MP5006EQ View Datasheet(PDF) - Monolithic Power Systems

Part Name

Description

MFG CO.

MP5006EQ

5V, 1A- 5A Programmable Current Limit Switch with Slew Rate Control and Auto Enable

Monolithic Power Systems 

MP5006 – 5V, 1A- 5A PROGRAMMABLE CURRENT LIMIT SWITCH WITH AUTO ENABLE

THERMAL PROTECTION

The MP5006 only considers a thermal overload

to be a fault. Under a fault condition the mp5006

will have two actions:

1) Turn off the output power device.

2) Drive the enable/fault pin to the low level.

The power device will remain off until the die

temperature drops below the hysteresis level.

When the die cools down below the thermal

hysteresis level, the MP5006 will restart in the

start up mode and the fault line will be pulled high

through a 25uA pull up current. If the cause of

the fault has been removed, the output will ramp

up in a controlled fashion with the ramp rate

controlled by the dv/dt function. If the cause of

the fault is still present, the excess power

dissipation will heat up the part. When the die

temperature reaches the thermal shutdown

temperature, the output will be turned off and the

enable/fault pin will be driven to the low level,

again. This cycle will repeat until the cause of the

fault is removed.

Figure 3―Thermal Protection in Short Condition

The drawing above shows the initial start up

sequence and the occurrence of a short at the

output.

At time T0 the input voltage begins to rise. At T1

the input voltage rises above the UVLO threshold

and the part starts up. The output current ramps

up and settles at the normal operating current

level until time T2. There is a very small

temperature heating of the die in normal

operation.

At time T2 the output is shorted. This brings the

output very close to ground. The output current

increases to the current limit level and is held

there by the MP5006. Because of the large

current and the large voltage across the power

device, the die will begin to heat up.

At time T3 the die temperature is at the thermal

shutdown level and the part will turn the power

device off. The enable/fault pin is driven to the

low level. Once the power device is off, the die

temperature will begin to drop.

At time T4 the part has cooled down below the

thermal hysteresis level. The enable pin goes

high and the part turns on again. But the short is

still present, causing the die temperature to

increase.

MP5006 Rev.0.92

www.MonolithicPower.com

11

12/27/2013

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