On 06/01/2022 02:31, Phil Hobbs wrote:> Artist wrote: >> The driven waveform must be sinusoidal. Purity is not critical. It can >> be somewhat ragged. >> >> A way to detect phase I am considering is to use comparators to >> convert sinewave to square wave, and then detect phase difference in >> the similar way the CD4046 does. The logic would have to be more >> complex than just an exclusive OR gate though, because the XOR adjusts >> phase to 90 degrees. >> >> I have trouble finding a successor to the EOL XR-2206. Suggestions >> would be appreciated. If I do not find one I may have to try self >> excitation. >> > A filtered square wave, or (for fun) a 74HC4017 and some weighted > resistors. We had a thread on that awhile back--2011, it was. The OP > was George Herold. (George? You still out there, man?) > > <https://groups.google.com/g/sci.electronics.design/c/sZWMknd6yjw/m/8HdJPZFUriAJ> > > > Cheers > > Phil Hobbs >It sounds like the product is not very cost-sensitive. There are pretty cheap DDS chips these days (AD9837 $2), which might solve the problem of generating the waveform well. Something like the AD5933, AD5934 could also measure the impedance of the transducer and a micro could use this for adjusting the tuning. This is what I would do.
Crystal Controlled Oscillator
Started by ●January 3, 2022
Reply by ●January 10, 20222022-01-10
Reply by ●January 10, 20222022-01-10
Chris Jones wrote:> On 06/01/2022 02:31, Phil Hobbs wrote: >> Artist wrote: >>> The driven waveform must be sinusoidal. Purity is not critical. It >>> can be somewhat ragged. >>> >>> A way to detect phase I am considering is to use comparators to >>> convert sinewave to square wave, and then detect phase difference in >>> the similar way the CD4046 does. The logic would have to be more >>> complex than just an exclusive OR gate though, because the XOR >>> adjusts phase to 90 degrees. >>> >>> I have trouble finding a successor to the EOL XR-2206. Suggestions >>> would be appreciated. If I do not find one I may have to try self >>> excitation. >>> >> A filtered square wave, or (for fun) a 74HC4017 and some weighted >> resistors. We had a thread on that awhile back--2011, it was. The OP >> was George Herold. (George? You still out there, man?) >> >> <https://groups.google.com/g/sci.electronics.design/c/sZWMknd6yjw/m/8HdJPZFUriAJ>> > It sounds like the product is not very cost-sensitive. > > There are pretty cheap DDS chips these days (AD9837 $2), which might > solve the problem of generating the waveform well. > > Something like the AD5933, AD5934 could also measure the impedance of > the transducer and a micro could use this for adjusting the tuning. This > is what I would do. > >I suspect that the technological impedance mismatch might be a bit of an issue--the previous version used an XR2206! (Nice part though.) Cheers Phil Hobbs -- Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC / Hobbs ElectroOptics Optics, Electro-optics, Photonics, Analog Electronics Briarcliff Manor NY 10510 http://electrooptical.net http://hobbs-eo.com
Reply by ●January 10, 20222022-01-10
On Fri, 7 Jan 2022 18:04:58 -0800, Artist <sepflanze@sj.gmail.com> wrote:>Why not a circuit similar to this self excited one used for the muRata >piezoelectric microblower: > >https://www.mouser.com/pdfdocs/MurataMicroblowerDriverInfo.pdf > >? > >The op amp I would use instead is the OPA552P. It is known this has the >bandwidth, and the output power, to do the job. I would, therefore, not >need the buffering transistors. > >To determine a compensation network I recognize I will need to >characterize the piezo electric actuator either with a resistor, and a >function generator, or a network analyzer if we have one. It may be that >it won't need one due to there being no buffering transistors.If the resonant load has a reasonable Q, you could drive it with a square wave in a self-oscillating circuit. One simple IC and a few passives might do it. -- If a man will begin with certainties, he shall end with doubts, but if he will be content to begin with doubts he shall end in certainties. Francis Bacon
Reply by ●January 10, 20222022-01-10
On Tuesday, January 11, 2022 at 6:09:08 AM UTC+11, John Larkin wrote:> On Fri, 7 Jan 2022 18:04:58 -0800, Artist <sepf...@sj.gmail.com> > wrote: > >Why not a circuit similar to this self excited one used for the muRata > >piezoelectric microblower: > > > >https://www.mouser.com/pdfdocs/MurataMicroblowerDriverInfo.pdf > >The op amp I would use instead is the OPA552P. It is known this has the > >bandwidth, and the output power, to do the job. I would, therefore, not > >need the buffering transistors. > > > >To determine a compensation network I recognize I will need to > >characterize the piezo electric actuator either with a resistor, and a > >function generator, or a network analyzer if we have one. It may be that > >it won't need one due to there being no buffering transistors. > > If the resonant load has a reasonable Q, you could drive it with a square wave in a self-oscillating circuit. One simple IC and a few passives might do it.A "modifed sine wave" would be almost as simple and would get rid of the third harmonic component. The OP didn't like that idea ether. His actuator produces a optical scan, and he'd prefer that it generated a smooth scan, but he's not up to specifying how smooth a scan he might need, and he clearly isn't up to monitoring how smooth it might be. -- Bill Sloman, Sydney
