TI中文支持网Part Number:BQ77905
我有幾點問題
1. 請問BQ7790508的VTB PIN為何無輸出電壓? 我有接上10K NTC!
2. CHG/DSG為何沒有輸出電壓? 有甚麼動作條件限制?
我的電路如下 , 我不需要SC保護, 所以沒有使用電流偵測功能. 我也不需要LD功能, 故沒接!!
Star Xu：
您好，不用 LD 功能，可以将 LD 引脚接地。
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LEE Willie：
有, 我已經將LD接地, 但問題還是一樣 CHG/DSG沒有輸出電壓…..
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Star Xu：
您好，正在查询，稍后回复。
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Star Xu：
您好，请参考下面的内容
The thermistor is sampled for temperature measurement as shown in figure 9 of the datasheet. If you are measuring the VTB pin with a meter, it will measure about 0v. If you inspect the signal with an oscilloscope, you should see it pulse high approximately every 120ms.
DSG and CHG are most likely disabled due to a fault. Depending on how you are connecting your cells, there could be a voltage spike/dip during cell attach that is causing the device to go into OV or UV, and is staying in a fault due to the recovery hysteresis threshold. I recommend connecting the cells starting with BAT- and keeping an eye on transients while connecting. Keep in mind that resetting the device will not clear the faults until the fault recovery conditions are met.
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LEE Willie：
我用電阻分壓板模擬cell並先連接好到BQ77905所有CELL輸入點後 , 才會連結上POWER SUPPLY , Power Supply供電順序是Gnd -> BAT+ , 理論上電壓尖峰/驟降的情況不太可能發生!
我可以從哪裡去判斷BQ77905進入 OV 或 UV 或是其他保護狀態???
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Star Xu：
您好，请参考数据手册表 8-4. State Comparator Operation Summary
