SNVSA47C February 2016 – December 2020 LM5165
The LM5165 manages overcurrent conditions by cycle-by-cycle current limiting of the peak inductor current. The current sensed in the high-side MOSFET is compared every switching cycle to the current limit threshold set by the ILIM pin. Current is sensed after a leading-edge blanking time following the high-side MOSFET turnon transition. The propagation delay of current limit comparator is 100 ns.
Four programmable peak current levels are available: 60 mA, 120 mA, 180 mA and 240 mA, corresponding to resistors of 100 kΩ, 56.2 kΩ, 24.9 kΩ and 0 Ω connected at the ILIM pin, respectively. In turn, 25-mA, 50-mA, 75-mA, and 100-mA output current levels in boundary conduction mode PFM operation are possible, respectively.
Note that in PFM mode, the inductor current ramps from zero to the chosen peak threshold every switching cycle. Consequently, the maximum output current is equal to half the peak inductor current. Meanwhile, the corresponding output current capability in COT mode is higher as the ripple current is determined by the input and output voltage and the chosen inductance.