TIDUF44 January 2024
For the design of primary protection (BQ7690x), follow the design recommendations in the data sheet.
In addition, D2 and D16 were added to prevent the voltage drop of BAT and REGOUT after short circuit.
A wake-up circuit for the TS pin was added, because the TS pin maximum withstand voltage is 2.1 V. D7 and D8 was added as voltage regulator and protection. The voltage of cell1 fluctuates the moment S1 is triggered. After wake-up, voltage monitoring returns to normal.
A balancing circuit was also designed in this design. In this design, 100 Ω and 220 nF are selected for the input of VC0 to VC7. (Limit the external cell input resistance times external input capacity to 200 μs or below,and note that the recommended value of the input resistance is 10 Ω, too large an input resistance affects the sampling accuracy.) For external balancing circuit design detail, see the Cell Balancing With BQ769x2 Battery Monitors application note.