DC-DC 50W Isolator (or Transformer )
DC-DC 50W Isolator (or Transformer )
(OP)
Hi
I want to design a DC-DC isolator with the following spoiec
Input voltage 24-48V DC
Input Current : 0-2A
Power : Approx 50W
Output voltage : 24-48V
Output Current 0-2A
Output Power :Approx 50W
Efficiency : about 90%
Isolation : Input isolated from Output
Control : No control of the duty Cycle required- Fixed Duty Cycle
Application : This module will be used to isolate the Input DC supply from the Output DC supply . Deos anyone know where I could find a suitable reference design or can suggest a suitable DC-DC converter design i could use ? Basically is it is a 1:1 DC-DC Isolation Transformer .
I want to design a DC-DC isolator with the following spoiec
Input voltage 24-48V DC
Input Current : 0-2A
Power : Approx 50W
Output voltage : 24-48V
Output Current 0-2A
Output Power :Approx 50W
Efficiency : about 90%
Isolation : Input isolated from Output
Control : No control of the duty Cycle required- Fixed Duty Cycle
Application : This module will be used to isolate the Input DC supply from the Output DC supply . Deos anyone know where I could find a suitable reference design or can suggest a suitable DC-DC converter design i could use ? Basically is it is a 1:1 DC-DC Isolation Transformer .





RE: DC-DC 50W Isolator (or Transformer )
TTFN
FAQ731-376: Eng-Tips.com Forum Policies
RE: DC-DC 50W Isolator (or Transformer )
RE: DC-DC 50W Isolator (or Transformer )
That defines regulation; not good regulation, but regulation nonetheless.
TTFN
FAQ731-376: Eng-Tips.com Forum Policies
RE: DC-DC 50W Isolator (or Transformer )
RE: DC-DC 50W Isolator (or Transformer )
RE: DC-DC 50W Isolator (or Transformer )
You proposed Push/Pull . Why did you choose push/pull ? Would a Two transistor forward coverter be easier to control and have simpler magnetics ?
Does the push pull have advantages over the forward converter for trhis application ?
RE: DC-DC 50W Isolator (or Transformer )
Yes it has advantages. Doesn't DC saturate the magnetics for one. Better efficiency, lots of other things going for it, too.
Gunnar Englund
www.gke.org
--------------------------------------
Half full - Half empty? I don't mind. It's what in it that counts.
RE: DC-DC 50W Isolator (or Transformer )
Here's a few tips to make it work:
* turns-ratio slightly higher that 1:1 to make up for the diode drops.
* 50% duty on each half. Use a dual-output switching regulator IC and ramp up the soft start enough to avoid over current at start up, but set the feedback pin low so it goes to full duty.
* small inductor at the center tap to avoid high cross coupling spikes and to keep the currents from being too trapezoidal.
* Do a quick model in spice and you'll see the waveforms of current I'm referring to above.
RE: DC-DC 50W Isolator (or Transformer )
RE: DC-DC 50W Isolator (or Transformer )
Make up your mind. Either it tracks or the duty cycle varies. The reasons for push pull are even more so.
RE: DC-DC 50W Isolator (or Transformer )
Thank you for your comments
The input will be suppleid from a current source . The output is connected to a constant voltage load . The input /output voltage ratio of the isolator will be fixed ( 50% duty cycle + transformer ratio) .Therefore the input to the islator module will look like a constant voltage load to the circuit driving the input . If the input /output voltage ratio of the Isolator Module is 1 then the input voltage will adjust to be the same as the output voltage .Do you see any issues with this ?
RE: DC-DC 50W Isolator (or Transformer )