IN Brief:
- TMCS2100-Q1 measures horizontal and vertical magnetic fields simultaneously around traction-inverter busbars.
- TI claims 20-times better displacement accuracy than single-axis coreless alternatives, with less than 1% error at 0.4mm movement.
- Production quantities, evaluation hardware, reference designs, and functional-safety documentation are available.
Texas Instruments has introduced the TMCS2100-Q1 multiaxial coreless Hall-effect current sensor for hybrid and battery-electric vehicle traction inverters. The device measures magnetic fields in horizontal and vertical directions simultaneously, allowing it to compensate for mechanical displacement and magnetic crosstalk without using a conventional magnetic core.
Traction inverters depend on accurate phase-current measurement for motor control and overcurrent protection. Magnetic-core sensors can achieve high accuracy but add size and weight, while compact coreless approaches are more sensitive to changes in the position of the sensing element relative to the busbar. That movement can arise from vibration, manufacturing tolerances, thermal expansion, or the mechanical stresses found inside a vehicle powertrain.
TMCS2100-Q1 uses multiple on-chip Hall elements with a proprietary processing algorithm to compensate for displacement. TI claims the architecture delivers 20-times greater accuracy than single-axis coreless alternatives in its comparison, with displacement error below 1% at 0.4mm of movement and 0.25% at 0.1mm.
The device is designed to operate relative to an unmodified busbar rather than requiring a notch, slot, or hole to shape the local magnetic field. That removes a constraint from conductor design because high-current busbars are part of the inverter’s electrical and thermal system. Narrowing or cutting the conductor for a current sensor can affect resistance, current density, mechanical strength, and heat flow.
Giving the power designer freedom to optimise the busbar independently of the sensor becomes increasingly useful as inverter packages become smaller. Conductors have to carry high phase currents with limited loss while fitting around gate drivers, capacitors, cooling plates, and switching modules. A measurement approach that does not dictate a local change in conductor geometry can simplify that packaging problem.
TI specifies the TMCS2100-Q1 for high-voltage, high-current multiphase systems and has qualified it to AEC-Q100 grade 0. The operating temperature range extends from -40°C to 150°C. The device provides 250kHz small-signal bandwidth, a 2.6µs response time, and overcurrent detection in 500ns, while its Functional Safety-Capable designation is supported by documentation for system-level safety development.
Timing is important because phase-current feedback forms part of the motor-control loop. A current sensor must provide an accurate measurement without adding enough delay or phase shift to compromise control performance. Faster fault detection also gives the protection system more time to respond before excessive current damages switching devices or other parts of the inverter.
The device includes active frequency compensation intended to reduce amplitude errors associated with eddy currents. These can arise in nearby conductive structures as magnetic fields change, with the resulting induced currents altering the field seen by the sensing element. Such effects become more difficult to ignore as inverter switching frequencies rise and mechanical packaging becomes denser.
TI says its characterisation method can reduce phase-to-phase magnetic crosstalk and achieve measurement errors below 0.5% at full-scale current levels that can exceed 1,000A. Those levels are relevant to increasingly power-dense traction systems, where the inverter still has to measure very high phase currents even as vehicle DC bus voltages move towards 800V architectures.
The current commercial step is production availability rather than the first disclosure of the device. TI has released production quantities alongside an evaluation module, characterisation hardware, and a reference design, while functional-safety and application documentation have continued to develop around the part.
Current sensors receive less attention than SiC MOSFETs or IGBTs in traction inverter discussions, but their errors feed directly into the control system governing those switches. As inverter power density rises, vibration, crosstalk, busbar geometry, and fault-response time become harder to absorb elsewhere in the design. TMCS2100-Q1 addresses those constraints without returning to a bulky magnetic core, leaving vehicle manufacturers to validate the claimed compensation across their own conductor layouts, temperature ranges, and production tolerances.
