Characterization

Characterization

Normally before you even start to design a PCB, you write a document characterizing all of the requirements for that board. This would include defining power levels, inputs, outputs, etc. For this onboarding project, however, the board's requirements are very simple for the sake of learning:

Inputs:

• 12V Power, through XT-30U Female Connector
• CAN Signal, through JST-GH BM02B Connector

Outputs:

• 28V Power, through XT-30U Male Connector
• CAN Signal, through JST-GH BM02B Connector

XT-30 cables are standard to RoboMaster power components, hence their connector usage here
JST-GH cables are also standard to RoboMaster, for data connections. This includes CAN, UART, and other proprietary standards in DJI's components

Internal Circuits (high-level overview)

• Boost converter, 12V to 28V
• CAN differential pair routing

Size & Shape:

• Rectangular, 1200mm² or less, with filleted corners (rounded)
  • Often the board size and exact shape is directly constrained by the Mechanical team, here I've kept it simpler
• M2 Screw hole reliefs in board corners

These characteristics are required for the onboarding project. I will not count it as completed until all these requirements are met.

Circuit Theory

This project assumes basic circuit knowledge (up to DC circuit analysis and basic understanding of inductor/capacitor behavior) and will definitely benefit from it (For ECE majors, ECE 302 will cover it). If you're totally new to circuits, the Khan academy Electrical Engineering course from Unit 1 through Unit 2 - Natural and forced response can provide the bare minimum knowledge.

Assuming this knowledge, taking ~20 minutes to read this overview on switched power supplies will be highly beneficial. This project is an implementation of the Boost Switch Mode Power Supply topology discussed in the tutorial.

Next Steps

See Schematic Design