Texas Instruments bq25970 User manual

bq25970 PWR893 Evaluation Module
User's Guide
Literature Number: SLUUBR4A
February 2018–Revised December 2018

2SLUUBR4A–February 2018–Revised December 2018
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bq25970 PWR893 Evaluation Module
User's Guide
SLUUBR4A–February 2018–Revised December 2018
bq25970 PWR893 Evaluation Module
This user's guide provides detailed testing instructions for the bq25970 evaluation modules (EVM). Also
included are descriptions of the necessary equipment, equipment setup, and procedures. The reference
documentation contains the printed-circuit board layouts, schematics, and the bill of materials (BOM).
1 Introduction
1.1 EVM Features
For detailed features and operation, refer to the device data sheet as listed in Table 1.
Table 1. Device Data Sheet
Device Datasheet EVM Label Variant
bq25970 SLUSD72A BQ25970EVM-893 001
The bq2597x evaluation module (EVM) is a complete charger module for evaluating the highly-integrated
battery switch in WCSP package for 1 cell Li-Ion and Li-polymer battery in a wide range of smartphones
and tablets.
This EVM does not include the EV2300 or EV2400 (EV2x00) interface board. To evaluate the EVM, a
EV2x00 interface board must be ordered separately.
There are two bq25970 on the EVM, users can configure the EVM either as a single bq25970 or a parallel
bq25970 operation based on the jumper setting described in next section.
1.2 I/O Descriptions
Table 2 lists the jumper connections available on this EVM.
Table 2. PWR893 EVM Header Jx Connections
Jack Description Single Setting Parallel Setting
J1 – VBUS Input Terminal Installed Installed
J2 – VOUT/PACK- Output terminal To battery To battery
J3 – I2C EV2x00 I2C 4-pin connector To host To host

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Table 3 lists the EVM jumper connections.
Table 3. EVM Jumper JPx Shunt Installation
Jack Description Single Setting Parallel Setting
JP1 VAC pin connection selection (2) short to (3) VAC (2) short to (1) VBUS
JP2 OVPGATE pin connection selection (2) short to (3) OVPGATES (2) short to (1) OVPGATEM
JP3 BATP connection selection (2) short to (1) VOUT (2) short to (1) SYNCOUT
JP4 SRP sense resistor selection (2) short to (1) SRP (2) short to (3) GND
JP5 SRN sense resistor selection (2) short to (1) SRN (2) short to (3) GND
JP6 VAC_M pin connection not installed installed
JP7 LDO input pin selection (2) short to (3) VOUT (2) short to (3) VOUT
JP8 ADDRMS pin selection for ADDR 0x66 installed not installed
JP9 ADDRMS pin selection for ADDR 0x65 not installed not installed
JP10 ADDRMS pin selection for parallel configuration not installed installed
JP11 I2C pull up selection installed installed
JP12 SDA and SCL pull up selection installed installed
JP13 TSBUS_M connection to charger not installed installed
JP14 TSBUS_M voltage adjustment not installed installed
JP15 TSBUS_M pull up to VOUT not installed installed
JP16 TSBUS_S connection to charger installed installed
JP17 TSBUS_S voltage adjustment installed installed
JP18 TSBUS_S pull up to VOUT installed installed
JP19 TSBAT_S connection to charger installed installed
JP20 TSBAT_S voltage adjustment installed installed
JP21 TSBAT_S pull up to VOUT installed installed
Table 4 lists the recommended operating conditions for this EVM.
(1) Over operating free-air temperature range (unless otherwise noted)
Table 4. Recommended Operating Conditions(1)
MIN MAX UNIT
Voltage
VAC 12 V
VBUS 12 V
VOUT 3 6 V
CFH1-VOUT, CFL1, CFH2-VOUT,CFL2 0 6 V
BATP_SYNCIN, BATN 0 6 V
SRP-SRN -0.05 0.05 V
TS_BAT_SUNCOUT, TSBUS 0 3 V
SDA, SCL, CDRVL_ADDRMS, INT 0 5 V
IVOUT Max current from VBUS to VOUT 0 8 A
TAOperating free-air temperature range –40 85 °C

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2 Test Summary
2.1 Equipment
2.1.1 Specify Equipment Needed to Perform Tests
1. Power Supplies (PS)
One power supply capable of supplying 12 V at 4 A (or above) is required. While this part can handle
larger voltage and current, it is not necessary for this procedure.
NOTE: If there is no display of current and voltage in this power supply, a separate current meter
and a separate voltage meter are required to measure the input current and input voltage,
respectively.
2. Battery Simulator (4-quadrant supply, constant voltage < 4.5 V)
A Kepco load: BOP 20–12 M, DC 0 to ±20 V, 0 to ±8 A (or higher), or equivalent.
NOTE: If there is no display of current and voltage in this electronic load, a separate current meter
and a separate voltage meter are required to measure the output current and output voltage,
respectively.
3. 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 8 A+ current.
NOTE: Only needed if required as described in Power Supplies (PS) and Battery Simulator.
4. Computer
A computer with at least one USB port and a USB cable. The bq25970EVM evaluation software must
be properly installed (bqStudio).
5. EV2x00 Communication Kit
The EV2x00 USB-based PC interface board.
2.1.2 Specify Software Needed for Testing
Download bqstudio from http://www.ti.com/tool/bqstudio. Follow the installation steps to install the tool.
The software supports the Microsoft®Windows®XP and Windows 7 operating systems.

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2.2 Equipment Setup
Set up the equipment using the following steps:
1. Set PS for 7.5-V DC output, 3A or above current limit and then turn off the supply.
2. Connect the output of PS to J1 (VAC and GND) as shown in Figure 1.
3. Turn on the battery simulator, set to constant voltage mode and output to 3.6 V. Turn off (disable) the
load. Connect load to J2 (VOUT and GND) as shown in Figure 1.
Figure 1. Test Setup for BQ25970
4. Connect the EV2x00 USB interface board to the computer with a USB cable and from I2C port to J3
with the 4-pin cable. The connections are shown in Figure 2.
Figure 2. Connections of the EV2300 Kit

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5. Turn on the computer. Launch Battery Management Studio (bqStudio). Select Charger and bq25970
evaluation software. The main window of the software is shown in Figure 3.
Figure 3. Select “Charger” in bqStudio Window
2.3 Test Procedure
The steps for the test procedure follow:
1. Ensure equipment setup steps are followed.
2. Launch the bq258970 EVM GUI software, if not already done.
3. Turn on PS and battery simulator.
4. Measure Input.
VAC(TP1) = 7.5 V ±0.2 V
VBUS(TP4) = 0 V, I_VBUS = 0 A
Measure →Output:
VOUT(TP17) = 3.6V ±0.2 V

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2.4 Communication Verification
Use the following steps for communication verification:
1. Click the Read button, Device ACK OK should appear.
2. In the EVM software, select Field View, specify correct device “I2C Address” as defined in the
datasheet, such as CC(66), and so forth.
3. Click the Read button, Device ACK OK should appear.
4. In the EVM software, make the following changes as necessary Figure 4:
• Select Disable for the Watchdog Timer
• Change VAC OVP for to 14V or higher and make sure VAC OVP Status is Normal
• Make Sure VBUS too low for converter to start and VBUS too high for converter to start are both
Normal
Figure 4. Sample of Register Map
5. Click the Read button.
Observe →Everything normal at Fault box

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2.5 Charger Mode Verification
Use the following steps for charger mode verification:
1. Select Charge Enable
2. Input and output voltage/current:
After enabling charge, the output current should be two times of the input current.
3. Change charge current:
By increasing the input voltage, the input current should increase together with the output current. The
output current should always be two times of the input current.
4. Unselect Charge Enable (→disable charge)
5. Measure the current at J3 and J5, both should go to zero amps.
6. Turn off and disconnect load
7. Turn off and disconnect PS
3 Board Layout, Schematic, and Bill of Materials
3.1 Board Layout
Figure 5 through Figure 10 illustrate the board layouts for this EVM.
Figure 5. BQ25970EVM-893 top layer

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Figure 6. BQ25970EVM-893 Mid Layer 1
Figure 7. BQ25970EVM-893 Mid-Layer 2

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Figure 8. BQ25970EVM-893 Mid-Layer 3
Figure 9. BQ25970EVM-893 Mid-Layer 4