International Journal of Power Electronics and Drive Systems (IJPEDS) Vol. 3, No. 3, September 2013, pp. 328 – 335 ISSN: 2088-8694 328 Soft Switched Multi-Output PWM DC-DC Converter Rashmi Sharma Electrical and Electronics Engineering, Indus University, Ahmedabad, India Article Info Article history: Received Jul 20, 2013 Revised Aug 17, 2013 Accepted Aug 28, 2013 Keyword: Pulse Width Modulation (PWM) Push-Pull converter Magnetic Ampliﬁer ABSTRACT In this paper, a new soft switched cell that overcomes most of the drawbacks of the normal ”hard switched-pulse width modulation” converter is proposed to contrive a new family of soft switched PWM converters. All of the semiconductor devices in this converter are turned on and oﬀ under exact or near zero voltage switching (ZVS) and/or zero current switching (ZCS). No additional voltage and current stresses on the main switch and main diode occur. A push-pull converter equipped with the proposed snubber cell is analyzed in detail. The predicted operation principles and theoretical analysis of the presented converter are veriﬁed with a prototype of a 50W PWM push-pull multi-output converter with insulated MOSFET and for regulation of slave outputs magnetic ampliﬁer post regulators are considered as post regulators. Moreover; this multioutput converter has a simple structure, low cost, and ease of control circuitry. Copyright c  2013 Insitute of Advanced Engineeering and Science. All rights reserved. Corresponding Author: Rashmi Sharma Electrical and Electronics Engineering Indus University, Ahmedabad, Gujarat, India Email: rashmi.electnirma@gmail.com 1. INTRODUCTION Pulse width modulated (PWM) DC-DC converters have been increasingly used as switched-mode power supplies in industry. The PWM technique is identiﬁed for its high power capability, ease of control circuitry, higher power density and faster transient response, this can be achieved by increasing the switching frequency. However, as the switching frequency increases, so do the switching losses and EMI noise. High switching losses reduce the power capabilities, while serious EMI noise interferes with the control of PWM DC/DC converters. To solve the problems resulting from the non ideal phenomena of switching losses, several kinds of soft-switching technologies have been adapted which are shown in diﬀerent papers [3]. Out of these technologies active clamps, as introduced in [4] can reduce all three loss mechanisms by using auxiliary switches. Unfortunately, an auxiliary switch increases the complexity of both power and control circuits as well as synchronization problems between control signals of the two switches during transient also complicate the control strategy. The circuit cost is increased and the reliability is decreased by using these active snubber techniques. Although many technologies came one by one to reduce these losses as one of the cheapest technique is by using resistors, capacitors, and diodes (RCD) as a snubber but could not perform well despite of having the simplest structures as the switching losses are dissipated in resistors and thus, it reduces the eﬃciency of the circuit. Other techniques comprised of resonant converters that commutate with either zero voltage switching (ZVS) or zero current switching (ZCS) are also introduced to reduce the switching losses; however conduction losses are increased in these circuits due to the high circulating current involved in it. Also complicated design of an EMI ﬁlter and control circuit because of a wide switching frequency range can cause great trouble in assessment of the circuit. Therefore compared with the three Journal Homepage: http://iaesjournal.com/online/index.php/IJPEDS