Jump to content
Electronics-Lab.com Community

Digitally controller PSU

Recommended Posts

To have a 35VDC regulated output, the circuit needs a 30VAC transformer. 30 x 1.414= 42.4V peak, minus 2V for the rectifier bridge and minus 1V of ripple in the filter capacitor = 39.4V unregulated.

If you power a 5VDC/4A regulator from unregulated 39.4V then the heat in the series pass transistor is (39.4V - 5V) x 4A= 138W. Two power transistors on a huge heatsink is needed.

If you have an adjustable output voltage supply going down to 0V (maybe when shorted) then its series pass transistor will heat with 39.4V x 3A= 118.2W and will need two power transistors on a huge heatsink.
The negative adustable output voltage supply will need the same.

If you have a 24VDC/5A supply then its series pass transistor will heat with (39.4V - 24V) x 5A= 77W and will need one or two power transistors on a huge heatsink.

The above totals 15A. The transformer should be rated at the peak voltage of 42.4V x 15A= 636VA.

If all the power is used at the outputs of this supply then you can heat your entire neighbourhood with it! It will be enormous! It will be expensive!

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.


  • Create New...