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BQ76930: 电流精度计算

Part Number: BQ76930

如何根据规格书给出的数据表来计算这个电流的采集误差呢?

  • 您好,

    • Divide the CC voltage by the sense resistor value, or: Current = CC value × CC LSB value / sense resistor.  Be sure to convert units where needed.  Remember that the CC is an integrating converter, and the calculation will give an ‘average’ current.

    More information can be found in sections 5.4 and 5.5 of the FAQ document: bq76920, bq76930, bq76940 AFE FAQ (Rev. A) (ti.com).

  • 该文档中给出的公式:Current = CC value × CC LSB value / sense resistor是用来计算电流值的大小。我想了解下这个器件的采集精度,比如说我使用采样电阻器为0.5mΩ。假设我的工作电流范围是0~50A,如何去计算这个电流精度?

  • 您好,请参考数据手册16-BIT CC FOR PACK CURRENT MEASUREMENT

    www.ti.com.cn/.../bq76930.pdf

  • 这也是我想请教的地方,如何使用规格书中的参数来计算这个电流误差值大小,能否提供下计算方法?

  • 您好,正在询问更了解这款芯片的TI工程师,稍后回复。

  • 您好,请参考下面内容

    Assuming we ignore non-linearity and offset. The current error would be determined by the gain error. 

    Datasheet gives a worst-case gain error of 1.5% of the full scale range of the coulomb counter. the full range is -270-mV to 270-mV. So, 1.5% of this range would correspond to ~4-mV of gain error across the whole range. This would be the error at the edges of the voltage range of the coulomb counter, so at ~270-mV.

    Let's assume that there is a 2000-mA current flowing through, if we assume the worst gain error is 1.5%, this means that the measurement could be read as 2030-mA. Although this depends on the sense resistor used. The current error due to gain will never be more than 1.5%.

    Offset and INL errors are given with respect to LSB's. Which is given as 8.44-uV per LSB.