AC/DC and DC-DC Converter : “Practice for potent power regulation”

By: Mannu Mathew | Sub Editor | ELE Times

The Power efficiency of Converter system is highly correlated to the relationship between voltage and the alternating current in a current source. Power factor correction is a widely discussed phenomenon and is very much important in voltage regulation and power management process. A typical PFC is important in many single-phase AC-DC converter circuits to reduce harmonic distortion, hence increase power efficiency of electric appliances. In recent years there has been an enormous upsurge of interest in AC adapters and other external power supplies.

The present LED driver circuit is designed to drive in a minimum module. It consists of two stages, AC-DC power factor correction stage and DC/DC power converter stage. The implementation of the PFC stage uses IC NCP1608, which uses the critical conduction mode to guarantee a unity input power factor with a wide range of input voltages.

There are three types of LED driver systems, Single-stage, Two-stage and integrated LED drivers. The single-stage LED driver is an AC/DC converter that provides a constant output current for the LED and a unity power factor. The two-stage system consists of two separate stages, an AC/DC power factor correction (PFC) converter and a DC/DC converter. Recently, some integrated topologies were introduced in order to reduce the size and cost. Single-stage and integrated solutions have some advantages such as low-cost designs and high efficiency due to only one energy conversion.

Manufacturers worldwide have developed innovative production techniques that enable the integration of multiple components and a DC-DC converter IC die into a single module. Producing such a dc-dc module involves protection for its associated die from the surrounding environment. It also has the ability to integrate multiple components into the module thereby accommodating more complex circuits and reduced heat emission.

The Buck- Boost Converters too play a major role in LED application. A light emitting diodes drivers is a method through which allows compact module to provide necessary requirement mainly Omni directional indoor LED bulbs. The system separates transmission path from existing system based on instant input voltage that makes users improve and provide better PF relative value than existing system in which fixed LED method which contains only one electrolytic capacitor. This proposed system factor provides high power conversion efficiency supply than the existing LED drivers. The advantage of buck boost converter is that small signal modelling includes higher efficiency than existing peak current mode control method. The experimental results of proposed dimmable LED driver are executed and determined successfully than existing fly back system. The result of proposed system consumes 40 watt power supply than existing system.

Applications

The combined approach and technicalities of conversion has always catered to various aspects of the society. Daily life applications like automotive, telecommunications, power management, smart lighting and industrial machinery are the sectors which demand day to day development in technologies. Decades of increasing regulation have made efficiency testing one of the most important factors in selecting and qualifying power supplies. Some of the applications are as mentioned below.

Wireless Technology

Converter are also implemented in integrated circuit of wireless power devices in order to reduce the input voltage and produce small voltage drop, thus increase power efficiency of the devices. Therefore, two techniques which commonly used are negative voltage converter with active diode and gate cross-coupled AC-DC converter with bootstrap capacitor.

Smart Lighting

Many lighting applications require LED backlight driver solutions with the following features like direct current control, high efficiency, PWM dimming, voltage protection, and design simplicity. A fundamental consideration in the evaluation DC/DC converters is the effect of system losses on efficiency. One method to increase efficiency is to reduce the current flowing in the inductor by reducing the resistive losses due to the active components and the inductor.

Automotive

The electronics on-board a vehicle control many functions. Power management systems cover not only lighting solutions but also infotainment solutions to offer comfort and a safe and pleasant ride. For high-power applications, such as exterior lighting used in the automotive sector, a switching regulator is generally used. LEDs generally require a constant current to produce a coherent light output.

Telecom Applications

Today’s market offers DC/DC converter modules that address the growing power requirements of high-reliability networking and telecommunications infrastructure equipment. The primary applications in this segment are networking and telecommunications infrastructure equipment, communications equipment, network security, routers, wireless base stations, telecommunications switches and electronics, computing equipment and other applications requiring power conversion to an intermediate bus voltage of 11.4 V.

Power Management

The DC-DC converters provide regulated DC voltage when only DC is available. This will enable conversion to various voltage levels, in addition to electrical isolation to help set up independent power supply systems. Depending on the model, DC-DC converters are available in enclosures or open-frame with wattages from 3W. These converters are DIN rail mountable or may be modifiable for DIN rail applications. The converters offers features such as high efficiency, overload protection, durable design and transient suppression.

Energy Conversion

Energy conversion is clearly oriented on multi-point conversion which is based on a parallel high voltage bus. The latest researches on energy conversion clearly show that the next generation systems will be both smarter and efficient, with insurance of greater security and modularity.

Industrial eminence and contemporary products in the market

AC/DC Converters and DC-DC Converters are used in various application as it is considered as the core aspect of any electronic system. The applications where it is used includes medical equipment, factory automation, building automation, process control systems, signage displays, telecommunication, renewable energy, test and measuring equipment, defence, aerospace and transportation system etc.

Every aspect of confined and sophisticated electronics in today’s world require new technologies in power management, regulators and current conversion techniques. Below are some of the latest products in the areas of AC/DC and DC-DC conversion.

RECOM RS12-Z series DC/DC Converters

The RS12 is an advanced DC/DC converter that uses planar transformer technology to offer a very high power density, 4:1 input voltage, regulated DC output with 3kVDC isolation and a wide operating temperature range of -40°C to +75°C. The SIP8 pin out is backward compatible with RS6 and RS3 offering the option of 3W, 6W or 12W of output power in the same sized package. The series features a metal casing providing EMI shielding as well as enhanced thermal performance with case tabs providing mechanical stability and additional heat sinking to the customer’s PCB.

Vicor DC-DC Converter Module

The DCM Chip is an isolated and regulated DC-DC converter. It consistently deliver high efficiency across their specified input line range. Modular DCM converters used independently or with downstream point of load products support efficient power distribution, providing superior power system performance and connectivity from a variety of unregulated power sources to the point of load. The DCM module provides a higher level of functionality with integrated EMI filtering, tight output voltage regulation and a secondary referenced control interface.

Cincon SIP-7 Unregulated DC-DC Converter

The EC2SANH series offer 2 watts of output power with Industry Standard Package in a 0.77 x 0.28 x 0.40inches. The EC2SANH series have a ±10% input voltage range of 5Vdc, 12Vdc and 24Vdc and provide an unregulated output. This series are with features as miniature size, 3000VDC of isolation and allow an operating ambient temperature range of –40°C to 105°C with de-rating above 85℃. All models are very suitable for telecommunications, distributed power systems, battery operated equipment, industrial, portable equipment applications.

RECOM RPHM-0.5 non-isolated DC/DC Switching Regulator

RECOM extends its RPM series with the launch of the RPMH-0.5, A 0.5A non-isolated DC/DC switching regulator in a low-profile DOSA-compatible LGA package. With 0.5A output, five trimmable fixed outputs are available: 3.3V, 5V, 12V, 15V or 24V. Input voltage range is 1V-1.5V above the set output up to 65V, making the parts suitable for systems operating on nominal 5, 12, 24 or 48V rails. The RPMH also features 6-sided shielding for low radiated EMI so class B EMI compliance is achieved with a simple low cost line inductor. Additional features include full protection along with power sequencing, soft start on/off control remote sensing and a power good signal.

Vicor AC input filter and Rectifier

The MI-AIM AC input module interfaces directly with AC mains to provide line rectification, EMI filtering, transient protection and inrush limiting. These front-end modules accept 115VAC and provide 250W of output power for any of the Vicor Mi-x7x family of full-brick and half-brick sized modules. The MI-AIM meets CE102 conducted emissions requirements of MIL-STD-461D/E, the transient and spike requirements of MIL-STD-704A and the environmental test requirements of MIL-STD-810.

TDK Corporation i6A step down Converters

Ideal for creating additional high current output voltages from a single output 12V, 24V or 48V AC-DC power supply, the highly efficient I6A series of step-down converters include the basic I6A supplying up to 14A, the wide input range i6A4W supplying up to 20A, and  the i6AN allowing the creation of negative voltages delivering currents up to 8A. The I6A series are suitable for use in medical, communications, industrial, test and measurement, broadcast and portable equipment.

Mornsun AC/DC Converter for Automotive application

CLS03_15A12SR2S is one of Mornsun’s high efficient green power AC-DC Converter
series. It features ultra-compact size (35.0*13.0*21.0mm), ultra-wide input range accepting either AC or DC voltage, high reliability, low power consumption or reinforced isolation. Production process in accordance with automotive standard IATF16949 system. It is suitable for automotive charging related equipment, such as portable on-board charger for electric vehicle, charging box, charging pile and so on. The Production process in accordance with IATF16949 system control, applied to automotive industry which also has universal input voltage of 85 – 264VAC/100 – 370VDC and an operating ambient temperature of -40℃ to +85℃.

STMicroelectronics VIPER222 High Voltage Converters

The VIPER222 Converters embed the high voltage startup and the current sense circuit, avoiding the use of extra components in the BoM. Frequency jittering spreads the EMI and allows the use of a small filter. The burst mode technique allows a very low input power consumption at light load. The convertor has a 730V avalanche rugged power MOSFET and a PWM controller. It caters to the applications such as auxiliary SMPS for home appliance, consumer, industrial and lighting applications.

Conclusion

AC/DC Converters are widely used in many power electronic apparatuses. The designed AC/DC Converter provides high Power Factor, using less number of components and therefore is economical compared to the traditional power electronic converters. In the industries where DC motors with less power rating are used, the Power Factor should be high which can be achieved by using the proposed converter circuit. Hence the proposed circuit acts as a power factor corrector in order to obtain high Power Factor. It is also evident that the future requires more sustainable and fast technologies in order to get a source of robust power management.

By: Mannu Mathew | Sub Editor | ELE Times

 

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