## 2 SJB Implementation
### Design of the SJB PCB Module
In addition, each component related to the IPS component was placed as close as possible to the load connector pins to minimize various factors, such as PCB resistance. To solve the problem due to high-density components mounting in the control section \begin{table}
\begin{tabular}{c c c} \hline \hline
**Items** & **Requirements** & **Descriptions** \\ \hline \multirow{4}{*}{Regulator} & \multirow{4}{*}{Output: 5 V, 200–500 mA} & TLE727220 (Infineon): - 5 V output, 300 mA output - 1 Inhibit input - - Over temperature shut down \\  & & SAK-XC2364B-40F80L AA (Infineon): - 16-bit micro controller - CAN: 2 ch - CPU cycle: up to 80 MHz - ADC:16 ch/10 bit resolution - I/O: up to 76 general purpose input/output lines \\  & & TLE6254-3G (Low speed): - - Data transmission rate up to 125 Kbaud - Standby, sleep mode operation, include bus - wake up - Failure management - Temperature protection - TLE6250G (High speed): - Data transmission rate up to 1 Mbaud - Temperature protection \\  & & M95020 (ST): - 2 kbit EEPROM - Compatible with SPI bus - 10 MHz clock rate, 5 ms write time \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Specifications of the main components. \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Items** & **Lamp Output** & **Actual Current** & **Specification of IPS** \\  & **[W]** & **Consumption [A]** & **Specification of IPS** \\ \hline H/LP Low LH & 55 & 4.07 & BTS6142D (Infineon): - \\ H/LP Low RH & 55 & 4.11 & - Rds (on): 12 m\(\Omega\) \\ H/LP High LH & 60 & 4.45 & - Load Current: 27 A \\ H/LP High RH & 60 & 4.51 & - Nominal Current: 7 A \\ Fog Lamp LH & 35 & 2.55 & - Current Limitation: 50 A \\ Fog Lamp RH & 35 & 2.59 & - Current Sense \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Specifications of the output in terms of the load, current consumed, and IPS. of the PCB, some of the components that were not significantly affected by noise were placed in the power section. In addition, to minimize the effects of the heat generated by the IPS components, the MCU and communication devices were placed in the lower section of the PCB. The layout of the PCB is shown in Figure 6.  
The developed SJB was thermally analyzed by way of a simulation to determine the heat dissipation of the IPS components when driving each load. To analyze the thermal distribution according to the behavior of the SJB PCB module, we used a commercial thermal analysis tool, PADS, and simulated the thermal distribution of the PCB module. An image of the temperature distribution is shown in Figure 7. The results of this analysis showed that under full load operating conditions with both headlights and wipers in operation, the initial maximum temperature on the board was 45.7 \({}^{\circ}\)C. The maximum temperature then increased to 66.9 \({}^{\circ}\)C when the wipers were set to high power. The temperature rise may be even higher if the SJB were to be installed in the engine compartment of a vehicle powered by an internal combustion engine; however, it is not a concern in this case as the focus of this study is on SJBs for electric vehicles. In the IPS section of the board, the components that experience higher temperatures were placed around the connector to improve the heat distribution to the connector side. In addition, the IPS component that powers the load was placed at the top of the PCB. These measures were considered to satisfactorily address any potential heat-related problems in the SJB. Figure 6: Diagrams showing the PCB layout of the SJB: (**a**) block diagram of the IPS circuitry, (**b**) arrangement of the components on the board, with the IPS circuitry contained within the area outlined in red and the control circuitry contained in the lower region, and (**c**) photographic image of the fabricated PCB.