Hello,

I've done my own PCB, on which the LCP1768 is plugged. Alone with my code running, the LCP1768 consumes about 140 mA. Alone too, my PCB consumes 120mA. The LCP1768 is powered by USB, and, when i plug it to the PCB, all is switching off (no more voltage on Vu pin). The PCB side is powered by Vu pin. It's look like the protection switch (FPF2123) on the +5Vusb detect too much current and become active. But, my system consumes about 260mA, and, looking at LPC1768 schematics and FPF2123 datasheet, i see the Rset resistor is 1kOhms, meaning the switch is active when the total current is about 460 mA. Should i change the Rset resistor to a lower value? Or anyone have other idea? Thanks for help,

Arnaud

Perhaps your problem stems from a current surge to charge on-board capacitors when the power connection is first made?

Thanks for the reply,

I've changed the Rset resitor to 600 Ohms value, and the problem doesn't occur anymore. I have still to measure the current to verify your idea Fred, but i think this is what happens!

Arnaud