Comprehensive Guide to Full Brick Aluminum DC/DC Module Power Supply Design

1. Components should be placed as neatly and evenly as possible, with horizontal and vertical alignment to facilitate SMT production;

2. There should be a clear isolation band between primary and secondary, with sufficient safety distance;

3. High and low voltage networks should reserve sufficient safety distance, and slots should be opened if necessary;

4. The power transformer is generally placed in the center of the PCB;

5. The layout of the power board must coordinate with the layout of the control board;

6. Isolation components on the control board such as auxiliary power transformers, optocouplers, signal isolators, or driver chips should be placed in isolation areas;

7. The shape of the control board should be processed according to the layout of the power board, with segmentation, slots, and holes to limit the overall height of the power supply;

8. The placement of components on the top and bottom layers of the control board must be adjusted according to the layout of the aluminum substrate and the overall height of the power supply;

9. Reserve appropriate test points (key voltage, waveform, etc.) on the control board and power board, facilitating debugging and testing before assembly;

10. Pin labels should be easily recognizable with brief English markings to prevent errors during testing;

11. The power board often uses single-sided aluminum substrate, but there are also single-layer double-sided aluminum substrates;

12. The MOS power tubes on the power board should be placed close to discharge resistors of 10K or other parameters;

13. If possible, the bottom layer of the control board can be left free of components;

14. The placement of pins (connecting the power board and control board) can consider the shortest routing on the power board (single-layer single-sided board); or can be routed to the edge of the aluminum substrate (single-layer double-sided);

1. Wiring should reduce jumpers, minimize current loops, and take the shortest path;

2. Current sampling should use differential wiring;

3. Reduce the length of drive signal wiring;

4. The top and bottom layers of the control board can flexibly place components as needed;

5. The middle layer of the control board is recommended to have wiring, and the middle second layer should have a complete ground plane (primary, secondary);

6. Single point grounding; the Y capacitor of the primary side should use independent wiring on both sides, and use single-point connection at the primary side port;

7. Current sampling, voltage sampling, and peripheral components of the control chip should use signal ground or ground plane; MOS drive, etc., should use power ground; the ground plane should be segmented or layered and connected at appropriate places;

8. Weak analog signals (such as current sampling signals) and strong signals (such as MOS drive signals, digital signals) should be spaced apart or have ground line intervals or vertical wiring to reduce interference;

1. Large current loops should have the maximum area of copper pouring;

2. Signal lines in the middle layer should be 10mil, power lines and drive signal lines can be appropriately increased, such as 20mil;

3. Minimize network segmentation; some wiring can be located at the boundary of the copper-poured network or at the edge of the board;

4. Try to pour copper uniformly across the entire layer; if there are large areas that are not copper-poured, adjust wiring to fill them;

5. Magnetic devices should have copper pouring at the bottom to aid heat dissipation;

6. Pour copper as evenly as possible to reduce PCB warpage and other deformations;

7. The control board should leave a complete layer of copper pouring to improve the high-frequency characteristics of the signal;

8. PWM chip heat dissipation ground, MOS chip heat dissipation ground can be appropriately copper poured or connected to other layers through vias to enhance heat conduction and reduce temperature rise;

1. The derating of components must meet the requirements of relevant specifications;

2. The material of magnetic components should be PC95 or not lower than PC95;

3. For resistors, the resistance value of 10Ω − 1MΩ is preferably “±1%/100ppm”; 0Ω − 10Ω is preferably “±1%/200ppm”; current sampling resistors should use alloy resistors, “±1%/50ppm, 2512/3W”;

4. For ceramic capacitors, X7R, NP0 and other materials are preferred;

5. For chips, smaller packages are preferred, with low temperatures below -40℃ and high temperatures above 85℃;

6. Component selection should consider cost, universality (with alternative components of different brands if necessary), and availability;

7. Power pins should have an outer diameter of 2mm, and can be selected as 3mm for special cases; signal pins should have an outer diameter of 1mm; materials should be brass plated with gold or tin, etc.;

8. The power board should use aluminum substrate, with a preferred thickness of 2.0mm and a copper foil thickness of 3OZ; the control board should preferably use a four-layer FR4 board, with a thickness of 1mm and a copper foil thickness of 2OZ/2OZ/2OZ/2OZ;