TPS2549-Q1: FAULT Behaviors under Overcurrent Conditions

Kenichiro

Part Number: TPS2549-Q1
Other Parts Discussed in Thread: TPS2549

[ TPS2549-Q1 ] FAULT Behaviors under Overcurrent Conditions

Hi,

Can you help to figure out two different behaviors of FAULT signal under overcurrent conditions?
Here are the conditions.

- TPS2549-Q1 on customer board
- ILIM_HI: 18kohm (2.926A according to equation (3))
- slightly different two overcurrent conditions, 1: 3A, 2: 2.98A

With regards to #1(3A), it seems that TPS2549-Q1 is in thermal cycling mode.

On the other hand, in #2, TPS2549-Q1 would be in thermal cycling mode, however FAULT transition is also involved.

I suppose that, in #2, after re-start from overtemp shut-down, TPS2549-Q1 is recovered from overcurrent condition. So, FAULT is relased after 8mS deglitch time. However, TPS2549-Q1 immedeately detects the overcurrent condition again, so FAULT is asserted after 8mS deglitch time.
(Because of the pulse width seems being constant, may be around 20mS (8mS + 8mS))

Anyway, it's not easy to explain this to my customer. it's appreciated if you can comment on this.

Thanks,
Ken

over 6 years ago

0 Aramis P. Alvarez over 6 years ago

TI__Genius 10370 points

Hi Kenichiro,

One of our expert engineers has been notified and will get back to you soon.

Best Regards,

Aramis P. Alvarez

0 Feifei Shen over 6 years ago in reply to Aramis P. Alvarez

TI__Expert 3275 points

Hi Kenichiro,
From your waveform, TPS2549 is entering thermal cycling mode.
For the two different test condition, only load current differenent?
One is 3A, the other is 2.98A.
Are you use electic load?

Best regards,
Feifei

0 Kenichiro over 6 years ago in reply to Feifei Shen

Mastermind 9165 points

Hi Feifei,

Yes, this time customer use electric load.
Can you explain the behavior?

Thanks,
Ken

0 Yongqiang Sun over 6 years ago in reply to Kenichiro

TI__Intellectual 2685 points

Hi Kenichiro,

1. if TPS2549 is over current protected but not over temperature protected, then FAULT will assert and de-assert 8ms.
2. if TPS2549 is over temperature protected, fault will assert immediately, no deglitch.
3. Please use CR mode of e-load, do not use CC mode.

0 Kenichiro over 6 years ago in reply to Yongqiang Sun

Mastermind 9165 points

Dear Yonqqiang,

Can we keep communicatoin at off-line?
My e-mail address is tanaka-k(at)clv.macnica.co.jp

It's appreciated, if you send an e-mail to me.

I have looked into the waveforms of datasheet and customer's. See below.

With regards to the mode setting of electrical load, I will let customer know.

Thanks,
Ken

0 Yongqiang Sun over 6 years ago in reply to Kenichiro

TI__Intellectual 2685 points

Hi,

I guess it should be overcurrent protected first and then OTSD.
yes, we can discuss offline, it will be more efficient. my email is yongqiang-sun@ti.com

Interface

Interface forum

TPS2549-Q1: FAULT Behaviors under Overcurrent Conditions

[ TPS2549-Q1 ] FAULT Behaviors under Overcurrent Conditions