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Electronics => Beginners => Topic started by: kendo on March 05, 2021, 12:05:25 pm

Title: Critique my DC-DC boost converter schematic
Post by: kendo on March 05, 2021, 12:05:25 pm
Hi. I have been working on this boost converter for a while now and Im at a point where Im kind of happy with the simulations. So Im looking for some feedback just to see if I made some big mistakes or if this wont work in reality. This is also the first time Im building a DC-DC converter so treat me as a complete beginner.

Im using this to power headphone amp/DAC so its fairly low power. I need about 150mA on positive rail and 20mA on negative rail. I designed it for +-7V which I will lower down to +-5V with a LDO.

Anyway this is the schematic.

(https://www.eevblog.com/forum/beginners/critique-my-dc-dc-boost-converter-schematic/?action=dlattach;attach=1186918;image)

For the most part I followed the datasheet and for the rest I played around with values in ltspice.

This is the startup voltage at positive output.

(https://www.eevblog.com/forum/beginners/critique-my-dc-dc-boost-converter-schematic/?action=dlattach;attach=1186922;image)

There are some oscillations there which I would like to get rid off. The inverting charge pump seems to cause them.

This is the inductor current waveform at the startup.

(https://www.eevblog.com/forum/beginners/critique-my-dc-dc-boost-converter-schematic/?action=dlattach;attach=1186926;image)
There is a big peak of 5.5A and more oscillations.

At steady state all of the waveforms look fine.

Im getting sub mV ripple which I was looking for. Ideally I would like to fix startup oscillations and lower down the peak current through the inductor.

What do you think?

EDIT: How do you put images inline? Figured it out.