Hello,
I have a question about the VPRE output voltage range of NXP S32M276XX IC.
I used external P-MOSFET voltage-regulator for VPRE in my design as below shows.
When external P-MOSFET regulator is activated(set CONFIG-VPREEXT = 1), the output voltage of VPRE pin is around 7.0V;
When external P-MOSFET regulator is not activated(set CONFIG-VPREEXT = 0, then internal regulator to be used), the output voltage of VPRE pin is around 6.3V.
The status that I described is normal or not? What exactly output range is the VPRE in both status?
By the way, In the datasheet, the typical output voltage of VPRE is 6.4V.
Hello @Ted_Qiao,
The two regulators, one using the external ballast PMOS and the other using the internal ballast PMOS, are enabled by default.
The external regulator has a slightly higher regulation point, so it is the only one active under normal conditions. The internal regulator becomes active only when the external regulator is disabled.
The exact regulation points are not specified in the datasheet. Only a typical value of 6.4 V is provided for both the internal and external regulators.
The actual regulation point depends on production variations and operating conditions.
For example, on my EVB I measured approximately 6.2 V with the internal ballast PMOS and approximately 6.8 V with the external ballast PMOS.
The absolute maximum rating for VPRE is 7.5 V, so the voltage you measured is well below this limit.
BR, Daniel
Hi @Ted_Qiao,
Between resets, these bits can only be changed once, from 1 to 0.
As shown below, the reset value of both bits is 1, and they can only be written to 0. Therefore, if you need to change any of them back to 1, the MCU must be reset.
Regards,
Daniel
Hi Daniel,
Thanks for your explanation. It's clear for me now.
My further question, how could I switch freely between internal regulator mode and external regulator mode in application software?
I try to set the relevant register according to [S32M27x Reference Manual],
Set if using VPRE internal regulator (VPREINT=1, VPREEXT=0) or using VPRE external regulator (VPREINT=0, VPREEXT=1). But it could not switch freely during operating mode.
The background for doing it is that I want to do some tests with the regulator mode switching. Thanks！
