College of Engineering
Electrical Engineering Department
BS in Electrical Engineering
While the number of transistors per microprocessor is rapidly increasing, the power requirements of converters are getting more and more important. The amount of current is increasing, while at the same time the output voltage is steadily decreasing. Today’s boards are exceeding 100A, while the buck converters have their output voltage below 1 V. Due to these new power requirements, multiphase buck converters are becoming more popular. In addition, this topology is usually used with voltage regulator modules (VRM).
The TPS40090EVM-002 board was used as the original multiphase buck with an input voltage of 12 V and output voltage of 1.5 V. The board also has an output current of 100 A, totaling the output power to 150 W. The revised board’s main aim was to reduce the output voltage ripple, while also improving the efficiency and line and load regulation. Through simulation, the revised board was able to drastically improve the output ripple by a factor of 30. When implementing the hardware, the revised board was only able to reduce the ripple by about half. However, the new board was unable to improve efficiency or line and load regulation.
Before the hardware tests were done, OrCad PSpice was used for an open loop simulation of the power stage. The power stage consisted purely of the four phase multiphase buck converter. Simulation was done for the regular converter as well as the revised buck converter. The hardware tests were then done for the EVM board and the revised board. The results were a success as the output voltage ripple was decreased, and now there is only more room to improve for the multiphase buck converter.