TPS4H000-Q1: How to understand the maximum nominal DC load current of 0.75A

Harvey Nie

Part Number: TPS4H000-Q1

Tool/software:

Hi expert，

Chapter 7.3 of the manual says the maximum nominal DC load current is 0.75A. Does this 0.75A refer to the total current of all channels, or a single channel current? The manual also says that the current limit of each channel can be up to 1A~1.6A (CL pin connected to GND). This is very confusing to me, I suggest adding more description to the manual.

In my system, only three channels are used, with a maximum current of 0.5A per channel. The thermal power consumption is about I^2*R*1.5*3=1.125W, where 1.5 is the Rdson change rate. TJ_max=P*Rja+85℃=128℃, which seems to be less than T(SD,rst) 155℃. Of course, this is just a rough calculation, but I think it can still verify that the design is feasible. Can you help me review it?

Thanks.

Harvey

25 days ago

0 Alan Whitehead 24 days ago

TI__Genius 10285 points

TPS4H000_RC_Network .xlsx

Hey Harvey,

The nominal DC load current in the screenshot above is PER channel. I have attached a thermal model excel for power profile evaluation.

BR,

Alan

0 Harvey Nie 22 days ago in reply to Alan Whitehead

Prodigy 180 points

Hi Alan,

Thanks for sharing your calculations. The results are exactly what I expected. So if a 0.5A load on all three channels (1.5A total) is acceptable, then the manual shouldn't indicate a maximum load of 0.75A.

Thanks.

Harvey

0 Alan Whitehead 21 days ago in reply to Harvey Nie

TI__Genius 10285 points

Hey Harvey,

The ambient temperature can have an influence on this performance. I believe at 25C the excel document supports the datasheet spec at 0.75A.

BR,

Alan

0 Harvey Nie 21 days ago in reply to Alan Whitehead

Prodigy 180 points

Hi Alan,

Sorry, please let me repeat my question. You said 0.75A refers to the PRE channel. Is this the total current of all channels? If so, then when I use three channels, each channel 0.5A, a total of 1.5A load, the calculation shows that it passes, so the total current should not be marked as 0.75A without stating the condition.

I will appreciate your patience as it will allow me to use this chip without any worries.

Thanks.

Harvey

+1 Alan Whitehead 20 days ago in reply to Harvey Nie

TI__Genius 10285 points

Hey Harvey,

I see the confusion. Yes, the 0.75A would be limited PER channel. Let me know if you have any other questions.

BR,

Alan

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TPS4H000-Q1: How to understand the maximum nominal DC load current of 0.75A