TPS25947: ITIMER setting question

Chao Fu Chen

Part Number: TPS25947

Hi Teams,

My customer using our EVM board to verify his system and original on the EVM board is latch type(TPS259474LRPWT) is normal can do, but when he change to the TPS259474ARPW on the EVM can see his ITMER is not holding the same time with his setting from 1.83ms becomes to 1.0048ms

And his all setting as below;

First he let the R13 floating and EN pin connect to 3.3V supply.

ITIMER pin connect the 2.2nf capacitor

ILIM pin connect the 1.1Kohm(for current limited around 3A)

His load is from 0A to turn on 3.1A to see the ITIMER time.

And all these setting is the same with TPS259474LRPWT and his action is normal can meet , but why he change to TPS259474ARPW will run away the for ITIMER.

Could you help to see any issue or wrong setting from my customer ? Or the latch type and retry type of IC had different inside ?

Eddie

over 4 years ago

0 Kunal Goel over 4 years ago

TI__Guru* 79151 points

Hi Eddie,

I will get back by tomorrow.

Regards

Kunal Goel

0 Kunal Goel over 4 years ago in reply to Kunal Goel

TI__Guru* 79151 points

Hi Eddie,

1. Do you see this difference in itimer when you apply overload very first time on auto retry variant or during retry events?

2. Can you share a waveform probing VIN,VOUT,ITIMER and input current?

3. There should not be a difference in timings.

Regards

Kunal Goel

0 Chao Fu Chen over 4 years ago

TI__Intellectual 1180 points

Hi Kunal

The waveform as attachment , Could you help to check what wrong to happen this issue?

If the setting is wrong way form my customer side I will told him to modify that.

Eddie

0 Kunal Goel over 4 years ago in reply to Chao Fu Chen

TI__Guru* 79151 points

Hi Eddie,

1. Can you also share waveform for latch part?

2. Current goes from 0 to 3A?

3. Every time we run test on retry part , time is 1ms?

4. I don't see issue with customer setting. Could be due to part to part variation(process variation).

Regards

Kunal Goel

0 Chao Fu Chen over 4 years ago in reply to Kunal Goel

TI__Intellectual 1180 points

Hi Kunal,

1.The Latch part as attachment

2. Yes

3.Yes

4. they try the other retry vision part still can see the same

Please help to verify what the different between latch and retry.

The latch type is on EVM board original one seems is very old part , you can compare together to check.

Is the issue come form the revision different ?

Eddie

0 Kunal Goel over 4 years ago in reply to Chao Fu Chen

TI__Guru* 79151 points

Hi Eddie,

Let me check with team on this. Please tell me the name EVM name written on PCB. Also you said that customer is changing current from 0 to 3A and current limit is 3A. But from waveform it looks current is changed from 2A to slightly above it and current limit is around 2 A. Can you confirm?

Regards

Kunal Goel

Power management

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TPS25947: ITIMER setting question