SLVSFZ1 December 2020 TPS27SA08-Q1
|Current Sense Ratio (KSNS)||4600|
|Largest diagnosable load current||20 A|
|Smallest diagnosable load current||50 mA|
|Full-scale ADC voltage||5 V|
|ADC resolution||10 bit|
The load current measurement requirements of 20 A ensures that current can be sensed up to the 20-A current limit, while the low level of 100 mA allows for accurate measurement of low load currents.
The RSNS resistor value should be selected such that the largest diagnosable load current puts VSNS at about 90% of the ADC full-scale. With this design, any ADC value above 90% can be considered a fault. Additionally, the RSNS resistor value should ensure that the smallest diagnosable load current does not cause VSNS to fall below 1 LSB of the ADC. With the given example values, a 1-kΩ sense resistor satisfies both requirements shown in Table 10-4.
|LOAD (A)||SENSE RATIO||ISNS (mA)||RSNS (Ω)||VSNS (V)||% OF 5-V ADC|