MP6231/MP6232 –CURRENT-LIMITED POWER DISTRIBUTION SWITCHES

MP6231/MP6232 Rev. 1.2

www.MonolithicPower.com

7

3/31/2010

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FUNCTION BLOCK DIAGRAM

Figure 2—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, MP6231/MP6232

switches into to a constant-current mode (current

limit value). MP6231/MP6232 will be shutdown

only if the overcurrent condition stays long

enough to trigger thermal protection.

Trigger

overcurrent

protection

for

different

overload conditions occurring in applications:

1) The output has been shorted or overloaded

before the device is enabled or input applied.

MP6231/MP6232

detects

the

short

or

overload and immediately switches into a

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

MP6231/MP6232 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 an over temp. or a voltage lockout.