By Tahar Allag, Wenjia Liu:
Cell phones are a good example of how functionality and performance have both increased significantly in portable devices over the last few decades. They have become more complex and can do many basic tasks as well as any computer. The extra functionality that has transitioned the smartphone from a phone-call-only device to a multipurpose portable device, which makes it more power hungry than ever before.
The internal battery pack is the main source of storing and delivering power to portable-device circuitry. Batterycharger ICs are responsible for charging the battery pack safely and efficiently. They must also control the power delivery to the system to maintain normal operation while plugged in to wall power. The battery pack is required to store a large amount of energy and be charged in a short amount of time without sacrificing weight and volume. The increased charge and discharge currents, as well as the smaller physical size, make the packs vulnerable to physical and thermal stresses. Therefore, battery chargers are no longer required to perform just as a simple standalone charger
AppNote: Battery charging considerations for high-power portabledevices - [Link]
Designers of rechargeable battery-powered equipment want a charger that minimizes charge time with maximum charge current by maximizing the power taken from the supply without collapsing the supply. Resistances between the supply and the battery present a challenge. This article explains how to design the charging circuit to achieve the maximum power from the adapter despite the undesired resistances between the supply and battery.
AppNote: Extract maximum power from the supply when charging a battery - [Link]
One, tiny Dart. Power for all your devices. Perfect for your mobile lifestyle.
The Dart is the world’s smallest, lightest laptop adapter. At a powerful 65W it is a perfect complement to today’s thin, lightweight, portable laptops. It fits in a pocket and is designed with a USB port and single outlet profile to make it easy for you to stay charged up when you’re on the road. We hope you are as excited about the Dart as we are and looking forward to finally carrying just one, tiny Dart to charge all your electronics. Join our campaign and never be stuck powerless again!
Dart: The World’s Smallest Laptop Adapter - [Link]
by Michael Dunn:
Most electronics today requires multiple supply voltages – four or more rails is not uncommon. But if you’re using multiple, unsynchronized DC-DC converters, you’ve not only got a sub-optimal design, you’re asking for trouble. This Design Idea solves both problems.
Why trouble? I have firsthand experience of multiple power frequencies used in a system which also included sensitive analog electronics. Under certain conditions, difference frequencies (e.g., 10kHz, if one switcher was running at 250kHz, and another at 260kHz) would show up in high-impedance analog sections. Not good.
Avoid problems with multiple DC-DC converters - [Link]
A group of Korean researchers have turned their focus on supplying a reliable, efficient power source for wearables. Professor Byung Jin Cho of the Korea Advanced Institute of Science and Technology (KAIST) and his team, recognizing that supplying power that is stable and reliable is critical to the successful commercialization of wearables, have come up with a wearable power band that made technology news this week. The team noted that a flexible thermoelectric (TE) power generator would be the way to go to realize a wearable self-powered mobile device. They developed a wearable band-shaped item that produces electricity from the heat of the human body, The device size is 10 cm x 10 cm. Wearable electronics must be light, flexible, and equipped with a power source, which could be a portable, long-lasting battery or no battery at all but a generator, according to a KAIST release on Thursday, providing details about their work.
Power arm band for wearables harvests body heat - [Link]
By European Editors:
Military and aerospace, where rugged operation and reliable performance in a confined, hostile environment are paramount, have long been the most dominant markets for thermoelectric energy harvesting. Typically, thermoelectric devices exploit heat from engines and motors and use it to power sensors and wireless sensor networks for condition monitoring applications. Recent innovations are generating growth in this sector, as well as in allied sectors.
This article will review some of the major avionics and aerospace applications that use thermoelectric devices. For example, commercial and military aircraft incorporate sensors and sensor networks powered by thermoelectric generators to monitor the aircraft skin for damage that can cause stresses and structural weakness. In the aerospace sector, the Mars Rover, Curiosity, Galileo satellites, New Horizons space probes, and Cassini spacecraft are all TEG users.
Typical devices that will be considered include the CP range of TEGs from CUI, and the eTEC modules from Laird Technologies. Further consideration will be given to the management of energy generated by TEGs, with reference to the LTC3108 DC/DC converter from Linear Technology.
Thermoelectric Energy Generation Takes Flight for Aircraft and Spacecraft Monitoring - [Link]
Hydrogen Fuel Cell Developer Kit – Open-Source Systems @ Arcola Energy.
Introducing the new range of Hydrogen Fuel Cell Developer Kits from Arcola Energy and Horizon Fuel Cell Technologies. The perfect starting point if you want to create your own fuel cell power system. Suitable for academic, hobby and commercial product developers. Easily design and build fuel cell systems using Horizon fuel cells. Integration with the popular Arduino, mbed and Raspberry Pi development boards allows easy connection to a computer to monitor performance.
Hydrogen Fuel Cell Developer Kit - [Link]
Milen @ instructables.com writes:
Normally the Joule thief produces output voltage, which value is difficult to predict. Without load (the LED) I have measured voltages over 30 V. I wanted to create a Joule thief, which can be used to supply some small electronic devices, but having well defined and stable output voltage. There are known some solutions in which instead the LED load, a one-diode rectifier is used, and the output voltage is stabilized by the use of Zenner diode. I did not like this solution, because through the Zenner diode flows always a constant DC current, what reduces drastically the efficiency of the device and empties fast the supply battery. I was looking for other, better solution of the output voltage stabilization (limitation).
High efficiency regulated Joule thief - [Link]
When engineers consider offline switchers for systems ranging from telecom and datacom equipment to PCs and industrial supplies, they mainly think of bulky AC/DC front-end solutions in a variety of forms such as bricks, modules, and open-frame. However, there are many applications where offline switchers powered by AC mains are needed in small packages or must occupy a small space on the motherboard. Some examples: USB adapters to power media players, e-readers, and GPS devices; and low-cost, offline LED drivers in lighting applications with high power factor to meet international requirements for total harmonic distortion (THD), EMC, and safety. Offline switchers are also used as standby power supplies in PCs and laptops, as well as in compact chargers for smartphones and other mobile devices. The point is that there are many applications where offline AC/DC switchers are needed in small form-factors.
Offline Switchers Come in Tiny Packages - [Link]