High Current Switching Voltage Regulator

[RohanDey]

Hello,

I am trying to design a voltage regulator with the following spec:

Input - 16VDC unregulated
Output - 12VDC, 1.5 Amp and 9VDC, 1.5 Amp (either one output will be used at a time not both)

I think a linear regulator will not work good for me at full load, so I would like some help in designing a switching regulator.

I have seen the IC LM2676 with which my requirement can be fulfilled, but LM2676 does not have a 9V variant. It only has for 3.3V, 5V, and 12V

Can someone please suggest which IC I should use or any other design methodologies to achieve the above.

Thanks..

 

[FvM]

Did you notice the LM2676-ADJ type, which can be programmed to an output voltage of your choice?

To achieve 12V regulated output, the instantaneous value of unregulated 16V input voltage must never fall below e.g. 13.5 V.

 

[RohanDey]

Yes I checked about LM2676-ADJ. But the problem is I am not getting this IC in our local market. Is there any other common IC I can use?

 

[FvM]

Is there any other common IC I can use?

´
At least 100 different ICs on the market...
You better go the other way, check which ICs with programmable voltage are available at your site.

You can also try LM2676-5 with a low resistance external voltage divider. The problem is that the resistance of internal voltage divider isn't well specified, so you may need to adjust the external resistor values. Also some additional temperature driftmust be expected.

 

[neddie]

Check out the 34063A chip. I'm sure you will be able to get that. There are much better switchers available ,
but that one is probable easy for you to get. It can be externally boosted to give you your 1.5A output
currents.
Neddie