ZHCSIH0B December 2017 – July 2019 LP87702-Q1
For both the buck converters and the boost the current limit must be set high enough to account for inductor ripple current on top of the maximum output current. Forward current limit for the buck converters is set by BUCK0_ILIM, BUCK1_ILIM and for boost 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.