Hi, I am looking for a suitable dc to dc boost converter for a servo drive power supply ( the servo drive itself has the servo control built-in, so I am only looking for a suitable power supply). The design specifications are:
Input voltage: 4.5v DC (will be using batteries, probably paralleled with some super caps).
Output voltage: 12v DC
Output current: less than 1.5A except when starting or changing direction.
Startup current: 7A for probably about 100mS.
Would you recommend the MP3437 for this application (if not please suggest another part)? My main concern is whether it will be able to supply the high surge current requirement on startup.
I would say not, the switch seems to be limited to 10A so 10A from 4.5V is 45W maximum input power ignoring efficiency loss and inductor ripple. Your output requirement is 7 x 12 84W. That is a mismatch. The workaround is to use a big output cap one that can provide the missing 40W for 100msec without unacceptable droop. So you have to decide how much droop can you tolerate?
If you can take 1V the cap has to provide about 4A for 100msec I=Cdv/dt so you need a 0.4F cap which is not practical. So you need to find a part with double the power or put two of these in parallel.
MP3428A is maybe going to just do it. Otherwise look for a controller