What inductor to use for boost circuit? - Page 1
Forum section: electronics / beginners

author: j209177
author_rank: Newbie
timestamp: December 18, 2017, 01:09:56 am
content: I am making a nixie tube watch.I need to use a small height inductor than the one this guy used, and i need a max Current Rating of 700ma.https://www.digikey.com/products/en?keywords=RLB9012-101KL-ND-- The one he usedhttps://threeneurons.wordpress.com/nixie-power-supply/hv-supply-kit/-- the kit and schematic he madethis is the inductor the guy uses but it is large and it has a 1.4A max ratingcould i use something like thishttps://www.digikey.com/product-detail/en/bourns-inc/SDR1006-101KL/SDR1006-101KLCT-ND/2127203is there something i missed?

author: Cliff Matthews
author_rank: Unknown
timestamp: December 18, 2017, 01:44:48 am
content: I'm not an engineer, but to make things smaller, try another switching regulator than the MC34063. Higher frequency = smaller size.* Edit: Someone here (Tim?) posted this a while ago on the forum..Suggested alternatives:Boost or flyback, offline under 100W:- UC3842 series, TOPSwitch, FPS, etc. Buck or forward, offline over 100W: - TL494, UC3524, etc.Buck, DC-DC, external switch:- LM5085, TLE6389, LTC3824, LTC3810, etc.Internal switch:- TPS54231, LM2675, LM5008, etc. There are many to choose from, and you will save greatly on the cost of other components.One of these chips may cost $1-3, but they all use much smaller support components. The huge caps and choke looming in the picture will cost more in total, plus board area. Plus, these newer chips are easier to use. And these are just a few excellent options for the most common uses.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: December 18, 2017, 05:56:59 am
content: Yes, that inductor is probably about right. Mind that it's SMT, so you need some pads to solder it onto (or tack some pigtails onto it, so you can shove it into a board).Quote from: Cliff Matthews on December 18, 2017, 01:44:48 amYes.But hey, at least it's current sensing at all, and not the stupid circuit that's open loop, with a 555 or MCU (uch) generating the square wave!Tim

author: j209177
author_rank: Newbie
timestamp: December 19, 2017, 12:31:00 am
content: Quote from: Cliff Matthews on December 18, 2017, 01:44:48 amI did not know about frequency and size.but i would like to stick with the MC34063 for now.Quote from: T3sl4co1l on December 18, 2017, 05:56:59 amI am aware of the smd nature of the device i am wouried about the Frequency - Self Resonan, Q @ Freq, Frequency - Test and ect. What are these things and do i need to worry about them.Quote from: blueskull on December 18, 2017, 06:21:04 amI would like to stick to the MC34063. for No other reason than someody already has desiged the circuit and knows it works, plus the time i have invested in the board layout and the likes. But thank you.The pictures are what i am trying to improve on (because they dont work, for various reason).The first picture is showing the inductor is the thickest component, the rest of them have the wrong footprint (or some else i did wrong), and the tubes would interfere the inductor. thats why i need a smaller one.The Second picture is a top down view. Inductor is the one in the middle.Third picture is the aluminum case i made and the tubes.Thank you all for your response.