I'm new to all this. I'm trying to design a power supply. I need 3.3v, 5v and 170v outputs.

power supply

Does this look OK? Are there any issue I need to fix? Is there any advice you can give?


Ok, based on the comments I've come up with this, based on this:

enter image description here

  • \$\begingroup\$ give more details.....What is the input voltage....why 170V required.this looks odd...what application? what are the current requiremts of rails.... \$\endgroup\$
    – user19579
    Commented May 9, 2014 at 4:48
  • \$\begingroup\$ 12V input. 170V to drive some nixies. This will will plug into another board at the jumpers, haven't gotten that far yet. I'm hoping to figure this out slowly. \$\endgroup\$
    – Justin808
    Commented May 9, 2014 at 4:52
  • 8
    \$\begingroup\$ I'd hesitate to use a 555 timer as a boost controller. Why not use an actual boost controller? Also, depending on Vin, you may have power dissipation issues with the linear regulators. Inrush current may be a problem. If the boost starts while the inrush current has the inductor in saturation the FET will likely blow. Often a diode is placed across the boost inductor to prevent that from happening. \$\endgroup\$
    – John D
    Commented May 9, 2014 at 5:05
  • \$\begingroup\$ For further input you'll have to let us know the range of Vin, and the load current you expect to draw from each of the supplies. It looks like your 555 boost circuit is using a VBE drop as the reference, so your high voltage will move with temperature. Hard to tell what the loop stability will be like or how you would compensate it if it's a problem. A feedforward cap across the top resistor in the feedback divider might help, but using a part that is designed to be a boost controller would help even more... \$\endgroup\$
    – John D
    Commented May 9, 2014 at 16:08
  • \$\begingroup\$ What's going on with the D2/Q1 FET driver circuit? Is that from the reference datasheet? Is daisy-chaining the LDOs a good idea? What is the current requirement, anyway? \$\endgroup\$
    – pjc50
    Commented Feb 23, 2015 at 11:53

1 Answer 1


No problem for 3.3V and 5V but Its really very difficult to achieve 170VDC cause current requirement is unknown.Ya it is always fine to use boost regulator with required specification as more options are available. thank you.


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