“World-renowned semiconductor manufacturer ROHM (headquartered in Kyoto, Japan) has developed SerDes IC*1 “BU18xMxx-C” and PMIC*2 “BD86852MUF-C” ideal for ADAS (Advanced Driver Assistance System) automotive camera modules . These two products not only meet the demand for miniaturization and low power consumption of modules, but also help reduce customers’ development man-hours due to their low electromagnetic noise (low EMI) characteristics.
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Great for car camera modules!
ROHM develops SerDes IC “BU18xMxx-C” and PMIC for camera “BD86852MUF-C” to provide solutions that help reduce power consumption and EMI in increasingly advanced ADAS
World-renowned semiconductor manufacturer ROHM (headquartered in Kyoto, Japan) has developed SerDes IC*1 “BU18xMxx-C” and PMIC*2 “BD86852MUF-C” ideal for ADAS (Advanced Driver Assistance System) automotive camera modules . These two products not only meet the demand for miniaturization and low power consumption of modules, but also help reduce customers’ development man-hours due to their low electromagnetic noise (low EMI) characteristics.
ADAS systems are built by combining devices with different sensing methods and sensing distances, such as LiDAR, sonar, and cameras. Among them, in units such as parking assist systems, the latest cars are equipped with about 10 cameras per vehicle since the on-board cameras play an important role in eliminating nearby blind spots. In addition, with the continuous development of ADAS, the number of its use is also further increasing, which also puts forward higher requirements for improving the performance of various cameras. On the other hand, as the number of cameras installed increases, there is an increasing demand for further reduction in board size and power consumption in vehicle-mounted camera modules due to the limited amount of power that can be supplied by batteries and the space for installing cameras.
ROHM has solved these problems by combining new products of SerDes IC and PMIC for camera. In addition, since both products have spread spectrum capabilities, EMI is lower, and EMI countermeasures have always been a major burden in automotive application design, which will help reduce the design man-hours for EMI countermeasures.
The SerDes IC “BU18xMxx-C” used to transmit images can optimize the transmission rate according to the resolution, so the power consumption can be reduced by 27% compared with ordinary products. In addition, through the transmission rate optimization function and the spread spectrum function*3, the peak EMI can be reduced by about 20dB. Not only that, the IC also has a freeze detection function that can detect the freezing state of the image, thereby also improving the reliability of the entire ADAS system.
The PMIC (Power Management IC) “BD86852MUF-C” for cameras can provide better management functions for the power supply systems of CMOS image sensors from various major manufacturers. Since voltage setting and timing control can be performed with only a single IC, the mounting area can be reduced by about 41%, contributing to the miniaturization of in-vehicle camera modules. In addition, since the circuit structure can dissipate the heat concentrated on the camera PMIC, by suppressing the heat generation, a high conversion efficiency of 78.6% is achieved, which contributes to further reduction of power consumption.
SerDes IC “BU18xMxx-C” has started to provide samples in February 2021 (sample price 1,000 yen ~ / piece, tax not included), and it is expected to start mass production from June 2021 with a monthly production scale of 200,000 pieces . In addition, the PMIC “BD86852MUF-C” for cameras has been put into mass production with a monthly production scale of 500,000 units from January 2021 (sample price 500 yen/unit, excluding tax).
In the future, ROHM will continue to develop products that further reduce power consumption and improve system reliability, and will continue to contribute to the development of the automotive industry.
＜Details of features＞
SerDes IC “BU18xMxx-C” ideal for in-vehicle camera modules and for cameras
The PMICs “BD86852MUF-C” are all compliant with the automotive electronics reliability standard AEC-Q100, which ensures the reliability required for in-vehicle applications. In addition, PMICs for cameras are currently developing new products that meet the stricter ISO 26262*4 process certification requirements, and are expected to launch product samples that meet the standard’s “ASIL-B” safety level in fiscal 2021.
●Features of SerDes IC “BU18xMxx-C”
1. The transmission rate is optimized to help reduce the power consumption of the vehicle camera module
Common SerDes ICs set a fixed transfer rate for each frequency band. However, since this way cannot set the transfer rate more finely, there is a power loss. And “BU18xMxx-C” is equipped with a function to optimize the transfer rate according to the resolution rather than the frequency band. Since a finer transmission rate setting than ordinary products can be made, the work efficiency is higher, which helps to further reduce the power consumption of the in-vehicle camera module. When this product is installed in an application product using four camera modules, the above advantages can reduce power consumption by about 27% compared to ordinary products.
2. Built-in transfer rate optimization function and spread spectrum function help reduce design man-hours for EMI countermeasures
Using the above-mentioned transmission rate optimization function, this product disperses the EMI peak by slightly changing the transmission rate of each path, and reduces the EMI by about 10dB (① in the figure below). In addition, by equipping the two ICs of the serializer and the deserializer with the spread spectrum function, the EMI can be further reduced by about 10dB (② in the figure below). In the design of automotive applications, EMI countermeasure design is a major burden, and the above advantages will greatly help reduce the design man-hours for EMI countermeasures.
3. Equipped with freeze detection function to help improve reliability
This product is also equipped with a function to detect the frozen state of the image. In addition to the basic function of confirming that the image is transmitted accurately by comparing the MIPI CRC value from the CMOS image sensor to the deserializer, by comparing the data frame CRC value of the camera image with the values before and after it in the serializer at all times, to monitor image freeze problems. If the CRC value of the data frame is consistently consistent, an error flag can be output to inform the IC of the subsequent stage that the image freezing problem has occurred, which will help improve the reliability of the ADAS system.
4. Complete product lineup, supporting various CMOS image sensors and SoCs
This product has a total of 3 product models, including a serializer and two deserializer products. Since all three products support the three major communication cables, a variety of CMOS image sensors and SoCs can be supported.
Features of PMIC “BD86852MUF-C” for camera
1. Optimized function for CMOS image sensor, smaller circuit board area
CMOS image sensors are the main components of automotive cameras. Different manufacturers have different drive voltage settings and timing control, and require many external components. The “BD86852MUF-C” is equipped with pins for setting the driving voltage and timing control of the main CMOS image sensor, eliminating the need for external parts for driving voltage setting and timing control. As a result, the number of parts and mounting area are significantly reduced compared to previous products, which will contribute to the miniaturization of in-vehicle camera modules.
2.High conversion efficiency helps reduce power consumption
This product supplies power to the CMOS image sensor through an external LDO*5, thereby dissipating the heat concentrated in the IC. By suppressing the heat generation of the entire circuit, the conversion efficiency of up to 78.6% is achieved, which is about 4% higher than that of ordinary products, which helps to further reduce the power consumption of the in-vehicle camera module. In addition, the distance between the CMOS image sensor and the LDO can be shortened, thereby reducing interference noise to the power supply line and stably supplying power to the CMOS image sensor.
3. With spread spectrum function, it helps to reduce the design man-hours for EMI countermeasures
This product is equipped with a spread spectrum function in the built-in switching regulator (DC/DC converter)*5, which can reduce the peak value of EMI noise caused by switching by about 10dB. Since noise can be reduced without replacing the circuit board, it helps to reduce the design man-hours for EMI countermeasures.
4. Built-in power supply system ideal for camera modules to ensure high reliability
Three DC/DC converters are built into this product as the power supply system required for the camera module. In addition, this product is also equipped with various protection functions. In addition to the sequence control function that reduces the number of external components, there are many functions such as Power Good for monitoring the voltage status, which can be used for camera modules while ensuring high reliability. low EMI and high efficiency power supply circuit.
＜Explanation of terminology＞
※1) SerDes IC
Generic term for two ICs that are used in pairs for high-speed data transfer for switching communication methods. The serializer is used to convert the data into a form that is easy to transmit at high speed (converting a parallel bus to a serial bus), and the deserializer is used to convert the transmitted data to the original format (converting a serial bus to a serial bus). is a parallel bus).
※2) PMIC (Power Management IC)
An IC that contains multiple power systems and integrates functions such as power management and sequence control on one chip. Compared with the circuit structure composed of DC/DC, LDO and discrete components, etc., it can significantly reduce the space and shorten the development cycle. Therefore, in recent years, whether in the field of automotive equipment or consumer Electronic equipment, it has become a multi-power supply. Common devices used in system applications.
※3) Spread spectrum function
The switching frequency is not fixed, but the switching frequency is changed within a certain range to spread the noise energy to a frequency of a certain width. EMI noise can be mitigated by reducing noise peaks.
※4) ISO 26262
International standards related to functional safety of automotive electrical and electronic systems officially promulgated and implemented in November 2011. A standardized development process aimed at achieving “functional safety” entails calculating the risk of failure in on-board electronic controls and pre-embedding a mechanism to reduce this risk into the system as one of the functions. The standard covers the entire life cycle of vehicle development from the vehicle concept stage through to systems, ECUs, embedded software, device development and its production, maintenance and end-of-life phases.
※5) LDO (Low Drop Out, Low Drop Out Regulator, Low Dropout Regulator), DC/DC Converter (Switching Regulator)
Both belong to a type of power IC and have the function of converting a direct current (DC) voltage into a direct current voltage.
A DC/DC converter, also known as a “switching regulator,” switches on and off to generate an output voltage. Usually, the power conversion efficiency is excellent, and there are mainly two types of “buck type” used to reduce voltage and “boost type” used to increase voltage.
LDOs are power ICs in the category of “linear regulators” that generate output voltages by dividing voltages by resistors. Compared with switching regulators such as DC/DC converters, it can only step down, but it has the characteristics of simple circuit structure and low noise.
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