Most of the notebook computer has a switching power supply, it is used to charge the battery and power the computer with 110V or 220V main electrics. As today, VOHO - Vehicle Office & Home Office (it is mine) is the another latest model of business, the main electrics is not an option by the Vehicle Office, the only power source is 12V battery equipped with most of those vechicles.
Getting worst more and more with aging of the notebook battery, it's power time shorter than ever before. To buy few more battery packs for your notebook computer, it is no doubt that a good idea has to be for backup purpose. Well, any other ideas of which is better then this GOOD one? Obviously, the power inverter is the brilliant idea to do this job, it can be plugged into the ciguatera lighter of your car, and produce nice AC voltage for some small wattage appliances, the common specification is about 110V or 220V, 100W-400W, will cost around NT$800 to NT$3000 something.
With this kind of power inverter, your notebook will has freedom ever since, not only a home plug for battery re-charge, but a mobile power source will do the trick as well as the electrical supply in your town. What is the next if the better idea is taking place? Let us lookafter the setup of this better idea with simple diagram following, CAR battery 12V DC -> Power Inverter -> 110V AC -> Notebook Power Supply -> 19V DC -> Notebook Computer Well, most peoples will do the same thinking, if the following is true, CAR battery 12V DC -> MAGIC BOX -> 19V DC -> Notebook Computer then........MAGIC BOX will replaces two units, the Power Inverter and the Notebook Power Supply. Of course, well marketed product of this kind of MAGIC BOX is not available yet with my living island, because no one will look after the market without gain. This turns to our goal, to design of DC-DC converter for the 12V battery, boost the voltage to 19V DC. It purpose the neat of equipment in usage, and the most important, to improve the effeiciency of voltage conversion without reduntant steps, to save energy. Design criteria Understand the available Began the DIY..... DC/AC invertor design for better understanding http://www.sydzdiy.com/article/power/0592820341992582_33908.html Reference for the charger design, not yet review, it purpose to has backup plan when the car is not around for charging the battery, the main electricity is a must http://www.elecdesign.com/Articles/Print.cfm?AD=1&ArticleID=1823 In order to maintain the battery alive without over discharged, there must have some voltage monitoring to do visual confirmation. Milestone, Mar/27/2007 Preliminary design has been given the result without statifaction, the issue was being the device getting hot. Base on trial & error and some practical advise, it should be the problem of MOSFET switching loss without controlled rise time & falling time, the temperature logger has recorded the MOSFET temperature against time of operation following, Milestone, Apr/08/2007 Improvement had been done, even thought no osc. scope for actual seeing of MOSFET driven performance, but it works for the purpose and this beautiful lady is flying all the height. the MOSFET is no longer heat up to 100*C Key to success of design & experiment - The magic box is feeding the notebook without any complaint A closer look of this lady 慢慢地, 市面開始有好多類似的產品出現, 售價 NT$700 - NT$3000 不等, 實在話, 一個DC-DC電源而已, NT$3000是貴了點. 以其中的技術成本來說, 比較合理的價格 NT$250 - NT$400. 不過還是可以參考參考 GOOGLE 搜尋以下, 會看到類似的資料 end-
1) Input 12V 6A, Output 19V 3A, 65W
2) uses common IC or discrete component, avoid specific PWM controller, aims for low cost and easy purchase parts
1) 555 IC, the very common part for oscillator, can be used for low cost PWM circuit;
2) Power transistor or FET, common for handling of 6A current with 50V;
3) wide speared of Switching Mode Power Supply and well known technology;
1) The introduction of DC/DC switching booster (Chinese)
2) Switching and Pulse Width Modulation with IC 555
3) 555 Timer/Oscillator Tutorial
4) 555 Timer and its Application
http://www.talkingelectronics.com/Projects/BatteryCharger-12vSLA/BatteryCharger-12vSLA.html
http://www.zen22142.zen.co.uk/Circuits/Power/svind.htm
RL, dummy load, 120V 60W, an incandescent lamp.
0.1uf & 470uf, the by pass cap did not show in the schematic but it is taking place.
no OSC scope, only have multimeter for hobby work.
initial test result:
No load, 18.7V, it is acceptable
Under Load, 17 V, Q1 + heat sink, hot, L1, not hot
1) fast recovery clamping for the POWER MOSFET;
2) sharpen the raise time by OSC output, no uses 555 any more, replace the OSC by a Freescale MCU HC908 or HC08;
3) Double the L & C for energy storage, improve the transient response;
筆記型電腦 車用充電
手提電腦 車用充電
Hey man, I love the works of Pond of Shadows too. We have something in common, we're both Ham Sup Los. Too bad I'm married... . Ha ha! I'm interested in knowing how you're developing your Vehicle Office. It's a new thing and I make little 24VDC modules too. We might be able to get something going if we can get together... .! Nice to meet you on this cyberspace.