LAPTOP MOTHERBOARD POWER CONTRIBUTION

CONTRIBUTION OF POWER 19V, 5V AND 3V AND HOW IT WORK
Starting from the DC jack where the main voltage is 19V coming from the adapter entry through the adapter (adp) Fet's PQ1 and PQ2, before going through adp fet's voltage is 19 V entered into charger ic through acdet (adapter current detector) through a resistor will reduce the voltage from 19V to 2.4 to 2.6 V (or in accordance with the request charger ic which can be seen in the ic charger datasheet or uses V_i_R calculation. Acdet (ACIN on other board) this is a voltage detection sensor that informs that the voltage coming from the adapter so that 19V voltage goes to adp fet's ic .BATDRV gate of Battery Fet activated charging system when the battery pack is attached.When ACIN detected this signal higher than voltage need charger ic will detect over voltage and activated protection by pushing analog ground through CSIP pin than stop 19V on R1.
Voltage of the power jack goes to (look at voltage flow on picture) PQ1 through source (S)pin 5,6,7,8 and out through Drain (D)pin 1,2,3 goes to pin 1,2,3 PQ2 exit through the pin 5,6,7,8 and distributes 19V voltage Battery Fet PQ3 Source 19V and stop there standby for charging voltage.The other Voltage flow goes to R1. then forward voltage of 19V to PU2 as VCC (power supply) for DC / DC ic power supply (PU2) which will process the voltage 19V to 3V and 5V.
PQ 4 and PQ 6 are upper n chanel also need 19V as a Sources ,make sure this Fets get supply 19V also
PU 2 is a trigger who passed a voltage of 19V upper n channel source by opening gate of PQ4 gate at 5V and PQ6 gate for 3V than supply for whole system.
PU2 need enable 5V and 3V signal trigger coming from MAINPWON# or +5AUXON# (in other circuit) to activated this upper n channel gate trigger..if this enable 3v and 5v signal not present then PU2 dc / dc power supply will not active and voltage 3v and 5v on PQ6 PQ4 drain will not be present.

 

 We need to know where the power contribution need to make the system work.make sure all 19VALW on this rail available,before we processing 3V AND 5V .understand this rail could fine missing power or signal or trigger what ever switching name is. Laptop motherboard requirements this Voltage work .

 Make sure 19V available on upper N channel Source and standby and flow to the drain as much as gate require . Many case founded that a leak N channel than 19V come for all 19V than burn of all 3V and 5V component.