TPS2H000-Q1: Accuracy of current sensing

Federico Battaglin

Part Number: TPS2H000-Q1

Hello,

for a new project at 28-30V, I have the need to measure the current of a line normally closed at the end with a 3,9k Ohm resistor.

I have to monitoring the current flow in these cases:
1) 3,9k Ohm end-of-line
2) 3,9k Ohm || 1kOhm
3) 500 Ohm || 1kOhm
4) 220 Ohm || 1kOhm
5) infinite Ohm (open circuit)
6) <10 Ohm (short circuit).
Normally in the old project I have a shunt resistor of 470 Ohm.
All resistors have 5% of tolerance, but the resistances for resistive dividers (to interface to MCU) have tolerance of 1%.

Now, for a new project I want to try us use TPS2H000 or TPS4H000, because I have 4 and 8 channels.
But my doubt is if the accuracy of current sensing is enough to measure these specific current values or the accuracy is not good for this application?

Thank You in advanced!
Best regards
Federico Battaglin

over 5 years ago

0 Cameron Phillips over 5 years ago

TI__Genius 12410 points

Hello,

I put together a spreadsheet with all of the relevant information. You will need to change the IOUT MAX according to what you want the current limit to be set at.

In short, the device has plenty of capability even using worse case scenario analysis to measure this current correctly enough to distinguish between each of the loads. By the way the short and open conditions just register as a fault so the current sensing pin just goes to high at that point.

You can see in the "SNS Curr Min" and "SNS Curr Max" That none of the currents over lap that would trigger a false reading for several of the loads.
This document is dense and requires a bit of time to digest. Let me know if you have questions about any of the numbers.

TPS2H000-Q1-E2E_SNS_ACC.xlsx

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TPS2H000-Q1: Accuracy of current sensing