MP6205 –CURRENT-LIMITED POWER DISTRIBUTION SWITCHE

MP6205 Rev. 0. 92

www.MonolithicPower.com

8

9/23/2009

MPS Proprietary Information. Unauthorized Photocopy and Duplication Prohibited.

© 2009 MPS. All Rights Reserved.

DETAILED DESCRIPTION

Over Current

When the load exceeds trip current (minimum

threshold current triggering constant-current

mode) or a short is present, MP6205 switches

into to a constant-current mode (current limit

value). MP6205 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.

MP6205 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 MP6205 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.

Thermal Protection

The purpose of thermal protection is to prevent

damage in the IC by allowing exceptive current to

flow

and

heating

the

junction.

The

die

temperature is internally monitored until the

thermal limit is reached. Once this temperature is

reached, the switch will turn off and allow the

chip to cool. The switch has a built-in hysteresis.

Under-voltage Lockout (UVLO)

This circuit is used to monitor the input voltage to

ensure that the MP6205 is operating correctly.

This UVLO circuit also ensures that there is no

operation until the input voltage reaches the

minimum spec.

Enable

The logic pin disables the chip to reduce the

supply current. The device will operate once the

enable signal reaches the appropriate level. The

input is compatible with both COMS and TTL.