MP5048

– 60V, 15A, 7mΩ RDS(ON) HOT-SWAP INTELLI-FUSE SOLUTION

MP5048 Rev. 1.1

www.MonolithicPower.com

18

4/30/2021

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© 2021 MPS. All Rights Reserved.

Where VCLREF_NORM is the CLREF voltage in

normal operation, and GCS is the current-sense

gain when the power FET is fully on (typically

25µA/A).

The FET works in the linear region.

Short-Circuit Protection (SCP)

If the load current increases rapidly due to a

short circuit condition, the current may exceed

the current limit threshold before the hot-swap

control loop can respond. If the Intelli-Fuse

current reaches 26A, a fast turn-off circuit in the

Intelli-Fuse is activated to turn off the power FET.

The total short-circuit response time is about

200ns. The FAULT signal pulls low when the

power FET current reaches the 26A current limit

and asserts low.

If the device is in latch mode, there will be no

retry response after short-circuit detection. The

FAULT pin remains low and the device remains

off. To clear the fault, the ON pin must be pulled

low and then high. This clears the fault condition,

and then the MP5048 initiates a new soft start. If

the short circuit condition is still present, the

device repeats this process. If the short circuit

condition has been removed, the MP5048 ramps

up VOUT following the soft-start ramp.

If the device is in hiccup mode, the retry timer

counts 9 cycles on the timer pin (see Figure 12

on page 17). At the end of the retry timer count,

the MP5048 tries to turn on again. If the short

condition persists, the process continues at the

rate of the retry timer for the hiccup process. If

the short has been removed, the MP5048 ramps

the output voltage up at the SS ramp rate.

VIN Fast Droop

In some conditions with a fast rising current due

to an SCP/OCP condition, the input voltage (VIN)

supply may collapse due to parasitics and PSU

capability.

If VIN decreases rapidly, SCP is triggered. This

may cause the SCP current level at which the

device turns off to be lower than expected. If this

event occurs, the device is re-enabled after an

insertion delay. The delay occurs even if the

device is set to latch-off mode. If the fault

condition is removed on the subsequent start-up,

the device turns on normally. If the fault condition

has not been removed, the device regulates at

the soft-start current limit or SCP condition, and

latches off.

FAULT Report

FAULT is an open-drain, active-low signal to

report fault conditions. FAULT monitors the

following fault events in the Intelli-Fuse:

1.

Over-current protection: If the CS voltage

exceeds the CLREF threshold during normal

operation, the FAULT signal is pulled low after

a configured gate regulation time.

2.

Short-circuit protection: If the Intelli-Fuse load

current reaches 26A quickly, FAULT is pulled

low immediately.

3.

Intelli-Fuse power FET drain-source, gate-

drain, or gate-source short detection: See the

Damaged Intelli-Fuse MOSFET Detection

section below for more details.

4.

Over-temperature

protection

when

the

junction temperature >153°C: If an over-

temperature protection fault is detected,

FAULT is pulled down.

If a latch fault occurs, FAULT is pulled low. The

latch can be released by cycling the power on

VIN or ON.

Damaged Intelli-Fuse MOSFET Detection

Damaged Intelli-Fuse power FET detection

includes FET drain-source short, gate-drain

short, and gate-source short detection. These

conditions are described in greater detail below.

Drain-Source Short Detection During Start-

Up

Once VCC on the Intelli-Fuse exceeds the under-

voltage lockout (UVLO) rising threshold, the

Intelli-Fuse starts to detect the drain-source

short during start-up. In this instance, it treats

any output voltage that exceeds 90% of VIN

during start-up as a short on the FET. The

FAULT signal remains low when the Intelli-Fuse

detects that VOUT has exceeded 90% of VIN

during start up. Once the short is removed and

the Intelli-Fuse detects that VOUT is once again

below 70% of VIN, the FAULT signal is released

to high again, and the MP5048 starts up normally.

Gate-Drain Short Detection During Start-Up

During power-up, the Intelli-Fuse detects a

power FET gate-drain short by monitoring its

drain-to-gate voltage (VDG) and gate-to-source