Back to Power
1124 results found, displaying items 121 - 140
Expect Big Changes In Digital POLs And Energy Harvesting
Electric Vehicles Zero In On Improved Power Management
Jury Hands Power-One A Victory: What Does It Mean To Engineers?
On November 15, a Texas jury decided the lawsuit brought by Power-One against Artesyn Technologies (now part of Emerson Network Power) in 2005. The decision has ramifications for engineers who design power systems that step down a bus voltage at a â??point of loadâ?? such as an FPGA or processor. Immediately after the verdict, both companies issued positive statements to the press. â??The jury found both of the two asserted patents to be valid and found that...
Handheld Multimedia ICs Hold The Key To Energy-Efficient Video
Energy efficiency is a key design consideration in a National Semiconductor line of ICs intended for batterypowered phone and video systems. Minimizing power consumption is the common thread in these circuits, which convert digital data into real-world video playback subsystems (see the figure). This involves efficient power sources plus digital techniques that minimize power dissipation using analog, digital,...
Get The Lowdown On Ultracapacitors
Call them ultracapacitors. Or supercapacitors. Whatever the name, they exhibit vastly greater capacitance than conventional caps. Singly, you can buy radiallead board-mount devices rated for 5 to 10 F at 2.5 V, flashlight-battery size units rated for 120 to 150 F at 5 V, and larger single-capacitor cans good for 650 to 3000 F at 2.7 V. Note that all of those capacitance values are in farads. Not so long ago, a couple of thousand microfarads were a lot of...
Putting Data-Center Power In Perspective
I had the opportunity to meet Roger Tipley at the recent Power Electronics Technology Exhibition & Conference in Dallas. Roger is a senior technologist and engineering strategist at Hewlett-Packard as well as a board member of an organization called The Green Grid (www.thegreengrid.org). The Green Grid has been operating since January and has already grown to 102 members. It is a consortium of information...
A Low-Power Solution For GPON Burst-Mode Receivers
The move to bring broadband services capable of supporting the triple-play applications of voice, video, and data to first-mile customers (small businesses and the home) continues to evolve. A key player in this FTTx movement is GPON (Gigabit Passive Optical Network), a fiber-based network that provides a higher bandwidth alternative to existing solutions such as DSL and cable. FTTx refers to the family of first-mile applications, such as Fiber to the Home (FTTH), Fiber to the Building...
What's All This Stability Stuff, Anyhow?
A guy recently asked me how I would look for a voltage reference that's stable versus temp cycling. I told him I would take several of the best voltage references I had and use a dual-slope DVM of at least six digits to compare them to the units in question. He then asked if comparing some references to some other ones was kind of incestuous. This is not rocket science. You take several good voltage references and leave them the heck alone! Apply some bias and just...
Next-Generation Multifunction Power ICs Help Shrink Mobile Systems
With mobile equipment manufacturers demanding ever smaller and lighter handheld systems, the trend is to create smaller ICs that offer greater functionality. However, meeting those functionality, size, and weight requirements becomes a more difficult proposition in power-oriented applications. For instance, switching regulators must be very efficient, particularly when multiple switchers are integrated into an IC. Battery- charger circuits must be...
Codec And System Power Management Share A Die
Put the whole power system for a portable audio and navigation system on the same die as the system's audio codec? That's what Wolfson Microelectronics has done in its Audio- Plus codec line. OEMs would like shorter bills of materials and more compact board layouts, but what's going to be integrated? Wolfson says mixed-signal audio and system power make the most sense. There are now three philosophies for power management in portable devices. ...
Multiple Modes Flatten Flyback Efficiency Curves
One trouble with most power converters is that they achieve their best efficiencies only at high load levels. At moderate and low loads, their efficiencies can fall to as low as 40%. This is unacceptable when systems being powered spend most of their on-time drawing less than full power. Dealing with this leads to power supplies that incorporate extra transformer windings, rectifiers, and control circuitry for standby operation. More elegantly (and...
Tesla's Tests Confirm Roadster's 245-Mile Range
Tesla Motors created quite a stir when it announced its all-electric Roadster in 2006, with 250 miles per charge and 0- to 60-mph acceleration in 4 seconds. Critics were quick with their skepticism. But in September, the company put its Validation Prototype 1 (VP1) to the test, confirming these claims with only some slight modifications (Fig. 1). According to Tesla vehicle systems ...
Control Leakage In Active Mode
Control of subthreshold leakage in standby mode is best accomplished with power-shutoff switches. But what can be done when the chip is fully awake and active? One approach is gate-length biasing, which is a way to achieve leakage reduction in a way that will minimally disrupt performance. The effects of gate-length biasing, long known to analog designers, are multifold. While lengthening a given gate can exponentially reduce leakage as well as process variability, it also...
Materials Play A Key Role In Stopping Leakage
The gate-leakage problem does indeed have hope, some of which has already arrived in the form of high-k dielectrics. Based on alloys of hafnium, such materials have been rolled out by Intel for its 45-nm generation of products expected to be shipped by the end of this year. IBM will follow suit with its own variation on high-k dielectrics early in 2008. High-k (or high dielectric-constant) gate insulators will aid in the struggle against leakage by virtue of the fact that they...
Stanch The Bleeding Of Leakage Power At 65 nm
As 90-nm process technologies began entering the mainstream a few years ago, it became clear that device delays were no longer the chief culprit. Interconnect delays had caught and passed them, becoming the number-one contributor to timing woes. Now as the 65-nm node is hitting its stride, a parallel trend has arisen for designers in the power domain. No longer is dynamic power consumption the dominant factor in total power budgets. Rather, leakage...
Resistor Trimming
What kinds of applications utilize precision resistor trimming? Obvious applications include setting operational-amplifier gain and offset and voltage regulator output (Fig. 1a and 1b). But there are many others, such as sensor bridges and various specialty IC applications (Fig. 1c). ...
Where Are We?
Looking at the last few months of battery-chip product announcements reveals some trends. In terms of chargers for handheld devices, chip makers are responding to customer pressure to accommodate both ac-adapter and USB charging. In fact, the OEMs want to use the USB port for connection to either USB or an ac charger. Thus, we find Microchip Technology announcing its USB-compatible MCP73811 and MCP73812 charge-management controllers. The MCP73811 has a digital...
Battery ICs Charge, Gauge, And Authenticate
OEMs and battery pirates are constantly in a quality-control tug of war. So how do companies ward off deviants and dodge the lemons? Battery-management ICs fall into three basic categories: chargers, gas gauges, and authentication chips. Chargers control how a charging current is safely applied to a battery pack. Gas gauges tell the system how much charge is stored in the battery at any given time. Authentication chips indicate whether the installed battery is...
Power Electronics Technology Conference Gets A Makeover
I'll be travelling to Dallas, Texas, to cover the Power Electronics Technology Exhibition and Conference, formerly known as PowerSystems World. If you ever attended that event, you know that it attracted a mixed bag of power companies. In one aisle, you might have seen a company hawking its latest flywheel technology, while an aisle later you may have found a manufacturer of dcdc converter chips. That all has changed, and for good reason. David Morrison, editor of...
With PV Technology, Spread Electronic Mayo On Your Roof
Today's PV market is a tremendous success story, with compound annual growth of more than 30% over the last 10 years, sales climbing to tens of billions of dollars, and the prospect of further growth fueled by a developing perfect storm of market forces - as long as the industry continues to achieve lower costs for solar-generated electricity. PV now uses as much or more of the silicon feedstock supply as other electronic devices, contributing to the runup of...
 prev. page
1
2
3
4
5
6
[7]
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
next page 
|
