Hi All,
I just heard that a 3.7V Li-on battery, the working voltage should >
3.4 V, even the device uses 3.0V as power supply ?
I'm not sure what "device" you are referring to. 3v7, sometimes 3v6, is usually
quoted as the nominal voltage for lithium-ion cells. Fully charged, depending
on the cell manufacturer and the anode material, the voltage is 4v1 or 4v2,
while most manufacturers recommend that the discharge cease at a voltage not
less than 3v0.
It is common in small portable single-cell equipment to use switchmode DC-DC
converters to deliver the desired load voltage, which in your case may well be
3v0. But the essential factor is to ensure the load cutoff is effected before
cell voltage is depressed below 3v0.