CAN CIRCUIT STRUCTURE AND VEHICLE DIAGNOSTIC DEVICE INCLUDING THE SAME

The present invention relates to a CAN circuit structure and a vehicle diagnostic device including the same. The CAN circuit structure includes: a pair of data buses on which differential signals are transmitted; a CAN transceiver operating in a first voltage domain, where the CAN transceiver is connected to the data buses for receiving and transmitting the differential signals; a clamp circuit disposed between the CAN transceiver and the data buses for clamping a high level or a low level of the differential signals, so that a difference between voltages of the differential signals is adapted to the CAN transceiver; a CAN controller operating in a second voltage domain, where the CAN controller is connected to the CAN transceiver for communicating with the CAN transceiver; and a signal isolation circuit disposed between the CAN transceiver and the CAN controller for isolating the first voltage domain from the second voltage domain. The circuit allows for the use of a standard CAN transceiver chip that meets a general standard in a special CAN circuit structure such as a CAN protocol system for a 24V trailer, thus effectively reducing manufacturing costs of related devices.