Summary of the eight points to ensure the normal operation of electronic products.
PCB novices have definitely encountered problems with wiring and layout, and the electromagnetic interference generated by switching power supplies often affects the normal operation of electronic products. Correct PCB layout of switching power supplies has become very important. A power supply that is perfectly designed on paper may not work properly during initial commissioning, because there are many problems with the PCB layout of the power supply. So is there any good way to solve it? This article summarizes the eight main points for fast wiring of switching power supply PCBs.
The electromagnetic interference generated by the switching power supply often affects the normal work of electronic products, and the correct layout of the switching power supply PCB becomes very important. In many cases, a power supply that is perfectly designed on paper may not work properly during initial commissioning, because there are many problems with the PCB layout of the power supply.
Nowadays, the electronic products are updated very fast, which is like a thunderbolt. Product design engineers are more inclined to choose AC / DC adapters that are easily available in the market and install multiple sets of DC power supplies directly on the system's lines. On the board. Because the electromagnetic interference generated by the switching power supply will affect the normal operation of its electronic products, the correct layout of the power supply PCB becomes very important. This article summarizes the basic points of PCB layout of eight-point switching power supply based on experience.
Here is a brief summary for each of these eight points.
Point 1 The capacitance of the bypass ceramic capacitor cannot be too large, and its parasitic series electrical induction is as small as possible. Multiple capacitors in parallel can improve the impedance characteristics of the capacitor;
Point 2 The parasitic parallel capacitance of the inductor should be as small as possible, and the farther the distance between the inductor pin pads is, the better;
Point 3 Avoid placing any power or signal traces on the ground plane;
Point 4 The area of the high-frequency loop should be reduced as much as possible;
Point 5 The placement of vias should not destroy the path of high-frequency current on the formation;
Point 6 A different circuit on the system board requires different ground planes. The ground planes of different circuits are connected to the power ground plane through a single point.
Point 7 The driving circuit loop from the control chip to the upper and lower FETs should be as short as possible;
Point 8 The components of the power circuit and control signal circuit need to be connected to different ground planes. These two ground planes are generally connected through a single point.