JOURNAL OF ELECTRICAL AND ELECTRONIC SYSTEMS RESEARCH https://doi.org/10.24191/jeesr.v21i1.001 1 Abstract— This paper proposes a new circuit topology of high frequency switching DC-DC Series Parallel Loaded Resonant Converter (SPLRC) at 120 KHz. The circuit is used for a wireless power transmission application that requires a fast-charging operation. The purposed circuit that used a series parallel loaded technique is transformed into a different equivalent circuit for mathematical analysis that efficiently analyses the operation of the circuit in AC and DC modes. For each equivalent circuit, the operation is described and explained. A full detailed circuit calculation using Matlab R2018A is then carried out to determine the purpose converter components' value. Psim software is used to prove the model's validity further. Both computer-based simulations were used to capture the resulting waveform. Initially, the simulation result waveform is captured by using PSIM and then send to Matlab R2018A to plot better. The proposed circuit is fabricated based on the simulation result, and actual experimentation is made. Then a comparison between lab test results and simulations had been made to verify the accuracy of the proposed circuit operation. Furthermore, the targeted 600 W output power can be considered high for a lower voltage input of 24 V, thus, resulting in the resonant tank components value than available in the market. Therefore, the percent error between lab test and simulation is 2.6316% for voltage output. The lower value of output power produces more accurate results rather than the higher value of output power. Most of the components are using low-cost and commercially available in the market. All the finding is explained and discussed from the simulation result, it is confirmed that a high-frequency switching circuit is operated as expected. Index Terms—DC-DC Converter, SPLRC, MOSFET, Matlab R2018A, Psim, Resonant Converter I. INTRODUCTION OWADAYS, a high-frequency driver in wireless power transfer, has been widely used, especially since the advent of amplitude-modulated radio in the early 20 th century Nevertheless, due to friction contacts, conventional conductive power interfaces affect the traditional conductive power efficiency of devices and restrict their use or render them unacceptable[1]. An efficient wireless power transfer method would enable advancements in various fields, including embedded computing, mobile computing, sensor networks, and micro robotics[2]. Typically, in wireless power transmission, the signal's frequency must be higher than the standard 50Hz. In an electrical transmission system, it raises series impedance. As a result of the reduced power transfer capabilities, thus, unable to realize the benefits of the transmission system. Most hard switching converters are inefficient, with bulky magnetics resulting in a low switching frequency[3]. It appears that high power losses are caused by high switching techniques[4]. Since hard-switching requires switching on and off with the full load current, it is prone to high switching losses in DC-DC converters. Nonetheless, switches in soft-switching resonant DC-DC converters turn on and off only when the voltage across or current through them is zero, thereby minimizing or eliminating switching losses[5]. Resonant converters are increasing steadily with a quicker transient response due to the benefits of smaller size and lighter weight[6]. Furthermore, resonant converters are ideal candidates to achieve zero current switchings (ZCS)[7]. Previous researchers proposed a different technique and approach as a solution to the problem. This paper will primarily focus on the development of an advanced power converter for wireless power transfer focusing on switching frequency of 120 kHz and voltage output. The proposed driver comprises a high- frequency DC-AC converter with a design example of a 240 V supply and a 24 V DC input produced by an adapter. In general, the energy dissipation in a power inverter increases as the operating frequency increases[8]. Following that, an AC to DC converter with a switching frequency of 120k Hz and a 19 V output voltage with a power output converter of 600 W will be used as the second stage[9]. This output voltage level is targeted because the output of this project will be used as the source A 120 kHz High-Frequency MOSFET Charging Circuit Using Series Parallel Resonant Converter Naufal Abdul Aziz Nuawi*, Ermeey Abdul Kadir and Mohammad Nawawi Seroji N This manuscript is submitted on 9 th September 202 and accepted on 26 th May 2022. This work was funded by Ministry of Higher Education & Research Management Institute (RMI), Universiti Teknologi Mara (UiTM) Fundamental Research Grant Scheme (FRGS) No: 600-IRMI/FRGS 5/3 (045/2019). N. A. A. Nuawi and M. N. Seroji are with the School of Electrical Engineering, College of Engineering, Universiti Teknologi MARA, 40450, Shah Alam, Selangor. E. A. Kadir is with the School of Electrical Engineering, College of Engineering, Universiti Teknologi MARA, Dungun Campus, 23000, Dungun, Terengganu. *Corresponding author Email address: naufalnuawi_95@yahoo.com 1985-5389/© 2021 The Authors. Published by UiTM Press. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/ licenses/by-nc-nd/4.0/).