BQ40Z50-R2: 異常觸發CFETF PF 失效- 保護板無量測到異常現象

目前分析一失效客訴案例, 發現 CFETF 發生PF, 但是量測硬體都是正常

修復Fuse 後, 電池組也可以正常運作. 輸出 gg 檢測發現, 同時也有 ASCCL (Bit 14): Short Circuit in Charge 觸發

但是MOSFET 檢測是正常. 請問這有可能是甚麼因素所造成的.

附上 logNo4_T0001362108701496.gg.csv

Star Xu：

您好，正在询问更了解这款芯片的TI工程师，稍后回复。

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Star Xu：

您好，请参考下面内容

This means that at one point, the charging current exceeded the programmed threshold limits. It does not mean that the CFET is defective. It means that there was a current through the sense resistor during charging that was higher than the programmed limits. In fact, if the CFET was damaged (burned out open), then there would be no ASCCL event.

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Norman Lin：

i am checking the record in Lifetimes. Max charge current show 2499mA. OCC1 was 3500 mA.

no safety event found in Lifetimes record. How to judge the current exceeded? OCP should be worked before short circuit.

i also cheking PCB, no component was abnormal exclude fuse. Short circuit should not be observed. 

How CFET PF actived?    Should current not be zero after  ASCCL actived ? 

Please advise if below idea is reasonable.

1. A noise couple into sense resistor. Gauge read abnormal current 

2.Surge event found during charging, cause sensing current abnormal

3. Any the other factor?

Lifetimes
Current
Max Charge Current
2499
mA

Lifetimes
Current
Max Discharge Current
-849
mA

Lifetimes
Current
Max Avg Dsg Current
-720
mA

Lifetimes
Current
Max Avg Dsg Power
-549
cW

Lifetimes
Safety Events
No Of ASCC Events
0
events

Lifetimes
Safety Events
Last ASCC Event
0
cycles

Protections
OCC1
Threshold
3500
mA

Protections
OCC1
Delay
6
s

Protections
OCC2
Threshold
4000
mA

Protections
OCC2
Delay
1
s

Protections
OCC
Recovery Threshold
-200
mA

Protections
OCC
Recovery Delay
5
s

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Star Xu：

您好，正在询问更了解这款芯片的TI工程师，稍后回复。

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Star Xu：

您好，The gauge will not catch every current spike in Lifetimes (it is fairly conservative with updates to avoid premature flash wear and it also won't catch all spikes due to HW protection events, which can turn off the FETs before the coulomb counter ADC even had a chance to measure anything).

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Kinden Lu：

Hi 你好,請教有什麼更好的方式可以避免current spike

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Star Xu：

您好，current spike取决于外部电源