Cristian Diaz

Mr. Cristian Diaz

orcid

Research Focus & Metrics

Academic Career Length

5Years (2022-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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15 April 2022 in Electronics
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Journal Article
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Salvador Pérez LitránSalvador Pérez Litrán
Salvador Pérez Litrán
Eladio Durán ArandaEladio Durán Aranda
Eladio Durán Aranda
JSJorge Filipe Leal Costa Semião
Jorge Filipe Leal Costa Semião
CDCristian Diaz
Cristian Diaz
Multiple-output DC–DC converters are essential in a multitude of applications where different DC output voltages are required. The interest and importance of this type of multiport configuration is also reflected in that many electronics manufacturers currently develop integrated solutions. Traditionally, the different output voltages required are obtained by means of a transformer with several windings, which are in addition to providing electrical isolation. However, the current trend in the development of multiple-output DC–DC converters follows general aspects, such as low losses, high-power density, and high efficiency, as well as the development of new architectures and control strategies. Certainly, simple structures with a reduced number of components and power switches will be one of the new trends, especially to reduce the size. In this sense, the incorporation of devices with a Wide Band Gap (WBG), particularly Gallium Nitride (GaN) and Silicon Carbide (SiC), will establish future trends, advantages, and disadvantages in the development and applications of multiple-output DC–DC converters. In this paper, we present a review of the most important topics related to multiple-output DC–DC converters based on their main topologies and configurations, applications, solutions, and trends. A wide variety of configurations and topologies of multiple-output DC–DC converters are shown (more than 30), isolated and non-isolated, single and multiple switches, and based on soft and hard switching techniques, which are used in many different applications and solutions.

30 July 2023 in Applied Sciences
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Journal Article
Open access
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CDCristian Diaz
Cristian Diaz
Eladio Durán ArandaEladio Durán Aranda
Eladio Durán Aranda
Salvador Pérez LitránSalvador Pérez Litrán
Salvador Pérez Litrán
JMJosé Luis Álvarez Macías
José Luis Álvarez Macías
JSJorge Filipe Leal Costa Semião
Jorge Filipe Leal Costa Semião
This paper describes a new configuration of Cuk and SEPIC (Single-Ended Primary Converter) ZVS-QR (zero-voltage switching quasi-resonant) combination DC-DC converter for bipolar output with a single switch. The proposed topology employs a single ground-referenced power switch, which simplifies the gate drive design with a single L-C resonant network and provides a bipolar output voltage with good regulation, acceptable efficiency and a step-down/up conversion ratio. This configuration provides dual-output voltage by switching the power switch to zero voltage, which is an interesting alternative for many applications where small size, light weight and high power density are very important aspects. In order to verify its performance, a SEPIC–Cuk Combination ZVS-QR prototype with a cost-effective commercial resonant controller was designed and tested. The experimental results show that the proposed combined topology is suitable for Single-Input Dual-Output (SIDO) applications.

2 April 2025 in Electronics
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Journal Article
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CDCristian Diaz
Cristian Diaz
Eladio Durán ArandaEladio Durán Aranda
Eladio Durán Aranda
Fernando Alves da SilvaFernando Alves da Silva
Fernando Alves da Silva
SASérgio André
Sérgio André
In order to obtain acceptable efficiencies, hard-switching techniques and the converters that implement them must operate at relatively low frequencies (tens of kilohertz), which translate into converters of large size, weight, and volume, and therefore higher cost. To improve these characteristics, this work introduces a new transformerless MHz-range DC–DC converter that provides symmetrical bipolar outputs. The developed topology uses a single grounded switch, achieves soft switching (ZVS) over a wide load range, and does not require the use of floating or isolated controllers, reducing cost, size, and complexity. The output voltages are self-regulated to maintain the same value, ensuring balanced bipolar operation. A comprehensive analysis, design, sizing, simulation, implementation and testing are provided on a 150 W prototype operating at a switching frequency of 1 MHz, with step-up and step-down capability and implemented with GaN FET. The evaluated configuration shows an efficiency close to 90% and high power density, making it suitable for compact designs in a variety of applications requiring reliable power management and high efficiency such as lighting, electric vehicles, or auxiliary power supplies.

30 April 2026 in Applied Sciences
Verified
Journal Article
Open access
PDF file
CDCristian Diaz
Cristian Diaz
Eladio Durán ArandaEladio Durán Aranda
Eladio Durán Aranda
Salvador Pérez LitránSalvador Pérez Litrán
Salvador Pérez Litrán
Fernando Alves da SilvaFernando Alves da Silva
Fernando Alves da Silva
Multi-output, single-switch, hard-switched Pulse-Width Modulated (PWM) converters suffer from high switching losses, which strictly limit their power density. To significantly reduce these losses, this work proposes a novel family of non-isolated multi-output DC-DC converters based on a quasi-resonant, single-switch cell operating in the megahertz (MHz) range. Sixteen configurations are derived to enhance power density and minimize component stress. A comprehensive analysis derives the fundamental analytical expressions for operation, switching conditions, and power flow. These expressions form the basis of a design tool that facilitates parametric component selection and optimization. The developed tool calculates voltage and current stresses, alongside power losses, using RMS current analysis and user-defined parameters such as ESR and semiconductor non-idealities. Finally, experimental results from prototypes operating at approximately 1 MHz in both full-wave and half-wave modes, with step-up and step-down capabilities, confirm the accuracy of the analytical design tool and the simulation model.