Auto Electronics

Micronas launches LIN bus MCU line and Hall-effect sensor

Micronas has introduced a line of 8-bit microcontrollers for LIN bus applications, and the first member of a new family of microcontroller-based Hall-effect sensors. All of the products target automotive applications.

The firm said its HVC 22xyA and HVC 24xyA easyLIN MCUs simplify the design and reduce the cost of LIN bus modules by combining all logic functions, peripheral modules, interfaces and a LIN bus interface in a single device. Target applications include doors, seats, mirrors, and powertrain applications. Micronas’ easyLIN devices integrate 5 V and 2.5 V regulators, true EEPROM, watchdogs, and power driver electronics. The internal voltage regulators operate directly from an automobile's 12 V supply and can withstand load dumps of up to 40 V. The devices also contain a switchable 5 V supply output that can be used to power external subsystems.

The easyLIN devices can directly drive up to eight 12 V loads. Relay driver protection is embedded. The devices’ on-chip transistors resist moderate loads and can drive external power transistors for large loads. Drivers include three fast-shutdown modules for power MOSFET transistor protection that respond almost instatnly, without CPU involvement. Working with on-chip pulse-width modulators (PWM), easyLIN devices can also drive brushed and brushless DC motors.

Micronas said an easyLIN device is typically the only component needed for a LIN bus slave application, and can reduce component counts by as many as 20 devices. It has a full LIN 2.0 physical layer interface, a 10-bit queued A/D converter, three multi-threshold comparators, an op-amp, and multiple interrupt inputs. It is available in flash and ROM versions, with both types including true EEPROM. An on-chip oscillator features Micronas’ LEAP (Low Emission Automotive Processor) technology, which actively suppresses EMI using precisely-timed clock phase offsets.

Other integrated peripherals include two 8-bit and two 16-bit timers, an SPI interface, a 16-bit PWM, and three enhanced 12-bit PWMs. The easyLIN also contains its own supervisory circuit. An on-chip temperature sensor against an overheat condition, and a supply monitor resets the device if the power supply goes out of range, even momentarily.

All easyLIN family devices operate from -40 to +125 °C. Current consumption as low as 20 µA while still preserving RAM data. The devices come in a PSOIC28 package and range in price from €1.60 to €2.20 in low quantities.

Micronas’ HAL 2810 linear Hall-effect sensor includes a programmable microcontroller and a LIN bus 2.0 interface. The device is a smart sensor that integrates the sensing element, all necessary compensation functions, digital signal processing, and full LIN bus connectivity. The firm said the sensor can replace potentiometers in automotive applications involving angular measurement, such as fuel-level sensing, and linear movement, as in seat-track position. It can also be used for passenger weight detection. U.S. Federal Motor Vehicle Safety Standard 208 requires passenger airbags that can sense the size and weight of front seat passengers and adjust accordingly. The HAL 2810 measures the force on the seat attachment points and determines passenger weight based on these measurements.

“The HAL 2810 makes it possible to build up a complete LIN network with multiple sensors, offering a cost advantage compared to today’s systems,” said Peter Zimmermann, market manager automotive. “Customers can save costs in the wiring harness as well as in the electronic architecture. In some applications a complete data acquisition and communication ECU can be eliminated.”

The HAL 2810 sensor offers 12-bit resolution and features both spinning-current and second-order temperature compensation over a range of -40 to 140 °C. Included on-chip with the sensor is an 8-bit microcontroller with boot ROM, EEPROM, RAM, and the LIN bus slave interface.

The LIN bus interface is compatible with LIN Specification Package 2.0 and supports data rates of 10.4 Kbps and 20 Kbps. The boot ROM includes firmware to drive the LIN bus. Micronas includes the physical interface and overvoltage and reverse-voltage protection on all three pins, so the device can be connected directly to the bus. The device is user-programmable via the LIN bus. HAL 2810 samples are available in a TO-92UT package, priced at $2.00 in 10K quantities.

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