Design and Simulation of a Three-Phase Switching Synchronous Buck Regulator

Single-phase buck converters are widely used for applications that require DC-DC, low voltage conversion. These types of converters suffer from high ripple at the output voltage and current, with a non-optimal efficiency and power dissipation. This work demonstrates a three phase synchronous buck converter utilizing a difference-amplifier-based compensator in the feedback loop. Starting from the uncompensated loop and rather than using standard type II or type III controller topologies, a compensator is built from scratch using a difference amplifier with series and parallel combinations of resistors and capacitors. In addition, a common compensator and Pulse Width Modulation (PWM) are used for all three phases in the feedback loop. A 300mA transient current was introduced at 100μs to test the ability of the controller to regulate the voltage to its average value when the output was changed. The system behaved well with worst case output voltage spike with a response of 24mV. Moreover, an efficiency of 89.9 %, quiescent current of 102.03μA and 1.63mVp-p of output voltage ripple were achieved. From the source voltage 3.3V, an output regulated voltage 2.5V is obtained.