MP8758H–22V, HIGH-CURRENT SYNCHRONOUS BUCK CONVERTER

MP8758H Rev.1.0

www.MonolithicPower.com

16

10/13/2015

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

© 2015 MPS. All Rights Reserved.

discharges the output, and tries to keep it within

the normal range. The part exits OVP when FB

falls below 105% of the target voltage.

If OTP occurs during OVP, the LS-FET turns off

and stops discharging the output until the silicon

temperature falls below 125°C.

When the feedback voltage falls below 60% of

the target voltage, the UVP comparator output

goes high. If the UV still occurs after a 12µs

delay, then hiccup mode is triggered.

Under-Voltage Lockout (UVLO)

The

MP8758H

has

under-voltage

lockout

protection (UVLO). When VCC is higher than

UVLO’s rising threshold voltage, the part powers

up, and shuts off when VCC falls below the

UVLO falling threshold voltage. This is called

non-latch protection. If an application requires a

higher UVLO, use two external resistors on EN to

adjust the input voltage UVLO (see Figure 9). It is

recommended to use the EN resistors to set the

enough hysteresis to allow for any input supply

variations.

Figure 9: Adjustable UVLO

Thermal Shutdown

The MP8758H has thermal shutdown protection.

The junction temperature of the IC is monitored

internally. The converter shuts off if the junction

temperature

exceeds

the

threshold

value,

typically

150ºC.

This

is

called

non-latch

protection. Hysteresis is about 25ºC. Once the

junction temperature drops to about 125ºC, a soft

start is initiated.

Output Discharge

The MP8758H discharges the output when EN is

low, or when the controller is turned off by the

protection

functions

(UVLO

and

thermal

shutdown). The part uses an internal 6Ω

MOSFET to discharge the output.

EN Comparator

EN

MP8758H

IN