I want to add current sense filtering to DRV8305N and have the following questions:
1. Should I add filters both at the input and the output for the DRV8305 like in the below picture or maybe only at input or only output?
2. For the input filter should I use two resistors and one capacitor (resistors Ri1 and Ri2 on SN and SP) or only one resistor (Ri1) as SP input is on the ground?
3. If i should use two input resistors then the time constatnt for that filter is 2*RC or RC or RC/2 ?
4. What is suggested Ci for the input filter? Sth around 100nF? I suppose I should choose firstly suggested input capacitance and then calculate resistors values based on required cut-off frequency, right?
5. Input and output filters should have the same cut-off frequency or maybe input should be according to electrical speed (20x higher) and output set to 2x below sampling of ADC? What is the best solution for most accurate current sensing?