by Publitek European Editors:
With the proliferation of high-brightness LEDs designed to provide replacement lamps for commercial and domestic lighting there comes an equal, if not greater, proliferation of power supply solutions. With hundreds of products from dozens of manufacturers, it becomes a question of how to make sense of all the permutations of input / output voltages and output current / power ratings, to say nothing of the mechanical dimensions / termination types and the many other features for dimming, remote control, and circuit protection that are offered. This article aims to unravel the mysteries of the different types of LED power supplies and how they operate in order to ease the selection process.
How to Choose the Right Power Supply for Your LED Lighting Project - [Link]
manekinen @ mdiy.pl builds a simple symmetrical power supply based on LM317 and LM337. Design is Eagle and includes PCB so you can build it your own.
This time, simple project that i made from simple need. Simple, cheap and functional regulated power supply 1,25V to 15V, two separately regulated positive lines and two negative. This power supply uses LM317 and LM337 integrated circuit stabilizers – or their stronger versions. Galvanically separated lines can be connected in various configurations.
1.25V to 15V Simple Dual Symmetrical Power Supply - [Link]
by Ashok Bindra:
Whether for driving white LED backlights or powering RF and analog circuits, laptops, tablets and other mobile devices often require voltages that are much higher than the input supply voltage. Consequently, step-up or boost DC/DC converters generate output voltages that are several times the input to serve a variety of circuits and functions in these systems. For instance, in battery powered systems, the input normally is 5 V and below, while voltages as high as 15 and 24 V or more are needed to power RF/analog functions or drive thin-film transistor (TFT) liquid crystal displays (LCDs). Similarly, high voltages also are needed to bias avalanche photodiodes (APDs) found in optical receivers.
Generating High DC Output Voltage from Low Input Supply - [Link]
Dusan Ponikvar writes:
Contemporary power supplies use switching techniques to achieve the desired output voltage from the primary source. Switching power supplies, however, are often too noisy to be used in sensitive analog circuits. You may find linear power supplies to be preferable in these cases.
A standard practice for a linear voltage regulator is shown in Figure 1. A higher-than-desired, unstable voltage is connected to the input, VIN, and the series-pass transistor, Q1, reduces the voltage to the desired level at output VOUT. An error amplifier, IC1, compares a fraction of VOUT with a reference voltage, VR, and controls Q1 to keep the output fixed regardless of the load current, IOUT, and variations of VIN. Such a circuit is suitable only for a small range of output voltages.
Regulate a 0 to 500V, 10-mA power supply in a different way - [Link]
This is an over-current and over-temperature protection circuit for power supplies. The circuit cuts power in case one of these two events happen, it also has an external shutdown pin so the supply can be controlled by a switch or microcontroller. [via]
When it is necessary to plug in a board into a system that is currently powered, it is critical to control the inrush current to prevent damage/system fault conditions. This application provides a simple circuit to achieve this function as well as an easy method for resetting the system and monitoring against temperature issues.
Power supply over-current and over-temperature protection - [Link]
I’ve recently become interested in Nixie tubes. Nixie tubes are neon filled glass tubes that contain cathodes in various shapes, numbers being the most common, and a mesh anode. Passing a current through the cathode causes the neon gas to ionize which makes it light up.
The problem with these tubes is that they voltages of around 170V in order to ionize the gas. Fortunately, most tubes only need a few mA which makes the supply design simpler and easy to run off a wall wart.
A low cost Nixie Tube Power Supply - [Link]
Online Voting Open for Readers through December 31, 2012
Miami, Florida, December 6, 2012 – T&M Atlantic today announced that Test & Measurement World has named power supplies AKTAKOM APS-73xxL series as a finalist in the Best in Test Awards competition. The awards recognize the best in test products and test professionals.
The Best in Test Product Awards honour important and innovative new products and services in the electronics test and measurement industry. Products from all areas of electronics testing and inspection are eligible. The annual Test of Time Award is presented to a product that continues to provide state-of-the-art service more than five years after its introduction. The Test Engineer of the Year Award pays tribute to the important contributions test engineers make to the quality of electronics components, products and systems. The award winner receives a $10,000 educational grant, courtesy of sponsor National Instruments, which is presented to an engineering school designated by the winner.
AKTAKOM APS-73xxL series of single-channel programmable power supplies have 3 LED displays, output voltage of 0…30 V, output current of 0…3 A (APS-7303L) or 0…5 A (APS-7305L), overheat protection and current and voltage stabilization mode. Read the rest of this entry »
This is a nice switchmode power supply with the following characteristics:
• Input Voltage 80-275 VAC
• Operating frequency. 47 -63 Hz 47 -63 Hz
• Maximum output power 320W
• Frequency of operation 130 KHz
• Adjustable Output Voltage 0 – 40V
• Output current adjustable from 0 – 20A at 15V
• Over temperature protection with indicator
• Automatic fan control with indicator
• 0-40V voltmeter and ammeter 0-40A LCD programmable USB
• Ammeter without resistive elements with Hall sensor 50A
Switchmode Laboratory Power Supply - [Link]
Gerard Fonte writes:
My client, a small manufacturer, was having a noise problem with a new batch of 1500V-dc supplies.
It had been a while since the company manufactured this product. The original engineer was long gone, and the only documentation was a schematic. The approach was a straightforward closed-loop design. An op amp controlled an oscillator that used a step-up transformer to create the high voltage, which the system rectified and filtered into dc. A small part of the output voltage fed back into the inverting input of the op amp as an error signal to adjust the oscillator frequency when necessary. The noninverting input was grounded.
Tracing down a noise problem – an interesting story - [Link]
Tamara Schmitz writes:
Combining the operation of a boost regulator and a negative voltage converter can generate a negative supply from a single low-voltage supply. The circuit in Figure 1 shows a standard application circuit for a +20 V supply along with two op amps, two diodes and two capacitors to generate the – 20 V supply. This article will discuss the basic operation of a boost converter to generate a larger positive supply voltage. Equations are derived to determine the minimum inductor value to maintain a safe peak inductor current, and a maximum inductor value to maintain continuous conduction mode (CCM) operation. The article will then discuss the generation of a negative supply and the restrictions of the design.
Simple Circuit to Generate Plus and Minus Supplies Using a Boost Regulator - [Link]