For tpa3255 there seems to be additional LC filtering after the 317, but seems to me the opamp inputstage is not after lm317, well will see when people receive these boards.
https://img.alicdn.com/imgextra/i4/90439224/TB2LC4iBxlmpuFjSZPfXXc9iXXa_!!90439224.jpg
https://img.alicdn.com/imgextra/i4/90439224/TB2LC4iBxlmpuFjSZPfXXc9iXXa_!!90439224.jpg
LM2575 operating frequency and tpa3255 outputfilter peaking frequency, currents with 3255 and fullrange chassis speaker could get interesting.
Isn't this information a bit useless without knowing the impedance curve of the cap and the switching frequency + ripple current of the converter?
You can get 100uF with 1R at 100kHz and/or 30mR at 100kHz.. both are 100uF. 😕
What ESR did you assumed within the formula?
It was a seat-of-the-pants guesstimate, so it could indeed be useless. We know the switching freq (52kHz) - why would we need the ripple current? I was assuming that this was an LC after the buck converter - perhaps my assumption's wrong.
I'm interested in the 100uF/16V with 30mohm ESR which isn't a polymer. Link please?
I assumed 1ohm ESR for the 22uF.
You're right mate, it needs to be an aluminium organic polymer formula at minimum to get down to 30mR with this low capacitance at 16V. But if you go for 25V+ and double the capacitance, you can find some from i.e. SunCon (Me-Wa, Me-Wg).
http://www.sunelec.co.jp/eng/catalog/pdf/eME-WG.pdf
http://www.sunelec.co.jp/eng/catalog/pdf/eME-WA.pdf
http://www.sunelec.co.jp/eng/catalog/pdf/eME-WG.pdf
http://www.sunelec.co.jp/eng/catalog/pdf/eME-WA.pdf
http://www.mouser.com/ds/2/315/ABA0000C1163-947466.pdf
C HD would be what I see, not lead free. 7.2 ohm
C HD would be what I see, not lead free. 7.2 ohm
What are trying to say?
Do you refer to the 22uF capacitors? If yes, please make a full sentence for better understanding. 😉
What about "lead free", the Panasonic HD caps are made for lead free reflow.
Do you refer to the 22uF capacitors? If yes, please make a full sentence for better understanding. 😉
What about "lead free", the Panasonic HD caps are made for lead free reflow.
The 22/C HD marked smd capacitors on YJ3255 do not seem to have a dot marking after C HD, datasheet suggests a dot there would be lead free product. But resolution of picture isn't very high, so could even be another capacitor.
Doctormord,
how is this board your showing here differing from what you've done on the 3251 thread? Are the circuits totally different or would the 3251 and 3255 be interchangeable here? Just trying to figure out the difference between your designs.
how is this board your showing here differing from what you've done on the 3251 thread? Are the circuits totally different or would the 3251 and 3255 be interchangeable here? Just trying to figure out the difference between your designs.
Compared to Rev 1.A. it does have an interchangeable analog-frontend and dual supply for the frontend via Flybuck. (+-15V)
The board works for all Akita TPA32XX with thermal-pad up but not the "Boxster" chips like TPA3221.
Compared to the REV 1.A it is meant to be used with PFFB at all times.
Differencies to Rev 1.A.:
- Analog Supply
- Flybuck IC at 950kHz
- HF decoupling
- GND layout
- PFFB layout
- Analog frontend
- Signal coupling
The board works for all Akita TPA32XX with thermal-pad up but not the "Boxster" chips like TPA3221.
Compared to the REV 1.A it is meant to be used with PFFB at all times.
Differencies to Rev 1.A.:
- Analog Supply
- Flybuck IC at 950kHz
- HF decoupling
- GND layout
- PFFB layout
- Analog frontend
- Signal coupling
How exactly do you adjust the "volume" on this chip? By adjusting the PVDD voltage, or by altering the audio signal?
doctormord,
Will the analog input module work with the earlier version of the TPA325x PCB I purchased? I am also very interested in the PFFB implementation based on the TI white paper.
I recently moved again for my work, so my lab is stored away for now, but I intend to build the TPA3255 amp once everything settles down. I am using gmarsh's Wiener 2.0 TPA3118 PBTL amp to drive a pair of KEF LS50 monitors, and frankly, I am surprised at how well this relatively low powered Class D amp works with these 85dB sensitive speakers. I suspect that the 13dB gain from from my Audio Research LS7 line stage preamp helps, but the Wiener amp fed with a decent amount of current from my linear regulated power supply is able to deal with the KEF impedance as well.
I would expect the TPA3255 with a more powerful power supply would work well with the KEF speakers.
Will the analog input module work with the earlier version of the TPA325x PCB I purchased? I am also very interested in the PFFB implementation based on the TI white paper.
I recently moved again for my work, so my lab is stored away for now, but I intend to build the TPA3255 amp once everything settles down. I am using gmarsh's Wiener 2.0 TPA3118 PBTL amp to drive a pair of KEF LS50 monitors, and frankly, I am surprised at how well this relatively low powered Class D amp works with these 85dB sensitive speakers. I suspect that the 13dB gain from from my Audio Research LS7 line stage preamp helps, but the Wiener amp fed with a decent amount of current from my linear regulated power supply is able to deal with the KEF impedance as well.
I would expect the TPA3255 with a more powerful power supply would work well with the KEF speakers.