Power Supply PCB Design – Best Method to Regulate 42V to 3.3V

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I am using a 36 V battey pack (10s 2.5 A each cell 3.6V.) Its maximum voltage is 42 V. I am using a STM32 microcontroller whose input is 3.3 V.

I am designing a PCB in which the power supply is drawn from the battery pack (42 V.) I would like to power the STM32 microcontroller from the battery pack power supply.

I would like to regulate 42 to 3.3 V so that I can power my STM32 microcontroller.

Which method is best to convert it either using regulator or buck converter based on the pcb designing?

Battery Specification: 10s1p

  • Battery pack nominal voltage: 36 V
  • Battery pack maximum voltage: 42 V
  • Battery pack current: 2500 mAh

Microcontroller specfication: STM32F401RCT6

  • Supply voltage: 3.3 to 3.6 V
  • Supply current: 100 to 160 mA

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Which method or component is best to regulate 42 V so that I can power my microcontroller with 3.3 V?

Best Answer

I quite like the LT8631 (1 amp at 3.3 volts and input voltage range up to 70 volts): -

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Or maybe the LT8630: -

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Or possibly the LTC7138: -

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Or choose your own buck converter using the Analog Device's selection tool.