Hi ! I need to make a 12V/500mA buck-boost converter... It must convert 8-16V to 12V. So far I tested a chinese module with XL6009 and it work fine, but is to big and it heats up in load. The coils and the IC are verry big and I don't have space on my project PCB for it. I need something smaller, working around 400KHz, with good efficiency. And which should stay warm at most at a load of 500mA. Can you recommend me something like that ?

 

Hi ! I need to make a 12V/500mA buck-boost converter... It must convert 8-16V to 12V. So far I tested a chinese module with XL6009 and it work fine, but is to big and it heats up in load. The coils and the IC are verry big and I don't have space on my project PCB for it. I need something smaller, working around 400KHz, with good efficiency. And which should stay warm at most at a load of 500mA. Can you recommend me something like that ?

Hello,

You could visit the Texas Instruments site and look for their listings for chips of various kinds, from linear regulators to switcher controllers, and a lot of other categories. When you look at the list, just look for the specs you need and see if the size is right. This is the best way to choose a chip for your application. Of course there are other sites too that make and/or sell IC chips you could look at those too.

 

It's hard to look for something when you don't know how it looks like. I am verry new to dc-dc converters. I made only a buck so far... with TPS54302. Ca I use this too to make a buck-boost or it has to be a special IC ?

 

You could make a SEPIC converter with an LM3478.
https://www.ti.com/lit/ds/symlink/lm3478.pdf
The circuit works with two separate inductors or with one dual-winding inductor.
https://docs.rs-online.com/30c0/0900766b8114d550.pdf

 

It's hard to look for something when you don't know how it looks like. I am verry new to dc-dc converters. I made only a buck so far... with TPS54302. Ca I use this too to make a buck-boost or it has to be a special IC ?

Hi,

What do you mean "you don't know what it looks like"?
You look for a buck boost convert IC chip on the site, that's all.
The TPS54302 looks like a chip dedicated as a buck converter not a buck boost, and although there are ways to rig it up to do other things the best bet is to find a chip that is made for buck boost.

See if this link helps:
Buck-boost & inverting regulators product selection | TI.com

 

That's a good point to start my research ! Thank you, both !

Is SEPIC beter than boost converter ?

 

That's a good point to start my research ! Thank you, both !

Is SEPIC beter than boost converter ?

It is, if your input voltage is greater than your output voltage!

 

That's a good point to start my research ! Thank you, both !

Is SEPIC beter than boost converter ?

Some power supply designs have the full current flowing through a capacitor to get to the output. I trust the ones that do not do that more than the ones that do use that idea. A filter capacitor is different because it only has to deal with the ripple current.

 

Some power supply designs have the full current flowing through a capacitor to get to the output. I trust the ones that do not do that more than the ones that do use that idea. A filter capacitor is different because it only has to deal with the ripple current.

Interesting to note that the SEPIC, if it is made with coupled inductors, would continue to work if you remove the capacitor, as it then becomes an isolated flyback-converter. All that changes that the input current ceases to be continuous.