Embedded microcontroller in conjunction with Hall-effect sensor for innovative BLDC system solution

Micronas showcases system solution for brushless DC motor control applications

Freiburg, March 2, 2010 – Micronas (SIX Swiss Exchange: MASN), a leading supplier of innovative application-specific sensor and IC system solutions for automotive electronics, today announced that it will showcase an innovative system solution for brushless DC motor (BLDC) drive applications. The system solution comprises Micronas Hall-effect sensors for the motor commutation and the Micronas embedded microcontroller HVC 2480A, a flash-based 8-Bit microcontroller directly working on 12V supplies.

With the introduced system solution Micronas is addressing the fast growing market on sensor-based brushless motor applications. Many EC (electrical commutated) motor applications will switch to brushless solutions due to its overall better performance – especially in the automotive environment.

Many BLDC applications today are using Hall-effect sensors for the motor commutation. Depending on the application requirements from one to three single digital Hall switches (Micronas Hall-effect sensor families HAL 2xy or HAL 5xy) are mainly used. The highly reliable Hall sensors include active compensation features to guarantee constant magnetic characteristics in the full supply voltage and temperature range, limiting the impact of process variations. The in-built active offset compensation leads to magnetic parameters which are robust against mechanical stress effects, rejecting offset affects in the signal path and the impact of mechanical stress in the package caused by molding, soldering and thermal effects.

Thanks to the wide operating temperature ranges, different level of accuracy and resolution, applications in several domains such as automotive, industrial and consumer can be addressed achieving an excellent performance-cost ratio. The controlling function for the feedback loop is done via the Micronas HVC 2480A, a member of the embedded microcontroller family HVC 2xyzA. It provides a very high integration level of embedded functionality with the flexibility of a general-purpose microcontroller. Due to the internal voltage regulator, the device can operate directly from an unregulated 12V power supply while a 5V switchable output is be used to supply 5V ICs. Built-in features dedicated to motor control applications enable a very compact design, preserving meanwhile the advantages of a microcontroller-based architecture.

The enhanced PWM (Pulse Width Modulation) modules allow easy implementation of sinusoidal and space vector modulation motor driving techniques while the ability to trigger the ADC by means of PWMs allows to monitor the current in a simple way. The four-stages ADC queue enables synchronous acquisition of many signals, e.g. power supply voltage.

The built-in amplifier for current monitoring and the embedded power MOS short-circuit protection further minimize the number of components required to built-up a complete brushless motor application.

For LIN-based applications, the integrated LIN bus driver enables a further step towards smaller PCB and the enhanced LIN-UART minimizes the CPU load for LIN protocol handling.

The on-chip temperature sensor allows detecting unusual operating conditions like very cold/hot environment and taking the appropriate counter measure such as reducing the current within the motor. For enhanced reliability the microcontroller has an under/overvoltage detection circuit and an over-temperature protection.

All HVC family members operate from Tambient = -40 to +125 °C, necessary in the harsh environment of automotive electronics. ROM versions are available for high-temperature applications.

The family offers a wide range of power-saving modes, with current consumption as low as 20 μA while still preserving RAM data for fast system wake-up. The true on-chip EEPROM allows non-volatile data storage over the whole temperature range.