SNVS710I March 2011 – December 2015 LMZ13608
PRODUCTION DATA.
The LMZ13608 is protected by both low-side (LS) and high-side (HS) current limit circuitry. The LS current limit detection is carried out during the off-time by monitoring the current through the LS synchronous MOSFET. Referring to the Functional Block Diagram, when the top MOSFET is turned off, the inductor current flows through the load, the PGND pin and the internal synchronous MOSFET. If this current exceeds 13 A (typical) the current limit comparator disables the start of the next switching period. Switching cycles are prohibited until current drops below the limit.
NOTE
DC current limit is dependent on duty cycle as illustrated in the graph in the Typical Characteristics.
The HS current limit monitors the current of top side MOSFET. Once HS current limit is detected (16 A typical) , the HS MOSFET is shutoff immediately, until the next cycle. Exceeding HS current limit causes VOUT to fall. Typical behavior of exceeding LS current limit is that fSW drops to 1/2 of the operating frequency.