Self-Driven Synchronous Rectification System for Converters with Symmetrically Driven Transformer Based on the Use of the Output Inductor

Abstract

Synchronous Rectifi cation (SR) is mandatory to achieve good effi ciencies with low output voltages. If the transformer is driven asymmetrically without dead times, Self-Driven Synchronous Rectifi cation (SDSR) is a very interesting solution. However, if the transformer is driven symmetrically, the synchronous rectifi ers are off during the dead times and, as a consequence, the effi ciency is lowered. This paper deals with the optimisation of a SDSR system that keeps the rectifi ers on even during the dead times. The system is based on using the output inductor to turn the SR on and the power transformer waveform to turn them off. Hence, the most important parameters have been studied in order to obtain the highest possible effi ciency. This system is very interesting because it can be used in any topology with a symmetrically driven transformer independently of the output voltage level and for a wide input voltage range. The system has been implemented in a prototype in order to measure the real effi ciency that can be achieved with the proposed scheme and compared with the effi ciency of the same prototype without SDSR.

Self-driven synchronous rectification scheme for wide range application of DC/DC converters with symmetrically driven transformers

“…The results were obtained independently and concurrently. Similar results in [7] were obtained independently and concurrently.…”

“…The principle of the proposed method is analyzed and experimental results are presented. Once again, we remark that after this paper was accepted, close to identical results appeared in [7]. The results were obtained independently and concurrently.…”

“…The signals from the transformer and the output inductor are combined together to keep the MOSFETs operating even during deadtimes, while at the same time, are able to turn off the MOSFETs properly by using auxiliary switches. (After the acceptance of this paper for PESC06, similar research results [7] from another university appeared in APEC06.) In addition to the description of the basic idea of utilizing the output inductor, this paper also put efforts on analysis and experimental verification for wide input range application.…”

Optimal Design Methodology of Zero-Voltage-Switching Full-Bridge Pulse Width Modulated Converter for Server Power Supplies Based on Self-driven Synchronous Rectifier Performance

“…The method has a complex structure, and therefore, it is a costly solution. The proposed method in [22] uses output inductor voltage to turn on SRs and uses the power transformer for the turn-off process of SRs to provide the conduction of SRs during dead time. However, this method requires two metal-oxide-semiconductor field-effect transistors (MOSFETs), two diodes, and two auxiliary windings coupled with the output inductor.…”