PF1510 VIN and VSYS

[Ando26]

Hi,

We have a question regarding the PF1510. In the datasheet there is somethng unclear (for us at least).

- In order to properly work, does the PF1510 needs a VIN or can it be supplied by VSYS ? 

- Is VSYS an input or an output ?

- If a Li-ion battery is connected to VSYS, it seems that LDO and SWx will not have a valid input when battery voltage has dropped around 3V1, is this correct ?

- Is this behaviour different on the PF1550 ?

- Do you have a typical application schematic for the PF1510 with a Li-ion battery supply ?

Regards

[Sadatan123]

So can I simply give 5V input to VIN and then use Vsys as input to all the switchers and LDOs of PMIC and also for few pull ups on my board?

Attached is the schematic for reference. 

[Ando26]

Thanks for the reply.

[gw]The VSYS voltage can be regulated to either 3.5 V, 3.7 V or 4.3 V
Does it mean that the input voltage of VSYS has to be regulated by an external IC (if VIN is not used)

- Is this behaviour different on the PF1550 ?

Could you develop a bit ? In my mind the PF1550 can be powered via an unregulated Li-ion battery, via which pin ?

[guoweisun]

- Is this behaviour different on the PF1550 ?

[gw] PF1550 page54- 8.6 Battery supplement mode, don’t have this function.

-Could you develop a bit ? In my mind the PF1550 can be powered via an unregulated Li-ion battery, via which pin ?

[gw]do you mean Battery supplement mode?

[guoweisun]

We have a question regarding the PF1510. In the datasheet there is something unclear (for us at least).

- In order to properly work, does the PF1510 needs a VIN or can it be supplied by VSYS ? 

[gw]You can supplied it by VSYS or Vbus.

- Is VSYS an input or an output ?

[gw]VSYS is output of LDO and input of regulators.

- If a Li-ion battery is connected to VSYS, it seems that LDO and SWx will not have a valid input when battery voltage has dropped around 3V1, is this correct ?

[gw]The VSYS voltage can be regulated to either 3.5 V, 3.7 V or 4.3 V

- Is this behaviour different on the PF1550 ?

[gw]Yes.

- Do you have a typical application schematic for the PF1510 with a Li-ion battery supply ?

[gw]No