I understand that this not practical watches, I calling my product
"party watch", not for daily usage but good eye catcher on special
Standby time is acceptable, in good condition more than 7 days. If
anybody think that 5 minutes run-time is low? it is abut 300seconds if
you display time
for 3 seconds you can check time 100 times or 350 times in low brightness.
Charging is very simple because vinatech scap are 3V, just I use 3V
fixed voltage LDO MCP1700T3002ETT with 10R resistor to limit charging
current + shottky diode
for protection reverse current to LDO .... charging voltage drop to
Heart is fixed 3V version of MAX1724 extremely low 1.5µA quiescent
supply current Step-Up DC-DC Converter which can work until 0.4V imput
I can use about 87% of stored energy. In all operation time I have
stable 3.001V for MCU.
I also have on board space for newest MAX17222 ... 300nA Iqc bu I am
unable to solder 6-Pin μDFN
Average consumption is now about 7uA.
I am using PICOPOWER Microchip/ATMEL ATMEGA328 stanby consumption with
runing RTC is 0.9uA
Every seconds MCU wake form sleep for add second to counter and flash
led on gauge to show remaining capacity level.
If you press button you can show time, long hold adjust time ...
I am satisfied with results, I have something unique in world ... non
practical but unique ;)