To achieve the most accurate current sense value, it is recommended to filter the SNS output. There are two methods of filtering:
- Low-Pass RC filter between the SNS pin and the
ADC input. This filter is illustrated in Figure 9-1 with typical values for the resistor and
capacitor. The designer should select a
CSNS capacitor value based on system
requirements. A larger value will provide improved
filtering but a smaller value will allow for
faster transient response.
- The ADC and microcontroller can also be used for
filtering. It is recommended that the ADC collects
several measurements of the current sense output.
The median value of this data set should be
considered as the most accurate result. By
performing this median calculation, the
microcontroller can filter out any noise or
outlier data.