Design and development of multiphase buck converters for voltage regulator modules

<p>Modern microprocessors in high-power applications require a low input voltage and a high input current, necessitating the use of multiphase buck converters. As per microprocessor computing complexity, the power requirements of the switching converter will also be more important and will be increasing as per load demand. Previous studies introduced some methods to achieve the advantages associated with multiphase regulators. This paper presents an effective closed closed-loop control scheme for multiphase buck converters that reduces ripple and improves transient response. It is suitable for applications that require regulated output voltage with effectively reduced ripple. The analysis began with a simulation of the entire design using the OrCAD tool, followed by the construction of a hardware setup. Experiments on a 200 Khz, 9 V, 12 A, 2-phase buck voltage regulator were conducted and the proposed experiment found to be useful.</p>

Destressing MOSFETs by Series Connection in Low Gain Buck Converters

<p>Low-gain buck converters will enable low voltage loads to access high voltage DC sources by a single stage converter at very low duty cycles. SiC MOSFETs are still limited to 1.7kV commercially and by seriesing them with adequate gate driving strategy, high voltages can be switched. This paper proposes a driving circuit for series SiC MOSFETs to block higher voltages. The driving circuit provides negative off-state voltage and turn on/off transitions in less than 100ns. The low-gain buck converter performance is assessed when using a single IGBT switch and series SiC MOSFETs. A simulation is implemented and shows the superiority of the proposed driven series SiC MOSFETs with distributed voltage and thermal stresses.</p>

Destressing MOSFETs by Series Connection in Low Gain Buck Converters

<p>Low-gain buck converters will enable low voltage loads to access high voltage DC sources by a single stage converter at very low duty cycles. SiC MOSFETs are still limited to 1.7kV commercially and by seriesing them with adequate gate driving strategy, high voltages can be switched. This paper proposes a driving circuit for series SiC MOSFETs to block higher voltages. The driving circuit provides negative off-state voltage and turn on/off transitions in less than 100ns. The low-gain buck converter performance is assessed when using a single IGBT switch and series SiC MOSFETs. A simulation is implemented and shows the superiority of the proposed driven series SiC MOSFETs with distributed voltage and thermal stresses.</p>

Modeling of Average Current in Non-Ideal Buck and Synchronous Buck Converters for Low Power Application

In this paper, a comparative analysis of the average switch/inductor current between ideal and non-ideal buck and synchronous buck converters is performed and verified against a standard LTspice model. The mathematical modeling of the converters was performed using volt-sec and amp-sec balance equations and analyzed using MATLAB/Simulink. The transients in the output voltage and the inductor current were observed. The transfer function of the switch current to the duty cycle (Gid) in open loop configuration for low-power converters operating in continuous conduction mode (CCM) was modeled using thestate space averaging (SSA) technique and analyzed using MATLAB/Simulink. Initially, using the volt-sec and amp-sec, balance equations for the converters were modeled. The switch current to duty ratio (Gid) was derived using the SSA technique and verified using standard average models available in LTspice software. Though the Gid was derived using various methods in earlier works, the analyses of parameters such as low frequency gain, stability, resonant frequency and the location of poles and zeros were not presented. It was observed that the converters were stable, and the non-ideal converter showed smaller resonant frequency than the ideal converter due to the equivalent series resistances (ESR) of the inductor and the capacitor. The non-ideal converters showed higher stability than the ideal converters due to the placement of the poles closer to the s-plane. However, the Gid of the non-ideal converters remained the same in the open loop configuration.