The need for a high speed and low power ADC is very essential for various applications. Flash ADCs are always the architecture choice where maximum sample rate and moderate resolution is needed. Even though flash ADC is the fastest type available it takes enormous amount of IC real estate to implement. The main disadvantage of flash ADC is that it need large area and dissipate large amount of power. To overcome this complexity number of comparators are reducing by using multiplexers. Here the multiplexers are used to generate reference voltages. A 4-bit CMOS based flash ADC is presenting, which uses reduced comparator and multiplexer based architecture. Here both the analog and the digital parts of the proposed ADC are completely modified. This architecture uses only 4 comparators for a 4 bit ADC. This 4-bit ADC is designed and simulated in Hspice with 1.2 V supply voltage.

This paper presents a new isolated multiport dc-dc converter for concurrent power management of several renewable energy sources which can be of similar types. The proposed dc-dc converter uses only one controllable switch in each port to which a source is connected. It has simple configuration and minimum number of power switches. The proposed converter is applied for simultaneous maximum power point tracking (MPPT) control of a wind/solar hybrid generation system consisting of one Wind Turbine Generator (WTG) and two different Photovoltaic (PV) panels. The experimental results are provided to validate the incisiveness of using the proposed converter to achieve MPPT simultaneously for the WTG and both PV panels. KEYWORDS:Multiport converter, maximum power point tracking (MPPT), photovoltaic (PV), wind turbine generator (WTG) solar energy, wind energy. I.INTRODUCTIONNowadays, there is a growing interest in generating electricity from distributed renewable energy sources. In numerous applications, it is required to connect multiple renewable energy sources of different types to a power grid or load. The multiport DC-DC converter has been proposed to efficient power management and grid integration for the multiple origins and development in a new era in a demand quality power in remote communities[8] [9]. The isolated dc-dc converter has multiple input ports for connecting different sources, such as photovoltaic (PV) panels, wind turbine generators (WTGs), fuel cells, etc., The multiport dc-dc converter not only regulates the low-level dc voltages of the sources to a constant high level required by the inverter but also provides other important control functions, such as maximum power point tracking (MPPT).The proposed isolated multiport dc-dc converter for simultaneous power management of multiple renewable energy sources uses only one power electronic switch in each input port connected to a source. The proposed converter does not use any controllable switch on the secondary side of the transformer [2]-[4]. The proposed converter has the least number of switches and thereby a lower cost. The newly introduced converter is applied for power management of a wind/solar hybrid generation systems, which consists of a WTG and two varied PV panels. The power generation from solar and wind energy are designed using perturbation and observation (P&O) MPPT algorithm, in which the WTG and PV panels can be controlled at the same time and extract the maximum power. II.PROPOSED ISOLATED MULTIPORT DC-DC CONVERTERThe Fig 1 shows the block diagram of the proposed isolated multiport DC-DC converter. Itconsists of PV Panels, Wind turbine generator, Boost converter, MPPT controller, High frequency transformer and an inverter.