Dear Steve:
see post 1587 schematic.
2stageEF high performance class AB power amp / 200W8R / 400W4R
Not every fan can be used in this circuit: avoid parts with built in DC speed control. Some post below is a circuit from diyaudio member sajti if you need an analog control.
BTW: my homecinema project is nearly finished and the new lab is mostly ready to start with new projects. Pictures will follow ...
BR, Toni
P.S.: lab status in Miami?
see post 1587 schematic.
2stageEF high performance class AB power amp / 200W8R / 400W4R
Not every fan can be used in this circuit: avoid parts with built in DC speed control. Some post below is a circuit from diyaudio member sajti if you need an analog control.
BTW: my homecinema project is nearly finished and the new lab is mostly ready to start with new projects. Pictures will follow ...
BR, Toni
P.S.: lab status in Miami?
Off topic: new home cinema and laboratory
Homecinema in "full production" - only top speaker for Auro 3D still missing but already in work.
BR, Toni
Homecinema in "full production" - only top speaker for Auro 3D still missing but already in work.
- all 4 corners equipped with bass traps
- absorbers "everywhere" also on top in color black to "black optimize" the cinemascreen.
- SA2012 4 channel high end Class D driving 4 subs
- SA2014 4 channel driving front speakers
- Denon AVC-X8500H driving other speakers
- Panasonic UHD player and 4K Sony laser projector
- (other SA20XX amps currently not mounted - rack to mount them is not yet finished ...)
BR, Toni
Attachments
AFAIK the lady's name is Diana
Diana Krall is not only a very beautiful lady, she is also a fantastic singer!
If you don't know her work I highly recommend to look it up. That is, if you like jazz.
You're very right
!Panasonic in general is among the top manufacturers regarding AV reproduction *imho*. My very first VCR, bought in 1991 for almost 2 kDM, was a Panasonic NV-F70, branded as Blaupunkt RTV-810 HiFi. It worked very well and especially had very good sonic qualities. In those days, VHS tapes were the cheapest medium for recording high quality audio, and that's what I used it for.
Due to my move last year, this unit is out of order at the moment and waiting on my shelves, but I am convinced that it still would work if I needed it. Once it had some minor issues in the PSU, caused by a voltage surge, but I managed to repair it easily.
Best regards!
Nice. Sony laser projector... This one?
4K SXRD™ Home Theater Projector | VPL-VW5000ES | Sony US
All my audio gear is still stuffed in a small spare room. Completely un-operational.
4K SXRD™ Home Theater Projector | VPL-VW5000ES | Sony US
All my audio gear is still stuffed in a small spare room. Completely un-operational.
What is the purpose of U5? Can't the MIC502 drive the fans directly?
And the jumpers on the supply side of things were required by board layout? I'm thinking about adding the parts necessary to control one fan to a 12V power supply and powering both fan and control circuitry straight from this supply board. Should be minimal parts and footprint I think.
MIC502 can't drive a fan directly output sink current is maximum 10mA and source current is maximum 25mA. So you need a driver:
U5 is a mosfet part with high current output and flyback diode included. The mic502 ist designed to normally run with 20Hz but I have trimmed it to run with a higher frequency above 20kHz for use with standard DC fan motor (no electronics inside the fan).
I have added jumpers and a small LDO regulator, if the supply can't provide regulated 12-13V for the fan's. If you design your own pcb you don't need the jumpers.
BR, Toni
U5 is a mosfet part with high current output and flyback diode included. The mic502 ist designed to normally run with 20Hz but I have trimmed it to run with a higher frequency above 20kHz for use with standard DC fan motor (no electronics inside the fan).
I have added jumpers and a small LDO regulator, if the supply can't provide regulated 12-13V for the fan's. If you design your own pcb you don't need the jumpers.
BR, Toni
Last edited:
Thx
Yes, I see how C1 etc have been changed to alter the PWM frequency.
I see the benefit of the included flyback diode. I also see using a small SOT-23 MOSFET with built-in diodes is largely prevented as a result of the high Vds (although there is presumably a decent drop across the fan itself?).
In the case of only one fan I'm thinking it easier to use a simple little BC817-40 and adding a diode. With high beta, Rbase can be quite high and the current demand on the MIC502 low. (Seems to be a typo in the electrical characteristics table of the MIC502 data sheet re output source current for Vdd=12V)
Would this fan be ok with the circuit?
MC30101V2-000U-A99 Sunon | Mouser
EDIT re MOSFET: I can just high side switch power to the fan. Vds is low (just the drop over Rdson). Select a Mosfet with very low Rdson and power dissipation is minimised. Or am I missing something...yes I am as I don't have a higher voltage to achieve Vgs. Duh
Yes, I see how C1 etc have been changed to alter the PWM frequency.
I see the benefit of the included flyback diode. I also see using a small SOT-23 MOSFET with built-in diodes is largely prevented as a result of the high Vds (although there is presumably a decent drop across the fan itself?).
In the case of only one fan I'm thinking it easier to use a simple little BC817-40 and adding a diode. With high beta, Rbase can be quite high and the current demand on the MIC502 low. (Seems to be a typo in the electrical characteristics table of the MIC502 data sheet re output source current for Vdd=12V)
Would this fan be ok with the circuit?
MC30101V2-000U-A99 Sunon | Mouser
EDIT re MOSFET: I can just high side switch power to the fan. Vds is low (just the drop over Rdson). Select a Mosfet with very low Rdson and power dissipation is minimised. Or am I missing something...yes I am as I don't have a higher voltage to achieve Vgs. Duh
Last edited:
Dear Steve,
you need to test the device if it is capable for PWM pulsed supply. E.g. if there is a capacitor and/or some other electronics inside the fan it may be unusable for this operation.
The costs are low - just test it and let us know the results.
You have selected a very small model. 30x30x10mm. Do you want to cool a high end dac equipped raspberry pi?
BR, Toni
you need to test the device if it is capable for PWM pulsed supply. E.g. if there is a capacitor and/or some other electronics inside the fan it may be unusable for this operation.
The costs are low - just test it and let us know the results
.You have selected a very small model. 30x30x10mm. Do you want to cool a high end dac equipped raspberry pi?
BR, Toni
I am playing around with a linear power supply for an Oppo 103 universal disk player. I'm unsure of the thermal side of things. While I don't think it will be needed, I figured I may as well add the footprint for the fan control components onto the supply board. The enclosure height doesn't leave room for a large fan. Maybe I can push it to 45x45mm.
There aren't that many to choose from at Mouser (even more so if silence is important):
12 VDC DC Fans | Mouser
There aren't that many to choose from at Mouser (even more so if silence is important):
12 VDC DC Fans | Mouser
Last edited:
Do I have it right that in your implementation (with 10k NTC) the fan hits full speed at a temp of just over 50C and, were it not for the sleep setting, would be running at about 47% speed at 25C? If your R25 and R26 are implemented, rather than the trimmer, the fans would sleep a little over 25C.
I have been trying to finesse a steeper or rather smoother ramp from nothing at around 25C to full between 50 and 60C (rather than that abrupt sleep to 47% duty cycle) but I have not been able to get the numbers to work with a 10k NTC. I think I need to play around with something higher.
I have been trying to finesse a steeper or rather smoother ramp from nothing at around 25C to full between 50 and 60C (rather than that abrupt sleep to 47% duty cycle) but I have not been able to get the numbers to work with a 10k NTC. I think I need to play around with something higher.
okey dokey. I think if I use this 50k NTC and set R1 at 215k ohms and R2 at 27k ohms (using the naming in the typical application example) then I get 100% PWM at 60C and 25% PWM at 25C. I will set Vslp such that it sleeps until about 30C = 27C + typical hysteresis. That should roughly be about 5V or 42% of Vdd. I can set R3 and R4 accordingly.
Which fans did you use? Perhaps if I select from the same series I will have less trial and error.
Which fans did you use? Perhaps if I select from the same series I will have less trial and error.