help on 48v power supply?

[buts101]

i need 48v suppy for dtmf telephone for operating it..but i've only power supply of maximum 30v..plz tell me..is it possible to use two power supply of 30v to get 48v...or if you have other ideas to get 48v??

 

[Ante]

Do you have a schematic for the 30 V power supply that you’ve got already?
How much current do you need at 48 Volts?

 

[echo47]

Be sure you understand how telephone works. Applying 48V to DTMF circuit would probably destroy it.
http://www.egyed.com/faq/phonework.html

 

[aibelectronics]

48 volts? wow that's high! I don't know any transformer of that rating, and it looks as if you'll have to construct a transformer. Much easier.

 

[Baljeet]

hi,
you can use dc-dc step up chopper circuit.

bye

 

[carrier]

you want to use the 30 volt power or need a schematic?

 

[echo47]

Most DC power supplies are designed to allow series connection, but some need a little help, such as installing a reverse diode across its output. That prevents possibly harmful reverse current from flowing through the power supply in case you don't power them up or down exactly simultaneously. Check the owner's manual for recommendations.

 

[eng_ahmed22]

i think if want to apply the 48 VDC to a DTMF phone u should sure that that phone is (On Hock)
becouse when the phone is connected to the CO lines, once the phone become Off hock, the CO remove the 48 VDC and apply only ~12 or ~9 VDC.
i think it will be harm for your phone if u applied the 48 VDC directly to The Phone.
take care

 

[funster]

you'd better to use a DC-DC converter to convert 30V voltage to

48 V voltage.

best regards

i need 48v suppy for dtmf telephone for operating it..but i've only power supply of maximum 30v..plz tell me..is it possible to use two power supply of 30v to get 48v...or if you have other ideas to get 48v??

 

[platonas]

What is the purpose of the 48V supply? Is it to simulate the Telecomms' line voltage and have your phone connected on it?
If so, 30v can do the job (on some phones the can not work but 90% are OK).
You also need series resistors with your supply in order to allow the high voltage (30v) to drop to about 8-12v when your phone is off-hook.
In fact, is not 48 or 30 v that you need to operate the phone but something around 9 to 12 volts.

 

[satya_vijayawada]

hai
you need, to the convert the 30Vdc Power supply in to 48V Power supply.(with out change the transformer).
which type power supply you can use( liner OR smps).????

I think your using liner power supply.
send me PM full details and i will give the circuit diagram and other details.

satya