AXP223 datasheet(19/56 Pages) ETC2

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AXP223

PMIC Optimized For Multi-Core High-Performance System

AXP223 Datasheet Revision 1.1

PAGE

9.1.5.

System Reset and Output Monitoring (PWROK)

The PWROK in AXP223 can be used as the reset signal of application system. During AXP223 startup, PWROK outputs low level,

which will then be pulled high to startup and reset the system after each output voltage reaches the regulated value.

When application system works normally, AXP223 will be always monitoring the voltage and load status. If overload or under-

voltage occurs, the PWROK will instantly drive low to reset the system and prevent data losses.

When application system works normally，drive low PWROK，then AXP223 will reboot，and power on timing sequence

9.Power Path management (IPS ™ )

Power input of AXP223 may come from Li-battery, USB VBUS input, external power ACIN (such as AC adapter). IPS can select

proper power according to external power and Li-battery status.

■

If only Li-battery is available, and no external power input, Li-battery is used for power input；

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If external power is available (VBUS or ACIN), it is preferred in power supply;

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If Li-battery is available, it will “Seamlessly”switch to Li-battery once external power is removed；

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When both VBUS and ACIN are available, ACIN will be applied to supply power in priority, and Li-battery will be charged；

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If ACIN drive capability is not enough, VBUS will be enabled to achieve ACIN/VBUS common power supply；

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If the drive capacity is still insufficient, charge current will be reduced to zero, and battery is used for power supply；

Host can set IPS ™ parameters and read the feedback by visiting internal registers in

AXP223 via P2WI/RSB.

9.2.1 Voltage-Limit/Current Mode and Direct mode

In order not to affect the USB communication, VBUS is always working under Voltage-Limit mode by default. In this

mode, AXP223 ensures that VBUS voltage remains above a configurable reference voltage VHOLD which can meet the

USB specification. The default VHOLD is 4.4V, adjustable in Reg30H [5:3] register.

If the system has limit on current obtained from USB VBUS, a current-limit mode is provided (See REG30H[1]

If the system just utilizes the USB for power supply rather than communication, or the USB power adapter is utilized, AXP223

can be set to “VBUS Direct Mode” by modifying register REG30H[6], and then AXP223 will give priority to the application

power demand. When the drive ability of USB Host is insufficient or system power consumption is large then the VBUS voltage

is lower than VHOLD, AXP223 will release IRQ to indicate the weak power supply ability of Host VBUS, which may affect USB

communication, and then Host software will follow up.

9.2.2 AXP223’s Reaction to External Power Supply Plugin

AXP223 can automatically detect the plugin of external powers and judge whether the power is usable or not. The result will

be set in corresponding registers, and IRQ will be released to inform the Host at the same time.

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