April 1, 2009

Features

Renewable Energy Through Micro-Inverters

A relatively new option for optimizing solar system efficiency and reliability is use of micro-inverters that connect to each individual solar panel....

SEPIC Converters Solve Automotive Power Problems: Part Two

SEPIC (Single Ended Primary Inductance Converter) topology is a good choice for automotive power systems that require an output voltage between the low and high values of the input voltage. SEPIC topology fits this application because you can vary its duty ratio around 50% to provide an output voltage that is either below or above the input voltage. Also, compared with flyback converters, SEPIC converters avoid the problems with leakage inductance and snubbers. Part two of this two-part series covers MOSFET and diode selection, current limiting and loop compensation....

Portable Power Management Centers on Battery Characteristics

Battery-based power management designs depend on the associated battery, so design starts by picking the specific battery type. A battery consists of a cell with two electrodes in contact with an electrolyte that produces a voltage determined by the chemistry used. One category of batteries is the primary type that is not rechargeable, since it employs a non-reversible chemical reaction to produce electricity. The second type is a secondary battery that is rechargeable. Here, we will only cover the rechargeable batteries for portable systems....

Optocouplers Support High Power, High Speed Switching Inverters

For inverter applications, such as motor drives, uninterruptible power supplies, switchmode power supplies, high intensity lamp ballasts, and induction heating, the gates of insulated gate bipolar transistors must be driven with stable on and off drive voltages, and relatively high current levels to allow rapid switching between on and off conduction. Besides allowing rapid switching, high drive current is also a requirement to switch larger power of IGBT....

Open-Standard Digital Current Sharing Benefits the Industry

Traditionally, analog current share between parallel modules has been used to provide load and thermal balancing for high power systems. The advent of new digital controllers across the industry provides the opportunity to adopt a common industry standard, allowing current sharing between units from different module manufacturers and IC suppliers. In this article the author proposes a digital current-sharing scheme and its potential to become an open standard and common industry sharing system....

Understanding the Right-Half-Plane Zero Part 1

The small signal analysis of power converters reveals the presence of poles and zeros in the transfer functions of interest (e.g., the control to the...

SPICE Simulation Provides Significant Advantages For a DSP-Based SMPS:Part 2

The techniques presented in this article will show the advantages of using special device models with a SPICE simulator to simulate the digital control algorithms for DSP, and advantageously create corresponding instructions to program the DSP's CPU through a development board. Such techniques will also minimize the total parts count in a DSP-based switchmode power supply design by putting their functionality into DSP firmware. Part two provides the results of a target design....

Editorial