Thanks for your reply. That's impressive. As a 3.3V regulator I'm using a simple MCP1700, but that takes about 6.5uA, that's "too much" vs 1.6uA declared in a the datasheet, I tried a few parts, maybe not a genuine batch...
Then 2.4uA is taken by the power supply DC/DC converter. This can be improved, but if I improve the efficiency of the power supply when on, then I find that the chip uses more current in stand-by. I mean, 2.4uA is nothing really but as I'm trying to break that even with solar panels, I need to reduce it further and as close to 0 as possible when in shutdown or I can try through a 'true shutdown'. The uC itself should take just about 1uA or less when in sleep mode. That is a total of 10uA stand-by current vs my goal of 2.1uA (I know it can be done, just not sure how yet). Perhaps think I need something like this, I believe the FQU11P06 is used as a high side load switch, although it may not be the best in terms of efficiency... https://www.facebook.com/Zx81NixieClock/photos/a.361754507268684/361754510602017/ Or a better solution could be to implement a high-side load switch as suggested by TI here (as a true shutdown): https://www.ti.com/lit/gpn/tps27081a I guess I'll have to run some experiments on the bench. If anyone has already done it, feel free to share more suggestions. Thanks again gregebert! Il giorno domenica 6 giugno 2021 alle 16:45:53 UTC+1 gregebert ha scritto: > I used the LT3561 to provide the 3.3V logic supply from the battery (3.7 > to 4.1V Li-ion), and it's standby leakage is practically zero. All I know > is the leakage current of this regulator, plus the operating current of the > DS3232 RTC and leakage of the HV driver, makes a very slight movement of my > 50uA meter. The RTC adjustment every 100 seconds pegs the meter. > > The only MOSFET I have is for the HV inverter (DMN6040SVT) , and it's > leakage is rated at 100nA. > > The standby current of my nixie watch board is so low that the battery > lasted *6 years* on a single charge. I should also mention this battery > was used in my cellphone for several years, so it's capacity is > significantly less than the original 1100ma-hr. This board is in my garage, > and every so often I would push the display button to energize the display. > Alas, I finally had to charge it last month because it could no longer > light all digits. > > On Sunday, June 6, 2021 at 2:41:25 AM UTC-7 [email protected] wrote: > >> Hello, >> >> I'm working on a solar powered nixie watch (similar to the Kopriso Nixie >> watch). >> >> It's crucial that I dramatically reduce stand-by power as much as >> possible and within 2.5uA, which is where the solar panels will balance off >> the stand-by current. >> >> Regardless of which power supply I use, even using the shutdown pin, the >> power supply still takes 2.5uA. This is perfectly in line with the >> electrical specifications of the datasheets. >> >> So, my question is, can I 'brute force' a shutdown, effectively removing >> the power from the VIN pin via a PNP high speed mosfet such as MMBTA42 or >> it will introduce too much of a delay in starting the power supply? >> >> I'm going to try it on the fly but if anyone has any suggestions on how >> to bring to 0 or to 0.01uA the stand-by current that would be great. >> >> As an example, I'm using the LT1308B DC/DC converter as on page 17 of the >> datasheet >> https://www.analog.com/media/en/technical-documentation/data-sheets/1308abfb.pdf >> >> Any suggestions will be much appreciated. >> >> Thank you, >> Max >> >> -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web, visit https://groups.google.com/d/msgid/neonixie-l/10505ed0-f6cb-43db-91c6-0184e73b2f7fn%40googlegroups.com.
