SLUAAN9 February   2023 BQ769142 , BQ76942 , BQ76952 , BQ76972 , ISO1640 , LM5168


  1.   Abstract
  2.   Trademarks
  3. 1Introduction
  4. 2Stacked AFE Communication
    1. 2.1 Data Communications
    2. 2.2 Control Signals
  5. 3High-Side N-Channel MOSFET
    1. 3.1 Discharge MOSFET Turn On and Off Processes
    2. 3.2 PACK Port High Voltage
    3. 3.3 Quickly Turning Off the Discharge MOSFET
  6. 4Current Consumption of Stacked Groups
  7. 5Summary
  8. 6References


One single BQ769x2 family battery monitor can support up to a 16s battery pack which is good enough for 36-V and 48-V applications. For 60 V and higher battery packs, two stacked BQ769x2 family monitors are required. This document describes how to stack devices for the BQ769x2 monitor family and utilize the integrated charge pump to drive high-side N-channel MOSFETs. The key design considerations are analyzed to secure fast and robust MOSFET switching on and off times, minimize the current gaps between two stacked groups, and enable easy communications design between the stacked BQ769x2 devices and host MCU.