The switching power supply produce EMI, often affect the normal work of the electronic products, the right switching power supply PCB layout becomes very important. In many cases, a design on the paper very perfect power may not work properly during initial commissioning, the reason is that the swithing power supply PCB wiring remains many problems.
The electronic products renewal fast speed, product design engineer is more likely to choose easy to purchase in the market to the AC/DC adapter, and the multiple sets of DC power supply directly installed on the system of the circuit board. The electromagnetic interference generated in the switching power supply will affect the normal work of the electronic products, the correct power supply PCB layout becomes very important. According to the experience summed up with the essentials of switching power supply PCB layout at eight point.
Below is simple for you to summarize what are the eight points, respectively.
Point 1. Ceramics capacitors capacitance cannot too big, and its parasitic series electric induction should be as small as possible, multiple capacitance can improve the impedance characteristics of capacitance in parallel;
Point 2. The inductance of the parasitic shunt capacitance should be as small as possible, the distance between the inductance pin pad should be as far as possible;
Point 3. Avoid walking in stratigraphic placed on any power or signal lines;
Point 4. The area of the high frequency loop should decrease as far as possible;
Point 5. Should not destroy the high frequency current on the formation of the path;
Point 6. On the system board need different strata with a small circuit, with small ground plane by a single point of the circuit connected to the power ground plane;
Point 7. Control chip to the top and bottom field effect tube driving circuit loop be short be possible;
Point 8. Switching power supply needs to connect to the power circuit and the control signal circuit components with small ground plane, the two strata are usually connected by a single point.