This user's guide provides detailed testing instructions for the bq25606 evaluation module (EVM). Also
included are descriptions of the necessary equipment, equipment setup, test procedures, the printedcircuit board layouts, schematics, and the bill of materials (BOM).
Throughout this user's guide, the abbreviations EVM, bq25606EVM, PWR772, and the term evaluationmodule are synonymous with the bq25606 evaluation module, unless otherwise noted.
Table 3. EVM Jumper Connections and Shunt Installation (continued)
JackDescriptionbq25606 Setting
JP17Add PMID capNot installed
JP18Add AT capNot installed
S1QON controlDefault open
S2Switch to short indicator LEDsDefault open
Table 4 lists the recommended operating conditions for this EVM.
SymbolDescriptionMINTYPMAXUnit
Supply voltage, V
Battery voltage, V
I
BAT
Supply current, I
VBUS
BAT
IN
2Test Summary
2.1Equipment
This section includes a list of supplies required for testing this EVM.
1. Power supply: Power supply #1 (PS#1): a power supply capable of supplying 5 V at 3 A is required.
While this part can handle larger voltage and current, it is not necessary for this procedure.
2. Load #1:
•(4-quadrant supply, constant voltage < 4.5 V) A 0–20 V, 0–5 A, > 30-W system, DC electronic load
and setting as constant voltage load mode
or
•Kepco load: BOP 20–5M, DC 0 to ±20 V, 0 to ±5 A (or higher)
3. Load #2: Use with Boost Mode, VAC to GND load, 10 Ω, 5 W or greater.
4. Meters:
•Six Fluke 75 multimeters, (equivalent or better)
or
•Four equivalent voltage meters and two equivalent current meters. The current meters must be
capable of measuring 5-A+ current
Test Summary
Table 4. Recommended Operating Conditions
Input voltage from AC adapter3.95.013.5V
Voltage applied at V
Fast charging current03.0A
Discharging current through internal MOSFET6.0A
Maximum input current from AC adapter input03.0A
terminal04.2084.4V
BAT
2.2Equipment Setup
Use the following list to set up the equipment:
1. Set PS#1 for 5-V DC, 3-A current limit and then turn off the supply.
2. Connect the output of PS#1 in series with a current meter (multimeter) to J1 (VAC and GND). It is
recommended to connect one voltage meter across TP24 and TP27 to measure the input current
sensing resistor voltage. The sensing resistor is 10 mΩ.
3. Connect one voltage meter across TP21 (VAC) and TP18 (GND), connect another voltage meter
across TP1 (VBUS) and TP18 (GND).
4. Turn on Load #1, set to constant voltage mode and output to 2.5 V. Turn off (disable) load. Connect
load to J5 (BAT and GND).
5. Connect one voltage meter across TP9 (BAT) and TP17 (GND) to measure the battery voltage and
another voltage meter across TP28 and TP29 to measure the battery current sensing resistor voltage.
The sensing resistor is 10 mΩ. An alternate method is to use the optional current meter in series to
measure the battery current.
2. Measure the voltage across J4 and J5 as follows:
•Measure → V(TP8(SYS), TP17(GND)) = 3.65 V (typical)
•Measure → V(TP9(BAT), TP17(GND)) = 2.5 V (typical)
•Measure → IBAT ( = pre-charge current)
3. Change Load #1 to 3.7 V
•Measure → V(TP8(SYS), TP17(GND)) = 3.8 V (typical)
•Measure → V(TP9(BAT), TP17(GND)) = 3.7 V (typical)
•Measure → IBAT ( = fast charge current)
4. Adjust R10 to change charging current.
5. Adjust R11 to change input current limit.
6. Turn off and disconnect Load #1.
7. Turn off and disconnect PS#1.
2.3.2Boost Mode Verification
1. Do not install JP3.
2. If the constant voltage load connected from BAT to GND is not a four-quadrant supply (sources
current), remove the load and use the power source disconnected in step 1, set to 3.7 V and 2-A
current limit and connect between BAT and GND.
3. Apply 10 Ω (5 W or greater) across J1 VAC(+) to GND(–).
4. Verify V
Measure → V
5. Turn off and disconnect power supply.
6. Remove 10-Ω resistor at VAC.
to GND since VBUS is the actual boost mode output voltage.
VBUS
= 5.15 V (Typical)
VBUS
Test Summary
2.3.3Helpful Tips
•The leads and cables to the various power supplies, batteries, and loads have resistance. The current
meters also have series resistance. The charger dynamically reduces charge current depending on the
voltage sensed at its VBUS pin (using the VINDPM feature), BAT pin (as part of normal termination),
and TS pin (through its battery temperature monitoring feature via battery thermistor). Therefore,
voltmeters must be used to measure the voltage as close to the IC pins as possible instead of relying
on the digital readouts of the power supply. If a battery thermistor is not available, make sure shunts
JP6 and JP7 are in place.
•When using a source meter that can source and sink current as your battery simulator, TI highly
recommends adding a large (1000+ μF) capacitor at the EVM BAT and GND connectors in order to
prevent oscillations at the BAT pin due to mismatched impedances of the charger output and source
meter input within their respective regulation loop bandwidths. Configuring the source meter for 4-wire
sensing eliminates the need for a separate voltmeter to measure the voltage at the BAT pin.
When using 4-wire sensing, always ensure that the sensing leads are connected in order to prevent
accidental overvoltage by the power leads.
•For precise measurements of charge current and battery regulation near termination, the current meter
in series with the battery or battery simulator should not be set to auto-range and may need be
removed entirely. An alternate method for measuring charge current is to either use an oscilloscope
with Hall effect current probe or place a 1% or better, thermally capable (for example, 0.010 Ω in 1210
or larger footprint) resistor in series between the BAT pin and battery and measure the voltage across
that resistor. The bq25606EVM has the sensing resistors onboard.
Minimize the switching node rise and fall times for minimum switching loss. Proper layout of the
components minimizing high-frequency current path loop is important to prevent electrical and magnetic
field radiation and high-frequency resonant problems. This PCB layout priority list must be followed in the
order presented for proper layout:
1. Place the input capacitor as close as possible to the PMID pin and GND pin connections and use the
shortest copper trace connection or GND plane.
2. Place the inductor input terminal as close to the SW pin as possible. Minimize the copper area of this
trace to lower electrical and magnetic field radiation but make the trace wide enough to carry the
charging current. Do not use multiple layers in parallel for this connection. Minimize parasitic
capacitance from this area to any other trace or plane.
3. Put an output capacitor near to the inductor and the IC. Tie ground connections to the IC ground with a
short copper trace connection or GND plane.
4. Route analog ground separately from the power ground. Connect analog ground and connect power
ground separately. Connect analog ground and power ground together using a power pad as the
single ground connection point or use a 0-Ω resistor to tie analog ground to power ground.
5. Use a single ground connection to tie the charger power ground to the charger analog ground just
beneath the IC. Use ground copper pour but avoid power pins to reduce inductive and capacitive noise
coupling.
6. Place decoupling capacitors next to the IC pins and make the trace connection as short as possible.
7. It is critical that the exposed power pad on the backside of the IC package be soldered to the PCB
ground. Ensure that there are sufficient thermal vias directly under the IC connecting to the ground
plane on the other layers.
8. The via size and number should be enough for a given current path.
See the EVM design for the recommended component placement with trace and via locations. For the
QFN information, see Quad Flatpack No-Lead Logic Packages and QFN/SON PCB Attachment.
SW1, SW2, SW3, SW40Compact Probe Tip Circuit Board Test Points, TH, 25 perTH Scope Probe131-5031-00Tektronix
TP120Test Point, Miniature, White, THWhite Miniature Testpoint5002Keystone
www.ti.com
Revision History
Revision History
NOTE: Page numbers for previous revisions may differ from page numbers in the current version.
Changes from June 2, 2017 to September 30, 2017 ....................................................................................................... Page
•Changed Schematic for bq25606EVM-772............................................................................................ 9
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