7 years, 1 month ago.

3,3 V regulator removed

Hi, I'd need to power my LPC 1768 with 3.3 V for a battery powered application, so I carefully removed the 3.3 V regulator and soldered a wire to the central pad of the pcb. I made this to avoid current flow back into the regulator output.

Everything was working fine for a while, when suddenly the mbed disk disappeared from PC and never come back. The issue stands still also after hard reset of mbed. Before, the program was still running and, anyway, it didn't involve USB file system coding. I also tried on another PC. Both computers detect something connected on USB but cannot enumerate it.

It seems to me that by removing the regulator I made it possible for mbed chipset to receive input signal voltages from USB when 3.3 V power ( that I furnish via a laboratory programmable DC power supply) is still off and this fact may have damaged the USB interface chipset on the LPC 1768. It may happen with other generic electronic chipset.

Waiting for your opinions and suggestions.......

Stefano

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