Re: Toshiba p200 power led flashing blue

Seems like the Vin to the 3v/5v regulator is oscillating, causing the 3v to bounce. Note this is a different laptop than my previous post.

Many thanks

Re: Tps51125 help needed in uderstanding this.



Vin comes from Adapter into mosfet (q504) that is switched by the Charger IC using the Ac detect signal, this then immediately goes through current limiting resistor and onto the 3v/5v (u511) regulator, 99% of laptop mobos work the exact same way. This Vin 19v voltage is used as the vin onto the 3v/5v regulator. Usually as long as you have the vin to the regulator the regulator will output 3.3v onto Sio and powerbutton. The powerbutton when brought to ground then starts the Sio working.

On this set I had...

Re: Tps51125 help needed in uderstanding this.

Thank you all for the input unfortunately Im still no nearer to understanding this circuit. Most other 3.3v regulators I have came across automatically release the 3.3v to power the sio and the powerbutton but with this circuit I cant see how I have vreg3 but no 3v on the sio or powerbutton? if its switched then how as the sio has no power to control the switching. I changed the Tps and was only getting .7v on the vin as opposed to 19v looks like it may have been faulty as well as I pulled from scrap board now the fet on the charging...

Hi anybody came across this issue before. There is no pattern to it just continuous flash with or without battery in.



Thank you

Re: Tps51125 help needed in uderstanding this.



No that's fine but thank you. I am just curious as to what makes this Ic start outputting. I have seen other regulators and understand them but this one Im confused as normally the 3v is present on the Sio and powerbutton without powering it on. But this tps51125 is confusing me....

Hi I am having trouble in understanding this regulator circuit. Basically I have 3v on pin 8 vreg3 and 5v on pin 17 vreg5 but I am not getting any 3v or 5v output across l3 or l6. There is no 3v on the Sio or powerbutton so the unit is dead. What is needed for this to start outputting the 3v needed from the powerbutton and SIO?.

The circuit is from a Toshiba l300

Many thanks....

Re: New Members - please post your introductions here

Hi to all , great to be here.