Texas Instruments BQ25172EVM, User Manual, Page: 2 / 18

1 Introduction
The Texas Instruments BQ25172EVM is a NiMH chemistry battery charger IC for single and multi cell
applications. Charging voltage can be adjusted using external resistors on VSET. Charging current can be set
from 60mA to 600mA with an external resistor on ISET.
1.1 Printed Circuit Board Assembly
The BQ25172EVM PCB contains the BQ25172 IC, LDO TPS7B8133 and support circuits. This board contains
several jumpers and connectors. S1 (VSET) allows selected output voltages to be programmed. S2 (TMR)
allows the charge timer to be configured. The R9 resistor allows a wide range of adjustment of VSET. R22 can
be used to change ISET value (fast charge current). R19 can be used to adjust TS, the 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 5V. Max operating input
voltage is 6.6V, OVP trip point. Max input voltage is 30V while in OVP.
J2 – OUT (BAT+) / GND (BAT-) / GND / TS Battery connection, TS should be 10k NTC but not needed.
JP1 – VSET ADJ Disable R9, default is installed.
JP2 – REG / IN / OUT Source voltage for housekeeping regulator, U2. Default Input voltage IN.
JP3 – TMR Connection to TMR pin
JP4 – ISET Sets Fast Charge Current. Fixed=400mA ADJ= R22 range 60mA to 600mA
JP5 - STAT LED Default setting is ON.
JP6 – TS NTC temp sensor. Fixed=10k (safe) ADJ=R19 range from 0 to 50k ohms. Default Fixed.
JP7 - TMR ADJ Bypasses R18 for TMR connection to S2
JP8 Not used, do not install
JP9 Not used, do not install
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 NiMH Configuration
#1 / R1 / 27k ohm 2-Cell + Intermittent
#2 / R2 / 24k ohm 3-Cell
#3 / R3 / 18k ohm 3-Cell + Intermittent
#4 / R4 / 11k ohm 4-Cell + Intermittent
#5 / R5 / 6.2k ohm 5-Cell + Intermittent
#6 / R6 / 4.7k ohm 6-Cell
#7 / R7 / 3.6k ohm 6-Cell + Intermittent
#8 / R8 / 0 ohm Short Circuit – No Charge
Table 1-3. TMR S2 Switch Positions
Position / RX / Value Charge Timer (HR)
#11 / R11 / 36k ohm 4hr
#12 / R12 / 18.2k ohm 10hr
#13 / R13 / 6.2k ohm 18hr
#14 / R14 / 0 ohm 0hr (Short-Circuit)
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2 BQ25172EVM Evaluation Module SLUUCO1 – JULY 2022
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