TI Tightens Accuracy and Integration of New Current Sensing Solutions
TI says the new Hall-effect current sensor and EZShunt integrated shunt portfolio balance the major features of current sensing solutions: cost, size, accuracy, and speed.
Today, Texas Instruments (TI) announced new current sensing solutions designed to offer more accuracy and higher integration while simplifying designs. The two products released include a Hall-effect current sensor, reported to offer the lowest drift in TI's portfolio, and new current shunt monitors with a built-in shunt resistor.
Hall-effect current sensors like TI's new TMCS1123 can help simplify high-voltage sensing. Image used courtesy of Texas Instruments
The TMCS1123 Hall-effect current sensor and the EZShunt portfolio can be used across a wide range of high-voltage systems and nonisolated voltage rails, respectively.
A New Hall-Effect Current Sensor
The flagship release is the TMCS1123 (datasheet linked), a Hall-effect current sensor. With galvanic isolation up to 5,000 Vrms and a continuous current capability of 75 Arms, the TMCS1123 is designed for sensing AC or DC current in high-power applications like solar inverters or industrial AC/DC converters. To support these kinds of industrial applications, the device is designed specifically to offer extremely high accuracy.
Block diagram of the TMCS1123. Image used courtesy of Texas Instruments
TI achieves this accuracy through built-in drift compensation, which enables less than 1.75% maximum total error over temperature and lifetime without calibration. With a one-time room calibration, that error is reduced to below 1%. Other notable accuracy specifications include a sensitivity error of 0.3%, an offset error of 0.5 mV, and a linearity error of 0.1%.
TI also says the sensor offers a reinforced isolation working voltage of 1,100 VDC—the highest in its class. The device keeps noise to a minimum while supporting faster control loops with its 600 ns propagation delay and 250 kHz bandwidth.
The device comes in many different varieties, ranging in sensitivity from 25 mV/A sensitivity to 150 mV/A. Each device in the family supports both bidirectional and unidirectional current sensing. TI also plans for these devices to reach UL 1577 and IEC/CB 62368-1 safety certifications.
The EZ Shunt Portfolio
The other release from Texas Instruments today is its new EZShunt technology portfolio (datasheet linked), a family of current sensing solutions that integrate the shunt resistor, removing the need for external components. Fitting all necessary components within a standard 1026 shunt resistor footprint, the EZShunt products are built to simplify design and minimize BOM.
A simplified block diagram of the INA781. Image used courtesy of Texas Instruments
The portfolio also includes the INA700, the "industry’s smallest" fully-integrated current shunt monitor, and the INA781, the "industry’s highest-accuracy" 75-A integrated shunt solution. The INA700 comes in a 1.319 mm × 1.239 mm PowerWCSP footprint and is said to reduce the size of sensing solutions by 84% compared to non-integrated solutions. These devices are designed for lighter applications like smartphones and notebook computers.
The INA781, on the other hand, offers an accuracy of ±2.5°C over the junction temperature range. Texas Instruments envisions this product being used for more industrial-facing applications like power delivery, grid infrastructure, and enterprise servers.
Current Sensing for More High-Voltage Systems
TI's new devices offer designers more ways to integrate current sensing into designs. By increasing the accuracy, lowering the propagation, and reducing the footprint of these products, TI hopes designers will be able to use Hall-effect sensors and current sensors in more high-voltage systems than before.
TI is now offering both the TMCS1123 and EZShunt solutions in pre-production quantities along with the TMCS1123EVM, an evaluation board for the product.