Blog - All Comments

RE: Integrated Design of Buck-Boost Regulator #2

jc2048 — Sun, 23 Feb 2020 23:00:49 GMT

Thanks for an interesting blog to read. It's neat seeing you doing your own design.

And now I understand what you were doing. I was a bit confused in the first blog by your calling it 'buck-boost'. I think I'd call this one a 'buck-or-boost' converter, rather than a 'buck-boost', not that it particularly matters [there seems to be quite a lot of confusion generally as to what it should be called, anyhow].

Have you been able to test to see what effect a step change of the load on the output has? It would be good to see some waveforms if you have access to an oscilloscope. That would give anyone who wanted to build one confidence that your control code was doing its job.

RE: Temperature-Dependent Characterization of Inductors 2 / 2

14rhb — Tue, 18 Feb 2020 21:51:29 GMT

Hi [mention:050549436bd64f50a71d3db7750d1220:e9ed411860ed4f2ba0265705b8793d05] ,

What a fantastic blog exploring far beyond the normal for inductors. A very well conducted experiment which I found very informative due to all the detail you've worked into it.

RE: Inductor Modeling and Simulation - Experimenting with Inductors - Part 2 of 2

14rhb — Tue, 18 Feb 2020 19:33:38 GMT

What a great and informative blog post on the seemingly 'humble' inductor - well done [View:/resized-image/__size/16x16/__key/commentfiles/f7d226abd59f475c9d224a79e3f0ec07-85772664-7865-4b35-8752-1243387e3de6/contentimage_5F00_1.png:16:16]

I love the graphical style of your blog as well as the actual technical content.

RE: Choosing the correct Inductor for a DC-DC step-up regulator - Part 3

weiwei2 — Tue, 18 Feb 2020 07:49:59 GMT

very interesting to do and measure own inductor. i am incline to do some simulation on them [View:/resized-image/__size/16x16/__key/commentfiles/f7d226abd59f475c9d224a79e3f0ec07-fd329e32-656c-4aac-a124-160c8d8efbf6/contentimage_5F00_1.png:16:16]

i used to see my father wind his own transformer in my younger days, back then (and i believe probably up to today), many electrician will need to make custom transformer for repair or customization purpose on the facility they maintain

the transformer has many similarity to inductor although i am far from being an expert in it

RE: Choosing the correct Inductor for a DC-DC step-up regulator - Part 3

shabaz — Tue, 18 Feb 2020 00:12:30 GMT

Hi Gene,

Awesome to see the self-wound inductor comparison. It can give excellent results, but as you suggest, home production rates of them can be low!

It's a great trick to pre-wind thick wire - I'll have to remember that.

I've still got an antenna project in-progress, in that case, the inductor 'wire' is copper pipe hehe. I don't have a tool for that, but fortunately found a supplier who sells that pre-shaped.

RE: Choosing the correct Inductor for a DC-DC step-up regulator - Part 3

three-phase — Mon, 17 Feb 2020 21:45:29 GMT

Very interesting blog, well done Gene.

Kind regards

RE: Choosing the correct Inductor for a DC-DC step-up regulator - Part 3

jw0752 — Mon, 17 Feb 2020 19:12:58 GMT

Hi Gene,

I liked that you took things one step further and wound your own inductor. There is always a lot to learn from getting involved with a part at as basic a level as possible.

John

RE: Choosing the correct Inductor for a DC-DC step-up regulator - Part 3

Andrew J — Mon, 17 Feb 2020 17:51:05 GMT

The hand wound inductor seems to perform pretty well. IIRC, your DC-DC regulator is fixed voltage output isn't it, controlled by jumper setting, so it's not possible to a load voltage change? There's not a lot of drooping/rising at the switch points in the graphs above - a bit more in the 1uH which takes longer to recover but not a lot in it. I think in your last post you said you would choose a 2.0uH or 3.3uH inductor in future and it looks like that would be a good trade off on ripple and transient change.

I've found this whole subject area of Inductors, regulators, switchers, capacitors, MOSFETs etc absolutely fascinating - infuriating at times, but fascinating. Thanks for doing these experiments, they have been really interesting to follow.

RE: Choosing the correct Inductor for a DC-DC step-up regulator - Part 2

Andrew J — Sat, 15 Feb 2020 22:38:34 GMT

Great work Gene, there’s some useful testing and data here. The specification (or should I say generalisation??) that relates induction size to ripple is ok as far as it goes - I think your test data shows that it is as much related to load as it is to size. You may find that reaction to transient changes in load also affects choice: that was something I could never quantify as I didn’t (still don’t) have the test tools, but I think a larger inductance leads to slower reaction to transient changes.

RE: Choosing the correct Inductor for a DC-DC step-up regulator - Part 2

jc2048 — Sat, 15 Feb 2020 16:12:18 GMT

That's an impressive amount of work you've done there and some interesting results to dig through.

Having the second MOSFET in place of the rectifier is new to me. I've used synchronous buck converters, but hadn't realised manufacturers were now doing this kind of thing with boost converters to improve the efficiency [which shows how out of touch with things it's possible to get in just a few years.]

I think those are the best hand-made probe sockets I've ever seen. Mine are really scrappy by comparison.

RE: Integrated Design of Buck-Boost Regulator #1

jc2048 — Sat, 15 Feb 2020 10:32:59 GMT

Ambitious project with all the datalogging and everything. Good luck with it.

You've got a small typo on the circuit. For a positive supply the output is negative, as you show with your equation and waveforms, so I think the + and - on the load resistor need to be swapped.

RE: Experiment With Inductor : RF Harvesting

three-phase — Tue, 11 Feb 2020 19:51:13 GMT

You are only using a half-wave rectifier in your circuit, would you not be able to harvest more power by switching to full-wave rectification? Good luck with your experiments.

Kind regards

RE: Inductor Modeling & Simulation - Experimenting with Inductors - Blog 1 of 2

three-phase — Tue, 11 Feb 2020 19:46:54 GMT

A very well written introduction, good luck with your experiments.

Kind regards

RE: Experiment With Inductor : RF Harvesting

dubbie — Tue, 11 Feb 2020 11:23:19 GMT

It will be interesting to see what you can achieve with this arrangement. My experience with energy harvesting was that the amount of energy captured was so small that the analogue side of the electronics had to be really good. Being a mostly digital/microprocessor person I was just not able to make it work. I hope you do better.

Dubbie

RE: The Crazy Inductor Learn-o-Nator Put to Use: Experimenting with Inductors Blog 2 of 2

shabaz — Fri, 07 Feb 2020 12:08:26 GMT

Hi Sean,

This is great to see the prototyping pre-PCB! The TI tool is awesome.

One small point (it doesn't detract from your conclusions which are right), the chart from the Oki part although it has the 78.. prefix, is a switching regulator, so easy to miss - I only know it because I've used that part previously and recognised the number.

The chart for linear regulators will look worse the higher the input voltage, since more power is being dissipated in the regulator versus the load. In other words, it will be high efficiency when the input voltage is close to the output voltage (there's the dropout voltage as the minimum difference), but will drop loads as the input voltage gets higher. Sometimes it's not bad (e.g. if the overall power consumption is low anyway, then efficiency might be less of a requirement, even though it is still inefficient, i.e. depends on the use-case) but often it's bad!