Brushless DC (BLDC) Motor Control ICs
Fuel and CO2 economy discussions demand in the automotive segment new system architectures. More and more systems will be operated “on demand”, meaning they will only be used as they are needed. This impacts classic, belt driven mechanical domains, moving them into electrically controlled ones.
Additional to that we have also new electric systems coming in, for instance battery cooling applications, which are needed in HEVs and EVs. Because of that, the number of electric motors per car is increasing. Another big demand in this domain are the nearly permanent running electric motors. Examples are fuel pumps, main and auxiliary water coolant pumps, oil pumps, engine cooling fans and HVAC blowers.
Especially these applications require energy efficient electric motor driving, so that the classic DC motors will be more and more replaced by BLDC (Brush less DC) motors.
The BLDC motors bring a higher energy density, higher energy efficiency and a much longer life time compared to an equivalent DC motor.
In comparison to a DC motor, a BLDC motor has no mechanical brushes to do the motor commutation. Therefore an electronic control is always mandatory to provide the needed rotating magnetic field in the fixed stator coils. The electronics will also insure over current protection and the already described “on demand” function.
For the detection of the rotor position two fundamental principles exist:
Position sensors, often Hall sensor based, track the rotor position and provide this information to the electronic control circuit. In the domain of permanent running applications as blowers, pumps and compressors, so called sensor less principles can be applied.
Melexis has combined under the name TruSense different sensor less algorithms, which start, accelerate and drive BLDC motors under unknown load conditions in a reliable way.
Very fast start up times can be reached, a common request for fuel and oil pump applications.
MLX81200 and MLX81201 are the 1st members of a 3 phase BLDC single chip controller family, that are consequently using Melexis TruSense. A single IC connected to a LIN or PWM interface with only a few external components is able to control a BLDC motor of the mentioned applications in the range from 10W…1500W.
An other product family - mostly used as fan drivers - addresses 1 phase and 2 phase BLDC motors. In these ICs Hall effect sensors and coil drivers are combined in one single piece of silicon, allowing an application build with only a few external components.