The best approach to designing a switching power supply layout closely mirrors its electrical design. The optimal design process follows these steps:
1. Place the transformer.
2. Design the PCB power switch current loop.
3. Design the output rectifier current loop.
4. Connect the control circuit to the AC power circuit.
5. Design the input current source loop and input filter.
When designing the output load loop and output filter based on the functional units of the circuit, and when laying out the components, the following principles must be observed:
– **First, consider the PCB size**. If the PCB is too large, the trace lengths increase, resulting in higher impedance, reduced noise immunity, and higher cost. Conversely, if the PCB is too small, heat dissipation becomes inadequate, and adjacent traces are more susceptible to interference. The ideal shape for the circuit board is rectangular, with aspect ratios of 3:2 or 4:3. Components on the edges of the PCB should generally be no less than 2mm from the board’s perimeter.
– **When placing components, consider ease of soldering**. Avoid overly dense placements.
– **Position the core components of each functional circuit at the center and lay out the surrounding components accordingly**. Components should be evenly, neatly, and compactly arranged on the PCB. Minimize the length of leads and connections between components, and place the decoupling capacitors as close as possible to the VCC pin of the devices.
– **For circuits operating at high frequencies, consider the distribution parameters between components**. Generally, components should be arranged in parallel as much as possible. This not only makes the layout more aesthetically pleasing but also simplifies installation, soldering, and mass production.
– **Arrange the functional circuit units based on the circuit flow**. This ensures that the layout facilitates efficient signal circulation, keeping signals in the same direction where possible.
– **The primary principle of PCB layout is to maximize routing efficiency**. Pay attention to the connections between components and place those that are interconnected near each other.
– **Minimize the loop area to reduce radiation interference from the switching power supply**.
4. **Wiring**.
1. The switching power supply contains high-frequency signals, and any printed trace on the PCB can act as an antenna. The length and width of these traces will impact their impedance and inductance, thus affecting the frequency response. Even traces carrying DC signals can couple with adjacent traces carrying radio frequency (RF) signals, causing circuit issues and potentially radiating interference. Therefore, all traces carrying AC current should be designed to be as short and wide as possible. This means that components connected to these traces, as well as other power traces, should be placed as close together as possible.
2. The length of a printed trace is directly proportional to its inductance and impedance, while the width is inversely proportional to both. The trace length is a key factor in determining the wavelength of the trace’s response. The longer the trace, the lower the frequency at which it can transmit and receive electromagnetic waves, which also makes it capable of radiating more RF energy. Based on the current requirements of the printed circuit board, try to increase the width of power traces to reduce loop resistance. At the same time, ensure that the direction of power and ground traces aligns with the current flow, which improves noise immunity. Grounding serves as the reference point for the switching power supply’s four current loops, and it plays a crucial role in controlling interference. As such, the placement of ground traces should be carefully considered during layout. Mixing different ground planes can lead to unstable power supply operation.
3. **Design Verification**
In 2018, Shenzhen Jiali made a significant price cut on bulk PCBs! After completing the routing design, it is essential to thoroughly verify that the layout complies with the designer’s specifications. It is also necessary to confirm that the defined rules align with the printed board production process. Typically, checks should include verifying the spacing between traces, trace and component pads, traces and vias, and between vias themselves to ensure that all distances are reasonable and meet production standards. Additionally, verify that the widths of power and ground traces are appropriate and ensure there is room to widen the ground traces if needed. Note that certain errors can be overlooked, such as when connector outlines are placed outside the board frame, causing spacing errors during checks. Furthermore, after any modification to traces or vias, the copper layer should be re-applied.
4. According to the “PCB Circuit Board Checklist,” key elements to review include design rules, layer definitions, trace widths, spacing, pad designs, via configurations, and the rationality of component placement. It is also important to review the layout of the power and ground networks, high-speed signal routing, clock network shielding, and the placement and connection of decoupling capacitors.
5. **Design Output**
**Precautions for Exporting Gerber Files:**
– The layers that need to be output include the routing layers (top and bottom), silk screen layers (top and bottom), solder mask layers (top and bottom), and the drilling layers (top and bottom), along with the drilling files (NC Drill).
– When configuring the silk screen layer, avoid selecting the “Part Type” option. Instead, choose the top or bottom layer and include the Outline, Text, and Line elements of the silk screen layer.
– When setting up each layer, be sure to select the “Board Outline.” For the silk screen layer, avoid selecting “Part Type” and instead select the top or bottom layer, as well as the Outline, Text, and Line elements of the silk screen layer.
– When generating drilling files, use PowerPCB.
If you have any PCB manufacturing needs, please do not hesitate to contact me.Contact me
1. Place the transformer.
2. Design the PCB power switch current loop.
3. Design the output rectifier current loop.
4. Connect the control circuit to the AC power circuit.
5. Design the input current source loop and input filter.
When designing the output load loop and output filter based on the functional units of the circuit, and when laying out the components, the following principles must be observed:
– **First, consider the PCB size**. If the PCB is too large, the trace lengths increase, resulting in higher impedance, reduced noise immunity, and higher cost. Conversely, if the PCB is too small, heat dissipation becomes inadequate, and adjacent traces are more susceptible to interference. The ideal shape for the circuit board is rectangular, with aspect ratios of 3:2 or 4:3. Components on the edges of the PCB should generally be no less than 2mm from the board’s perimeter.
– **When placing components, consider ease of soldering**. Avoid overly dense placements.
– **Position the core components of each functional circuit at the center and lay out the surrounding components accordingly**. Components should be evenly, neatly, and compactly arranged on the PCB. Minimize the length of leads and connections between components, and place the decoupling capacitors as close as possible to the VCC pin of the devices.
– **For circuits operating at high frequencies, consider the distribution parameters between components**. Generally, components should be arranged in parallel as much as possible. This not only makes the layout more aesthetically pleasing but also simplifies installation, soldering, and mass production.
– **Arrange the functional circuit units based on the circuit flow**. This ensures that the layout facilitates efficient signal circulation, keeping signals in the same direction where possible.
– **The primary principle of PCB layout is to maximize routing efficiency**. Pay attention to the connections between components and place those that are interconnected near each other.
– **Minimize the loop area to reduce radiation interference from the switching power supply**.
4. **Wiring**.
1. The switching power supply contains high-frequency signals, and any printed trace on the PCB can act as an antenna. The length and width of these traces will impact their impedance and inductance, thus affecting the frequency response. Even traces carrying DC signals can couple with adjacent traces carrying radio frequency (RF) signals, causing circuit issues and potentially radiating interference. Therefore, all traces carrying AC current should be designed to be as short and wide as possible. This means that components connected to these traces, as well as other power traces, should be placed as close together as possible.
2. The length of a printed trace is directly proportional to its inductance and impedance, while the width is inversely proportional to both. The trace length is a key factor in determining the wavelength of the trace’s response. The longer the trace, the lower the frequency at which it can transmit and receive electromagnetic waves, which also makes it capable of radiating more RF energy. Based on the current requirements of the printed circuit board, try to increase the width of power traces to reduce loop resistance. At the same time, ensure that the direction of power and ground traces aligns with the current flow, which improves noise immunity. Grounding serves as the reference point for the switching power supply’s four current loops, and it plays a crucial role in controlling interference. As such, the placement of ground traces should be carefully considered during layout. Mixing different ground planes can lead to unstable power supply operation.
3. **Design Verification**
In 2018, Shenzhen Jiali made a significant price cut on bulk PCBs! After completing the routing design, it is essential to thoroughly verify that the layout complies with the designer’s specifications. It is also necessary to confirm that the defined rules align with the printed board production process. Typically, checks should include verifying the spacing between traces, trace and component pads, traces and vias, and between vias themselves to ensure that all distances are reasonable and meet production standards. Additionally, verify that the widths of power and ground traces are appropriate and ensure there is room to widen the ground traces if needed. Note that certain errors can be overlooked, such as when connector outlines are placed outside the board frame, causing spacing errors during checks. Furthermore, after any modification to traces or vias, the copper layer should be re-applied.
4. According to the “PCB Circuit Board Checklist,” key elements to review include design rules, layer definitions, trace widths, spacing, pad designs, via configurations, and the rationality of component placement. It is also important to review the layout of the power and ground networks, high-speed signal routing, clock network shielding, and the placement and connection of decoupling capacitors.
5. **Design Output**
**Precautions for Exporting Gerber Files:**
– The layers that need to be output include the routing layers (top and bottom), silk screen layers (top and bottom), solder mask layers (top and bottom), and the drilling layers (top and bottom), along with the drilling files (NC Drill).
– When configuring the silk screen layer, avoid selecting the “Part Type” option. Instead, choose the top or bottom layer and include the Outline, Text, and Line elements of the silk screen layer.
– When setting up each layer, be sure to select the “Board Outline.” For the silk screen layer, avoid selecting “Part Type” and instead select the top or bottom layer, as well as the Outline, Text, and Line elements of the silk screen layer.
– When generating drilling files, use PowerPCB.
If you have any PCB manufacturing needs, please do not hesitate to contact me.Contact me
