7.3.4 Short-Circuit Protection

When the voltage across the sense resistor measured on the I_SEN pin exceeds 343 mV, short circuit current limit protection gets activated. A comparator inside the LM3478 reduces the switching frequency by a factor of 5 and maintains this condition until the short is removed. In normal operation the sensed current will trigger the power MOSFET to turn off. During the blanking interval the PWM comparator will not react to an over current so that this additional 343 mV current limit threshold is implemented to protect the device in a short circuit or severe overload condition.