Inductive position sensor family include ISO 26262-compliant model
As the electric vehicle (EV) adoption programme continues, Microchip has identified that developers of motor control systems are replacing Hall effect position sensors and older magnetic resolvers with inductive alternatives that eliminate expensive magnets and other heavy transformer-based structures to be integrated onto simple, compact PCBs.
The company has added the LX34070 IC to what it says is the world’s broadest line of inductive position sensors. It has been purpose-built for EV motor control applications. It is a replacement for magnetic resolvers and linear voltage differential transducers (LVDTs), at a fraction of the cost, said Microchip.
The IC includes differential outputs, fast sample rates and features that make it functional-safety-ready for ISO 26262-compliance in the Automotive Safety Integrity Level–C (ASIL–C) classification.
“The LX34070 inductive position sensor enables lighter, smaller, more reliable motor control solutions that meet stringent safety requirements, reduce overall system costs, and can operate seamlessly and precisely in the noisy environment of an automobile’s DC motors, high currents and solenoids,” said Fanie Duvenhage, vice president of Microchip’s mixed signal and linear analogue business unit. “Designers can use the LX34070 to further streamline EV motor control designs by pairing it with other functional-safety-ready Microchip devices including our eight-bit AVR and PIC microcontrollers, our 32-bit microcontrollers and our dsPIC digital signal controllers,” he continued.
By using PCB traces rather than transformer-based magnetic windings and coil structures, the LX34070 device has negligible size and mass compared to alternatives that weigh as much as a pound or 450g. Accuracy is improved since the LX34070 does not depend on magnet strength, and the device improves robustness by actively rejecting stray magnetic fields.
PCB-based inductive position sensors use a primary coil to generate an AC magnetic field that couples with two secondary coils. A small metal target object disturbs the magnetic field so that each secondary coil receives a different voltage whose ratio is used to calculate absolute position. The LX34070 uses the same PCB materials, approaches and simplified, low-cost packaging for EV motor control and other applications that need high speed and low latency performance, said Microchip.
The LX34070 inductive position sensor IC is available today.
