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]
by University of Bristol:
A breakthrough in the design of signal amplifiers for mobile phone masts could deliver a massive 200MW cut in the load on UK power stations, reducing CO2 emissions by around 0.5 million tonnes a year.
Funded by the Engineering and Physical Sciences Research Council (EPSRC), the Universities of Bristol and Cardiff have designed an amplifier that works at 50 per cent efficiency compared with the 30 per cent now typically achieved.
Currently, a 40W transmitter in a phone mast’s base station* requires just over 130W of power to amplify signals and send them wirelessly to people’s mobiles. The new design, however, enables the transmitter to work effectively while using just 80W of power.
New design for mobile phone masts could cut carbon emissions – [Link]
Compact battery chargers require overcurrent protection and temperature monitoring to ensure safety. These chargers also need to fit into small form factors, and generally have a lot of pressure to also be very inexpensive, but only have to provide a simple charging ability.
Furthermore, compact packaging is required to integrate the battery charger into a system. Renesas has 8/16-bit microcontrollers available in compact packages with as few as 10 pins, making them ideal for these applications.
78K0/Kx2: 8-bit All Flash microcontroller: wealth of on-chip peripheral functions such as a reset circuit and on-chip oscillator; low power consumption,30 to 80 pins.
78K0/Kx2-L: 8-bit All Flash microcontroller: wealth of on-chip peripheral functions such as a reset circuit, on-chip oscillator, and operational amplifier; ultra-low power consumption, 16 to 48 pins
78K0S/Kx1+: 8-bit All Flash microcontroller: wealth of on-chip peripheral functions such as a reset circuit and on-chip oscillator; 10 to 30 pins
R8C Family: Timer, 5 V operation, and Small Package
P-ch MOSFET: Low on-resistance, compact low-profile
Renesas Battery Charger Solutions – [Link]
by Hua (Walker) Bai:
The meaning of the term “high power LED” is rapidly evolving. Although a 350mA LED could easily earn the stamp of “high power” a few years ago, it could not hold a candle to the 20A LEDs or the 40A laser diodes of today. High power LEDs are now used in DLP projectors, surgical equipment, stage lighting, automotive lighting, and other applications traditionally served by high intensity bulbs. To meet the light output requirements of these applications, high power LEDs are often used in series. The problem is that several series-connected LEDs require a high voltage LED driver circuit. LED driver design is further complicated by applications that require fast LED current response to PWM dimming signals.
Design Notes: 60V, Synchronous Step-Down High Current LED Driver – [Link]
By Ashok Bindra:
The use of low-dropout regulators, popularly known as LDOs, is common in many applications today because they provide a simple and inexpensive way to regulate an output voltage that is stepped-down from a higher input voltage. In addition, linear LDO voltage regulators contribute very-low noise as compared to switching regulators.
Nonetheless, to keep system power consumption low, such regulators must also feature ultra-low quiescent current (IQ) while providing excellent dynamic performance to ensure a stable, noise-free voltage rail, suitable for driving IC loads such as microprocessors, FPGAs, and other devices on the system board.
Selecting the Right Ultra-Low Quiescent-Current LDO Regulator – [Link]