Current-mode circuit technique for SenseFET application in BLDC drive

grantor: University of TorontoThis thesis presents a novel approach of current sensing in smart power integrated circuits with current-mode circuit technique. The proposed system is to be used for brushless DC motor drive for the application of integrated intelligent motion control. By virtue of a current conveyor, the current information is obtained from a current sensing power MOSFET (SenseFET). Current signal conditioned for the purpose of control and protection is quantized by a switched-current 2nd order [Sigma]/[Delta] A/D converter. The use of current mode signal processing technique eliminates conventional current sensing resistor to increase sensing accuracy. In addition, this current data acquisition system makes the integration of small signal processing, control logic and power parts into single chip with CMOS compatible fabrication technology a possibility. The introduction of an innovative current memory cell to switched-current A/D converter greatly increases the current signal handling capability and reduces the power consumption and silicon area. The advantages of the new memory cell are verified by mathematical analysis and Hspice simulations. The data acquisition system was implemented in TSMC 0.35[mu]m CMOS process. The simulation result verified functionalities of the proposed system, however, chip testing is needed to evaluate the performance of the design.M.Sc.A