SDAA280 March   2026 MSPM0G5187

 

  1.   1
  2.   Abstract
  3. 1USB Makes a Complex System Appear Simple
    1. 1.1 Why Has USB Been so Successful?
    2. 1.2 Why Does USB Look Simple?
  4. 2MSPM0 USB Silicon
    1. 2.1 How MSPM0 Devices are Documented
    2. 2.2 MSPM0 USB Module
  5. 3MSPM0 USB Hardware Design
    1. 3.1 Block Diagram
    2. 3.2 USB Mode of Operation
      1. 3.2.1 USB Device Mode: Bus Powered
      2. 3.2.2 USB Device Mode: Self-Powered
      3. 3.2.3 USB Host Mode Power Considerations
      4. 3.2.4 ESD Considerations
      5. 3.2.5 Layout Considerations
    3. 3.3 USB Clock Implementation
      1. 3.3.1 Selecting a Clock Source
      2. 3.3.2 Selecting a Clock Frequency
    4. 3.4 Example Implementation
  6. 4Software Overview
    1. 4.1 USB Stacks: Features
    2. 4.2 SysConfig Descriptor Tool
    3. 4.3 Selecting a Device Class
      1. 4.3.1 Example Process for Deciding on a USB Device Class
    4. 4.4 How to Select a Vendor ID (VID) and Product ID (PID)
      1. 4.4.1 Choosing and Obtaining VID and PID
      2. 4.4.2 Using VIDs and PIDs During Development
    5. 4.5 TinyUSB API Programmer's Guide and Examples
  7. 5Getting Started: Evaluating MSPM0 USB
  8. 6Summary
  9. 7References
  10. 8USB Glossary

3.2.2 USB Device Mode: Self-Powered

Another option for power on a USB device can be self-powering. This means that on the device, there is some external power supply apart from the USB power, which provides power to the chip and the connection when necessary.

A typical example of such a mode can be an audio or storage device, where power is required despite being disconnected. These designs require additional power management when compared to the bus-powered mode, with some form of primary power regulator and sequencing depending on the complexity of the power tree.

Oftentimes, self-powered devices can also be considered hybrid, meaning they either use the bus power when connected or charge a battery when connected. For this reason, oftentimes a VBUS monitoring circuit is necessary to detect a connection and switch to the power path provided by the bus. This can be accomplished by something as simple as a resistor divider hooked up to an ADC pin on the MSPM0G5187, which toggles a switch on the power path.