What cameras are installed in ADAS and AD systems? - Groups of devices that contribute to the enhanced performance of equipment -　

Trends of the camera module market and equipment

With regard to market trends, the number of cameras installed in vehicles is expected to increase as the number of vehicles increases and the level of autonomous driving improves, and the performance of sensing functions is also expected to further improve. The functions and performance required for camera modules in the future include "higher power," "higher-speed communication," and "miniaturization and weight reduction." The requirements for each improvement are as follows.

●Higher power
The amount of data is expected to increase due to requirements for higher performance such as higher resolutions and higher dynamic ranges of image sensors. In addition, SoCs are also required to achieve faster and more precise recognition and decision processing. Higher power is essential as the power loss of electronic components increases due to the increased amount of data processing.

●Higher-speed communication
The increased amount of image data transmitted requires improved high-frequency processing and high-speed data transmission.

●Miniaturization and weight reduction
In addition to the above challenges, it is necessary to reduce the size of electronic components.

Circuit configuration of each camera module

This section explains the circuit configuration of sensing cameras, driver monitoring cameras, and surround view cameras.

Sensing camera, driver monitoring camera

Sensing cameras and driver monitoring cameras are made up of the following components, with their circuit configuration shown in Figure 1.

●Image sensor: Sensor necessary for capturing images. It converts the light coming through the camera lens into electrical signals.
●SoC: Device for processing data acquired by an image sensor.
●MCU (microcomputer): Feeds control instructions such as "apply the brake" and "turn the steering wheel" to an external ECU.
●Transceiver: Device for communicating with an external device.
●Memory (DDR): Used as a buffer during data processing.
●Memory (flash): Stores control software and sensor data.
●DC/DC converter: Converts the voltage from a lead battery to the voltage required by each electronic component.

Surround view camera

A camera ECU and surround view ECU are used to make up a surround view camera. Unlike other types of camera modules, multiple camera units are mounted on a vehicle to make up the surround view camera. Therefore, transceiver circuits must communicate larger amounts of data. An FPGA is used to integrate the acquired image data into one, where image processing is performed at high speed.

Other configurations are the same as those of sensing cameras and driver monitoring cameras.

Specific examples and uses of each component

DC/DC converters and transceiver circuits are commonly used in sensing cameras, driver monitoring cameras, and surround view cameras. This section explains the electronic components that constitute each circuit and their effects.

DC/DC converter

n general, DC/DC converter circuits use conductive polymer hybrid aluminum electrolytic capacitors for noise reduction at the input and smoothing at the output, automotive power inductors for voltage conversion, and chip resistors (high-precision chip resistors) for voltage measurements.

【Components used】

Noise reduction, switching, and smoothing ―― Conductive polymer hybrid aluminum electrolytic capacitor

POINT

1. ❶ Its high capacitance, low ESR, and high ripple performance contribute to circuit miniaturization and higher power features (low voltage and high current).
2. ❷ Improved capacitance characteristics at high frequencies contribute to the elimination of noise, including high frequency components generated by high frequency switching of circuits over a wide band of frequencies.

Voltage conversion ―― Automotive power inductor

POINT

1. ❶ Contributes to circuit miniaturization and higher power features (low voltage and high current) due to the low loss and high current performance of metallic magnetic materials.
2. ❷ Improved loss characteristics (low ACR) at higher frequencies contribute to the suppression of losses in high frequency switching circuits.

Voltage measurement ―― Chip resistor (high-precision chip resistor)

POINT

1. ❶ Contributes to the high-precision control of circuit output characteristics through the low resistance tolerance and low TCR performance with a thin-film structure.

Transceiver I/F

As shown in the figure, a transceiver circuit uses two lines to communicate with external devices (CAN, Ethernet, etc.). Care must be taken for static electricity and noise for the circuit. This is because when static electricity or noise enters from the communication line, this can lead to the failure of electronic components in the worst case. In general, a chip varistor and ESD suppressor are used to prevent static electricity.

【Components used】

Static electricity measures ―― Chip varistor, ESD suppressor

POINT

1. ❶ Contributes to the suppression of electrostatic (ESD) noise while maintaining circuit communication quality with a lineup of products having a wide range of capacitance characteristics.
2. ❷ Chip varistors support low to high communication speeds with capacitance characteristics ranging from 8 to 250 pF.
3. ❸ ESD suppressors support high-speed communication speeds with their capacitance characteristics of 0.1 pF.

Summary

As the level of autonomous driving improves and the number of vehicles increases, the number of cameras installed in vehicles is expected to increase. Moreover, there is also a demand for improved performance of the sensing function of cameras. When trying to process a large amount of image data acquired from cameras, losses in electronic components increase accordingly. In the future, automotive electronic components will be required to have "high current," "low losses," "high frequency operation," and "small sizes." Aiming for camera applications, Panasonic Industry offers a wide product lineup of devices equipped with functions required in the future (Table 4).

Components	Features	Large current	Low loss	High frequency	Miniaturization	High precision
Conductive polymer hybrid aluminum electrolytic capacitors	Low ESR High-reliability	✔	✔	✔	✔
Automotive power inductor	High current, low loss High-reliability	✔	✔	✔	✔
Chip resistors(high-precision chip resistors)	High-precision, high heat resistance				✔	✔
Chip varistors	Miniaturization and weight reduction				✔
ESD suppressors	Low capacitance Ultra high-speed data I/F			✔	✔