The working principle of CAN isolators is mainly based on the principle of galvanic isolation. It uses an isolation chip to isolate the input and output of the CAN bus, thereby blocking the electrical connection between the input and output, and realizing the isolated transmission of signals. This isolation resists common-mode voltage interference and protects devices on the CAN bus from damage.
Common-mode voltage interference is when data is transmitted between two systems via the CAN bus, resulting in a potential difference between the two systems due to the independent CAN signal reference ground levels of the two systems. When this common-mode level exceeds the common-mode withstand voltage level of the CAN chip, the CAN chip will be damaged. CAN isolators eliminate the influence of common-mode voltages on the CAN bus by isolating the input and output signals through galvanic isolation.
In addition, CAN isolators use suitable isolation chips, such as optocoupler isolation chips or complementary metal-oxide-semiconductor field-effect transistor (CMOS) chips. These isolation chips have different isolation characteristics and transmission performance, and the appropriate isolation chip can be selected according to the specific application scenario.