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2 Test Summary
2.1 Equipment
2.2 Setup
2.3 Test Procedure
Test Summary
This section covers the test setups and tests performed in evaluating the EVM.
• Power Source: Current-limited, 15-V laboratory power supply with its current limit set to 25% above the
programmed charging current (1.7 A for setup from factory). This is basically a safety limit. The actual
DC input current should be less than the charging current.
• Two Fluke 75 digital multimeters: (optional) To measure input and output voltage and voltage drop
across current-sense resistor.
The bq2412x EVM board requires a regulated supply approximating 0.3 V minimum above the regulated
voltage of the battery pack (1-cell pack: 4.2 V; 2-cell pack: 8.4 V; 3-cell pack: 12.6 V) to a maximum input
voltage of 16 V
DC
.
A 1- to 3-cell battery pack is needed for EVM evaluation. The EVM should be chosen and set up to charge
the same numbers of cells as the battery pack to be evaluated (see Table 2 ).
Set up the EVM as shown in Table 2 . Preset the input supply to the desired voltage, turn off the supply,
and then connect the supply to J1. Set the supply's current limit 25% above the programmed charging
current. The test setup connections and jumper setting selections are configured for a stand-alone
evaluation but can be changed to interface with external hardware such as a microcontroller. See the EVM
schematic (Figure 1 ) and SLUS688 data sheet for additional functional information on other optional
connections.
Table 2. I/O and Jumper Connections
ASSEMBLY –001 –002 -003
U1 Device bq24120 bq24123
(1)
bq24125
(2)
J1 DC+/DC-:Input voltage range (V) 5 to 16
(3)
5 to 16 5 to 16
J2 BAT+/BAT-No. cell in series 1 1 1
Output regulation voltage (V) 4.2 4.2 4.2
J5 PG LED or EXT LED or EXT LED or EXT
J6 STAT1 LED or EXT LED or EXT LED or EXT
J7 STAT2 LED or EXT LED or EXT LED or EXT
J8 TTC or CMOD TTC no jumper TTC no jumper TTC no jumper
J9 CE CE jumper LO CE jumper LO CE jumper LO
J10 Cells or FB No jumper Cells jumper LO No jumper
(1)
To operate as a 2-cell version (8.4 V), replace battery with a 2-series cell pack, set J10 to High, and adjust the input voltage
between 9.2 V to 16 V.
(2)
R5 and R7 can be changed to regulate output between approximately 3.2 V to 15.5 V. Adjust the input voltage as required.
Output set to operate at 4.2 VDC from the factory.
(3)
Factory jumper selections display in bold text.
Set up the evaluation board as previously described by making the necessary I/O connections and jumper
selections. Prior to test and evaluation, it is important to verify that the EVM selected is set up correctly for
the battery pack to be charged (several evaluation modules have a CELLs option that can be programmed
for two different size – number of series cells). It is strongly recommended that the battery pack to be
charged has internal protection as a safety backup.
1. Turn on the power supply, preset to the suggested value in Table 2 and approximately 1.7 A for the
current-limit setting.
2. The PG LED should turn on along with STAT1, if the battery is charging.
6 Using the bq2412x (bqSWITCHER™) EVM SLUU236A – March 2006 – Revised November 2007
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