Laptop charging

[Jane]

When I charge a laptop, the voltage is coming
through this path:

mains charger --> the laptop charger circuit --> battery.

A question is: How to find out that the reason for NOT charging is the laptop charge circuit fault.( battery is OK, charger also tested). How to repair it?
What steps to take ?

I think that a similar voltage path , the same principles, are the same for various devices including cell phones.
From my experience regarding cell phones , I had mobile that indicated charging, yet not charging the battery in fact( only pretending charging).
How can it be then?

[gabiz_ro]

Re: Laptop charging

In most laptops is like that.
Charger go to
- power switch
-charging part
Power switch is like its name,give power to laptop from battery or charger.
Charging part just charge battery.

For charger use some conditions must be OK
In some cases is AC_Detect or Chg_detect or present or OK
Name on schematic depends by manufacturer.
Also voltage must be OK,same naming style.
For all this EC is responsible.

So Even charger is OK (tested on other laptop) some defective parts may give problems.If reguired signals that charger is connected and voltage is in range are not OK then EC will not switch to charger and enable charger circuit.

If laptop power up an works from charger,then problem is in charging part or battery.
If laptop doesn't power from charger,some protection circuit (over voltage or under voltage) may be defective or EC doesn't detect charger connected or voltage OK as result no battery charge and power source is battery (on power switch)

Most of charger IC talk with battery via SMBUS protocol.If battery not OK will not charge.

Also in charger-battery section,on some models exists one or two signals,one is for battery detect (system,detect if battery connected) the other one is system present (battery detect that is connected)


As for phones,break solder joint on micro USB socket on VBus pin.
Still make some contact,phone detect some voltage,even 5V in some cases,and enable charging.As current increase,broken solder have some ohm resistance,charger IC is unable to charge,even battery percentage decrease,not increase like usual.
Is like ( for a working fine phone ) cutting VBus in cable and inserting in series some 50-100 ohm resistor.
Will detect charger and say charging but cannot charge in that case.

[jasko_jacker]

Re: Laptop charging

if the battery LED does not light and we are sure that the adapter and the battery are functioning then there are probably problems with the charging circuit. This does not mean that you have to definitely change the chip, there are other components that can cause this problem, and must be verified with the tester and the circuit diagram.