Magnetic Current Sensors

Product OverviewCUR 423x – TMR-Based Closed-Loop Sensor for High-Current Coreless Applications

Motion SensorsThe CUR 423x current sensors feature non-intrusive, galvanically isolated contactless current measurement based on closed-loop TMR technology.
This article clearly describes and explains information valuable for our customers related to the features of TDK's CUR 423x current sensors.

Product Description

The CUR 423x sensor was developed for current measurements in automotive and industrial applications. The sensor is based on the TDK TMR technology, which has already been proven in existing TDK automotive sensor products. The CUR 423x sensors are the first family members, suited for DC and AC measurements in high-power applications and are able to measure currents above 1200A. The galvanically isolated power and sensing circuits are of particular benefit in high-voltage battery monitoring systems of hybrid and electric vehicles (xEV). A very good signal-to-noise ratio and a total error below 1% (full scale) over temperature allow for precise current measurements in applications with a signal bandwidth of up to 5kHz.

All the necessary components for a closed-loop circuit, such as compensation coil, Rshunt, and TMR sensor bridge, are integrated into a small 1mm thin industry standard TSSOP16 SMD package. By avoiding the need for a large magnetic-field concentrator core, space and costs can be saved.

Figure 1 : CUR 423x busbar setup
 Figure 1 : CUR 423x busbar setup

Digital offset and gain temperature compensation, low-pass filter, and clamping can easily be programmed by using TDK-Micronas' programming toolchain.Two variants are available that offer magnetic-flux density ranges of either ±7mT or ±40mT. A fine adjustment of the field ranges allows for adaptation to different application current ranges. Current sensing modules equipped with CUR 423x can be programmed via the output pin during the manufacturing process. Customer-selectable output interfaces, like SENT acc. to SAEJ2716 Rev.4, SPI or full ratiometric analog, allow for flexible adaptation to application requirements.
The CUR 423x is developed according to ISO26262. ASIL-B ready Functional Safety level is achieved due to various integrated diagnostic functions.
The device is qualified according to AEC-Q100 and is designed for automotive applications with temperatures ranging from –40°C to +170 °C (TJ).

Figure 2 : CUR 423x block diagram
 Figure 2 : CUR 423x block diagram

Main Applications

  • xEV battery monitoring
  • Stationary battery management

Main Features and Benefits

  • High-precision, linear closed-loop TMR technology
  • Non-intrusive, galvanically isolated contactless and coreless current sensing
  • Total error <1% over temperature
  • SENT according to SAE J2716 Rev. 4
  • Ratiometric analog output with selectable output inversion
  • SPI interface for test, debugging and direct microcontroller connection
  • Operates from –40 °C up to 170 °C (TJ)
  • Operates from 4.5V up to 5.5V
  • ISO26262 ASIL-B ready
  • Qualified according to AEC-Q100-Rev-H

Key data

Type CUR 423x
Package TSSOP16
Output formats SENT, SPI, analog
Total error over temperature <1%
Magnetic-flux density range ±7mT or ±40mT
Safety ASIL-B ready development according to ISO 26262