Both.
Fast charging is to shorten the charging time by increasing the charging power P. There are three ways to increase the charging power: increase the voltage, increase the current and increase the charging power at the same time. There are three ways to increase the power: increase the voltage, increase the current, and increase the voltage and current at the same time.
To realize fast charging on a cell phone, three elements need to be satisfied, and one of the three is indispensable. The charger, the battery, the charge IC, the charger needs to meet the sufficient output current and output voltage, because the charger alignment has a large parasitic resistance, if you want to achieve a larger charging current, the charger's on-load output voltage needs to be higher.
Extended information:
Battery charging is done by the cell phone's charging program and power management chip MT6305N(U400) control.
1, when the charger is inserted into the charging I/O port, the VCHG signal is sent to the power management IC MT6305, which triggers the generation of the charging interrupt signal CHRDET;
2, the CPU accepts the interrupt request, turns to execute the charging program, displays the charging icon, and outputs the charging control signal CHRCNTL to the MT6305;
3 MT6305 outputs the control signal GATEDRY to turn on U405 to charge the battery;
4. MT6305 detects the charging current through the current detection signal ISENSE and the battery voltage through the voltage detection signal VBATSENSE to control the state of charging;
5. When it detects that the battery has been fully charged. MT6305 through the GATEDRY output off charging signal, terminate the charging process, charging end.
Reference:
. Strong>Reference: