# Single-Switch Non-Isolated Resonant DC-DC Converter for Single-Input Dual-Output Applications
On the other hand, Single-Input Dual-Output (SIDO), bipolar symmetric outputs, dual and bipolar output DC-DC converters are receiving renewed interest in a wide variety of applications where two output voltages of the same magnitude but different signs are required from a single input supply. Among other reasons, this interest is due to the fact that SIDO converters can provide an additional higher supply voltage between both positive and negative output voltages. In this sense, it is increasingly common to find applications that require 24 V voltages from intermediate 12 V DC buses (Distributed Power Architecture, DPA), which in turn supply the traditional 1.8 V, 3.3 V and 5 V voltages. In this context, SIDO converters cover applications such as industrial, communications and computing power supplies [18], Electric Vehicles [19], LED lighting [20], as well as medical devices [21], photovoltaic systems [22], Low-voltage bipolar DC microgrids [23], advanced driver assistance (ADA) systems for cars, vans, trucks and buses (12 V and 24 V supplies) as emergency braking, detection systems (front and reverse cameras) for cyclists and pedestrians and intelligent speed assistance, which make driving more comfortable, safer and easier, and where small size and high power density are important aspects to account for. Many of the communications systems installed in commercial vehicles are powered by a 24 V battery and require up to 25 W of output power. A bipolar output is used to plug in electric vehicle charging stations in both AC and DC types and in DC fast charging, portable chargers, Grid-to-Vehicle (G2V) and Home-to-Vehicle (H2V), as well as Vehicle-to-Home (V2H), Vehicle-to-Grid (V2G), Vehicle-to-Vehicle (V2V), Vehicle-to-Building (V2B) and Vehicle-to-Everything (V2X) concepts. In addition, the combination of basic converters can reduce the power density since it allows for the combination of basic configurations to obtain dual-output voltages with a single power switch and requires a smaller number of components. This converter combination methodology has been proposed as a solution in hard switching [24] and soft switching [25], and it contemplates the combination of simple structures with the same front end, sharing switching nodes and giving rise to combined structures with different conversion ratios. In this paper, a new combination of Cuk and SEPIC (Single-Ended Primary Converter) ZVS-QR converter for bipolar output is presented. This combined configuration produces a step-down/step-up-type converter that allows the development of dual-output transformerless converters. Two main additional advantages of the proposed combined configuration are highlighted: (i) simple structure, since the converter is designed with a single switch and does not require synchronization among the switches, which increases the power density; (ii) the control terminal of the switch is grounded, which simplifies the implementation of the gate drive. In order to verify the proposed configuration, an experimental prototype has been developed with a cost-effective commercial resonant controller, and its performance has been confirmed for different regulating conditions. The prototype provides a dual-output voltage of \(\pm\)12 V from a single input in the range of 10-14 V, operating in step/up and step/down modes. The results obtained show that the designed converter is suitable for applications where SIDO voltage is required. This work is organized as follows: In Section 2, the new topology is presented and analyzed, along with the operation mode. Section 3 describes the simulation model and the prototype developed, which have allowed, through experimental results, to verify the behavior of the proposed combination converter for several loads and operating modes. In Section 4, some conclusions are drawn.