| Electronics > Projects, Designs, and Technical Stuff |
| To Double or not to double? |
| (1/2) > >> |
| NivagSwerdna:
I built myself a 35V Boost regulator but have discovered I would really be much better off with 70V... I came across this (from Pile o Poo)... Now my boost regulator looks very much like... i.e. it has an inductor and a diode and a mosfet switch.... So with 2 Capacitors and 2 Diodes I could get my 35V to 70? I need around 3W... i.e. 50mA at 70V Or should I go back to the drawing board and design a 70V regulator? Thanks in advance |
| james_s:
Can you not just make a few tweaks to the inductor size and feedback loop to get 70V? Boost converters often give you quite a bit of wiggle room. |
| MagicSmoker:
--- Quote from: NivagSwerdna on July 17, 2019, 03:46:31 pm ---I built myself a 35V Boost regulator but have discovered I would really be much better off with 70V... ... I need around 3W... i.e. 50mA at 70V --- End quote --- You can do this easily enough with a boost, and you can use your existing circuit if you change the feedback resistor ratio, the timing capacitor value and the boost inductor. See OnSemi AN920 for a comprehensive explanation of how to do the above. Oh, and be wary of saddling the FB pin with too much capacitance - the '34063 is a hysteretic controller and does not need frequency compensation, so adding a capacitor to the FB pin just slows down its response to voltage over/undershoot. That said, 47-100pF on the FB can help suppress early pulse termination from noise, so don't delete it entirely. |
| SiliconWizard:
http://www.ti.com/product/LM5001 |
| NivagSwerdna:
Sadly I opted for a chip TPS61175 with an inbuilt switch rated at 38V. (I said it was alike not the same :) ) I can redesign but just wondered about the merits and weaknesses of doubling. |
| Navigation |
| Message Index |
| Next page |