SNVSBU3 March 2021 LP87702
The current limit must be set high enough to account for the inductor ripple current on top of the maximum output current for the buck converters and boost. The forward current limit for the buck converters is set by BUCK0_ILIM, BUCK1_ILIM and for boost it is set by BOOST_ILIM.
|VIN(max) = 5.5 V|
|VOUT = 1 V|
|η = 0.75|
|fSW = 1.8 MHz|
|L = 0.38 µH|
|then D = 0.242 and ΔIL = 1.59 A|
Peak current is half of the current ripple. If ILIM_FWD_SET_OTP is 3 A, the minimum forward current limit would be 2.85 A when taking the –5% tolerance into account. In this case the difference between set peak current and maximum load current = 0.795 A + 0.15 A = 0.945 A.