Other Parts Discussed in Thread: CSD17318Q2
Tool/software:
Dear TI Support Team,
We are working on a secondary battery protection circuit and need clarification regarding part selection from the BQ297xy family. Below is our setup and findings:
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IC: We have replaced BQ29707 with BQ29702.
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FETs: We replaced CSD17318Q2 with SSM6K517NU (Rds(on) = 39.1 mΩ).
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Test Results:
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Charging overcurrent was limited to around 2.1 A
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Discharging overcurrent was limited to around 2.1 A
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These results align with our expectations based on calculations:
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OCC = 0.155 V → Charge limit ≈ 1.98 A
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OCD = 0.160 V → Discharge limit ≈ 2.04 A
Our system requires:
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Charging current limit up to 2.4 A
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Discharging current limit up to 2.0 A
To achieve this with a 39.1 mΩ FET, we would need:
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OCC ≈ 0.187 V
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OCD ≈ 0.156 V
We found that the BQ297xy series (highlighted in the datasheet table) provides OCC and OCD configurability, but we couldn't locate the exact part number or ordering information that supports OCC = ~187 mV and OCD = ~156 mV.
Questions:
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Can you help confirm if a part from the BQ297xy family supports this specific OCC/OCD configuration?
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If not, should we consider FETs with lower Rds(on) (e.g., 31–32 mΩ) to meet our current requirements within available thresholds?
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Can you guide us on how to select the exact BQ297xy part number based on OCC/OCD values?
Please review this setup and let us know the best path forward.
