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1 Introduction
1.1 Background
1.2 Performance Specification Summary
User's Guide
SLUU235 – February 2006
bq2406x Evaluation Module
This user’s guide describes the bq2406x evaluation module (EVM). The EVM provides a convenient
method for evaluating the performance of a charge management solution for portable applications using
the bq2406x product family. A complete designed and tested charger is presented. The charger is
designed to deliver up to 1 A of continuous charge current for single-cell Li-Ion or Li-polymer applications
using a DC power supply.
The bq2406x series are highly integrated Li-Ion and Li-polymer linear chargers, targeted at space-limited
portable applications. The bq2406x series offers a variety of safety features and functional options, while
still implementing a complete charging system in a small package. The battery is charged in three phases:
conditioning, constant or thermally regulated current, and constant voltage. Charge is terminated based on
minimum current. An internal programmable charge timer provides a backup safety feature for charge
termination and is dynamically adjusted during the thermal regulation phase. The bq2406x automatically
re-starts the charge if the battery voltage falls below an internal threshold; sleep mode is set when the
external input supply is removed. Multiple versions of this device family enable easy design of the
bq2406x in cradle chargers or in the end equipment, while using low-cost or high-end AC adapters.
This section summarizes the performance specifications of the EVM. Table 1 gives the EVM performance
specifications.
Table 1. Performance Specification Summary
SPECIFICATION TEST CONDITIONS MIN TYP MAX UNITS
Input DC Voltage, V
I(DC)
V
REG
+0.5 5 12
(1)
Volts
Battery Charge Current, I
O(CHG)
1
(1)
Amperes
Power Dissipation (V
(DC+)
– V
(BAT+)
) × I
(CHG)
1.5 Watts
(1)
This maximum recommended input of the IC is 16.5 V. The IC has an OVP (overvoltage protection) input circuit that disables
the charging circuit if the threshold is exceeded. Most IC selections are set for 6.5 V, but some are set as high as 12 V (see
data sheet specification). The EVM can handle an input voltage up to the recommended maximum of 16.5 V, but the IC will be
shut down due to the internal voltage protection. It is recommended that in normal operation the IC be designed and run below
the thermal regulation junction temperature of 125 ° C. The thermal loop can run continuously without any issues, but the
suggested thermal loop operational use is for more harsh environments where the ambient temperature is high (e.g., in an
automobile during the summer) or with an incorrect adaptor with a higher input voltage. For typical input and ambient conditions
with the PowerPAD™ tied to a copper plane, one can expect 1.5 W of heat dissipation prior to the thermal loop reducing the
current. P
dissIC
= I
CHG
x (V
DC+
- V
BAT+
). For the worst-case, steady-state thermal condition, V
BAT+
= 3.4 VDC (the battery when
transitioning from precharge to fast charge reaches a steady-state value after approximately 2 minutes). If the thermal
regulation limit of 125 ° C is reached, then the charging current is adjusted lower.
SLUU235 – February 2006 bq2406x Evaluation Module 1
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