A Low-Cost, Real-Time Current Sensing Full-Bridge MOSFET Topology for Efficient Operation With Resistive/Inductive Loads

This article introduces an economical and real-time current measurement technique specifically designed for mosfet full bridge topology with both resistive and inductive loads. The diverse range of current sensing approaches underscores the significance of a careful selection process tailored to meet the specific needs of the application, taking into account factors such as cost, accuracy, space utilization, and efficiency. The proposed on-state current measurement scheme effectively reduces the current sensor's impact, minimizes power loss across the sensing element, and addresses cost and size considerations. In addition, the junction temperature is estimated by establishing a relationship between the mosfet drain pad temperature and coefficient “k.” The effectiveness of the proposed methodology is validated on a printed circuit board under both resistive and inductive load conditions. The measurement results demonstrate close adherence of the on-state current to the reference current. Noteworthy is the minimal error observed in the case of an inductive load, with a recorded value of 0.06 A at a duty cycle of 10% and a frequency of 25 kHz.