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bq76920低压3.5V以下显示不准

Other Parts Discussed in Thread: BQ76920

我用bq76920做了一个检测3节电池的方案,当电池总电压为3.5v(每节单电池是通过电阻分压来接入的) 或更低的时候显示就出现较大的偏差:

9.2V的电压打印如下:

i= 0-------CellVoltage = 3061

i= 1-------CellVoltage = 3065

i= 2-------CellVoltage = 49

i= 3-------CellVoltage = 48

i= 4-------CellVoltage = 3050

Battery_Patch_Voltage = 9295

 

3.5V的电压打印如下:(0,1相差快200MV)

i= 0-------CellVoltage = 1211

i= 1-------CellVoltage = 1068

i= 2-------CellVoltage = 48

i= 3-------CellVoltage = 48

i= 4-------CellVoltage = 1208

Battery_Patch_Voltage = 3587

 

3.0V的电压打印如下:

i= 0-------CellVoltage = 1049

i= 1-------CellVoltage = 771

i= 2-------CellVoltage = 48

i= 3-------CellVoltage = 48

i= 4-------CellVoltage = 1047

Battery_Patch_Voltage = 2967

 

2.0V的电压打印如下:

i= 0-------CellVoltage = 714

i= 1-------CellVoltage = 48

i= 2-------CellVoltage = 48

i= 3-------CellVoltage = 49

i= 4-------CellVoltage = 1226

Battery_Patch_Voltage = 2088

 

1.5V的电压打印如下:总电压都相差200MV了

i= 0-------CellVoltage = 563

i= 1-------CellVoltage = 48

i= 2-------CellVoltage = 48

i= 3-------CellVoltage = 48

i= 4-------CellVoltage = 655

Battery_Patch_Voltage = 1366

 日本客户要求能检单节0.5V

用万用表实测各个点的电压是对的,为什么读出来的值相差这么大?电压高就不会出现这个情况

 

还有如果我吧第二节不接到VC2,8v的时候显示

i= 0-------CellVoltage = 2680

i= 1-------CellVoltage = 746

i= 2-------CellVoltage = 48

i= 3-------CellVoltage = 48

i= 4-------CellVoltage = 4618

Battery_Patch_Voltage = 8044

实测VC1电压是对的,VC2电压有2.22v ,没接电池进来怎么还有这么高的电压

这些个是没有打开cell banlance的,

以上的这些情况要怎么处理啊,谁帮指导下!