Single-Ended to Differential Signal Converter

As Aristurtle continuously strives for improved performance in the Formula Student competition, ensuring the credibility of sensor signals is crucial for accurate data transmission. Our vehicle relies on multiple sensors, such as the steering sensor, brake pressure sensor, APPS, and suspension potentiometers, to provide critical data for performance optimization. However, single-ended signals are highly sensitive to noise, leading to inaccurate readings that can compromise our control strategies. To resolve this issue, we implemented a Single-Ended to Differential Signaling system that consists of two PCBs—one for single-ended to differential conversion and another for differential to single-ended conversion—allowing sensor signals to travel as differential pairs which are significantly less susceptible to electromagnetic interference. This upgrade ensures that our measurements are more precise, ultimately enhancing the reliability of our vehicle’s systems.

In our system, the sensor outputs—originally single-ended—are initially converted into differential signals. This conversion is achieved by a carefully designed inverter circuit that transforms the sensor’s single-ended voltage into a balanced differential pair. Transmitting the signal as a differential pair is crucial in an automotive environment, where high levels of electromagnetic interference (EMI) and noise are common. The differential transmission allows the system to effectively cancel out common-mode noise, ensuring that the integrity of the sensor data is maintained as it travels over the vehicle’s wiring. At the receiving end, another conversion circuit reverts the differential signal back into a single-ended format, making it compatible with the microcontroller’s analog-to-digital converter (ADC) for accurate measurement and processing.

To validate the design, we conducted a series of simulations using SPICE. The SPICE models for both the single-ended to differential (S-to-D) and differential to single-ended (D-to-S) circuits were developed and tested under various simulated noise conditions typical of a car environment. The simulation results showed that the differential signal maintains its integrity over long transmission distances and in the presence of significant interference.

The next phase involved translating the simulation-verified design into detailed schematics for PCB fabrication. The schematics were developed using industry-standard PCB design software and feature two distinct circuit boards.

The S-to-D PCB consists of:

1x TLV9352QDGKRQ1 operational amplifier (2-channel)

4x 0603-inch code, 10KOhms, low tolerance resistors

1x 3-pin, nano-fit, right-angle connector

1x 6-pin, nano-fit, right-angle connector

The D-to-S PCB consists of:

1x TLV9352QDGKRQ1 operational amplifier (2-channel)

4x 0603-inch code, 10KOhms, low tolerance resistors

1x 0603-inch code, 5KOhms, low tolerance resistor

1x 6-pin, nano-fit, right-angle connector

These are according to the schematics above.

Here, we would like to take this opportunity to express our gratitude towards JLCPCB for providing the PCBs and making this project a reality. You can order your own PCBs from JLCPCB by clicking here. Firstly, you must add a gerber file. Gerber files can be exported from the software with which you design the PCB. In our case that software is Altium Designer. The next step is to select all the characteristics you require for your PCB. After that, you will have to add any additional files, such as the BOM files and the pick and place files. Upload these files and you are ready to complete the order

We have tested our Single-Ended to Differential Signaling system on track and confirmed that in long distance transmissions the sensor signals remain accurate and resistant to electromagnetic interference. We validated that the two custom PCBs effectively eliminate external noise, allowing for precise measurements and thus making them an essential implementation for the team’s vehicle.