ZHCSJN4C February 2018 – February 2020 TPS2HB16-Q1
PRODUCTION DATA.
Table 19 shows the requirements for the load current sense in this application. The KSNS value is specified for the device and can be found in the Specifications section.
PARAMETER | EXAMPLE VALUE |
---|---|
Current Sense Ratio (KSNS) | 3000 |
Largest diagnosable load current | 12 A |
Smallest diagnosable load current | 60 mA |
Full-scale ADC voltage | 5-V |
ADC resolution | 10-bit |
The load current measurement requirements of 12 A ensures that even in the event of a overcurrent surpassing the device internal 6-A limit, the MCU can register and react by shutting down the TPS2HB16-Q1, while the low level of 60 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 95% of the ADC full-scale. With this design, any ADC value above 95% 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 1.2-kΩ sense resistor satisfies both requirements shown in Table 20.
LOAD (A) | SENSE RATIO | ISNS (mA) | RSNS (Ω) | VSNS (V) | % of 5-V ADC |
---|---|---|---|---|---|
0.060 | 3000 | 0.02 | 1200 | 0.024 | 0.5% |
12 | 3000 | 4 | 1200 | 4.800 | 96.0% |