Texas Instruments BQ7961 Q1 Series User Manual

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User's Guide
BQ7961x-Q1 Design Recommendations for High Voltage
Automotive BMS
Taylor Vogt
The BQ79616-Q1 provides high-accuracy cell voltage measurements for 6S to 16S battery modules in <200 µs.
The integrated front end filters enable the system to implement simple, low-cost, differential RC filters on the
cell input channels. The integrated, post-ADC, low-pass filters enable filtered, DC-like, voltage measurements for
better SOC calculation. This device supports autonomous internal cell balancing with temperature monitoring to
auto-pause and resume balancing to avoid an overtemperature condition.
The inclusion of the isolated, bidirectional, daisy chain ports supports both capacitor- and transformer-based
isolation, allowing the use of the most effective components for centralized or distribution architectures
commonly found in the xEV powertrain system. This device also includes eight GPIOs and auxiliary inputs
that can be used for NTC thermistor measurements.
1 NPN LDO Supply.....................................................................................................................................................................3
2 AVDD, CVDD Outputs and DVDD, NEG5, REFHP and REFHM...........................................................................................
3 OTP Programming..................................................................................................................................................................
4 Cell Voltage Sense (VCn) and Cell Balancing (CBn)...........................................................................................................
5 Bus Bar Support...................................................................................................................................................................
6 TSREF....................................................................................................................................................................................
7 General Purpose Input-Output (GPIO) Configurations.....................................................................................................
8 Base and Bridge Device Configuration..............................................................................................................................
9 Daisy-Chain Stack Configuration........................................................................................................................................29
10 Multidrop Configuration.....................................................................................................................................................36
11 Main ADC Digital LPF.........................................................................................................................................................
12 AUX Anti Aliasing Filter
13 Layout Guidelines...............................................................................................................................................................39
14 BCI Performance.................................................................................................................................................................42
15 Common and Differential Mode
16 Summary.............................................................................................................................................................................
17 References..........................................................................................................................................................................
18 Revision History.................................................................................................................................................................
Figure 1-1. Power Supply Schematic..........................................................................................................................................
Figure 2-1. Regulator Connection for Base Device.....................................................................................................................
Figure 4-1. Cell Voltage Monitoring.............................................................................................................................................
Figure 4-2. Internal CB Diagram (no adjacent cell balancing).....................................................................................................
Figure 4-3. Cell Balancing Resistor Example Calculation...........................................................................................................
Figure 4-4. Adjacent Cell Balancing..........................................................................................................................................
Figure 4-5. External FET Cell
Figure 4-6. Connecting Fewer Than 16 Cells............................................................................................................................
Figure 5-1. Alternative Bus Bar Connection to the Lower Stack
Figure 5-2. Example of BBP/BBN Connections at Different Module
Figure 5-3. BBP or BBN Connection With Bus Bar Connected in any Middle VC Channel .....................................................
Figure 5-4. BBP or BBN Connection With Bus Bar Connected Above Top of a Module ..........................................................
SLVAE87B – DECEMBER 2020 – REVISED JUNE 2025
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ABSTRACT
Table of Contents
(AAF)...........................................................................................................................................38
Noise..............................................................................................................................42
List of Figures
Balancing....................................................................................................................................11
Copyright © 2025 Texas Instruments Incorporated
Device....................................................................................14
Size..................................................................................15
BQ7961x-Q1 Design Recommendations for High Voltage Automotive BMS
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