Texas Instruments bq2000EVM User Manual

1 Introduction
This user's guide describes the bq2000EVM EVM (an evaluation module for the bq2000 and bq2000T).
The EVM provides a convenient method for evaluating the performance of a charge management solution
for portable applications using either the bq2000 or bq2000T. A complete and tested charger is presented.
The charger is designed to deliver up to 1.0A of continuous output current. The DV2000S1 is shipped with
a programmed default charging current of 1.0A. Refer to the bq2000/bq2000T data sheet (literature ID
"bq2000") prior to using this EVM for detailed information on the bq2000 or bq2000T device.
1.1 Device Background
The bq2000 is a programmable, monolithic IC for fast-charge management of nickel cadmium (NiCd),
nickel metal-hydride (NiMH), or lithium-ion (Li-Ion) batteries in single or multi-chemistry applications. The
bq2000 detects the battery chemistry and proceeds with the optimal charging and termination algorithms.
This process eliminates undesirable undercharged or overcharged conditions and allows accurate and
safe termination of fast charge. Depending on the chemistry, the bq2000 provides a number of charge
termination criteria. The bq2000 can terminate charge based on peak voltage detection (PVD) for NiCd
and NiMH batteries, minimum charging current for Li-Ion batteries, maximum temperature, or maximum
charge time. For safety, the bq2000 inhibits fast charge until the battery voltage and temperature are
within user-defined limits. If the battery voltage is below the low-voltage threshold, the bq2000 uses
trickle-charge to condition the battery. For NiMH batteries, the bq2000 provides an optional top-off charge
to maximize the battery capacity. The integrated high-frequency comparator allows the bq2000 to be the
basis for a complete, high-efficiency power-conversion circuit for both nickel-based and lithium-based
chemistries.
1.2 EVM Differences
In addition to this bq2000EVM EVM, there are also DV2000S1 and DV2000TS1 EVMs available for
evaluating the performance of the bq2000 or bq2000T. The DV2000S1/TS1 boards make use of
through-hole devices while the bq2000EVM board was later developed to utilize all surface-mount devices
and reduce the physical size of the EVM. Both EVMs provide complete evaluation environments for the
bq2000/bq2000T, support up to 4 Li-Ion or 10 NiCd/NiMH cells, are user-programmable for other cell
counts, and can operate with or without a charge top-off period. To correctly operate each EVM, consult
its corresponding user's guide.
1.3 Performance Specification Summary
Input DC voltage, V(DC+) – V(DC–)
Battery voltage, V(BAT+) – V(BAT–)
Battery charge current, I(BAT+)
Thermistor voltage, V(TS)
SLUU270 – June 2007
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Specification
User's Guide
SLUU270 – June 2007
Using the bq2000EVM
Min Typ
10
0
Using the bq2000EVM
Max Unit
25 V
18 V
1.0 A
5 V
1