UCC2818A: UCC2818A question

Masazumi Ishii

Part Number: UCC2818A

Hello.

I have a question.

We configured the power supply using UCC2818A.
We are doing power supply operation test.
UCC2818A stops when we perform the following operation test with the attached circuit.
Why did it stop?
It will not return unless the power is turned on again.
Is there a protection circuit not listed on the data sheet?

Situation
・Environment that works with UCC 2818A alone.
・From RVOUT, flow a 400 mA current using a load device.
・After that, the load device was turned off.
・After that, the UCC2818A stopped its operation after the ON width of DRVOUT changed.
・When stopped, the VREF voltage of UCC2818A is decreasing.
・After that, operation of UCC2818A is restored by turning on the power again.(Latch stop)

In the power supply we created, even when carrying out the noise test, the power supply will stop in the same way.(Latch stop)

Thank you.

UCC2818ATEST.pdf

over 8 years ago

0 John Griffin1 over 8 years ago

TI__Mastermind 34465 points

Hello,

It is very unclear what this test that you are doing is all about.
Are you trying to get some characterization data for the UCC2818A that is not given in the data sheet ?

Regards

John

0 Masazumi Ishii over 8 years ago in reply to John Griffin1

Genius 3945 points

Hello.

I have a question.

Datasheet of UCC 2818 A Page 9.
9.3.2 There is Zero Power Block function.

Which pins and how do you detect this function?

The Vsense pin was dropped below 0.33V.
Output stopped.
However, latch stop state will not be set.

thank　you.

0 John Griffin1 over 8 years ago in reply to Masazumi Ishii

TI__Mastermind 34465 points

Hello,

The word latch should not have been used in the description of this function in Section 9.3.2

Thank you for this observation.

When the output of the error amp (VAOUT) drops below 0.33V the zero power comparator turns off the gate drive.

This is not the VSENSE pin as in your posting.

This happens at very light loads and it prevents an over voltage condition from happening.

Regards

John

0 Masazumi Ishii over 8 years ago in reply to John Griffin1

Genius 3945 points

Hello.

please tell me.

I am checking the data sheet of UCC2818A.
I think that UCC 2818 A will automatically recover if it stops due to some phenomenon.
However, please let me know if there is a phenomenon that must be restarted?

thank you.

0 John Griffin1 over 8 years ago in reply to Masazumi Ishii

TI__Mastermind 34465 points

Yes you are correct.

This part does not have a latch function.

It will recover from a fault once the fault is removed

Regards

John

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UCC2818A: UCC2818A question