bq24351EVM for Li-Ion Charger Front-End Protection IC
This user's guide describes the features, setup, and operation of the bq24351EVM evaluation module.
Included are the bill of materials, board layout, and schematic.
The bq24351 evaluation module (EVM) is a complete charger module for evaluating a charger front-end
protection and charger solution using the bq24351 and bq2057C devices. It is designed to deliver up to
560 mA of charge current to Li-ion or Li-polymer applications. The charger front-end protection current is
designed to 1.2 A.
The bq24351 protects the charging system against three types of failures: input overvoltage when the ac
adapter fails to regulate its voltage, load overcurrent when failures such as a short circuit occur in the
charging system, and battery overcharge.
For details, see the bq24351 data sheet (SLUSA62).
1.2EVM Features
•Evaluation module for bq24351 DSG
•Evaluation module for bq2057C charger integrated circuit (IC)
•Input operating range for bq24351 4.5 V–26 V
•Input overvoltage protection.
•Input overcurrent protection.
•Battery overvoltage protection.
•LED indication for status signals.
•Test points for key signals available for testing purposes. Easy probe hook-up
•Jumpers available. Easy to change connections
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1.3I/O Description
JackDescription
J1–DC+AC adapter, positive output
J1–DC–AC adapter, negative output, ground
J2–FAULTReserved for other ICs
J2–VBATbq24351 VBAT pin
J2–GATDRVbq24351 GATDRV pin
J2–CHGINbq24351 CHGIN pin
J3–BATENReserved for ohter ICs
J3–OUTbq24351 OUT pin
J3–BAT+Battery positive output
J3–GNDGround
J4–BAT+Connect to battery positive output
J4–BAT–Connect to battery negative output, ground
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bq24351EVM for Li-Ion Charger Front-End Protection ICSLUU455–October 2010
JP1If on, high-side sensing resistor is disabledJumper on
JP2Reserved for other ICsJumper (BATEN, GND) on
JP3bq24351 GATDRV pinJumper off
JP4bq2057C BAT pin connection to bq24351Jumper on
JP5bq2057C VCC pin connection to bq24351Jumper on
JP6bq2057C CC pin connection to bq24351Jumper on
JP7If on, low-side current-sensing resistor is disabledJumper off
(1)
Short JP1, JP4, JP5, and JP6, and disconnect JP7 to use onboard bq2057C as charger; to use external charger to control
bq24351, disconnect JP1, JP4, JP5, and JP6 and short JP7.
DescriptionFactory Setting
1.5Recommended Operating Conditions
SymbolDescriptionMINTYPMAXUnit
Supply voltage, V
Battery voltage, V
Supply current, I
Charge current, I
Operating junction temperature range, T
IN
BAT
AC
chrg
Input voltage from ac adapter input4.5526V
Voltage applied at VBAT terminal of J403–4.25V
Maximum input current from ac adapter input01.5A
Battery charge current0.050.561A
J
Test Summary
0125°C
2Test Summary
2.1Definitions
This procedure details how to configure the evaluation board. On the test procedure, the following naming
conventions are followed. See the schematic for details.
VXXXExternal voltage supply name (VIN, VBAT, VOUT)
LOADWExternal load name (LOADR, LOADI)
V(TPyyy)Voltage at internal test point TPyyy. For example, V(TP1) means the voltage at
V(Jxx):Voltage at jack terminal Jxx.
V(TP(XXXXX))Voltage at test point XXXXX. For example, V(ACDET) means the voltage at the
V(XXX, YYY)Voltage across points XXX and YYY.
I(JXX(YYY))Current going out from the YYY terminal of jack XX.
Jxx(BBB)Terminal or pin BBB of jack xx
Jxx ONInternal jumper Jxx terminals are shorted
Jxx OFFInternal jumper Jxx terminals are open
Jxx (-YY-) ONInternal jumper Jxx adjacent terminals marked as YY are shorted
Measure → A,BCheck specified parameters A, B. If measured values are not within specified
Observe → A,BObserve if A, B occur. If they do not occur, the unit under test has failed.
TP1.
test point which is marked as ACDET.
limits, the unit under test has failed.
Assembly drawings show locations for jumpers, test points, and individual components.
2.2Equipment
2.2.1Power Supplies
Power supply 1 (PS 1): a power supply capable of supplying 15 V at 2 A is required.
SLUU455–October 2010bq24351EVM for Li-Ion Charger Front-End Protection IC
A 10-V (or above), 2-A (or above) electronic load that can operate in constant-current mode.
2.2.3Load 2
A 10-V (or above), 2-A (or above) electronic load that can operate in constant-voltage mode.
2.2.4Meters
Four Fluke 75 multimeters (equivalent or better)
Or:
Three equivalent voltage meters and one equivalent current meter
The current meter must be capable of measuring 2-A+ current.
2.2.5Wire Gauge
All wires connected to the EVM input power supply and output load must be at least AWG 22. The
maximum current is up to 1 A.
2.3Equipment Setup
1. Set PS 1 for 0 V ±100 mVdc, 2 ± 0.1 A current limit, and then disable the output.
2. Connect the output of PS 1 to J1 (DC+, DC–).
3. Connect a voltage meter across J1 (DC+, DC–).
4. Connect the output of load 1 in series with a current meter (multimeter) to J2 (CHGIN) and J3 (GND).
Turn on the power of load 1. Set the load current to 1.5 A ±50 mA, but disable the output.
5. Connect the output of load 2 in series with a current meter (multimeter) to J4 (BAT+, BAT–).
6. Connect a voltage meter across J4 (BAT+, BAT–).
7. Set the voltage of load 2 to 3.6 V ±0.1 V, and disable output of load 2.
8. JP1: ON, JP2 (BATEN, GND): ON, JP3: OFF, JP4: ON, JP5: ON, JP6: ON, JP7: OFF.
After the preceding steps have been taken, the test setup for HPA666 (bq24351 DSG EVM) appears as is
shown in Figure 1.
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Figure 1. Original Test Setup for HPA666 (bq24351 DSG EVM)
4
bq24351EVM for Li-Ion Charger Front-End Protection ICSLUU455–October 2010
3. Increase the output voltage of PS 1 to 5 V ±0.1 V.
4. Enable the output of load 2.
Measure → V(J2(OUT)) = 3.6 V ±200 mV
Measure → Ibat = 560 mA ±70 mA
Observe → D2 on, D3 on, D6 off, D7 on.
2.4.2CFET Input Overvoltage Protection
1. Increase the voltage of PS 1 to 11 V ±0.1 V.
Observe → D2 on, D3 off, D6 off, D7 off.
2. Decrease the voltage of PS 1 to 5 V ±0.1 V.
Observe → D2 on, D3 on, D6 off, D7 on.
2.4.3CFET Load Overcurrent Protection
1. Enable the output of load 1.
Observe → D2 on, D3 off, D6 off, D7 off.
2. Disable the output of load 1.
Observe → D2 on, D3 on, D6 off, D7 on.
3. Decrease the voltage of PS 1 to 0 V ±0.1 V.
PCB Layout Guideline
3PCB Layout Guideline
1. It is critical that the exposed thermal pad on the back side of the bq24351 package be soldered to the
printed-circuit board (PCB) ground. Ensure that sufficient thermal vias are located underneath the IC,
connecting to the ground plane on the other layers.
2. The high-current charge paths into ACIN and from the CHGIN and OUT pins must be sized
appropriately for the maximum charge current in order to avoid excessive voltage drops in these
traces.
3. Decoupling capacitors for ACIN and CHGIN must be placed to make the interconnections to the IC as
short as possible.
4. Resistors for VBAT pin must be placed close to the corresponding IC pins and make the
interconnections to the IC as short as possible.
SLUU455–October 2010bq24351EVM for Li-Ion Charger Front-End Protection IC
Texas Instruments (TI) provides the enclosed product(s) under the following conditions:
This evaluation board/kit is intended for use for ENGINEERING DEVELOPMENT, DEMONSTRATION, OR EVALUATION
PURPOSES ONLY and is not considered by TI to be a finished end-product fit for general consumer use. Persons handling the
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This evaluation board/kit is intended for use for ENGINEERING DEVELOPMENT, DEMONSTRATION, OR EVALUATION
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EVM Warnings and Restrictions
It is important to operate this EVM within the input voltage range of 4.5 V to 26 V and the output voltage range of 0 V to 4.2 V .
Exceeding the specified input range may cause unexpected operation and/or irreversible damage to the EVM. If there are
questions concerning the input range, please contact a TI field representative prior to connecting the input power.
Applying loads outside of the specified output range may result in unintended operation and/or possible permanent damage to the
EVM. Please consult the EVM User's Guide prior to connecting any load to the EVM output. If there is uncertainty as to the load
specification, please contact a TI field representative.
During normal operation, some circuit components may have case temperatures greater than 70°C. The EVM is designed to
operate properly with certain components above 125°C as long as the input and output ranges are maintained. These components
include but are not limited to linear regulators, switching transistors, pass transistors, and current sense resistors. These types of
devices can be identified using the EVM schematic located in the EVM User's Guide. When placing measurement probes near
these devices during operation, please be aware that these devices may be very warm to the touch.
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