What is the voltage of LIN bus?
3 Answers
The voltage of LIN bus is 12 volts. The units controlled by LIN bus are distributed in a relatively close space, and the data transmission is single-wire. The data line can reach up to 40 meters. In the main node, a 1 kilo-ohm resistor is configured to terminate the 12-volt power supply, while in the slave node, a 30 kilo-ohm resistor is configured to terminate the 12-volt power supply. LIN bus is a low-cost serial communication network defined for automotive distributed electronic systems, serving as a supplement to other automotive multiplex networks such as Controller Area Network (CAN). It is suitable for applications that do not require high bandwidth, performance, or fault tolerance, with the purpose of providing auxiliary functions.
I'm the type who enjoys tinkering with automotive electronics and often fiddle with the control modules in cars. The LIN bus in vehicles is primarily used to control less complex functions like windows and mirrors. Its voltage standard is such that during signal transmission, the logic low level is approximately close to 0 volts, while the logic high level is close to the vehicle's battery voltage, typically around 12 volts. This mainly depends on the car's power system—for instance, most small cars use a 12V battery. If the voltage is unstable, due to reasons like an aging battery or poor wiring connections, the LIN bus can malfunction, leading to issues like windows not opening. I recommend that car owners regularly check their battery health to avoid such minor troubles. After all, these low-speed communication designs are meant to be cost-effective and simple, but maintenance is crucial.
I've been driving for decades and have encountered numerous minor car issues, so I have some understanding of LIN bus. Simply put, its voltage typically follows the vehicle's power supply, with low level around 0 volts and high level approximately 12 volts. During normal operation, this voltage remains relatively stable. However, if a fault occurs—such as a burnt relay or a short circuit—the voltage may become abnormal, affecting LIN-connected devices like a sunroof that won't close. I once witnessed this firsthand on a rainy night when the headlights flickered erratically; later inspection revealed it was due to LIN voltage issues causing control errors. That's why experienced drivers know that besides regular oil changes, it's crucial to monitor the battery condition and wiring connections—don't wait for small issues to escalate into big problems.
