New product balances measurement accuracy, scalability and high speed isolated communications for automotive and industrial battery management

NOVI, Mich. — (BUSINESS WIRE) — September 16, 2014 — (Electric and Hybrid Vehicle Technology Expo) – Freescale Semiconductor (NYSE: FSL) today announced a highly integrated 14-cell lithium-ion battery cell controller for industrial and automotive applications, designed to cost effectively meet the stringent requirements for ASIL-C functional safety.

With fourteen cell balancing transistors, a current sensor with ±0.5% accuracy from milliamps to kiloamps, and 2 Mbps communication transceiver interface integrated into a single 64-pin QFP package, Freescale’s MC33771 battery cell controller and companion MC33664 isolated communications interface deliver robust, reliable performance for 48 V battery systems, enabling economical scalability beyond 1000 volts. The solution’s built-in diagnostics help protect automotive and industrial battery packs against critical fault conditions, and its transformer coupled isolated high speed transceiver eliminates the need for expensive isolated CAN busses to meet ASIL-C requirements. Together, these features make the solution ideal for a broad range of automotive and industrial applications including 48 V battery packs, hybrid and electric cars, E-bikes and energy storage systems.

As automotive and industrial batteries are placed under increasing strain by new, mission-critical applications, challenges such as overcharge, overheating and internal short circuit or overload must be controlled in order to help ensure safe operating conditions. It is crucial that the battery cell controller provide precise and reliable battery diagnostics by accurately measuring differential cell voltages, temperatures and currents. It is equally critical that this information be communicated quickly and accurately from the battery cell controller to the pack controller for system-wide control and safety of the battery, allowing the full energy content of the battery to be utilized.

“The robust design and comprehensive integration of our new battery cell controller reflects Freescale’s system-level approach to cost effectively manage battery charging while helping to prevent failures and dangerous conditions,” said James Bates, senior vice president and general manager for Freescale’s Analog & Sensors Group. “This new battery cell controller leverages Freescale’s automotive heritage and long history of creating reliable, highly integrated, high-performance solutions to reduce the cost of meeting stringent safety requirements.”

The MC33771 incorporates many critical functions required for controlling a single 48 V battery pack, including the capability to synchronously measure currents and voltages with 2 millivolts of accuracy within 65 us, making it easier to meet ISO 26262 ASIL-C requirements. Embedded functional verification and fault diagnostics enable compliance with ISO 26262 ASIL-C functional safety standards without additional external circuitry. For higher voltage systems, the integrated daisy chain differential transceiver communicates at 2 Mbps using robust transformer coupled isolation up to 3750 volts instead of expensive isolated CAN busses, while the MC33664 connects the battery pack directly to the system MCU’s dual SPI interface using the same transformer coupled isolation. Freescale’s battery cell controller solution delivers exceptional performance with a lower system bill of materials and robust system isolation for ASIL-C rated battery packs.

The MC33771, in combination with Freescale’s MC33664 isolated communication device, supports optimal lifecycles for a variety of battery architectures, including centralized, distributed CAN and distributed daisy chain topologies. The battery cell controller features a robust and safe high-speed daisy chain communication design that serves as a replacement for expensive isolated CAN busses. The device’s ability to serve as an alternative to CAN-based solutions eliminates the need for local microcontrollers, voltage regulators and isolated CAN layers within the battery, helping to reduce costs and design complexity.

The MC33771, a SafeAssure functional safety solution, has been developed to enable customers to easily meet stringent ISO 26262 ASIL-C requirements, as well as rigorous standards for ESD, EMC, low current consumption and AEC-Q100 automotive qualified design. While Freescale’s MC33771 is usable across most known battery topologies, it features a specific feature set to address a typical 48 V LFP Battery with one device that includes fourteen differential voltage measurements, fourteen embedded cell balancing transistors, seven analog inputs for temperature measurement, one embedded current sensor that synchronizes with the cell voltage measurements to allow determination of individual cell impedance, and a coulomb counter for enhanced state of charge determination.

Additional features include:

• 9.6 V ≤ VPWR ≤ 61.6 V Operation, 70 V transient
• SPI or isolated 2 MHz differential communication
• Current sensor with ±0.5% accuracy from milliamps to kiloamps
• 14x differential cell voltage measurement and stack voltage measurement
• Synchronized cell voltage/current measurement
• Coulomb counting
• 7x ADC/GPIO/temperature sensor inputs
• Addressable on initialization
• Onboard 300 mA passive cell balancing
• Low-power modes
• 64-pin QFP package

Availability and pricing

The MC33771 and MC33664 devices are sampling now. The versions for the industrial market are expected to be in production by Q1 2015 and the versions for the automotive market are planned for production by Q3 2015. The MC33771 will be available for a suggested retail price of $4.86 - $10.95 in 10kU quantities. The MC33664 will be available for a suggested retail price of $1.65 in 10kU quantities. Additional derivative products are planned to be introduced in 2015 as well. For more information, please visit: http://www.freescale.com/Battery

Freescale offers hardware to support the MC33771 battery cell controller and the MC33664 transformer physical layer with the KIT33771ASP1EVB and KIT33664EVB evaluation kits. These boards are engineered to help accelerate time-to-market and demonstrate the benefits of the multiple embedded functions of the devices.

Robust and reliable analog performance

The majority of Freescale analog products meet critical automotive and industrial market requirements, including operation across extended temperature ranges. These products are designed and manufactured with rigorous process controls, and qualified using industry standard methodologies designed to yield defect rates in line with the stringent requirements of the automotive and industrial markets. The MC33771 and MC33664 devices are included in Freescale’s product longevity program, which provides assurance of supply for a minimum of 10 or 15 years from the time of introduction. For terms and conditions, and to see a list of participating Freescale products, visit www.freescale.com/productlongevity.

Freescale SafeAssure program: Functional Safety. Simplified.

The Freescale SafeAssure functional safety program is designed to help system manufacturers more easily achieve system compliance with functional safety standards: International Standards Organization (ISO) 26262 and International Electrotechnical Commission (IEC) 61508. The program highlights Freescale solutions – hardware and software – that are optimally designed to support functional safety implementations and come with a rich set of enablement collateral. For more information, visit www.freescale.com/SafeAssure.

About Freescale

Freescale Semiconductor (NYSE: FSL) is a global leader in embedded processing solutions, providing industry leading products that are advancing the automotive, consumer, industrial and networking markets. From microprocessors and microcontrollers to sensors, analog integrated circuits and connectivity – our technologies are the foundation for the innovations that make our world greener, safer, healthier and more connected. Some of our key applications and end-markets include automotive safety, hybrid and all-electric vehicles, next generation wireless infrastructure, smart energy management, portable medical devices, consumer appliances and smart mobile devices. The company is based in Austin, Texas, and has design, research and development, manufacturing and sales operations around the world.  www.freescale.com

Freescale and the Freescale logo are trademarks of Freescale Semiconductor, Inc., Reg. U.S. Pat. & Tm. Off. All other product or service names are the property of their respective owners. All rights reserved. © 2014 Freescale Semiconductor, Inc.

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