ZHCSJN5A February 2018 – April 2019 TPS2HB50-Q1
ADVANCE INFORMATION for pre-production products; subject to change without notice.
Table 16 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) | 1500 |
Largest diagnosable load current | 6 A |
Smallest diagnosable load current | 30 mA |
Full-scale ADC voltage | 5-V |
ADC resolution | 10-bit |
The load current measurement requirements of 6 A ensures that even in the event of a overcurrent surpassing the device internal 4 A limit, the MCU can register and react by shutting down the TPS2HB50-Q1, while the low level of 30 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 17.
LOAD (A) | SENSE RATIO | ISNS (mA) | RSNS (Ω) | VSNS (V) | % of 5-V ADC |
---|---|---|---|---|---|
0.030 | 1500 | 0.02 | 1200 | 0.024 | 0.5% |
6 | 1500 | 4 | 1200 | 4.800 | 96.0% |