LINEAR REGULATOR. 5-100Vin, 2-??out. Prefer 1A output.

[fastline]

We are trying to find a high voltage reg. They are not as abundant. I am having a hard time finding 1A of output and with a low drop out. I have found a Ti piece that is 5-125V in and 700mA out but requires a min of 20V delta from input to output voltage to reach max current rating. Our would likely run at 5V.

Are there any other mfgrs I might look at? Looked at Supertex and Ti so far.

 

[mneary]

Your power requirements (Vin = 5 to 125V, Vout = 5V at 1A) looks like you need a very unusual design. A simple "Linear regulator" would be dissipating 120W at maximum input (at 4% efficiency).

Your requirements are very unusual. We occasionally see all-purpose requirements like this posted by someone who doesn't understand the system they are designing.

 

[Hero999]

It's not possible, the input current is only 700mA so you won't be able to get 5V@1A out with 5V@700mA in.

Even 5V to 125V to 5VDC@1A isn't easy to do efficiently.

 

[fastline]

I thought my question was fairly straight forward. Yes, I know what the circuit does, no, it will not be dissipating 120watts. No, we are not trying use 700mA/5V in and get 1A/5V out.

I am not quite sure every time I visit, my questions are more or less just a target for pros to take aim at and try to shoot holes through. We have reg with a Vdelta in of 450V and 20mA out. They would not make them and sell them if they would not work....

 

[mneary]

OK, what is your input voltage range? I tried using my crystal ball with the numbers that you did provide and I guessed wrong. If it is not 5-125V then were those numbers given as a diversion? And now, you mention 450V. Is that related to the device that you're seeking?

And what is your output current? I guessed 1A which obviously is wrong because now you say 20mA. Maybe it is some other number. Enlighten us.

When looking for a LDO regulator, the input voltage range and maximum current are paramount. You have given many numbers, none of which are useful. Do you not know how to define a regulator?

[edit - I see your title says you want 5-100Vin, 1A out, which means that it would be a whopping 5% efficient instead of the 4% that I said earlier, and would only dissipate 95 watts. I regret the error.]

The part that you need may very well exist but you won't find it by providing random numbers that are not related to your requirement.

 

[Gary B]

To get what you want, I think you are going to have to cook your own. To get the range you want, you will need a SCR phase control preregulator followed by a final regulator.

 

[canadaelk]

Supertex has a device (LR745) Vin 10-450, Vout 10 V at 4mA. They may have other parts too. Check their app. note AN-D17 for guidance. E