Hi Guys,
I have built an audio circuit that is connected via an ADC to the Teensy 3.1. I have split the VUSB and the VIN, and am powering the Teensy with my own workbench power supply. When the USB cable is connected to my laptop I get about an extra 15mV of noise on my power line as can be seen in my scope output:
USB disconnected:
USB connected:
I thought it might be something in the code but have removed everything and am left with this:
My amplifier design is not great as I don't have any filters and now this noise on the power line is being picked up:
I have already soldered the board so any modifications to it are going to be a bit of a hack but might be necessary, the real pain being that there are 5 of these amps on the board...
My question is then, if I have separated the VIN and VUSB how does this noise get into my power line and is there anything I can do to remove it?
I have built an audio circuit that is connected via an ADC to the Teensy 3.1. I have split the VUSB and the VIN, and am powering the Teensy with my own workbench power supply. When the USB cable is connected to my laptop I get about an extra 15mV of noise on my power line as can be seen in my scope output:
USB disconnected:
USB connected:
I thought it might be something in the code but have removed everything and am left with this:
Code:
#include <stdint.h>
void setup() {
}
void loop() {
return;
}
My amplifier design is not great as I don't have any filters and now this noise on the power line is being picked up:
I have already soldered the board so any modifications to it are going to be a bit of a hack but might be necessary, the real pain being that there are 5 of these amps on the board...
My question is then, if I have separated the VIN and VUSB how does this noise get into my power line and is there anything I can do to remove it?