An Efficiency Step-Up Converter with a Low Switch Stress

A novel approach is proposed for a high step-up and high efficiency converters with a low switch stress. The integrated boost-flyback converter uses coupled-inductor techniques to achieve high step-up voltage with low duty ratio, and thus the slope compensation circuit is disregarded. The proposed circuit topology improving highgain ratio, increasing efficiency, reducing the secondary side of copper loss, and having an active-clamp effect that can reduce the switch stress on power components and have the energy feedback mechanism. Such a method of high efficiency and simple control can reduce cost and production size are in increasing demand at present. Therefore, designing converters becomes a challenge when stepping up voltage with high efficiency and high power output. This thesis is a design of a high-efficiency step-up converter with low switch stress. The design is simple in that the circuit requires only a pulse width modulation (PWM) signal output. In addition, at cut-off time, the MOSFET generates a spike by way of a circuit sent to the output. This way can achieve the goal of energy recovery, an active-clamp, and can reduce the switch stress of power switch to improve circuit efficiency. Experimental results have confirmed that the proposed converter possesses high step-up, high efficiency, and low switch stress. Keyword: Step-up, low switch stress, active-clamp