July 25, 2023

#640 – Software Defined Power Supplies with Werner Johansson

1 hour 11 minutes

Welcome Werner Johansson of Qoitech!

Chris and Werner met when Werner gave a talk at HDDG in 2017

The talk focused on Xmega parts, which have a 2 Msps ADC

Qoitech is a Sony spinoff, where Werner was working on testing batteries on the cellphones.He had previously also worked on automation during linux mainline work.

Serial port control is an important thing when doing automated testing

CDB assist

PSOC5-LP has a CPLD in it

The Otii Arc was the first product from Qoitech, it’s a 2 quandrant power supply. They started in 2015/2016.

Chris asked if Werner had previously had used the Keithley 2306

Field testing is an imporant area for the Otii product line. “Measuremenets on the go” are easier with the extruded case form factor.

No computer will give you USB PD output power of more than 15W. Test equipment would benefit from a full 200W

Analyzer (Twinkie?)

A hub might be possible

USB Extended Power Range (EPR) will allow 240W

Are you sure you should plug that into your computer? Reminder about the OMG cable discussed on the show with MG

New EPR at 48V has specific shape for arcing

When designing a power supply for tattoo machine, it could only weigh half the weight of the cable (64g)

Software defined buck boost was discussed on CNLohr episode

Digital control is easier to get stable than analog because of programmable delays in the pipeline. You need to measure how long it takes to get the output to “show up”

Audio project real time jam sessions

The new product from Qoitech (that Chris got to see at Embedded World in 2023) is the Otii Ace

PJRC convinced Werner to check out the NXP RT106x family (instead of RT105x)

Otii is working on battery stuff

Arc has been out since 2017, but was limited output voltages 500 mv – 5V

Ace came out recently and goes up to 25V at 5A

3 isolation domains in Ace – chassis, banana jacks, expansion ports

Want resistor on low side for coloumb counter

Can stack Aces up to 200V

Dealing with RFI when different domains

Increased sample rate

8 simultaneous sampled ADCs

Turns readings into audio signals for RT1060, which allows data to stream easier

There is one reference voltage driving everything in the design, they send frequency spike across gaps to all isolated sections using RF isolators

Hard time getting the RT1060 parts during shortage

Battery stuff

Stepping through the battery internal resistance

Edging into the world of SMUs

Building a curve

Replaying battery data

Battery emulation

Continuous integration testing

Syncing to firmware

Battery aging

Devices running on coin cells

Cycling and automated testing and see it degrade over time

Thinking of batteries as impedance devices

Batteries having a passivation layer

“Low power” means different things to different people

Teardown of battery emulator

Low power is less than 200W

Qoitech equipment has been used in testing and production, including “in-the-loop” testing

“Generational degrade” when using previous versions of the product to validate new versions of the product. Instead they have a NIST traceable DMM in the loop

Chris mentions ever calibration shop has a Fluke calibrator. Apparently the HP 8753 wasn’t available in EU because of RoHS.

To learn more about Werner and the Qoitech team, check out the Otii Ace page

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By The Amp Hour (Chris Gammell and David L Jones)

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