High efficiency DC-DC converter design

Abstract

The Final Year Project pertains to the design of building blocks of a high switching-frequency DC-DC Buck converter and compares the power efficiency with the use of pulse width modulator as well as delta-sigma modulator.

The design circuit operates at an input voltage of 3.3V supply to the other components, 1.65V output voltage and 300mA load current with 5MHz switching frequency. A DC-DC Buck converter was used to implement to carry out the testing. Both the switch and diode however had been replaced by the use of PMOS and NMOS respectively. The width of the MOSFET had also play a major role as a driver to give us a high output current to the load. By obtaining an optimal width for the MOSFET it will helps in the reduction of the unnecessary energy dissipation to meet our requirement. In return, it would also be efficient to increase the power saving as well as the overall efficiency.

Delta-Sigma Modulation was also look into and used to compare with the pulse width modulation (PWM). Instantaneous power waveform was obtained to allow us to analyze the power efficiency and determine which modulator would better allowed us to achieve 80% power efficiency.

In conclusion, after analysis of the result we are able to show that pulse width modulation is able to provide better power efficiency as compare with delta- sigma modulation.