Yint Electronics Has Proposed a Comprehensive Protection Solution for the PEPS System Vehicle Base Station and positioning tag

During the communication or control process of the PEPS system, the system PEPS main control MCU, LIN communication lines, CAN communication lines and other units are susceptible to electromagnetic interference such as surges and static electricity due to the influence of the use environment such as power supply changes, human body proximity induction or release, and line induction. , causing the main control MCU, body control module BCM, antenna transceiver chip, and other components to work abnormally or even be damaged, affecting communication reliability and testing the overall stability of the vehicle base station system.

During the use of the PEPS smart key, due to factors such as pressing or releasing the button, changes in the inductive load of the antenna, proximity of the human body, induction of the electromagnetic environment, etc., the main control IC, LF low-frequency receiving module, RF radio frequency transmitting module and other units in the smart key system It is susceptible to interference from static electricity or surges, causing abnormal operation or even damage.

Based on many years of experience in electromagnetic compatibility of automotive electronics and combined with the advantages of its own automotive grade products, Yint Electronics has proposed a comprehensive protection solution for the PEPS system vehicle base station (vehicle base station) and positioning tag (smart key) for user design reference.

PEPS system controller (vehicle base station) protection solution

The circuit protection of vehicle base stations mainly includes the following aspects:

1、Power PDU Management Unit Surge Protection 

The power PDU management in the PEPS system mainly includes the power supply for components such as the electronic steering column lock ESCL, and Yint Electronics TVS is used for surge protection.

Commonly used protective devices are:

SM8S24CA, SM8S33CA, SM8S33A, SM8S36CA, etc.

The specific selection needs to be based on the vehicle power system and component power.

Fig.1

Table.1

CAN Bus Communication Protection

The PEPS system communicates with the body control system BCM and other major components of the car through the CAN bus.

Yint Electronics provides automotive-grade CAN bus protection special device ESD24VAPB designed close to the CAN bus interface of the module.

Fig.2

Table.2

3、LIN Bus Communication Protection

LIN bus communication is mainly used between the PEPS system and the electronic steering column lock ESCL.

LIN interface protection can use LIN special devices ESDLIN1524D3B, ESD24VAPB, etc. for protection.

Fig.3

4、LF Low Frequency Communication Protection

●2PEPS system LF low-frequency communication uses 125kHz frequency for communication. The 6 (or 8) antennas of the base station send out 125kHz signals to find the location of the tag (smart key) and match and wake it up. When the tag (smart key) is located in the car and the key is matched, the anti-theft controller IMMO and electronic steering column ESCL unlocking instructions can be given, and the driver can start the engine through the ignition button.

●Changes in the antenna signal and equivalent load changes for the transmitting module require surge or electrostatic protection. It is recommended to use Yint Electronics 5V, SOD323 packaged electrostatic protection device ESD5V0D3B. The PCB layout design is recommended to be close to the antenna access port of the module.

Fig.4

Table.4

5、RF Radio Frequency Communication Protection

●The PEPS system controls the vehicle base station to wait for tag return instructions and mainly uses 315MHz~433MHz radio frequency for communication. The PEPS system positioning tag (smart key) combines the door handle button switch instructions to send RF radio frequency encrypted signals to the vehicle base station. After matching, the vehicle base station will provide access control and unlock, and the occupants can enter the car.

●For the RF radio frequency receiving module, we use Yint Electronics' low-capacitance electrostatic protection device ESDLC5V0D3B, SOD323, and the <1pF capacitance will not affect the normal communication of the signal. At the same time, it can clamp and protect the transient voltage at the ps level. RF receiving module.

Fig.5

Table.5

6、One-Click Start Button Electrostatic Protection

The PEPS system engine start button usually has an LED light color change indicator to indicate status information. In order to prevent static electricity from giving error information to the main control chip, the key-activated unit needs to add a small package of electrostatic protection devices. Yint Electronics' automotive grade electrostatic protection device ESD5V0D9B is packaged in SOD923 (dimensions: length, width, and height 1.0mm, 0.5mm, 0.4mm) and can withstand up to 30kV electrostatic disturbance.

Fig.6

Table.6