Dual-battery redundant design for automobile

Update: November 24, 2021

There are indications that the revolutionary development of self-driving cars is about to come in an all-round way. Automobile companies are cooperating with technology giants such as Google and Uber and startups to develop a new generation of self-driving cars. These car technologies will change our urban roads and highways and lay the foundation for future smart cities. They will use machine learning, Internet of Things (IoT) and cloud technology to accelerate this development.

There are indications that the revolutionary development of self-driving cars is about to come in an all-round way. Automobile companies are working with technology giants such as Google and Uber, as well as startups, to develop a new generation of self-driving cars. These car technologies will change our urban roads and highways and lay the foundation for future smart cities. They will use machine learning, Internet of Things (IoT) and cloud technology to accelerate this development.

More importantly, autonomous vehicles will continue to promote industry changes that have been initiated by shared travel service providers such as Uber and Lyft. The convergence of various technologies will create a world of future transportation composed of intelligent unmanned vehicles.

In the end, all self-driving cars will achieve a certain degree of autonomy through integrated sensors, cameras, radar, high-performance GPS, light detection and ranging (lidar), artificial intelligence (AI) and machine learning. And its connection with secure and scalable IoT, data management, and cloud solutions is also important because they provide a resilient and high-performance foundation for collecting, managing, and analyzing sensor data. From environmental benefits to safety enhancements, the rise of the Internet of Vehicles has a profound social impact. The reduction of cars on the road also means a reduction in greenhouse gas emissions, thereby reducing energy consumption and improving air quality.

For autonomous vehicles and smart road systems, endpoint telemetry, smart software, and cloud technology are all indispensable. The on-board cameras and various sensors in self-driving cars collect a large amount of data, and these data must be processed in real time to make the vehicle drive in the correct lane and drive safely to the destination.

Cloud-based networks and connections are also an important part of this system. Self-driving cars will be equipped with on-board systems that support inter-vehicle communication, allowing them to learn from other vehicles on the road in order to adjust to changes in weather and road conditions (such as detours and road debris). Advanced algorithms and deep learning systems are the key to ensuring that autonomous vehicles can quickly and automatically adapt to various scene changes.

In addition to specific components (such as the scalability of cloud computing infrastructure and intelligent data management), redundancy of key systems including power supplies is also required. The battery redundancy solution that has been released, such as the LTC3871, can work between two battery systems with different rated voltages, such as 48V lithium-ion batteries and 12V lead-acid batteries. But most existing solutions fail to provide redundancy for batteries of the same voltage, such as two 12V, 24V, or 48V batteries, at least so far.

Obviously, a bidirectional buck-boost DC/DC converter that can work between two 12V batteries is needed. This DC/DC converter can be used to charge any one of the batteries, and it can also allow two batteries to supply power to the same load at the same time. In addition, if any of the two batteries fails, it needs to be able to detect the failure and isolate it from the other battery so that it can continue to supply power to the load without interruption. Z recently released the LT8708 two-way DC/DC controller, which can connect two batteries with the same voltage, thus solving this key problem.

Single channel bidirectional control IC solution

The LT8708 is a two-way buck-boost switching power supply controller with an efficiency of up to 98%. It can work between two batteries with the same voltage and is very suitable for realizing battery redundancy in autonomous vehicles. At the same time, it can work when the input voltage is higher than, lower than or equal to the output voltage, which is very suitable for two 12V, 24V or 48V battery systems commonly found in electric and hybrid vehicles. LT8708 works between two battery systems, even if one of the batteries fails, it can prevent the system from shutting down. LT8708 can also be used in 48V/12V and 48V/24V dual battery systems.

The LT8708 uses a single Inductor. When the working input voltage range is 2.8V to 80V and the output voltage range is 1.3V to 80V, it can provide up to several kilowatts of conversion power according to the selected peripheral components and the phase number of the main circuit. It simplifies the two-way power conversion of the battery/capacitor backup system when VOUT, VIN and/or IOUT, IIN are adjusted in the forward or reverse direction. LT8708 has six independent adjustment modes, which can be applied to many different applications.

LT8708-1 and LT8708 are used in parallel to increase the conversion power and the number of phases. LT8708-1 always works as a slave of the host LT8708, can set the clock out of phase, and can provide conversion power equivalent to that of the host. A master Z can connect up to 12 slaves at the same time, thereby increasing the power and current conversion capabilities of the system.

The forward and reverse currents at the input and output of the converter can be monitored and limited, and all four current limits (forward input, reverse input, forward output and reverse output) can be independently set through four resistors. Combined with the direction setting (DIR) pin, the LT8708 can be configured to handle power from VIN to VOUT or VOUT to VIN, which is very suitable for automotive, solar, telecommunications, and battery-powered systems.

The LT8708 is available in a 5mm to 8mm, 40-pin QFN package. There are three temperature grades to choose from, including

There are indications that the revolutionary development of self-driving cars is about to come in an all-round way. Automobile companies are cooperating with technology giants such as Google and Uber and startups to develop a new generation of self-driving cars. These car technologies will change our urban roads and highways and lay the foundation for future smart cities. They will use machine learning, Internet of Things (IoT) and cloud technology to accelerate this development.

More importantly, autonomous vehicles will continue to promote industry changes that have been initiated by shared travel service providers such as Uber and Lyft. The convergence of various technologies will create a world of future transportation composed of intelligent unmanned vehicles.

In the end, all self-driving cars will achieve a certain degree of autonomy through integrated sensors, cameras, radar, high-performance GPS, light detection and ranging (lidar), artificial intelligence (AI) and machine learning. And its connection with secure and scalable IoT, data management, and cloud solutions is also important because they provide a resilient and high-performance foundation for collecting, managing, and analyzing sensor data. From environmental benefits to safety enhancements, the rise of the Internet of Vehicles has a profound social impact. The reduction of cars on the road also means a reduction in greenhouse gas emissions, thereby reducing energy consumption and improving air quality.

For autonomous vehicles and smart road systems, endpoint telemetry, smart software, and cloud technology are all indispensable. The on-board cameras and various sensors in self-driving cars collect a large amount of data, and these data must be processed in real time to make the vehicle drive in the correct lane and drive safely to the destination.

Cloud-based networks and connections are also an important part of this system. Self-driving cars will be equipped with in-vehicle systems that support inter-vehicle communication, allowing them to learn from other vehicles on the road in order to adjust to changes in weather and road conditions (such as detours and road debris). Advanced algorithms and deep learning systems are the key to ensuring that autonomous vehicles can quickly and automatically adapt to various scene changes.

In addition to specific components (such as the scalability of cloud computing infrastructure and intelligent data management), redundancy of key systems including power supplies is also required. The battery redundancy solution that has been released, such as the LTC3871, can work between two battery systems with different rated voltages, such as 48V lithium-ion batteries and 12V lead-acid batteries. But most existing solutions fail to provide redundancy for batteries of the same voltage, such as two 12V, 24V, or 48V batteries, at least so far.

Obviously, a bidirectional buck-boost DC/DC converter that can work between two 12V batteries is needed. This DC/DC converter can be used to charge any one of the batteries, and it can also allow two batteries to supply power to the same load at the same time. In addition, if any of the two batteries fails, it needs to be able to detect the failure and isolate it from the other battery so that it can continue to supply power to the load without interruption. Z recently released the LT8708 two-way DC/DC controller, which can connect two batteries with the same voltage, thus solving this key problem.

Single channel bidirectional control IC solution

The LT8708 is a two-way buck-boost switching power supply controller with an efficiency of up to 98%. It can work between two batteries with the same voltage and is very suitable for realizing battery redundancy in autonomous vehicles. At the same time, it can work when the input voltage is higher than, lower than or equal to the output voltage, which is very suitable for two 12V, 24V or 48V battery systems commonly found in electric and hybrid vehicles. LT8708 works between two battery systems, even if one of the batteries fails, it can prevent the system from shutting down. LT8708 can also be used in 48V/12V and 48V/24V dual battery systems.

The LT8708 uses a single inductor. When the working input voltage range is 2.8V to 80V and the output voltage range is 1.3V to 80V, it can provide up to several kilowatts of conversion power according to the selected peripheral components and the phase number of the main circuit. It simplifies the two-way power conversion of the battery/capacitor backup system when VOUT, VIN and/or IOUT, IIN are adjusted in the forward or reverse direction. LT8708 has six independent adjustment modes, which can be applied to many different applications.

LT8708-1 and LT8708 are used in parallel to increase the conversion power and the number of phases. LT8708-1 always works as a slave of the host LT8708, can set the clock out of phase, and can provide conversion power equivalent to that of the host. A master Z can connect up to 12 slaves at the same time, thereby increasing the power and current conversion capabilities of the system.

The forward and reverse currents at the input and output of the converter can be monitored and limited, and all four current limits (forward input, reverse input, forward output and reverse output) can be independently set through four resistors. Combined with the direction setting (DIR) pin, the LT8708 can be configured to handle power from VIN to VOUT or VOUT to VIN, which is very suitable for automotive, solar, telecommunications, and battery-powered systems.

The LT8708 is available in a 5mm to 8mm, 40-pin QFN package. There are three temperature grades to choose from, including