Texas Instruments BQ25171EVM User manual

User’s Guide
BQ25171EVM Evaluation Module
ABSTRACT
This user’s guide describes the characteristics, operation, and use of the BQ25171EVM evaluation module
(EVM). This EVM is designed to help the user evaluate and test the various operating modes of the BQ25171.
This user’s guide includes setup instructions for the hardware and software, a schematic diagram, a bill of
materials (BOM), and PCB layout drawings for the evaluation module.
Throughout this user's guide, the abbreviations EVM, BQ25171EVM, BMS032, and the term evaluation module
are synonymous with the BMS032 evaluation module, unless otherwise noted.
Table of Contents
1 Introduction.............................................................................................................................................................................2
1.1 Printed Circuit Board Assembly......................................................................................................................................... 2
1.2 I/O Descriptions..................................................................................................................................................................2
2 Test Summary......................................................................................................................................................................... 3
2.1 Equipment.......................................................................................................................................................................... 3
2.2 Cautions............................................................................................................................................................................. 3
2.3 Test Instructions................................................................................................................................................................. 3
3 Board Layout, Schematic, and Bill of Materials...................................................................................................................4
3.1 Board Layout......................................................................................................................................................................4
3.2 Schematic........................................................................................................................................................................ 10
3.3 Bill of Materials................................................................................................................................................................. 11
4 Revision History................................................................................................................................................................... 14
Trademarks
All trademarks are the property of their respective owners.
WARNING
Hot surface! Contact may cause burns. Do not touch!
Some components may reach high temperatures >55°C when the board is powered on. The user
must not touch the board at any point during operation or immediately after operating, as high
temperatures may be present.
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1 Introduction
The Texas Instruments BQ25171EVM is a multi-chemistry battery charger IC for 1-2 cell Li-Ion/LiFePO4/Li-
Polymer or 1-6 cell NiMH. Battery chemistry is programed using the CHM_TMR pin with external resistor.
Charging voltage can be adjusted using external resistors on VSET. Charging current can be set from 60mA to
600mA with external resistor on ISET.
1.1 Printed Circuit Board Assembly
The BQ25171EVM PCB contains the BQ25171 IC, LDO TPS7B8133 and support circuits. This board contains
several jumpers and connectors. S1 (VSET) allows selected output voltages to be programmed. R9 resistor
allows a wide range of adjustment of VSET. S2 (CHM_TMR) allows selection of select chemistry / timer. R10 is
used to select wider range of options. R22 can be used to change ISET value, fast charge current. R19 can be
used to adjust TS, battery temp sensor to simulate hot and cold fault.
1.2 I/O Descriptions
Table 1-1 lists the input and output connections available on this EVM and their respective descriptions.
Table 1-1. EVM I/O Connections
I/O Connector Description
J1 – VIN / GND
Input voltage from external power supply, recommended 5 V to 12 V
depending on output configuration. Max input voltage is 18 V, OVP
trip point and above this the device is off. Max input voltage is 40 V
while in OVP.
J2 – OUT (BAT+) / GND (BAT-) / GND / TS Interface with battery, can be up to 8.4 V out at 800 mA. TS should
be 10k NTC but not needed.
JP1 – REG / IN / OUT Source voltage for housekeeping regulator, U2. Default Input voltage
IN.
JP2 – CE Charge Enable Low=On, Hi=Off. Default Low.
JP3 – ISET Sets Fast Charge Current. Fixed 400 mA ADJ = R22 range 60 mA to
600 mA. Default Fixed.
JP4 – STAT1 LED, default setting is ON.
JP5 - STAT2 LED, default setting is ON.
JP6 – TS NTC temp sensor. Fixed = 10k (safe) ADJ=R19 range from 0 to 50k
Ω. Default Fixed.
JP7 – CHM/TMR ADJ Disable R10 Default is installed.
JP8 – VSET ADJ Disable R9 Default is installed.
Table 1-2 lists the S1 switch positions for VSET and their respective descriptions. Use only one postion ON, do
not combine.
Table 1-2. VSET S1 Switch Positions
Position / RX / Value Li+Voltage / Configuration NiMH Voltage / Configuration
#1 / R1 / 82k Ω 3.6V / 1-Cell LiFePO4 No Charge (Open Circuit)
#2 / R2 / 47k Ω 3.8V / 1-Cell Li-Ion 1-Cell / Intermittent Charge
#3 / R3 / 24k Ω 4.1V / 1-Cell Li-Ion 3-Cell
#4 / R4 / 18k Ω 4.2V / 1-Cell Li-Ion 3-Cell / Intermittent Charge
#5 / R5 / 8.2k Ω 7.2V / 2 -Cell LiFePO4 5-Cell
#6 / R6 / 6.2k Ω 7.4V / 2 -Cell LiFePO4 5-Cell / Intermittent Charge
#7 / R7 / 3.6k Ω 8.4V / 2 -Cell Li-Ion 6-Cell / Intermittent Charge
#8 / R8 / 0 Ω Short Circuit – No Charge Short Circuit – No Charge
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Table 1-3 lists the S2 switch positions for CHM_TMR and their respective descriptions. Use only one postion ON,
do not combine.
Table 1-3. CHM_TMR S2 Switch Positions
Position/RX/Value Chemistry/Timer
#1 / R11 / 75k Ω Li-Ion / 10 hr
#2 / R12 / 56k Ω Li-Ion / Timer Disabled
#3 / R13 / 18k Ω NiMH / 10 hr
#4 / R14 / 0 Short Circuit / No Charge
2 Test Summary
This section describes the jumpers and connectors on the EVM as well as how to properly connect, setup, and
use the BQ25171EVM. Note that the default jumper setting of headers are marked with two dots to indicate the
shorting jumper position. This will put the unit into a single cell Li-Ion configuration, 4.2 V at 400 mA.
2.1 Equipment
This section includes a list of supplies required to perform tests on this EVM.
1. Battery simulator such as kiethly 2400 or equilvalent. Or a single/dual-cell battery.
2. Power supply, for single cell 5V 1A input, for dual cell 12V 1A input . Note that unit can operate up to 18V
input.
3. Voltage meter and current meter.
2.2 Cautions
To prevent possible damage to battery under test verify that charging conditions of the cell are not exceeded.
Check max charge voltage and current.
Power dissipation of the device can be exceeded with too high an input to output voltage drop and current.
Thermal regulation begins reducing current at 125 °C, at 150 °C device will shut off.
Device can get hot during high input-to-output voltage drop and high current conditions. Use caution when
handling the board.
2.3 Test Instructions
In order for this EVM to operate properly, the following components must be connected and properly configured.
The configuration below will put the EVM in a single cell Li-Ion charger configuration.
1. Set input power supply to 5 V and Battery Simulator to 3.6 V with compliance to support 400 mA. Turn off
Supply and Batter Simulator.
2. Connect input voltages to J1 and Battery Simulator J2 to the EVM.
3. Configure all EVM jumpers to factory setting, see Table 2-1.
4. Turn on all supplies and loads
a. 5 V Input supply current limit should be greater than 500 mA
b. Out voltage should be 3.6 V and charge current 400 mA
c. LED D1 will be ON, Normal charge. D3 is OFF
5. Simulate battery completing charge by increasing Battery Simulator voltage to 4.2 V.
a. Current will decrease to 0 mA.
b. LED D2 will switch to OFF.
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Table 2-1. Jumper Factory Setting
I/O Connector Factory Setting
JP1 IN
JP2 ON
JP3 Fixed
JP4 Installed
JP5 Installed
JP6 Fixed
JP7 Installed
JP8 Installed
S1 Position 4
S2 Position 1
Note
IN, ON, Fixed are positions of a 3 pin header. If it is a 2 pin header then it is installed or not installed.
3 Board Layout, Schematic, and Bill of Materials
3.1 Board Layout
The board layout is shown in Figure 3-1 to Figure 3-6.
Figure 3-1. Top Overlay
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Figure 3-2. Top Solder
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Figure 3-3. Top Layer
Board Layout, Schematic, and Bill of Materials www.ti.com
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Figure 3-4. Bottom Layer
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Figure 3-5. Bottom Solder
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Figure 3-6. Bottom Overlay
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3.2 Schematic
The BQ25171EVM schematic is shown in Figure 3-7.
Figure 3-7. Schematic
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