Questions about VMA402 step up converter


#1

Hello,

I plan on buying a VMA402 step up converter but I’m not sure if it will suit my needs, and the datasheet doesn’t helps me enough.

I need to power a LM358N Op amp.
So I plan on using a 9V battery on the input of the step up converter and tune it (using the knob) to output 48V.

I have 3 questions regarding this module :

  1. I don’t know if the step up can really output 48V from 9V (by reading the datasheet I’d say yes, but I feel I’m missing something because its seems like a huge voltage conversion)
  2. How much intput current does it require ? The datasheet says 2 different values (2A - 3A which seems really high for a module designed to step up the voltage of a MCU)
  3. How would you advise me to power this step up converter ? (battery, powerbank, else ? (I need something relatively small and portable))

Thanks in advance for your help, let me know if you need further details,

Regards,

Ant1


#2
  1. Yes, there’s no problem to convert 9V to 48V (will draw a lot of current tho @ the input side)
  2. current consumption depends on what your Op Amp circuit uses.
  3. Put the 9V batteries in serie to increase the voltage? Maybe a powerbank or a big LiPo, (maybe buy a Tesla battery pack :stuck_out_tongue: )

The power on the output must be similar to the input (without counting the efficiency of the switcher).
with the formula P=U x I we can do the following:
So if you consume for example 48V@100mA = 4.8W => 4.8W@9V = 530mA. (this is an ideal situation).
With that you should know what max current you will draw. So you can choose the best power supply for it.


#3

Thanks for the quick answer !

  1. Alright ! After further search I will limit to 24V instead of 48V
  2. it’s a really small circuit, so there is not much current consumed (a little voltage display)
  3. I will finally use a 9V batterie to power the step up converter

The display consume 50mA, so 24V@50mA = 1.2W => 1.2W@9V = 133mA so in the best case as you said, so I’m good to go :wink: