IP1203 datasheet(11/23 Pages) IRF

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iP1203

Overcurrent Protection HICCUP

The overcurrent protection function of the iP1203

offers a hiccup feature. During overloads, when the

overcurrent trip threshold is reached, the power sup-

ply output shuts down and attempts to restart (out-

put HICCUP mode). The time duration between the

shutdown of the output and the restart is determined

by the time it takes to discharge the soft start ca-

pacitor. Typically, the discharge time of the soft start

capacitor is 10 times the charge time. The duty cycle

of the hiccup process is typically 5%. The output will

stay in hiccup indefinitely until the overload is re-

moved. The typical overcurrent trip threshold of the

device is internally set at 30A. The overcurrent shut-

down / HICCUP threshold is about ±30% accurate.

The iP1203 overcurrent shutdown and HICCUP

threshold can be set externally by adding R

OCSET re-

sistor from OCSET pin. Refer to Fig.8 for R

OCSET se-

lection.

Overvoltage Protection (OVP)

Overvoltage is sensed through output voltage sense

pin FBs. The OVP threshold is set to 115% of the

output voltage. Upon overvoltage condition, the OVP

forces a latched shutdown. In this mode, the upper

FET turns off and the lower FET turns on, thus

crowbaring the output. Reset is performed by recy-

cling the input voltage. Overvoltage can be sensed

by either connecting FBs to its corresponding output

through a separate output voltage divider resistor

network, or it can be connected directly to its corre-

sponding feedback pin FB. For Type III control loop

compensation, FBs should be connected through

voltage dividers only.

Refer to the iP1203 Design Procedure section on

how to set the OVP trip threshold.

PGOOD

This is an output voltage status signal that is open

collector and is pulled low when the output voltage

falls below 85% of the output voltage. High state in-

dicates that outputs are in regulation. The PGOOD

pin can be left floating if not used.

Thermal Shutdown

The iP1203 provides thermal shutdown. The thresh-

old typically is set to 140°C. When the trip threshold

is exceeded, thermal shutdown turns the output off.

Thermal shutdown is not latched and automatic re-

start is initiated when the sensed temperature drops

to the normal range.

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