CAN Bus Shield Design

flux

Based on the requirements and the need for robustness under frequent power cycling, a switching regulator such as the LM2596 is a solid choice. It is more efficient and typically better at withstanding the voltage fluctuations and transient conditions common in automotive applications compared to a linear regulator like the LM7805.
Here’s a summary of the proposed design:

Table

SectionComponents & Details
CAN Bus Section- CAN Controller: MCP2515 - CAN Transceiver: SN65HVD230 - Include decoupling capacitors for each IC's power pins - Use Ground connections
OBD-II Section- OBD-II Connector (J1): with connections for   • CAN High (OBD-II Pin 6)   • CAN Low (OBD-II Pin 14)   • +12V (power input)   • GND
Power Supply Section- Input: +12V supplied via the OBD-II connector - Regulation: LM2596 switching regulator to step down the 12V to a regulated 5V (for powering the Arduino/RPi) - Include decoupling capacitors at the LM2596 input and output - Consider additional protection (e.g., diode arrays or transient suppression) if extreme voltage spikes are expected
Stackable Headers- Include stackable header pins to interface both the CAN bus circuit and the regulated power output to the microcontroller (Arduino/RPi)
If this design summary meets your requirements, we can proceed with a schematic update suggestion outlining these components and interconnections. Let me know if you would like to apply these schematic changes or if any modifications are needed.
H

hackingjack

LM2596 looks like the right choice given the frequent on/off cycles. Please add the LM2596 to the schematic with proper decoupling capacitors at both its input and output, and include surge protection elements for voltage spikes.

flux

Below is a summary of the schematic updates to be made for the power regulation and surge protection section of your CAN bus shield design:
  • Regulation:
    • Add a switching regulator using the LM2596 (designator U3). This regulator will step down the 12V from the OBD-II connector to a regulated 5V for powering the Arduino/RPi.
  • Decoupling Capacitors:
    • Add a decoupling capacitor at the input of the LM2596:
      • Example: C1 (e.g., 100 µF capacitor) connected between the LM2596 input and GND.
    • Add a decoupling capacitor at the output of the LM2596:
      • Example: C2 (e.g., 220 µF capacitor) connected between the LM2596 output and GND.
  • Surge Protection:
    • To protect against voltage spikes on the 12V line, include a surge protection element:
      • Example: TVS Diode (designator D1) placed across the incoming +12V and GND before the LM2596 regulator input.
  • Additional Connections:
    • Ensure that all added components (the LM2596, capacitors, and TVS diode) have proper ground connections via the Ground component.
You can use the "Apply changes" button to update your schematic with these modifications.
Apply schematic changes
Add LM2596 with protections
Implement LM2596 section
Sign up to send
No schematic yet

Talk to Flux to get started.