Today, a wide variety of industrial and automotive applications are demanding higher efficiency which impacts many design decisions including the current sensing requirements. The demands are so dramatic that it may be that existing magnetic-based solutions will be obsolete by 2030. These applications demand wide band gap (WBG) power devices pushing the performance requirements for current sensing.
As EE Times notes, “WBG SiC and GaN materials enable significant efficiency improvements in applications such as traction inverters for SiC and adapters/ chargers for GaN. SiC and GaN technologies have grown enormously over the past few years, proving to be commercially available energy-saving technologies.”
WBG materials deliver smaller, faster, more reliable power electronic components with higher efficiency than their silicon-based counterparts. EVs, renewables, and power efficiency in general (including server power supplies, automotive onboard charges, solar inverters, etc.) all require accurate, high bandwidth current sensors.
The new requirements for current measurement, conversion optimization, and power-factor correction mean that this type of new, better performing, more efficient technology is essential. Today’s Hall based solutions simply can’t cut it. While Hall based solutions are faltering, TMR is just getting started, already surpassing Hall in performance with first generation products. It’s the classic technology S-curve, with Hall tapering off of at the top of the curve, while TMR is just ramping upwards.
Power Electronics News points out that “TMR technology has advantages over both shunt resistors and hall effect-based sensing solutions, offering lower power consumption, better thermal stability, better resolution, and higher sensitivity.
The Future is TMR
The demand for higher sensitivity in industrial applications will most likely lead to a replacement of Hall effect sensors by GMR or TMR sensors, which in turn will have to become more affordable. – IOPscience Scientific Paper
For a new technology to take over an established one, it must offer dramatically better performance and efficiency. When it comes to new requirements for industrial applications, TMR delivers in spades.
TMR sensors are a good choice for applications where high bandwidth, high accuracy, and lifetime performance are important. TMR sensors are now generally available and boast significantly better Signal-to-Noise Ratio (SNR) than Hall-effect sensors. In addition, Crocus’ TMR sensor solutions are BEOL-compatible. This means that its TMR sensors can be manufactured using the same equipment and processes that are used to manufacture other semiconductor devices, reducing the cost of production. Unlike Hall, Crocus TMR does not require any space on the silicon substrate, it lives in the BEOL layers, allowing for a bigger sensing area while achieving a smaller overall die size.
TMR sensors’ higher SNR, means they can detect small changes in the magnetic field. They also have a wider dynamic range, which means they can measure magnetic fields with high resolution. This sensitivity, paired with exceptional Signal-to-Noise Ratio, offer unmatched contactless sensing performance – not an option with Hall solutions. These sensors are also more stable over temperature, which means they can provide more accurate measurements in harsh environments, such as automotive.
Sensor accuracy is substantially affected by Common Mode Field Rejection (CMFR), In current sensing modules, stray magnetic fields can be induced by adjacent current carrying conductors or magnets. These magnetic fields impact the sensor performance and lead to lower system inefficiencies. To solve this, Crocus TMR solutions offer vastly superior common-mode field rejection capability reaching up to -54dB both in contact and contactless current sensor products.
Using standard CMOS manufacturing, test and packaging along with smaller die size and improvements in test times, Crocus Technology’s TMR products have closed the cost gap with Hall based sensors all while offering superior performance.
Crocus Technology’s CT43x and CT45x, for example, are very well suited for EV applications with proven success, offering high bandwidth (1MHz) without the need for magnetic flux concentrators. They also provide high accuracy, overcurrent fault detection, and immunity to Common Mode Fields – CMFR: -54dB.
As an example, recently Suncall Corporation realized these advantages and employed Crocus TMR Sensors for a new lineup of electric vehicle products based on a magnetic sensors. This new current sensor achieves high accuracy of 1.0% or less over the entire temperature range and low power consumption of 6mA or less, making it more efficient than conventional products.
Crocus Technology is a TMR manufacturer whose products have decisively demonstrated technically superiority at competitive pricing. High end applications need superior performance that is delivered by TMR solutions and the performance exhibited by Crocus TMR solutions will be the standard required for future applications.
