Brief introduction to the design of switching power supply on electronic circuit board
More than 60% of our electronic products-reliability problems appear in the PCB design of electronic circuit boards; PCBs with good work and performance require relevant theoretical and practical experience; I often encounter various problems in product design practice. Various problems; for example, the electronic circuit board cannot pass the system EMS test standard, the high-frequency noise problem occurs when testing the function pins of the key device IC, and the circuit function IC pin detects interference noise for abnormal protection, etc.
Through the combination of theory and practice; use test data to test the differences between our theory and practice! Excellent design is inseparable from long-term experience summary!
1. The switching power supply shares the overall design principles through the following schematic diagram
A． The area of the main current return path of the switching power supply topology is minimized; the driving pulse current loop is minimized.
B． For the isolated switching power supply topology, the current loop is isolated by the transformer into two or more loops (primary side and secondary side), and the current loop should be separated for minimum return area layout and wiring design.
C． If the current loop has multiple grounding points, the grounding point should coincide with the central grounding point.
D． In the actual design, we will be limited by the conditions; if the capacitance of the two loops may not be close to the common ground!
Key points of the design:
We will use electrical parallel connection to add a high-frequency capacitor nearby to achieve a common ground (as shown in the red dotted line)!
2. PCB design ideas for non-isolated IC controller and main power loop system
The non-isolated power supplies power to the IC controller, which controls the LED load and performs dimming and other functional control applications. The power supply of the controller and the design of the driving circuit will affect the function and reliability of the system.
