoring battery cells. Referring to figure one, a precision
programmable gain instrumentation amplifier (PGIA)
measures the battery’s charge/discharge current and a
programmable gain difference amplifier (PGDA) measures the
battery’s voltage. Internal laser trimmed resistor networks set
the gains for the PGIA and the PGDA, optimizing the AD8450’s
performance over the rated temperature range. PGIA gains are
26×, 66×, 133×, and 200×. PGDA gains are 0.2×, 0.27×,0.4×,
and 0.8×.
Voltages at the ISET and VSET inputs set the desired constant
voltage (CV) and constant current (CC) values. CC to CV
switching is automatic and transparent to the system.
A TTL level logic input, MODE, selects between charge and
discharge modes (high for charge, low for discharge). An analog
output, VCTRL, interfaces directly with ADI’s ADP1972 &
ADP1974 PWM controllers.
The AD8450 includes resistor programmable overvoltage and
overcurrent detection and current sharing circuitry. Current
sharing is used to balance charge among multiple batteries.
The AD8450 simplifies designs by providing excellent accuracy,
performance over temperature, flexibility with functionality,
and overall reliability in a space-saving package. The AD8450 is
available in an 80 lead 14 mm ×14 mm × 1 mm LQFP package
and is rated at −40 °C to +85 °C operating temperature.
APPLICATIONS
- Battery cell testing & formation
- Battery module testing
