The adoption of electronically-integrated panels for instrument cluster, electronic mirrors, and other systems in the car has risen significantly. Many of these applications are safety-critical, requiring the semiconductors and drivers to meet the requirements of functional safety. Auto Tech Review met Daisuke Nakamura, Managing Director, ROHM Semiconductor India, to understand the latest offerings from the company for the Indian market.
ROHM is a major global manufacturer of semiconductors and has recently announced its intent to enter the Indian market with its low power and energy efficient power supplies, to meet the growing demand for electric vehicles and other hybrid-electric-vehicles (xEVs). There has been a drive towards eco-friendly mobility in the country, which has made electric vehicles a key focus area for ROHM in India, said Nakamura. Smart infrastructure along with efficient power is a key focus area in IoT and in India, ROHM plans to focus on automotive and industrial equipment space.
NANO PULSE CONTROL TECHNOLOGY
The industry has adopted advanced driver assistance systems (ADAS) towards reducing accidents caused due to human errors. In a country with the highest incidence of road accidents and fatalities, consumers will be benefitted from adopting some, if not all of the ADAS systems, like pedestrian avoidance, obstruction detection, automatic parking, etc. Besides, the number of electric motors in an automobile is steadily increasing, along with the electronics needed for the control. ROHM is working with the key enablers of some of these technologies to supply highly-efficient semiconductor devices.
To cater to such and other complex requirements, ROHM has developed a new power supply IC based on Nano Pulse Control technology for the Indian market. It is essentially a 2 MHz switching regulator with built-in MOSFET that achieves the highest step-down ratio in the industry. This is required for 48 V automotive systems such as mild hybrid vehicles.
Nano Pulse Control refers to the ultra-fast switching technology that can achieve very high step down ratio. It is a combination of analogue circuit design, layout, besides other processes and utilises ROHM’s vertically integrated production system to the maximum. This technology contributes towards greater miniaturisation in 48 V applications ranging from mild hybrid vehicles and industrial robots to base station power supplies.
The latest switching regulator from ROHM utilises proprietary technology to reduce the minimum ‘on’ time, which is 10 times shorter than the existing technology, thus enabling step-down operation from high input voltages like 60 V to around 2.5 V, at a constant frequency of 2 MHz. In addition, current-mode control provides easy phase compensation and use fewer external parts, while the integrated high-voltage MOSFET expands the input voltage range to 65 V, enabling wide adoption.
WHY NANO CONTROL?
Mild hybrid vehicles with 48 V systems provide better cost and fuel-efficiency over full hybrid cars that run on 12 V power supply systems. Precisely for this requirement, ROHM leveraged its vertically integrated production system that includes analogue design technology and power processes to develop the Nano Pulse Control to achieve a single-chip power system.
The automotive industry always wanted a switching regulator operating at 2 MHz, mentioned Nakamura. Besides, there has not been a power supply IC capable of stepping down 48 V to the 3.3 V or 5 V needed for low power devices inside the ECU. Typically such a regulator always used 2-stage step down, which this product will enable in a single stage, improving efficiency to a large extent, mentioned Nakamura.
A key area of focus for ROHM’s India operations would also be chipsets. These come integrated with a gamma correction IC, timing controller, source driver, and gate driver for driving HD/ FHD class displays, along with a power management IC (PMIC) to ensure optimum drive operation. Each device is designed to share information as needed, achieving automotive-grade reliability and for the first time functional safety was successfully introduced in devices for displays. Compatibility with LCDs for side mirrors and speedometers that can lead to accidents is also provided.
In addition, chipset optimisation allowed ROHM to cover a wide range of specifications while at the same time integrate a fail detection function in the timing controller to verify operation, making it possible to configure high resolution LCD panels.
The PMIC includes a double register for detecting abnormalities and auto-refresh function to enable recovery during abnormal operation, ensuring high reliability against unexpected influences such as electromagnetic noise.
Each IC configured in the chipset integrates a function for mutually selecting the expected failure mode. As a result, it is possible to complementarily detect panel failure and confirm and provide feedback on information such as input signals to the LCD, as well as peeling/ destruction of the LCD driver. Introducing functional safety contributes to the prevention of serious accidents caused by the malfunction of monitors for the speedometer, side mirrors, and other systems.
For example, the driver may not notice that the screen for the side mirrors has frozen in the case no object is detected at the time, presenting a danger that can lead to serious injury if someone suddenly were to go behind the car while the car is moving. To prevent this, ROHM delivers functional safety that can detect if the screen is frozen.
TEXT: Anwesh Koley