Tool/software:
Hello TI team,
I’m designing a 4-cell LiFePO₄ battery protection board around the BQ7791514 for my application (100Amp inverter), And I’d appreciate your guidance on the external components used around the CHG / DSG / LD pins. I’m following the datasheet and evaluation model recommended topology (Section 10.1.1) and I’ve attached a snippet of my current schematic (same image I referenced earlier) so you can see how I wired the gate networks and protection clamps.
My goals are simple: keep gate rise/fall times reasonable (avoid large di/dt ringing and excessive switching losses), protect the CHG/LD pins and the MOSFET gates from overvoltage when PACK− can be driven by the load/charger, and make the design robust for 100 A continuous rating with short surges.
1) R_DSG
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Requested: numeric value(s) (Ω), tolerance and recommended power rating.
2) R_CHG1 and R_CHD2
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Requested: numeric value(s) and power rating.
3) Rmos_gate (per-MOSFET gate resistor placed immediately at each gate)
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Requested: numeric value(s) (Ω) and recommended footprint/power.
Is a single common resistor acceptable, or do you recommend one resistor per MOSFET?
4) RGS_CHG/ RGS_DSG
5) Diode and Zener diode in CHG to mosfets.
6) LD pin series diode
Image: 