MP8796B datasheet(46/52 Pages) MPS

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MP8796B – 16V, 30A, SYNCHRONOUS STEP-DOWN CONVERTER WITH PMBUS

MP8796B Rev. 1.0

www.MonolithicPower.com

1/19/2020

MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited.

MFR_OVP_NOCP_SET (D5h)

This MFR_OVP_NOCP_SET command sets the responses of the output voltage OVP.

Bits

Name

Access

Behavior

Default

Description

[7:4]

RESERVED

0000

[3]

DELAY_NOCP

(D400)

R/W

Live

0: 100ns delay after NOCP

1: 200ns delay after NOCP

[2]

NOCP

R/W

Live

0: Set NOCP to -10A

1: Set NOCP to -15A

[1:0]

VOUT_OV

_Response

R/W

Live

00: Latch off with output voltage discharge

01: Latch off without output voltage discharge in DCM

10: Hiccup with output voltage discharge

11: Hiccup without output voltage discharge in DCM

Bit[1:0] of the MFR_OVP_NOCP_SET command tells the converter what action to take in response to

an output over-voltage fault. The device also:



Sets the VOUT_OV bit in STATUS_BYTE



Sets the VOUT bit in STATUS_WORD



Sets the VOUT over-voltage fault bit in the STATUS_VOUT command



Notifies the host by asserting the ALERT pin

There are four OVP response modes that can be chosen through bit[1:0] of MFR_VOUT_OVP_

NOCP_SET:



Latch off with output discharge: Once the MP8796B reaches the OV entry threshold, the LS-FET

turns on until the MP8796B reaches NOCP. The MP8796B turns off for a fixed amount of time then

turns on again. This operation repeats until FB drops below the OVP exit threshold set by register

D4[3:2]. Then the LS-FET turns off. If FB rises beyond the OV entry threshold again, the LS-FET is

turns on again to discharge the output voltage. However, the converter does not attempt to restart

until the power of either VIN, VCC, or CTRL is recycled.



Latch off without output discharge (only effective in DCM): Once the MP8796B reaches the OV

entry threshold, the LS-FET turns on. When the inductor current crosses zero, the converter enters

Hi-Z mode (output disabled). The converter stops discharging the output voltage. The converter

does not attempt to restart until the power of either VIN, VCC, or CTRL is recycled.



Hiccup with output discharge: Once the MP8796B reaches the OV entry threshold, the LS-FET

remains on until the MP8796B reaches NOCP. The MP8796B turns off for a fixed amount of time

then turns on again. This operation repeats until FB drops below the OVP exit threshold set by



Hiccup without output discharge (only effective in DCM): Once the MP8796B reaches OV, the LS-

FET remains on until the MP8796B reaches NOCP. Then a new SS is initiated.

The default value of D5h is 0x00.

MP8796B Datasheet(PDF) 46 Page - Monolithic Power Systems

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