Basis of 3.7V & 4.2V mobile battery?
 

Since no reasonable series voltage combination satisfies
Nv=3,7; Mv=4,2
how are these strange voltages achieved, and why?

What semiconductor technology do modern mobiles use:
bipolar, CMOS ... or what?

Where are these topics documented?

TIA.

Basis of 3.7V & 4.2V mobile battery?
 

On 5/5/2019 11:49 AM, wrote:
Since no reasonable series voltage combination satisfies
Nv=3,7; Mv=4,2
how are these strange voltages achieved, and why?

What semiconductor technology do modern mobiles use:
bipolar, CMOS ... or what?

Where are these topics documented?

TIA.

You'll have to define Mv more precisely as it has numerous meanings. As for
3.7v (assuming that is what you are referring to) that is the operating
voltage of your typical lithium secondary cell and is defined by the
chemistry and physics involved. It is the voltage of a single cell so no
series combination is needed to satisfy it. It gets more peculiar when you
start looking at the advertised voltages in various battery-powered tools
where ad-speak and reality become inextricably woven together and confused
in the process: there is no combination of cell voltages that will satisfy
the 18V or 24V numbers that are bandied about when adverts brag of
lithium-powered equipment.

Basis of 3.7V & 4.2V mobile battery?
 

wrote:
Since no reasonable series voltage combination satisfies
Nv=3,7; Mv=4,2
how are these strange voltages achieved, and why?

What semiconductor technology do modern mobiles use:
bipolar, CMOS ... or what?

Where are these topics documented?

TIA.


Keyword: electrochemistry

Sites: # Practical details of batteries
https://batteryuniversity.com/learn/...ased_batteries
# "Characteristics hexagon" for battery chemistries, why we use them
https://batteryuniversity.com/index....of_lithium_ion
# Details of charging
https://batteryuniversity.com/learn/..._ion_batteries

# whizzy chemistry
https://en.wikipedia.org/wiki/Lithium_battery

# list of battery types
https://en.wikipedia.org/wiki/List_of_battery_types

# good stable but half-capacity tech, yard lamps
https://en.wikipedia.org/wiki/Lithiu...sphate_battery

# LiCoO2 is mentioned here, a high capacity but not entirely stable cell.
# Since Cobalt is expensive, other materials are used to cut the cells.
# Probably no Wikipedia article tracks latest chem evolution for these.
# You would need some sort of science journal. Like maybe electrochemistry.
https://en.wikipedia.org/wiki/Compar..._battery_types

*******

Modern mobiles are mostly CMOS. Bipolar for RF amps and radio stuff.
You can do radios in CMOS, but bipolar lasts longer (stable characteristic).
Doing radios in CMOS is "abuse" (and this is not from direct engineering
knowledge, just from observing how long CMOS-only products last, which
is about three months before the RF power level drops).

BiCMOS was discontinued some time ago, but is a great technology
for the engineers who used it. You could drive a 50 ohm line with the stuff.

HBT will run at 100GHz, but is not practical for computing, nor
does Moores law apply. Features are on the order of 2 microns.

CMOS is cheap, which is why we use it. And human psychology is such,
they will optimize the hell out of it, just to make Moores law
continue to hold.

The documentation is, well... everywhere.

Paul