PCB Layout

Board Layer Stack Manager - 4 Layers

The layer stack manager on the Altium Design Software allows users to input board layer and thickness specifications. Furthermore, users can choose desired dielectric materials for the Printed Circuit Board. The layer stack manager allows Printed Circuit Board manufactures to easily adhere to the board specifications listed by the user when creating the Gerber files. After the Gerber Files were generated by the Altium Design software, the files were uploaded to Bay Area Circuits' website in order to check the DFM (Design for Manufacturability). Performing a DFM check will identify and notify customers of underlying design issues in the PCB, which can cause errors during manufacturing. After the Battery Management PCB was uploaded for a DFM check, there were several errors that can potentially cause manufacturing problems. However, after updating the PCB layout and rechecking the DFM, the same problems were raised. A Manufacturing Engineer from Bay Area Circuits stated that the problem was in the Board's Polygon Pour. However, the Manufacturing Engineer stated that this should not cause any errors in manufacturing. In our PCB design, we managed to reduce the number of layers of our board to four layers instead of the Texas Instruments Datasheet recommendation of six layers.

Layout of Components Before Placement

Accurate component placement is essential when designing a PCB. There were more than 200 components that was needed to be manually routed using the Altium software, requiring an abundance of time and care making sure components are properly placed. Furthermore, components were placed on the front and back of the PCB in order to save space and reduce the overall size.

Top Layer PCB Routing

The figures below shows the PCB Layout routing of the Battery Management System. Two methods were taken into consideration when routing the PCB: Auto-Routing and Manual Routing. The Texas Instruments BQ76pl455a-Q1 datasheet states careful consideration must be taken into account when routing the PCB Layout. Texas Instruments suggests performing a manual route rather than auto routing due to Altium software not being able to understand the most optimal route for design. In order to make the most desirable PCB, we decided to manually route the entire layout. This was the most difficult and time consuming task of this project. A total of 35 hours was spent manually routing, choosing the appropriate thickness of the power/component trace's, and careful placement of each component was taken in consideration in order to avoid thermal issues on the PCB.

Bottom Layer PCB Routing

Another image showing the PCB layer routing of the Battery Management System for the bottom layer.

Final Component Layout - All Layers

The figure below shows all 4 routing layers of our Battery Management System PCB.

Polygon Pour

A Polygon Pour is used to create a large Ground area on the Printed Circuit Board and are necessary when dealing with multiple layers. The figure below shows a Polygon Pour for the top and middle layers of our board. The middle Polygon layer colored in yellow is the ground plane of the PCB. A solid ground plane on a printed circuit board acts as an EMC (Electromagnetic Compatibility) shield. Separate polygon pours are used to isolate the High Voltage and Low Voltage signals on the PCB.