TPS25985: TPS25985 questions

Neo.Wang

Part Number: TPS25985

Tool/software:

Hi TI experts,

A few questions for TPS25985 datasheets.

1. Below ratio is 50% but other statement mentioned the fast trip threshold is 1.5x ILIM during inrush. Does these spec align to each other?

2. Different statement for fast trip threshold during startup/inrush, page42 mentions 2x ILIM while page55 gives 1.5x ILIM. Which one is correct?

3. At steady state, the fast trip threshold is 2x IOCP for primary device while 2.25x IOCP for secondary device. For parallel application when output is hard shorted during steady state, will fast OCP of master device be triggered firstly as the threshold is lower than secondary device? Please help me understand the details.

Thanks

Neo

over 1 year ago

0 Kunal Goel over 1 year ago

TI__Guru* 79181 points

Hi Neo,

I will check and get back on this.

Regards

Kunal Goel

0 Kunal Goel over 1 year ago in reply to Kunal Goel

TI__Guru* 79181 points

Hi Neo,

Those look like typing mistakes. During inrush scalable fast-trip threshold is 1.5*ILIM and during steady state it is 2 or 2.25 * IOCP.

Q1: At steady state, the fast trip threshold is 2x IOCP for primary device while 2.25x IOCP for secondary device. For parallel application when output is hard shorted during steady state, will fast OCP of master device be triggered firstly as the threshold is lower than secondary device? Please help me understand the details. Yes. That will ensure that master trips first and make SWEN low to turn off all other devices in parallel.

Regards

Kunal Goel

0 Neo.Wang over 1 year ago in reply to Kunal Goel

Intellectual 950 points

Hi Kunal,

Thanks for clarification.

More questions:

1. I was told from FAE that during startup/inrush, the IMON is inactive but ILIM voltage represents the inrush current of each TPS25985 device. However, when i monitor IMON during normal startup and startup into short, i do see there is some voltage on master device's IMON pin. Is this reasonable?

2. When shutdown TPS25985 devices, i observed there is a few mV voltage on IMON as well, is this expected?

Thanks

Normal Startup, Cload=9400uF. Observed voltage on IMON.