S32M276XX VPRE external MOSFET

[Ted_Qiao]

Hi,

I set the VPRE external MOSFET as datasheet recommends, for external thermal dissipation. When the input voltage = 16V, and the ambient temperature is 120degree, the case temperature of this MOSFET(VT200) will go up to 138degree, very high.

I am considering the solution to lower the temperature of this MOSFET. Could I parallel a MOSFET with the same model to VT200, and use GCTL to drive both MOSFETs simultaneously. In this way, the external MOSFET power will be reduced to half. Kindly ask your help to give comments of this solution or any better proposals also keep me informed. Thank you in advance.

BR, Ted

[PavelL · Accepted solution]

Hello @Ted_Qiao ,

The total gate charge or input capacitance of the external PMOS is not specified. Therefore, your solution should work - using MOSFETs in parallel is safe, as the temperature of each device is balanced due to the positive temperature coefficient of channel resistivity. You may also consider adding a heatsink, if applicable.

Best regards,

Pavel

[Ted_Qiao]

Many thanks for your reply.

I would like to ask another question about how to decrease the power dissipation for S32M276XX system.

May I ask you about the feasibility of the following solution?

I would like to delete the Qpmos_vpre, and replace it with a DCDC converter. The DCDC converter got the power from battery, then generate 6.4Vtype directly connect to VPRE-pin.

This DCDC converter has an Enable pin, so the output could be controlled by S32M276XX. When in the working voltage range, for example:>9V, the DCDC will be enabled by SOC, when it is <9V, the DCDC will be stopped, the current will generated by MCU internally(low voltage drop, low power dissipation).

Pls. also checked the below block, kindly ask your comments about this solution.

Thanks and nice day!

[PavelL]

Hello @Ted_Qiao ,

Your approach seems interesting; however, since this configuration is not documented in the Hardware Design Guidelines for S32M2xx Microcontrollers, nor in any other official resources, and is not implemented on any evaluation board, I am unable to confirm its validity.

Please note: Once an answer is marked as a solution, the original query is no longer actively tracked in our system. I only receive subscription emails for updates, and those can occasionally be missed.
If you need further assistance, the best approach is to create a new query.

Best regards,

Pavel