In this paper, a new high step-up current-fed LLC resonant DC-DC converter with a center-tapped transformer is proposed. By selecting the switching frequency to be lower than, but near to, the series resonant frequency of the LLC resonant tank, soft-switching operation of all semiconductors, i.e., zero voltage switching (ZVS) turn-on of power MOSFETs and zero current switching (ZCS) turn-off of diodes is achieved. This leads to lower electromagnetic interference (EMI) and lower switching losses and improves the converter efficiency. An interleaved structure is used at the primary side. Thus, input current ripple is smaller, and its frequency is twice the switching frequency. Consequently, a smaller input filter is necessary in practice. The converter with 1.2 kW output power and 760 V regulated output voltage with 80-200 V input voltage variations is simulated. The output voltage is regulated by using asymmetric pulse width modulation (APWM) at 200 kHz switching frequency. Finally, a 700-W prototype has been implemented and experimental results are also presented to verify the simulation results.

This paper proposes a 2.4 GHz active mixer without passive inductor for the transceiver system. Taking into account the design requirements of the mixer, a double-balanced down-conversion structure with active inductor and negative resistance is designed. The proposed mixer with 130 nm CMOS technology is designed and simulated using Cadence software at 1.5 V supply voltage. Although we had to compromise conversion gain with linearity, we were able to achieve very high conversion gain with average linearity. Based on the results of post-layout simulations, the conversion gain of 27.57 dB, IIP3 equal to -7.88 dBm, 1-dB compression point equal to -17.34 dBm and IIP2 equal to 44.22 dBm with power consumption of 2.5 mW was obtained for the proposed mixer. The chip size without input and output pads is 95.18 µm × 117.68 µm, which leads to a chip area of 0.0112mm2.

In this paper, a boost converter with a clamp circuit is proposed for high intensity discharge (HID) lamp application. The clamp circuit provides zero voltage turn on for both main and clamp switches. Compared to conventional boost converters, the proposed converter has the following advantages: (i) high voltage gain without suffering from extreme duty ratio, (ii) low stress on the switches and (iii) low switching losses. Simulation and experimental results show that the voltage stress on the switches are well within acceptable limits and prove the converter’s performance over a wide load range.

Limitations of traditional power sources and the rising need for renewable energy sources have encouraged researchers and manufacturers to enhance the effectiveness of power converters. Recently, numerous high gain topologies have been extensively designed to solve the main issues of the earlier DC-DC boost converters. In this study, a voltage-lift technique is applied to develop a modified high efficiency, high step-up DC-DC converter derived from a typical Cuk converter. The suggested transformer-less circuit also has the benefits of comprising few components and low-cost implementation compared to similar existing converters. Also, the proposed topology effectively boosts voltage gain by including an additional capacitor and a diode. The operational principle and steady-state analysis of the suggested converter in CCM and DCM are discussed in detail. The capabilities of the recommended topology are then demonstrated by mathematical analysis and comparison with previous similar configurations. Furthermore, the parasitic components are considered in the circuit for precisely computing the voltage gain and efficiency. Finally, experimental test results with nearly 210W output power indicate that the proposed converter can be appropriately employed.

This paper introduces a new high step-down converter that achieves zero voltage switching in both primary and auxiliary switches without relying on coupled inductors, thus ensuring low ripple in input and output currents. The auxiliary circuit is optimized with the fewest possible components, facilitating zero voltage switching for the main and auxiliary switches and solving the reverse recovery issue of freewheeling diodes through zero current switching conditions. Additionally, this design reduces voltage stress on the switches, allowing the use of MOSFETs with lower drain-source resistance. A key advantage of this converter is that it avoids using coupled inductors, which eliminates issues related to leakage inductance and potential increases in the converter's size and weight. This enhances the converter's efficiency and practicality. The auxiliary circuit design can also be extended to multiple phases, making it adaptable for various applications. The control mechanism is simple because the auxiliary switch operates in complementary with the main switch, simplifying the overall circuit design and integration. The proposed converter's design and operational principles have been validated through PSpice simulations, and a 90W prototype has been constructed. Experimental results demonstrate an impressive 95 percent efficiency at full load.

In this study, a novel high step-up converter without utilizing a coupled inductor at the input is presented. The converter incorporates two coupled inductors: one to enhance the voltage gain and the other to facilitate zero-current switching (ZCS) and transfer snubber energy. A lossless snubber is employed to achieve soft-switching conditions. All diodes in the circuit operate under ZCS, effectively eliminating the issue of reverse recovery. The converter features a continuous input current and reduced conduction losses due to low voltage stress on the switches. The proposed converter has been comprehensively analyzed, and a 60 W prototype was simulated in PSPICE and subsequently implemented to validate the circuit analysis. The converter achieves an efficiency of 96% under full-load conditions, representing a 6% improvement compared to a hard-switching boost converter.

In this paper, a new isolated dc-dc bidirectional converter is proposed. This converter consists of two transformers (flyback and forward) and only one switch in primary side and one switch in secondary side of transformers. In this converter energy transfers to the output in both on and off switch states so power density of this converter is high This converter controlled by PWM signal. Also this converter operates over a wide input voltage range. Theoretical analysis is presented and computer simulation and experimental results verify the converter analysis.