What things should be considered when designing a board which can use either External or Internal Voltage regulator?
Is a major change needed if we have to move from External voltage regulator to Internal voltage regulator?
In general the choice of internal or external core voltage regulators depends on the application. The internal regulator is easily adjusted for temporary slow speed low power operation. The internal regulator also responds automatically to hibernate and wake from hibernate. Most other users will find external regulators a more efficient, accurate and less expensive option.
Additional information can be found in application notes EE228 and EE339.
Most Blackfin devices will not require changes in hardware or software other than a switch or jumper to select the internal regulator or external source of core voltage. Some processors like the BF527 have extra features like a ‘power good’ signal for external regulators or a ‘slow start’ feature for the internal regulator. In this case there would be small changes to the hardware.
It is also possible to control the voltage of an external regulator but this would alter both the hardware and software design.
This FAQ was generated from the following thread: External Voltage Regulator and Internal voltage regulator Blackfin