Schematics attached. The main issue I'm having is when powered via USB, everything works fine. When powered via a 12V car battery, the chips seem to not have enough power. There are two comparator circuits, one to monitor USB/Batt and report how the unit is being powered. The 2nd actually provides the power. One chip will occasionally draw ~150-400ma of power causing the board to lock up. Chips are powered via Vin.
What I don't understand is why everything works perfectly on USB but has issues when powered via 12V. On Tue, Feb 26, 2019 at 11:53 AM <ch...@wbmfg.com> wrote: > Circle of stability, miller capacitance all good stuff. > > *From:* Mark Radabaugh > *Sent:* Tuesday, February 26, 2019 9:48 AM > *To:* AnimalFarm Microwave Users Group > *Subject:* Re: [AFMUG] OT: EE Consultant > > Oh sure, now you probably want me to believe transistors have states other > than off and on. > > Mark > > On Feb 26, 2019, at 11:20 AM, Ken Hohhof <af...@kwisp.com> wrote: > > > And good luck finding an analog circuit guy anymore ;-) > > That’s what I was. Not much demand, that’s why I’ve been doing other > things for over 20 years. Actually made the switch to engineering > management in the 80’s but still did some design work for another 10 years > because all the engineers wanted to do digital and processor designs. I > still have the books, the brain is rusty though. > > I tried to convince the new engineers that high speed digital design meant > knowing analog, RF and microstrip techniques, but they weren’t buying it. > Getting their products through regulatory emissions testing did give them a > bit of religion. > > I still remember laying out PCBs using red and blue tape. > > *From:* AF <af-boun...@af.afmug.com> *On Behalf Of *Mark Radabaugh > *Sent:* Tuesday, February 26, 2019 9:09 AM > *To:* AnimalFarm Microwave Users Group <af@af.afmug.com> > *Subject:* Re: [AFMUG] OT: EE Consultant > > Yep - I’m qualified to answer some things and would be totally lost on > others. EE has become a huge field with many many disciplines. > > And good luck finding an analog circuit guy anymore ;-) > > Mark > > > On Feb 26, 2019, at 9:56 AM, Ken Hohhof <af...@kwisp.com> wrote: > > Analog? Digital? Even with those there tend to be specialties like > emissions, safety, PLD/ASIC design, microprocessor/microcontroller, RF, > etc. Or do you need a generalist? > > *From:* AF <af-boun...@af.afmug.com> *On Behalf Of * > can...@believewireless.net > *Sent:* Tuesday, February 26, 2019 8:33 AM > *To:* AnimalFarm Microwave Users Group <af@af.afmug.com> > *Subject:* [AFMUG] OT: EE Consultant > > Having an issue with a circuit design, anyone know a good electrical > engineer they can > recommend? > -- > AF mailing list > AF@af.afmug.com > http://af.afmug.com/mailman/listinfo/af_af.afmug.com > > > -- > AF mailing list > AF@af.afmug.com > http://af.afmug.com/mailman/listinfo/af_af.afmug.com > > > > ------------------------------ > -- > AF mailing list > AF@af.afmug.com > http://af.afmug.com/mailman/listinfo/af_af.afmug.com > > -- > AF mailing list > AF@af.afmug.com > http://af.afmug.com/mailman/listinfo/af_af.afmug.com >
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