HELP - DC45V to DC30V voltage regulator

[nene81]

Hello,

I ´m new in the forum! I´m spanish.

I have a question about voltage regulators.
I need help with chips or boards.

I have a rectifier board with voltaje out @DC45V.
Can I convert the DC45V to DC30V though a circuit?
I´ve been looking at the LM317, but the max. voltage input is 40V.

On the other hand, alternatively,
I have a toroidal transformer @AC230V to AC30V.
Can I convert the AC30V to AC21V though a circuit?

I´ve been looking at Ebay, and I´ve found this item, but I don´t know if it will work:
DC to DC AC to AC Converter Board Step Down Voltage Regulator Module 12-48V New | eBay

Please, help me.

Thanks!

 

[woody]

Depending on how much current you need the TL783c might work out for you. It is much like the LM317T but with a voltage rating of 125v and a .7A max output current.

 

[Minion]

the LM317 will work to regulate 45v down to 30v ..... the 40v for the lm317 is the Voltage Differential not the max input voltage .....

 

[nene81]

Hello,

Thank you very much Woody and Minion.

I've been checking the items LM317 and LM317T.
LM317 provides a maximum current of 1.5A

My rectifier has a dual output DC45V-0V-45V (100W).
I need an output DC30V-0V-30V and ~3.15A
(LM parts >4A for safety).

I´ve though to use this units:
LM338 (5A) (1 for each 30V)
- Reference Voltage 3V < (Vin - Vout) < 35V
- Current Limit at 15V@25ºC provides 5A

What do you think?


Alternatively, I would like to make this circuit:

10 Amp Regulated Power Supply Circuit​

But LM107 is obsolete, and I don't find an equivalent part.

LM107 ~~ LM318 for this circuit?

thank you very much.