MP62150/MP62151 –CURRENT-LIMITED POWER DISTRIBUTION SWITCH

MP62150/MP62151 Rev. 0.9

www.MonolithicPower.com

7

9/18/2009

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© 2009 MPS. All Rights Reserved.

FUNCTION BLOCK DIAGRAM

Vref

Deglitch

Logic

Charge

Pump

GND

Thermal

Sense

UVLO

IN

EN

FLAG

OUT

Current

Sense

AMP

--

--

--

--

--

--

+

+

--

Figure2—Functional Block Diagram

DETAILED DESCRIPTION

Over Current

When the load exceeds trip current (minimum

threshold current triggering constant-current

mode) or a short is present, MP62150/MP62151

switches into to a constant-current mode (current

limit value). MP62150/MP62151 will be shutdown

only if the over current condition stays long

enough to trigger thermal protection.

Trigger over current protection for different

overload conditions occurring in applications:

1) The output has been shorted or overloaded

before the device is enabled or input applied.

MP62150/MP62151 detects the short or

overload and immediately switches into

constant-current mode.

2) A short or an overload occurs after the device

is enabled. After the current-limit circuit has

been tripped (reached the trip current

threshold), the device switches into constant-

current mode. However, high current may

flow for a short period of time before the

current-limit circuit can react.

3）Output current has been gradually increased

beyond the recommended operating current. The

load current rises until the trip current threshold is

reached or until the thermal limit of the device is

exceeded. The MP62150/MP62151 is capable of

delivering current up to the trip current threshold

without damaging the device. Once the trip

threshold has been reached, the device switches

into its constant-current mode.

Flag Response

The FLAG pin is an open drain configuration.

This FAULT will report a fail mode after an 8ms

deglitch timeout. This is used to ensure that no

false fault signals are reported. This internal

deglitch circuit eliminates the need for extend

components. The FLAG pin is not deglitched

during over temperature or voltage lockout.