Power analysis on NGX LPC4337-Xplorer board

Discussion created by lpcware Employee on Jun 15, 2016
Content originally posted in LPCWare by Michele84 on Thu Nov 14 03:51:03 MST 2013


I am doing some power analysis on a NGX LPC4337-Xplorer board by measuring the input voltage signals (USB_5V and 3V3 pins) on an oscilloscope.
In both cases I have noticed that, every 18 [ms], a periodic signal is visible on the screen (see image 66).
This periodic signal is always present (also when the RESET switch is pressed) and is composed by 22 negative peaks (see image 68).
The time between two consecutive peaks is sometimes 65 [us] (e.g. first ones) or 130 [us] (e.g. last ones).

Does someone know the cause of this signal and, if so, whether is possible to remove it?
Thanks in advance.