The Amp Hour

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Natural Sciences
**The Amp Hour**

The Amp Hour is a weekly conversation about electronics and the people who design them.

Latest Episodes:

The Rodeo Drive of Electronics Nov 22, 2021

Show notes

"Time is a (flat) circle"
Dave has been making videos about jellybean components, the latest about references and regulators
PCB requirements
Pricing pressures
There was a fire in the Eurocircuits Hungarian factory. Chris was told about the DFM tool from past guest Joris
Digikey was mentioned in a recent episode of Planet Money talking about the runway in Thief River Falls
Wendover Productions talks about How Ocean Shipping Works
Digikey location on a map
Chris recently took a train to Washington DC
Dave warned Chris about doing electronics on public transport, as someone was recently arrested for messing around with a vintage camera
Adrian Studer from episode 450 makes an AIS receiver
Differential front end for AD2
Analog Discovery Pro
What kind of scope can I get for $30k?
Rochester Electronics
Most expensive component? Molex tool for 1.8M
New part from Renesas, a low logic size FPGA
Shared on Twitter from former guest, Steve Leibson!
Hard logic cores inside of FPGAs? Chris talked with Brian Faith of QuickLogic about this
Dave getting a Digikey catalog in a Swiss Air mail sack
This amazing mechanism:

https://twitter.com/BellTreeNursing/status/1457953376025526280

Sting operation where they manufactured their own smartphones
Cryptonomicon by Neal Stephenson
Thunder Below by Gene Fluckey (recommended on the Smarter Every Day sub series, which was awesome)

Switching Converter Engineering with Carmen Parisi Nov 15, 2021

Show notes

Chris and Carmen have both been co-hosts of The Engineering Commons and both wrote on EngineerBlogs.org
Carmen is a Staff Application Engineer at Renesas, in the division that used to be Intersil
Field Application Engineers (FAE) vs Application Engineer (AE)
The chips Carmen works on help power Intel / AMD processors
AE vs Silicon designer
Regulators
TDP - Total Dissipated Power
Core rail - 200A over short timelines (!)
Intel proprietary bus is called SVID
Multi-phase regulators can have up to 8 buck converters in line
Slewing current is still limited to V = L * dI/dt
AMD processors have proprietary buses called SVI2 or SVI3
Many of these chips provide telemetry (temperatures at various points, current draw, etc)
Carmen doesn't want to make 12 layer eval boards because most customers wouldn't be able to implement that sort of thing
Taller inductors are better
Processors throttling themselves
Battery upstream
Parasitics
DrMOS
Driver is needed to drive MOS with significant current
Voltage vs current mode control
"Virus mode" is a stress test that Intel specs
Performance tuning with digital
PMBus
App notes
People Carmen follows on Signal Integrity Journal
- Steve Sandler
- Eric Bogatin
- Istvan Novak
Past training materials that are easy to find
- SLVA882B - Multiphase Buck Design From Start to Finish (Part 1)
- Power Supply Design Seminar
- Voltage regulator design and optimization for high-current, fast-slew-rate load transients
Carmen has been simulating using Cadence Sigrity
Connect with Carmen on LinkedIn

Here for a reason Nov 08, 2021

Show notes

Great Scott has a new video about synchronous switching converters that was great!
Chris was hanging out with a friend in the chip industry, talking about power converters. Past guests at chip companies
There was a presentation by Werner Johansson about doing a digitally controlled power circuit using Atmel parts
Should Dave be programming in Aussie++? It is now "officially endorsed" by Dave
In Dave's 1024th video, he got really old code working
Raspberry Pi Zero 2 W has been released and is "the most efficient"
Mentoring exercise talking to a student looking to get hired, Chris mentioned the student should get lots of tools in their toolbelt
Dave expanded on us talking about Flux.ai last week in a video on EEVblog2 about tools
Chris is now looking for an engineering laptop, but it really doesn't have to be that different from a normal laptop
The Framework laptop is modular, but how often will you use those features?
Chris has been trying out the Sparkfun Micromod system, but thinks it will have limited usefulness
Are modular standards doomed to fail over the long term? What are some good examples of a truly modular system? PC/104 is an older modular system discussed before (and is still around)

Pavlovian Cheapskates Oct 31, 2021

Show notes

This week Chris recorded a crossover episode with The Macrofab Engineering podcast to celebrate their 300th episode! Congrats to them for the achievement! We’re glad to have other fun podcasts in the space!

For a selection of notes on the episode, check out the MEP300 page

You can watch the episode recording here: https://www.twitch.tv/videos/1187912406

Grumpy Collaboration Oct 25, 2021

Show notes

CM4 vs CM4-Lite
The connector for a board implementing a CM4 is the Hirose DF40C-100DS-0.4V(51). Unsurprisingly, these are very hard to find right now.
Complaints
There is a new site for commercial Raspberry Pi stuff (now a .com domain)
Apex Electronics in LA
Tempo Automation is going public via SPAC
Flux (a new online CAD tool) raised $12M
This seems similar to Upverter, which was acquired by Altium and is still around in a slightly modified form
Advanced designs
Collaborative design work
KiCad lost control of the kicad-pcb [dot] org domain name when it was sold by a former team member, everything should be directed to KiCad.org
Dave insists that Wordstar pioneered the use of ctrl+c, ctrl+v
Acrylic vs Silicone conformal coat
Dave is looking at building his own microphone pre-amp using the THAT432 0, an analog front end chip for audio systems

Thanks to freesvg.com for the Grumpy Cat image

Electroboom! Oct 18, 2021

Show notes

Mehdi Sadaghdar from the Electroboom Youtube channel joins Dave to talk about his hobby and professional background, and how he got started in Youtubing. Along with moving to Canada, the Iranian hobby movement, Maker spaces, commercial spaces, Linus Tech Tips and the infamous conflict between practical engineering and theoretical physics in electricity vs magnetism in his stoush with Professor Walter Lewin

Assembly Chat Oct 11, 2021

Show notes

Chris didn’t take any notes this week because he was busy assembling. Here are some guesses at the links:

See links on The Amp Hour subreddit for anything discussed from there

High End Audio with Remco Stoutjesdijk Oct 04, 2021

Show notes

Welcome Remco Stoutjesdijk of ItsOnlyAudio.com!

Remco calls himself a "recovering audiophile"
Why didn't we stop trying to improve audio setups in the 70s?
Remco started with vacuum tubes but moved into silicon at Wolfson Micro. He got his first job by writing a letter asking if they needed anyone and his hobby projects helped to place him into special projects group.
"If you work in hardware you play with simulators. If you work in software, you play with hardware". This is why he moved into applications.
For a little while, he worked at Rohm Semi on LEDs
Back into audio with ASK industries, who make hardware that is used in stereo setups for cars that are branded with Bang & Olafsson and Burmester.
Differences between car and home
- Extreme conditions, like Audi running a 36 hour "sun test"
- Fixed acoustic environment
One thing they did was to develop a tuning tool for the end brand (ie. B&O) to tweak with their experts
Big things they were working on was outside noise cancellation and engine noise cancellation
However, not all sound is bad. "Putting the car in 'sport mode' pumps more sound into the cabin"
They're really trying to find the acoustic transfer function (of say, the engine) to reverse any impact it has on the listener's ears.
Unwanted noise is first put through a filter. Then they have to apply filter before sound arrives.
An example transform is a Levinson-Durbin recursion
Active Noise Control (ANC) isn't really "cancellation"
It's important to think about the stability, since it's a control system
Often they're looking for the lambda coefficient
After going out on his own, Remco and his family moved to Poland. Polish is a difficult language to learn. It's on a remote branch of the "tree of languages" (which show the inheritance of different languages and the other languages they're based upon)
Poland has a growing tech scene
Past guests Jan Rychter and Michael Gielda from Ant Micro (and most of the team) are based in Poland, though in different areas. "7Sensing" is another dev shop out there.
Remco is now consulting via ItsOnlyAudio.com and is a member of the Consulting forum (apply here if interested in joining).
When not working on client projects, he is building up IP library and bringing demos to audio shows
ADI Sharc DSP
Shannon Parks episode
Tools of the trade for doing audio on chips
- CMSIS DSP library
- Components of that library
  - Biquad filter
  - DMA buffers
  - Ring buffers
Loudness war website
Push to custom silicon are necessary for super phase sensitive items
PTP - Precision Time Protocol based on UDP
Chris wondered if Disney World does something like this to synchronize speakers throughout the park? BoingBoing article
Dunte protocol
AVB
Audio ecosystem is fairly small, though there are some startups now
Modern audio need to tie into Alexa / Google / Apple for streaming
OCA - open control alliance (warning: autoplay audio??)
Signal processing / fidelity is as good as it can get, wow we need to improve playback environment
Improving noise comfort for loud urban environment
Chris and Remco have both used binaural beats to try and drown out sound in the past
Find Remco online
- His website
- His YouTube