Heavy Duty Buck Converter

[Mithun_K_Das]

Need a Heavy Duty Buck Converter with Negative Common.

Conditions and Ratings:

Input: 18 ~ 30V DC
Output: 12.5V / 10A Continuous.
Run time: 24hrs at 10A.
Cooling system: None / Air Cooling.
Input and Output Ground is common.
N-Channel MOSFET.

This was the conditions. I tried with Push-Pull type, Single Inductor Buck converter and also linear one. but no one was effective. All are getting heated and burnt out. Also tried with N-Channel FET with charge pump for gate drive. But it was not effective too. Fets get hot so quick.

One was effective and I got good efficiency up to 93% with N-Channel FET but it was not Ground common. Then What may be a good solution. What topology will be effective and good for this type of buck converter?

Note: P-Channel MOSFET is not available in my local market.

 

[mtwieg]

What do you mean by negative common? Show a schematic.

 

[Mithun_K_Das]

Oh sorry, negative common means input and output ground line will be common.

 

[mtwieg]

Okay, so it's just a simple step down converter with no isolation and only positive voltages? Then you probably just have poor component selection or thermal management. We'll need a specific design, including details on the enclosure, to help.

 

[BradtheRad]

It may help if you divide the burden among several interleaved buck converters.

You can use N-devices at the high side, although this requires stepping up the bias voltage.



The 0.2 ohm resistor is unnecessary.

 

[Mithun_K_Das]

OK, Let me try again. Its a good idea using 2 or 3 inductors rather than single inductor.

 

[--BawA--]

Your power requirement is about 125 watt , so i think you should go with "flyback topology" .

 

[Mithun_K_Das]

Flyback is giving me poor performance bro. So I tried push-pull. Now I'm trying with buck converter with multi-Channel inductor.