Date: 11/03/2009

Precision Hall-Effect switches and latches for motor control and automation

Infineon has released new family of Hall-effect switches and latches for motor control and automation systems. The new TLI49x6 product family includes high precision Hall-effect switches and latches based on chopped Hall probes.

The new product family includes five devices; the TLI4906x series of switches and the TLI4946x series of latches, both with various package options.

The TLI4906x is a high precision Hall-effect switch with high-accuracy switching thresholds for ambient operating temperatures of up to 125 °C. It is ideally suited for a broad portfolio of industrial and consumer applications that require high precision switching points for position sensing, such as security systems, alignment control, push buttons, keyboards, key switches, and machine tools.

TLI4946x latches are ideal for controlling Brushless DC (BLDC) motors. The major advantage of the brushless technology in comparison to motors using brushes is that commutation is performed without mechanical contact: Therefore, BLDC motors are more reliable, more efficient and run quieter at faster speed. The TLI4946x latches are designed to exactly detect the rotor position of BLDC motors, for example in air conditioning systems, pumps, washing machines, DVD players and rolling shutters. Apart from effective control, the latches can also be used for index counting.

"Infineon is a leading and well-established supplier of high-quality, reliable Hall sensors for the automotive industry. With the new TLI49x6 switch and latch family, Infineon expands its offering to customers in the industrial and consumer market," said Frank Findeis, Head of Marketing for Magnetics and Sensor Interfaces at Infineon Technologies. "Various industrial applications like control of energy efficient BLDC motors will profit from the high precision and reliability of the products, while designers of motor drive solutions have the additional benefit of getting all related high-quality and perfectly matched key components like microcontrollers, power devices and sensors from one source, Infineon."

The Hall-effect switches comprise a chopped Hall probe, bias generator, compensation circuits, oscillator and an output transistor. The bias generator supplies the Hall probe and the active circuits. Compensation circuits stabilize response of the IC over temperature and reduce the impact of process variations. The sensor module delivers the same and stable outputs regardless of temperature. Active error compensation reject offset affects in the signal path and the impact of mechanical stress in the package caused by molding, soldering and thermal effects. The chopper technique together with the threshold generator and the comparator ensure high sensitivity and high stability of magnetic switching points. The industrial Hall-effect devices offer a low jitter of typically 1µs.

The ICs have an open collector output stage with 20mA current sink capability. A wide operating voltage range from 2.7V to 18V with reverse polarity protection down to -18V and high ESD protection of ±4kV (HBM) make the TLI49x6 switch/latch family suitable for a variety of applications. A magnetic south pole with field strength above B op turns the output on, while a magnetic north pole exceeding B rp turns it off.