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Basic usage and slow dynamic current measurement.

A project log for USB Power Injector

USB Power Injector allows for a way to power up USB 2.0 devices from a lab power supply, while allowing data transfer from host to device.

Nikola ManolovNikola Manolov 09/23/2022 at 11:420 Comments

Experiment Block Diagram
Experiment Block Diagram

In the first test we are going to explore a basic use case for the USB Power Injector. As shown in the video, we have an Arduino Nano connected to a PC running the Arduino IDE. At the same time, the Nano is powered by a benchtop PSU and we can set its supply voltage and a protective current limit. This setup allows for full control of the Arduino, both in terms of how we power it and how we communicate with it. A new firmware can be uploaded, as shown in the video (I change the blink time). It also allows for communication via the virtual COM port.

This setup also allows for some slow dynamic power measurements. A milliamp meter is connected in series with the Arduino, in order to measure the supply current more accurately. When the Arduino LED is off, the board draws 27.2mA and when it’s on it drawn 32.5mA. This functionality can be quite useful to roughly determine what state a board is. For example, if a wireless transmitter is off, the product under test will draw less current. For general purpose development work I usually skip the amp meter and just use the amp meter embedded in the power supply. 

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