ST CAN chip
supports “partial networking” for improved fuel efficiency and emissions in auto apps
Toni McConnel 10/17/2011 9:25 AM EDT
The L99PM72PXP is a new member of ST’s family of power management system ICs that integrates both High-Speed CAN (HS-CAN) and LIN physical layers, providing all the functions needed to build up a complete Electronic Control Unit (ECU) for car body applications.
Its features are tailored to particular uses such as in climate control modules and door control units, as well as seat modules, trunk and trailer modules, sunroof and rear-view modules.
Unlike standard CAN transceivers or system-basis chips, the L99PM72PXP is able to monitor the CAN bus autonomously, without the module’s main processor being active.
It activates the module only when a correctly addressed wake-up signal is detected.
By allowing parts of the CAN network to be deactivated in this way, the L99PM72PXP contributes to reduce overall electrical energy consumption.
Advanced fail-safe functionality is an additional and unique feature which improves the sustainability and reliability of automotive electronic control units.
Built-in features such as supervision of the microcontroller, supply voltages and temperatures provide protection against causes of failure. In addition, cost-efficient peripheral functions such as high-side and low-side gate drivers, operational amplifiers and voltage regulators reduce the number of external components and lower overall system costs.
The chip will help car makers respond to changing new-car legislation in major markets worldwide, aiming to save fuel and reduce emissions. In Europe, Euro 6 regulations will replace Euro 5 in 2014, and the average CO2 emissions limit will fall to 95g/km by 2020. Chinese 4 standards, similar to Euro 4, came into force in China in 2011 and the city of Beijing is planning to adopt Chinese 5. In the USA, Corporate Average Fuel Economy (CAFE) requirements for passenger cars will increase from 30.4 to 37.8 mpg by 2016 and 50.6 mpg by 2025.
One of the ways to meet these increasingly stringent regulations is to reduce the energy consumed by systems such as door electronics and climate controls.
ST’s new IC achieves this by allowing modules to be turned off individually when not being used, taking advantage of “partial networking.”
This is a new feature in the latest CAN specification, ISO 11898-6, and could reduce an average vehicle’s CO2 emission by more than 2g/km.
Key features:
- Two 5 V voltage regulators for microcontroller and peripheral supply
- No electrolytic capacitor required on regulator outputs
- Ultra low quiescent current in standby modes
- Programmable reset generator for power-on and undervoltage
- Configurable window watchdog and fail safe output
- LIN 2.1 compliant (SAEJ2602 compatible) transceiver
- Advanced high speed CAN transceiver (ISO 11898-2/-5 and SAE J2284 compliant) with local failure and bus failure diagnosis and selective wake-up functionality according to ISO 11898-6
- Complete 3 channel contact monitoring interface with programmable cyclic sense functionality
- Programmable periodic system wake-up feature
- ST SPI interface for mode control and diagnosis
- 5 fully protected high-side drivers with internal 4-channel PWM generator
- 2 low-side drivers with active Zener clamping
- 4 Internal PWM timers
- 2 operational amplifiers with rail-to-rail outputs (VS) and low voltage inputs
- Temperature warning and thermal shutdown
The L99PM72PXP is housed in a PowerSSO-36 package and is scheduled for volume production in Q3 2012, priced at $2.95 for orders up to 1000 units. Alternative pricing options may be available for larger order quantities.
Further information on can be found at www.st.com.
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