Infineon magnetic position sensors improve energy efficiency, reduce noise in BLDC motor control applications
November 15, 2012 by John Day
Infineon Technologies introduced a new generation of Hall switches (TLE496x) and angle sensors (TLE5009 and TLE5012B) that enable more energy-efficient and compact design of brushless DC (BLDC) motor drives.
Compared with conventional motors with brushes, BLDC motors provide greater efficiency, longer life cycles, more compact design, less noise and improved reliability. Infineon said its new devices are precise and fast magnetic position sensors with high resolution. They accurately sense the rotor position thus providing ideal solutions for current commutation in BLDC drives in a broad range of automotive and other applications; for example in clutch actuators, window lifters, and e-bikes.
Many drives require conventional block commutation. These benefit from the TLE496x family of Hall switches on energy savings and precise, compact system designs. With current consumption of 1.6mA, TLE496x devices can cut energy needs by up to 50 percent compared to similar products on the market, according to Infineon. In the SOT (Small Outline Transistor)-23 package they require less than 22 percent of the PCB area compared to the usual SC (SemiConductor)-59 package. The TLE496x family’s small magnetic hysteresis enables precise switching points in systems. Integrated circuits compensate magnetic drifts and enable stable performance over temperature and lifetime. Active chopping techniques compensate offsets in the signal path and the influence of mechanical stress on the Hall element.
Directly measuring the rotor angle can raise efficiency levels even further and eliminates vibrations, which in turn cuts noise levels and ensures smoother integration. Based on iGMR (integrated Giant Magnetic Resistive) technology, the TLE5009 and TLE5012B angle sensor products pave the way for more comfortable and energy-saving motor control concepts. The angle sensors in the TLE5009 and TLE5012B series are characterized by extremely rapid updating in combination with short delay times of 9 µs for the TLE5009 and 42 µs for theTLE5012B. Thus, high efficiency is achieved, even with fast rotating speeds and load changes. In addition, integrated signal processing in the TLE5012B reduces the load of the microcontroller by carrying out precise angle calculations and calibration algorithms: The angle value provided from TLE5012B can be directly used in the motor control loop.
Key features of the Hall switches TLE4961 and TLE4968
The Hall switches TLE4961 (latch) and TLE 4968 (bipolar switch) can be operated in the range of 3V to 32V with an uncontrolled power supply. They withstand voltages of up to 42V without the need for an additional external resistor. They provide a high degree of sensitivity and stability with regard to the magnetic switching points (Bop = +/- 1mT and +/- 2mT) and are extremely resistant to mechanical stress thanks to integrated error compensation. Outputs are protected against over currents and over temperature and are extremely resistant to electrostatic discharges (+/- 7kV HBM). Jitter at typical speeds is about 0.35µs. In addition to the small leadless SOT-23 they are also available in a leaded SSO (Single Small Outline)-3 package.
Key features of the angle sensors TLE5009 and TLE5012B
The TLE5009 and TLE5012B angle sensors measure the orientation of a magnetic field in parallel to their package surface within a range of 0° to 360°. The TLE5009 is a cost-effective solution with an analog interface and easy implementation, whereas the TLE5012B has extended data processing functions and several user-selectable interfaces. Infineon said that with a 42μs update rate, the TLE5012B sets new standards with regard to the combination of a short delay time and a high signal resolution. It provides angle accuracy of 1° with 15-bit resolution over the entire functionality range. This makes the TLE5012B suitable for precise recording of rotor positions in highly dynamic applications like robotics or electric power steering.
For a high degree of functional reliability the TLE5012B sensor has advanced self-testing functions and status monitoring, and special architectural features such as separate data paths for each of the two integrated Wheatstone sensor bridges. Both, the TLE5009 and TLE5012B, operate at a supply voltage of 3.3V or 5V and are available in a DSO (Dual Small Outline)-8 package.
Further information on Infineon sensor products is available at www.infineon.com/sensors