Continue to Site

Welcome to our site!

Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.

  • Welcome to our site! Electro Tech is an online community (with over 170,000 members) who enjoy talking about and building electronic circuits, projects and gadgets. To participate you need to register. Registration is free. Click here to register now.

Replacing a old dc-dc converter

Status
Not open for further replies.

mitchjs

New Member
Hi all,

Im trying to repair an old piece of audio gear
it has a DC-DC convertor in it, and encapsulated one

its small, gives me +5v and -8.5v

so im gonna use one that gets me +9 and -9 v out and send the +9 into a 7805

anyway... on the circuit board, the input ground and the output ground are one, does that mean its is UN-ISOLATED?

and if i use an isolated one, and tie the input ground and output 0v together all should be fine?

mitch
 
mitchjs said:
Hi all,

Im trying to repair an old piece of audio gear
it has a DC-DC convertor in it, and encapsulated one

its small, gives me +5v and -8.5v

so im gonna use one that gets me +9 and -9 v out and send the +9 into a 7805

anyway... on the circuit board, the input ground and the output ground are one, does that mean its is UN-ISOLATED?

and if i use an isolated one, and tie the input ground and output 0v together all should be fine?

Yes, that should be fine.

What is the converter used for?, and what is it's input voltage?.
 
well... in one of the cases


there are two parts to this piece of gear (SONY XES-P1)

in the display, the DC-DC converter takes 12V and produces 5V < 50ma to power the logic, ie. Microcontroller, some Sram, and such. The Dc-Dc converter also has a -8.5v out, that goes to a trim pot and the to VEE of the LCD display... so thats just for contrast


so im gonna get a +/- 9V dc-dc converter, and take the +9 and regulate it to 5V with 7805 and -9v is close enough to -8.5v for the contrast VEE


now in the main unit, there is another DC-DC converter, it takes
12V and produces +/- 18V and +/- 8V

the 8v rails go into 7805/7905 combo and get +/- 5V and thats used for logic and -5v to a ADC.
the +/-18v railes go into 7815/7915 combo and power DACs and Op amps for the gears analog outputs

so, my plan was to replace that 1 quad output dc-dc with 2 separate dc dc converters, 1 is +/-5V and 1 +/-15v

and bypass the the existing 7805/7905 & 7815/7915 regulators
since the new dc-dc converted out is regulated

any thoughts?

mitch
 
Status
Not open for further replies.

Latest threads

New Articles From Microcontroller Tips

Back
Top