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Casio fx-61F: Scientific Electric Formula 27
04-12-2016, 12:38 PM
Post: #14
RE: Casio fx-61F: Scientific Electric Formula 27
The HD62021A04 SoC seems to be able to work at really low power supply voltages, most probably at around a minimum of 1 Volt.

Some more details on the hybrid power supply:

The two diodes allowing for solar panel/battery switching are marked on the PCB as MA700 and MA723 which should be schottky diodes. I measured them to check for Vf:
- The MA700 has a Vf=0.5V.
- The MA723 has a Vf=0.3V.
This later diode must have a lower forward drop voltage as it is in series with the 1.5V single battery cell. So for a fresh battery, the SoC will see around 1.2Volt when operating in very low ambient light conditions.

[Image: fx-61f_ps_001.jpg] [Image: fx-61f_ps_002.jpg] [Image: fx-61f_ps_003.jpg]

Jose Mesquita
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RE: Casio fx-61F: Scientific Electric Formula 27 - jebem - 04-12-2016 12:38 PM



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