TPS2660: TPS26601: Condition for Fault output on startup timing

Satoshi

Guru 19655 points

Part Number: TPS2660
Other Parts Discussed in Thread: OPA2374

On the startup timing, /FLT output assert Low (probably UVLO) and not release to High in spite of /SHDN Low ⇒High.

Please let me know about two points below;

・Timing or the other condition for Latch to restart (/FLT to high)

・If below connection wrong or any advice for fault output condition, please let me know.

【Information】

・Connection diagram is attached below.

　Timing delay circuit is based on OPAMP(OPA2374), in order to make time lag for /FLT output reset after +12V startup.

・Waveform is attached below, please ignore ch4 waveform.

・About /SHDN time for High ⇒ Low ⇒ High; when Low term set too long: 0.5sec and 1sec, /FLT is also keep Low.

・When change to TPS26602 (auto retry), /FLT output become high for after startup.

　But one customer need to use latch function of TPS26601.

　We hope to solve on TPS26601.

Best regards,

Satoshi

over 3 years ago

0 Rakesh over 3 years ago

TI__Guru** 107381 points

Hi Satoshi,

/FLT response during startup is same for both TPS26601 and TPS26602.

Does Vout came up during startup ? else /FLT remains LOW.

What is the load on eFuse during startup? Can you ask customer to test at no-load and confirm

Best Regards,

Rakesh

0 Satoshi over 3 years ago in reply to Rakesh

Guru 19655 points

Hi Rakesh

Thank you for reply,

Above condition is Vout come up and (nearly) no load condition.

（Load is increase by CPU control for detect the /FLT: High output）

We investigating why /FLT keep Low after Vout startup, and way to control /FLT change High.

If there find the any other notice, please let me know.

By the way, when /SHDN set High ⇒ Low ⇒ High, at the moment output current increase, but /FLT is keep Low.

I guess that any TPS26601 function prevent current flow.

Best regards,

Satoshi

0 Rakesh over 3 years ago in reply to Satoshi

TI__Guru** 107381 points

Hi Satoshi,

We will have similar issue for the devices with reverse current protection.

Best Regards,

Rakesh

0 Satoshi over 3 years ago in reply to Rakesh

Guru 19655 points

Hi Rakesh

Additional information, when these board replaced TPS26601 to TPS26602 (Auto retry), problem was resolved.

TPS26602 waveform is attached below;

If possible, customer want to use TPS26601.

Is there any idea the other than replace to TPS26602?

Best regards,

Satoshi

0 Rakesh over 3 years ago in reply to Satoshi

TI__Guru** 107381 points

Hi Satoshi,

The startup behavior should be same for both these variants of devices. Can you please include Vout also in the test waveforms and share the result for TPS26601 and TPS26602 to understand.

Where is the MODE pin connected ?

Best Regards,

Rakesh

0 Satoshi over 3 years ago in reply to Rakesh

Guru 19655 points

Hi Rakesh

Thank you for advice,

Waveform is confirming to customer, please wait a few days.

MODE pin is left open.

Best regards,

Satoshi

0 Rakesh over 3 years ago in reply to Satoshi

TI__Guru** 107381 points

Ok Satoshi.

Power management

Power management forum

TPS2660: TPS26601: Condition for Fault output on startup timing