Linearity Improvement of High Current Hall Effect Current Sensors

PI: Prof. Partha Sensharma

Electrohms, a Bangalore-based company is the only Indian manufacturer of Hall-effect based closed-loop sensors, the market of which is dominated by Swiss and other European players. Recently they had noted a problem in their 500 A sensors at mid-range frequencies, which after discussion turned out to be a problem of linearity improvement, over the declared bandwidth. The manufacturer had provided all circuit details and the project suggested some preliminary modifications.  A few sensor samples were tested using their specialized equipment and measurement instruments available here. Initially, the frequency range involving maximum deviation was bracketed and its performance was analyzed in this bracket.  Additional improvements in circuit design were proposed, incorporated and tested to ensure that subsequent performance matched international benchmarks. Detailed analysis of the component tolerances were conducted to ensure less than 0.1% error in linearity over the declared current range, with marginal cost increment. We are now in the process of getting a sponsored project from Electrohms for improvement in bandwidth of their high current sensors (closed-loop) and achieving a flatter gain response over the extended bandwidth.