I'm working on a dual voltage power supply using the LTC3649 and the LTC7149 ICs to generate a positive and negative voltage up to +12 and -12 V. For testing, the output here is shown to be +10 and -10 V with 2 amps at the outputs. Previously, I've used the LT1765 IC in an inverting buck-boost configuration, but it could only output 0.5 amps (with a 10 uH inductor and 10 uF capacitor). I want to increase the amount of current in my design, so I switched to these components instead, ICs that are meant specifically to output a negative voltage.
I've tried to follow the recommended values for both ICs (surprisingly, they're mostly the same), and I've tried to keep the components the same at each IC, but I was wondering if these values were adequate for the ICs? I've based them off of the demo board circuit components. I'm using ceramic capacitors for everything because I've looked at the large electrolytic bulk caps for the output. I'm concerned that their ESR is too high, so I stuck with only ceramic caps at the output and inputs. Is this adequate? With that said, I'm also concerned about the ripple current. Using the 5.6 uH inductor, following the values for the LTC7149, I've calculated a ripple current of 1.04 amps. Increasing the inductance would reduce that, but what else would that change?
