High accuracy, low power 3D magnetic sensor protects smart meters

May 13, 2015 // By Graham Prophet
Infineon Technologies’ 3D magnetic sensor, TLV493D-A1B6, features highly accurate three-dimensional sensing with low power consumption in a 6-pin TSOP package. Magnetic field detection in x, y, and z directions allow the sensor to reliably measure three-dimensional, linear and rotation movements.

The chip incorporates an I²C interface for fast, bidirectional communication between sensor and microcontroller. TLV493D-A1B6 suits consumer and industrial applications that require accurate three-dimensional measurements or angular measurements and/or low power consumption, such as joysticks; control elements used for white goods and multi-function knobs; and electric meters where the 3D magnetic sensor helps to protect against tampering. With its contactless position sensing and high temperature stability of magnetic threshold, the TLV493D-A1B6 enables these systems to become smaller, more accurate and robust.

Infineon positions the TLV493D-A1B6 as the starting point for a new 3D magnetic sensor family, and intends to offer a 3D sensor for automotive applications such as gear sticks and steering column controls later in 2015.

The 3D magnetic sensor TLV493D-A1B6 enables smaller and more energy efficient e-meter systems; existing designs typically use up to three magnetic sensors – one for each dimension of an external magnetic field – to measure tampering attempts with large magnets. The 3D magnetic sensor can replace all three dimension sensors making e-meters smaller and more energy efficient.

The sensor detects all three dimensions of a magnetic field. Using lateral Hall plates for the z direction and vertical Hall plates for the x and y direction of the magnetic field, the sensor can be used in a large magnetic field range of ±150mT (milli Tesla) for all three dimensions. This allows measuring and covering a long magnet movement. The large operation range also makes the magnet circuit design easy, robust and flexible.

TLV493D-A1B6 provides 12-bit data resolution for each measurement direction. This allows a high data resolution of 0.098 mT per bit (LSB) so that even the smallest magnet movements can be measured.

In “Power Down mode,” the sensor requires 7 nA supply current. To perform magnetic measurements, the sensor can be set in one of five different power modes. In “Ultra Low Power Mode,” for example, the sensor performs a magnetic measurement