(January 2007) Single-Cell Li-Ion Systems Spawn Compatible ICs
From Electronic Design, Jan 11, 2007, pp. 84-86
Because of the popularity of single Lithium-ion cells in handheld devices, the makers of regulator chips are adding to the offerings which improve performance and reduce power consumption. Single cells provide 4.2 to 3.0 Volt supply during a discharge profile, so the power regulators are tuned to accept ranges of 2.7 to 5.5 Volts. Fixed and adjustable outputs nominally range from 1.2 to 3.3 Volts, but are limited to the input, not usually having boost circuitry.
National Semiconductor incorporates automatic intelligent switching between pulse -width and pulse-frequency modulation to optimize battery life for high-load, light load and standby applications. At light loads and standby, the quiescent current is typically 16 FA. In shutdown, the current drops to 0.01 FA.
Maxim provides regulators with intelligent control operations such as bypass via a 60 mOhm path for high power transmission.
Texas Instruments offers LED drivers with 2.7 to 5.5 Volt inputs suitable for backlighting applications. PWM signals control brightness from off to full brightness.
Because of the input Voltage range, the regulators are also suitable for use with multiple Alkaline and Nickel-metal hydride battery packs.
Linear Technology offers a single cell Lithium-ion battery charger which works from a 5 Volt wall charger. Complete charge termination, auto recharge, float, and end of charge indication are part of each package.
Observers believe that Lithium-ion prices will continue to decline; single cell applications will increase and more charger offerings will become available. BD
(July2006) Battery Backup Uses Delay To Avoid Glitches
ELECTRONIC DESIGN,May 25, 2006, p. 60
A backup scheme is described which adds a diode-OR connected backup battery only as the main supply drops to a predetermined value. On return of the main supply, the disconnect of the backup could add a glitch to the power bus and possibly reset a downstream microcontroller. With the addition of a delay circuit to the disconnect circuit, the main supply has additional time to build and reduce the possibility of a transfer glitch. The circuit and waveforms are included.
Reserve Power Cell, LLC’s IntellicellTM packs an isolated reserve cell with the regular car battery. The battery’s electronics monitors the electrical flow and automatically switches to the reserve cell, if warranted. President David Elder states, “In the event of main battery or alternator failure, the IntellicellTM battery will still enable the driver to operate the vehicle for a limited period of time, in order to seek service or reach safety....” This battery system also incorporates Default Switching to avoid thermal runaway. The system also has the ability to communicate any problematic situation before it causes the car to become inoperable.
(July 2003) BD Editorial: Cell phones do have problems with batteries, but I am not selling them short on run time but referring to the numerous designs for phones where no two phones seem to have the exact same battery. Each new model of a cell phone by each manufacturer seems to have just a little different configuration, so that batteries for a particular phone can become obsolete in a year. Recently, I tired to replace the battery on a two year old cell phone. Having bought the phone and a service contract from Best Buy, I was confident that I could obtain a battery through their organization, but I soon learned Best Buy had no batteries to match the cell phone, and it was only after a time consuming search of the Internet that I was finally able to locate a battery and purchase one (actually two).
In my view batteries are not the major problems with cell phones; reliability stems from service needs far beyond the hand held power source itself.
In recent weeks, when my husband tried to reach me via a cell phone in an area near the boundary waters in northern Minnesota, our dual band phone provided an analog roam signal, but no phone connection. This problem could be somewhat anticipated since this area is sparsely populated, but in another instance in a hotel near the Los Angeles Airport, the same phone in a digital service area, failed repeatedly; the battery was fully charged, but in a “dead zone” it didn’t make any difference.
People are complaining to their service provider, but wait time to connect to a service provider is time consuming -sometimes up it takes up to a half hour or more to voice a complaint but in the process find no solution from the company representative.
In New York City, the office of Senator Charles Schumer reports that there are 200 dead zones (areas of heavy interference, frequently dropped calls and failed connections) from an overabundance of concurrent usage and call volume. The Senator has proposed legislation that would require service providers to disclose these dead zones.
If you would like to read about more problems and anecdotal situations, peruse the article, “10 Things Your Cell Phone Service Won’t Tell You,” by Ryan Malkin; the article appeared in SmartMoney.com on June 17th. He covers such topics as ‘911 is a joke’ and ‘the wireless Web will leave you disconnected.’
I mention these facts, not just to complain, but to point out that the main goal of the cellular industry doesn’t seem to provide for correction of the current problems and reliability, but rather to ‘enhance service’ with more options. “Theevolution of color displays, digital imaging, and converged handheld devices continues to drive growth in the worldwide handset market,” said Ross Sealton, research analyst in IDC’s Smart Handheld Devices Program (April 30, 2003).
I am not convinced that I need a handheld mobile game deck, an MP3 player, multicolor displays, multimedia capabilities, text/voice messaging and a connection to the Internet all rolled into one handheld wireless device. What I do need is a reliable cell phone which I can count on to communicate in an emergency, anywhere and anytime. I also need an accurate indication of the state of charge of my battery. It would be helpful to see at a glance how many prime time and off-time minutes remain for the month. Aren’t these fundemntals needs of a cell phone? But, to make such things happen, the cellular industry has to take a serious look at correcting their current problems, and the answers are neither found in converging more gimmicks on one device nor in creating a longer run-time battery. SAG
(July 2003) Austria Micro Systems (AMS) proposes creation of chip, JouleDoc, which actively monitors the hardware’s power performance and adjusts parts of processing cycle as needed. This system in SIP package architecture , in contrast to system on chip (SOC) , is cheaper and works by creating all the required chips for a device at once on a single die. This model is said to improve the energy efficiency of a device (such an MP3 player) by reducing the distance electricity has to travel through circuits, reducing resistance and improving battery life. With standard batteries accounting for 78 per cent of a package using the smallest available electronics, this new SIP should reduce the bulky size of the current device (i.e. MP3 player).
ThinSOT Step-Down Regulator Delivers 600 mA and 96% efficiency.
For product designers of single-cell Lithium-ion, multi-cell Alkaline or Nickel-metal hydride power packs with input ranges of from 2.5 to 5.5 Volts, this Linear Technology IC uses internal low-on-resistance switches to provide high efficiency conversion to maximize battery run time. The price at the 1,000 piece level is $1.95 each.(09-02BD78-12)
Battery Power Products and Technology
August 2002, p.1
Batteries forever included
The new owner of a Hewlett Packard PDA was unhappy that the battery was not replaceable. The company responded saying that the decision was made to reduce product size. (Ed. note: the consumer should be made aware of products with such configurations and have the opportunity to choose alternate products by other manufacturers. Caveat emptor!)
December 20, 2001, p. 29
Low-power DRAMs ramped for smart, mobile apps
New DRAM (memory) products are being produced which operate at 2.5 Volts and will reduce power consumption by 50% to 80%. Conventional power saving methods of reducing core operating Voltages, bus interface Voltages or frequency of the self refresh cycle may not yield significant results. Projections for 1.8 Volt parts are expected later this year with greater power savings.
Manufacturers peg the applications to be most welcomed by the makers of 2.5G handsets and PDAs.
Electronic Engineering Times
January 28, 2002. p. 4
(May, 02) Allied Business Intelligence states that cellular handsets will spur explosive growth in component sectors. The move toward complete solutions will impact gallium arsenide and silicon players alike, as multimedia functionality is emphasized over conventional communications . Relative newcomers such as GSM, CDMA, TDMA, AMPS and 2.5G are slowly being lured into cellular space as the grand debut for 3G solutions is delayed. As a result, the bill of materials for 3G phones will warrant a 79% increase from today’s basic GSM model . New phones will also translate into new batteries. According to Ken Dulaney, an analyst with Gartner Inc., the spread of the new devices is expected after 2005, “...when several alternative battery technologies will be brought to market.”
PowerSmart receives U.S. Patent for ‘SmartShuntTM’. The SmartShunt is an advanced battery monitoring and reporting sensor which is integrated onto a high-current shunt assembly. It performs and reports on functions including: Voltage, temperature, current and current integration (Ahr) measurements, state-of-charge and battery health via an advanced communications bus. The sensor can be used in HEV starting battery systems, telecommunications and UPS battery backup applications.
Toshiba, Sony and IBM sign a multiyear agreement to jointly develop new chip-making technologies to extend battery life. As part of the joint project, IBM will transfer its latest SOI (silicon-on-insulator) technologies to Sony and Toshiba, and the partner companies will each send engineers to IBM’s research center in New York to work on the joint project.
VOCAL quadruples battery life in IEEE 802.11a, 802.11b, and 802.11g Wireless LAN mobile units. By using VOCAL LDPC Codes in the downlink and Turbo Codes in the uplink, WLAN system designers can increase the battery life of mobile units by a factor of 4. This use of LDPC Codes and Turbo codes shift the majority of the power requirements to the transmitter and receiver of the base unit. The same technique can also be used in satellite and cellular system, increasing battery life for satellite and cellar handsets.(05-02 BD74-6)
Understanding linear regulators
The devices which convert unregulated battery Voltage to regulated Voltage for use by electronic devices can either use linear or switching technology. This article provides important basics of the less efficient linear types which have superior regulation and noise properties. Key factors such as the stability of the regulator being dependent on the reference stability, operating fundamentals and excellent references make this a required fundamental resource for all but the weathered designer.(04-02 BD73-13)
October 2001, p. 28
(April, 02) Midtronics introduced their latest in-vehicle battery monitoring and management platform inGEN EV. The inGEN EV is an engineering evaluation unit of the inGEN platform. It provides vehicle and electrical system designers an ability to view and assess the advanced features of inGEN technology on any 14-Volt Lead-acid automotive battery. These features include continuous Voltage, current, temperature and conductance measurements that enable real-time state-of-charge and state-of health diagnostics to provide advanced warning of battery problems. The diagnostics can also enable deliverable energy, charge acceptance, and state of life calculations for advanced electrical and charging systems in 14V, 24V, 42V or EV/HEV applications.
Texas Instruments’ power-efficient DSP (digital signal processor) is awarded ‘Product of the Year’ by Electronic Products magazine. The C5509 chip was selected since it offers integration to allow designers of battery-operated and PC-connected products to reduce board space and power usage by a factor of three, while supporting most popular removable storage standards and multimedia formats with processing power to spare.(02-02 BD71-8)
SP6231 develops a smart LDO voltage regulator specifically designed to manage dual power sources in USB enabled, battery powered peripherals. The company says this is an industry “first;” this Voltage regulator is said to dramatically extend battery life by switching the peripheral’s power source to the host’s USB bus when the peripheral device is connected to the host port. Switching between battery and USB power sources occurs essentially “glitch free.” (02-01-01, BD 70-8)