LM5176: Peak current limit activation time

Liang Tsai

Part Number: LM5176

Tool/software:

Hi Teams,

Could you please help me answer the URGENT question from customer?

1. Since there is 128 consecutive cycles before the soft start capacitor is discharged, customer is curious about why there is no accurate time for the OCP?

2. Could you briefly explain the MOSFET behavior while the controller shut down? ( HDRV1 / LDRV1 / HDRV2 / LDRV2 )

Best,

Liang Tsai

8 months ago

0 Stefan Schauer 8 months ago

TI__Guru 60201 points

Hi Liang,

1. You are right there is an accurate time till when the Overcurrent is triggered with Hiccup : it is after 128 consecutive cycles.

Has there been another statement somewhere else which does not confirm that, in this case please let me know so that we can clarify.

2. HDRVx will turn off and LDRVx will turn on to discharge the inductor.

Best regards,

Stefan

0 Liang Tsai 8 months ago in reply to Stefan Schauer

TI__Expert 5580 points

HI Stefan,

Yes, I cannot fine the exact time in the datasheet. please help me with the "128 consecutive cycle" question. Is it the switching cycle we are talking about here?

Best,

Liang Tsai

0 Stefan Schauer 8 months ago in reply to Liang Tsai

TI__Guru 60201 points

Hi Liang,

see your point now - yes this is clock cycles of the switching frequency set by the resistor on the RT pin.

Best regards,

Stefan

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LM5176: Peak current limit activation time