MP4572

– 60V, 2A, SYNCHRONOUS STEP-DOWN CONVERTER

MP4572 Rev. 1.0

www.MonolithicPower.com

23

3/9/2020

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

© 2020 MPS. All Rights Reserved.

when the input voltage drops below the UVLO

falling threshold. This function prevents the

device from operating at an insufficient voltage. It

is a non-latch protection.

Over-Current Protection (OCP)

The MP4572 has a 3.5A peak current limit. Once

the inductor current reaches the current limit, the

HS-FET turns off immediately. Then the LS-FET

turns on to discharge the energy, and the

inductor current decreases. The HS-FET does

not turn on again until the inductor current drops

below the current threshold (the valley current

limit). This protection prevents the inductor

current from running away and damaging the

components.

Short-Circuit Protection (SCP)

When

a

short-circuit

condition

occurs,

the

MP4572 immediately reaches its current limit.

Meanwhile, the output voltage drops until VFB

falls below 50% of VREF. The device considers

this an output dead short, and triggers hiccup

short-circuit

protection

(SCP)

mode

to

periodically restart the part.

In hiccup mode, the MP4572 disables its output

power stage, slowly discharges the soft-start

capacitor, then initiates a soft start. If the short-

circuit condition remains after soft start ends, the

device repeats this operation until the short

circuit disappears and the output returns to the

regulation level. This protection mode greatly

reduces the average short-circuit current to

alleviate thermal issues and protect the regulator.

Negative Current Protection

The MP4572 has a -1.3A negative current limit.

Once the inductor current reaches the current

limit, the LS-FET immediately turns off and the

HS-FET turns on. The current limit prevents the

negative current from dropping too low and

damaging the components.

Thermal Shutdown

For thermal protection, the MP4572 monitors the

IC temperature internally. This function prevents

the chip from operating at exceedingly high

temperatures.

If

the

junction

temperature

exceeds the threshold value (about 170°C), it

shuts down the whole chip. This is a non-latch

protection. There is a 25°C hysteresis. Once the

junction temperature drops to about 145°C, the

device resumes operation by initiating a soft

start.