Looking for switching controller

Thread Starter

Lolrapa

Joined Sep 19, 2018
22
Hello, I'm looking for a switching controller IC to make a high power power supply. I've been looking but I couldn't find what I'm looking for.

I need to design a power supply (switching for max. efficiency) with a voltage control pin that allow me to change the output voltage.
I need it also to have a current limiting functionality (probably set by a resistor). When the output current is under 20A the supply should behave as a constant voltage source (with adjustable output). When the maximum of 20A is reached the supply must behave as a constant current source and drop the output voltage to maintain 20A.

Input-Output insulation is not needed

This are some specs for my design:

Vin: 20V DC
Vout: from as low as possible to as close to Vin as possible
Max power: 400W
Max current: 20A
Efficiency: > 90%

I was wondering if there is any IC that can perform all of the above, the idea is to use the minimum amount of components.

If there isn't any IC capable of doing all that, whats the best IC (or topology) that allows good feedback manipulation (through opamps) to give it output voltage control and current limiting features?

Thank you for your help!
 

Papabravo

Joined Feb 24, 2006
17,580
Hello, I'm looking for a switching controller IC to make a high power power supply. I've been looking but I couldn't find what I'm looking for.

I need to design a power supply (switching for max. efficiency) with a voltage control pin that allow me to change the output voltage.
I need it also to have a current limiting functionality (probably set by a resistor). When the output current is under 20A the supply should behave as a constant voltage source (with adjustable output). When the maximum of 20A is reached the supply must behave as a constant current source and drop the output voltage to maintain 20A.

Input-Output insulation is not needed

This are some specs for my design:

Vin: 20V DC
Vout: from as low as possible to as close to Vin as possible
Max power: 400W
Max current: 20A
Efficiency: > 90%

I was wondering if there is any IC that can perform all of the above, the idea is to use the minimum amount of components.

If there isn't any IC capable of doing all that, whats the best IC (or topology) that allows good feedback manipulation (through opamps) to give it output voltage control and current limiting features?

Thank you for your help!
Changing the output voltage over a wide range is a non-trivial feature to implement properly.

There probably is a chip that you can use, but your chances of finding it and successfully integrating it into a working design are pretty slim if you have never designed a power supply of this type before. In addition to the IC there are quire a few additional components that require substantial engineering effort to identify, procure, and qualify before putting them into a design under development. A functioning 400 Watt power supply that won't kill you or burn your house down is a non-trivial undertaking.

You will be much better off looking for one to buy.
 

ronsimpson

Joined Oct 7, 2019
1,750
In power supplies it is hard when Vout approaches 0V. Even 2.5V gets hard. What about Vout = 5V to 18V?
How accurate for the 20A?
Most "buck supplies" have a common ground. Vin=20V and Vout is 15V using a common ground.
There is a type of buck supply where +20V is common. Vout is from +20 to Vout. (the load is not connected to ground) Is this OK? What is the load?
 

Juhahoo

Joined Jun 3, 2019
257
Only thing that troubles me is this " Vout: from as low as possible to as close to Vin as possible"
If your input is 20, what will be the output then? Is it variable, or fixed? Why does it need to be regulated so close to Vin?
What is your previous experience with SMPS power supplies?
 

DickCappels

Joined Aug 21, 2008
8,159
The 90% is going to be a challenge, especially for low output voltages. There are solution, it is just that they complicate things.

How many are you planning to make? Is cost a major factor?

Have you looked into any voltage regulator chips yet? -What did you find and what would you want different?

Do you have any noise and/or regulation specifications for this?
 
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