battery wall charger cc/cv question

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ljy4468

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Hi all

I have a simple question about wall charger.
In fact, there are many ic which provide cc and cv regulation.

Then, when we make wall charger (adaptor) for battery charging application, i think it should be operated in cv mode for constant output voltage.
Because mobile charger uses this voltage (for example, 5V) and if this adoptor voltage drops, several protections would occur.

So my question is, cc mode in adaptor never used in battery charger adaptor applications?
 



Please, if I understood you;
1. cc means constant current
2. cv means constant voltage
3. then you are asking why is cc not used in wall battery chargers.
Clear me on your question because it is not clear.

Remember that if you are using cc, you need to monitor the battery to avoid over-charging which is not good to the battery, because even when the battery is fully charged the charger will still supply cc.
 

In case of most "wall chargers", e.g. with USB connector, there's a charging circuit inside the device (mobile phone, MP3 player, whatsoever). The charger suppies 5V as standard voltage, but the charger circuit passes only 3.7/4.2 V with current limit to the LiIon battery.
 

Let me clarify my question.

let's make simple block for charging application.
AC Plug - AC/DC (flyback, psr) - Electronic device (Buck charger)
and I know that both CC and CV mode is used in Electronic device (Buck).

What I'm asking is about AC/DC flyback stage (aka wall charger, TA)
The main purpose of AC/DC is providing stable DC voltage for electronic device. right?

Then AC/DC is used only in cv mode? or does it need to operate in cc mode??
 

If you are talking about a general purpose "wall charger", it's operated as CV power supply. There will be additional short circuit/overload protection. It may be implemented as continuous or "hick-up" current limit.

A different point is the internal control topology of the flyback converter which often implements "current mode", means there's an inner control loop for the primary peak current.
 

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