PCB Technical - Ensure the normal operation of electronic products

In PCB design and layout, PCB rookies must have encountered difficult wiring and layout problems. The electromagnetic interference generated by switching power supplies often affects the normal operation of electronic products. Correct switching power supply PCB circuit board layout becomes Very important. A power supply that is perfectly designed on paper may not work properly during the first commissioning because there are many problems with the PCB wiring of the power supply. So is there any good way to solve it? This article summarizes the eight key points for fast wiring of switching power supply PCB circuit boards.

In the PCB design and layout, the electromagnetic interference generated by the switching power supply often affects the normal operation 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 the initial commissioning. The reason is that there are many problems with the PCB circuit board wiring of the power supply.

In the PCB design and layout, the current electronic products are updated very quickly, which is simply a trend of lightning. Product design engineers are more inclined to choose AC/DC adapters that are easily available in the market, and combine multiple sets of DC The power supply is directly installed on the circuit board of the system. Since 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 the layout of the eight-point switching power supply PCB circuit board based on experience.

In the PCB design and layout, here is a brief summary of what these eight points are.

Point 1 The capacitance of the bypass ceramic capacitor should not be too large, and its parasitic series inductance should be 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 distance between the inductor's pin pads should be as far as possible;

Point 3 Avoid placing any power or signal traces on the ground;

Point 4 The area of the high-frequency loop should be as small as possible;

Point 5 Via placement should not destroy the path of high-frequency current on the ground;

Point 6 A different circuit on the system board requires different ground planes, and the ground planes of different circuits are connected to the power ground plane through a single point;

Point 7 The drive circuit loop from the control chip to the upper and lower FETs should be as short as possible;

Point 8 The power circuit and the control signal circuit components need to be connected to different ground planes. These two ground planes are generally connected through a single point.