Electronics > Projects, Designs, and Technical Stuff
VFD Display 101
Ian.M:
That's likely as there is really no other way of using it effectively, but as I have been unable to find a copy of the original Sovtek ИB-18 datasheet, I'd be extremely cautious. There are various somewhat contradictory translations of parts of it around under the transliterated Latin part numbers IV-18 and possibly IW-18, but without the original to compare with and maybe some assistance from a Russian speaking technician, as I don't have hands-on experience with this particular VFD, I cant make a definite statement.
I am suspicious about the filament voltage specs - there seem to be different numbers out there. For initial experiments I would recommend bringing up the voltage slowly till a filament current within the nominal range is obtained.
Its obviously designed for 1/9 duty cycle multiplexing. Driving it with 1/8 multiplexing, ignoring the symbol digit is unlikely to be a problem, but IMHO it would be a bad idea to use it in a clock with 1/6 multiplexing at full rated anode voltage without PWMed or duty cycle based brightness control.
NivagSwerdna:
Awaiting my PCB from Elecrow now... went for cheap postage so will be a while. :)
niekvs:
--- Quote from: NivagSwerdna on May 23, 2019, 01:15:26 pm ---
--- Quote from: niekvs on May 23, 2019, 11:45:35 am ---PT6312BLQ
--- End quote ---
I can see some merit although a bit unobtainium perhaps, also my IV-18 has 9 Grids and 8 Anodes.
Tell us about your filament drive and bias... :)
--- End quote ---
Unobtainium..? Just check that link, many sources for this chip, and at least 10x cheaper than those HV5812s :)
https://www.aliexpress.com/wholesale?ltype=wholesale&d=y&CatId=0&SearchText=pt6312blq&trafficChannel=main&SortType=price_asc&groupsort=1&page=1&switch_new_app=y
Filament drive is similar as in the first link of the OP.
NivagSwerdna:
PT6312BLQ seems like a really nice chip but I have been brainwashed by the Microchip samples program. :) Might give a PT6312BLQ is I ever get to v2 of this project.
My definition of obtainable is "Farnell stocks it" ;)
NivagSwerdna:
Well I assembled my driver board and I'm not 100% happy... the display is multiplexed across the 9 digits... I have a 27kHz interrupt and follow a pattern of 1 blank, 29 display across the 9 digits... i.e. 100Hz per digit. The Filament drive seems to work OK and the HV measures 34.8V which is close to my design target.
It seems I need to increase the Grid Voltage quite significantly... 50V? 60V? (And that requires a re-design of the HV PSU as my TP61175 will only take me to 38V)
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