Vignan University

About: Vignan University is a education organization based out in Guntur, Andhra Pradesh, India. It is known for research contribution in the topics: Computer science & Control theory. The organization has 1138 authors who have published 1381 publications receiving 7798 citations.

Comparative analysis of the CMOS 180nm technology-based flash ADC designs using dynamic comparator and TIQ comparator

Abstract: Flash ADC is the device popularly used in high speed data processing wireless communication systems. The submicron area overhead and the power dissipation of the flash ADC are the important metric parameters in such a high speed applications. Comparator is a major block that increase the power dissipation and area overhead of the data converter. This paper presents the two different types of Flash ADC structures with performance comparisons. The two structures of the ADC have been designed using dynamic comparators and TIQ comparators respectively. The design structures are simulated using 180nm CMOS technology for area, power and delay analysis.

Transformer design to achieve soft switching in low power Flyback converters

Abstract: Soft switching in DC-DC converters is a well accepted technique and its advantages are widely discussed. Undoubtedly, the soft switching reduces the power loss in the Main switch while improving the overall EMI in the converters. This facilitates the increase of switching frequency of converters. This paper highlights a design methodology for the transformer in a fly back converter, which automatically accomplishes the complete soft switching of the main switch. No extra circuit or the control scheme is needed to attain Zero Current Turn On and total Zero Voltage Switching (both during turn ON and Turn OFF) of the Main MOSFET switch. Also, it eliminates the Dissipative snubber which is an essential component in fly back converter. However, this scheme is wholly applicable to fixed Input and constant load applications. Nevertheless, most of the Industry scenarios are similar at low power range of about 50 to 100 watts, because invariably the DC-DC converters are operated from a Power factor correction module (Whose output is fairly regulated to around 400V DC) and the output load is constant. The design concept is demonstrated on a 60 watt fly back converter operating from a 400V DC bus and operated at 100 KHz.

Dynamic Channel State Information based Relay Selection in Device-to-Device Communication

Abstract: Relay selection in Device-to-Device (D2D) communication network is a prominent task due to the imperfect channel conditions and sensing intervals. This paper presents a dynamic channel state interval (CSI) based feedback design for improving the features of relay selection to improve the performance of the D2D communication networks. Based on the dynamic detection of imperfect channel conditions and sensing intervals, the precoding process is employed for the signal derivative in the relay selection process. The relay with a high order of signal output determines its selection. The performance of the proposed method is verified for the sum rate metric for the varying CSI bits, transmit power and inter-user distance.