Hot carriers injection

Recently I am studying some kind of welder, call capacitive discharge welder, I may be make one to replace my old age big transformer machine, and thus come across with the term above, hot carriers injection.

Eventually, I understand why those nvidia graphic in notebook PC usually fail after few years. It is actually some kind of defect and imperfection of semiconductor material.

As the transistor in a chip become smaller, the oxide layer of the semiconductor become thinner, easily the carrier (either electron or hole) can inject into the oxide layer if the graphic chip become too hot.

The present of the carrier in the oxide layer make the transistor have relatively higher gate leakage and eventually the chip fail.

The carrier can be easily remove with heat, but these kind of damage is permanent, if it already have the room for the carrier, it simply won't be repair so easily. As Murphy's law stated 'anything that can go wrong will go wrong.'

Therefore, trying to reflow the graphic chip or blow it with hot air, simply can not solve the problem. It may last let say few months or few weeks, but it simply won't cure the problem.

Try not to play graphic intensive game on notebook too frequently, it is not a good idea. Change the notebook power plan to Power Saver may actually prolong the notebook life.

bqJunior

Netbook battery pack that use bq27210 fuel gauge can be recelled now. It can also be upgraded to battery cell with higher capacity.





The charging curve of new cell is like being bite at at the corner, I guess the new chemical have two different layer of electrode to enhanced the material structure for deep discharge, the manufacturer site state in their remark NCM/LCO as positive active material. As LCO based material are safer but less reliable, but increase use of cobalt also mean increase the cost. To achieve both safe and reliable, the new cell may have combined material, LCO can be used near end of discharge.

NCM=lithium-nickel-cobalt-manganese oxide (LiNiCoMnO₂)
LCO=lithium-cobalt oxide(LiCoO₂)

Information is given as is without any confirmation of error free, please do your research and further study, comments are welcome to correct the information above.

Order while it is fresh!

Refill your battery now to get benefit from fresh cell, fresh cell last you longer! Come out from factory recently and still in perfect condition.

2600mAH cell is coming back! This cell is commonly use in 5200mAh or 56Whr battery pack. Higher real capacity than most battery you could possible found somewhere else! Give you more standby time, quality assured or your money 100% back.




Real capacity calculated:
--------------New Graph Initialized at 2/10/2010 3:46:10 PM--------------
2/10/2010 3:46:11 PM;12606;0;5200;31649.89;2573.132;100;118;30.85;4200;4202;4204;0
2/10/2010 3:46:21 PM;12606;0;5200;0;0;100;118;30.85;4200;4202;4204;0
2/10/2010 3:46:31 PM;12333;-3066;5198;0;0;100;118;30.85;4118;4098;4114;0
2/10/2010 3:46:41 PM;12298;-3064;5189;-104.9032;-8.516665;100;118;30.95;4107;4087;4102;0
2/10/2010 3:46:51 PM;12274;-3064;5180;-209.515;-17.03;100;118;30.95;4099;4080;4095;0
2/10/2010 3:47:02 PM;12257;-3064;5172;-313.9379;-25.54222;99;118;31.15;4093;4074;4089;0
2/10/2010 3:47:12 PM;12242;-3064;5163;-418.2296;-34.05555;99;117;31.15;4088;4069;4084;0
......
.......
........
2/10/2010 5:27:21 PM;9331;-3070;26;-55988.05;-5067.858;1;1;45.05;3120;3093;3115;0
2/10/2010 5:27:31 PM;9267;-3070;26;-56059.46;-5075.533;1;1;45.15;3100;3071;3095;0
2/10/2010 5:27:41 PM;9196;-3070;26;-56138.25;-5084.059;1;1;45.15;3075;3047;3071;0
2/10/2010 5:27:51 PM;9118;-3070;26;-56216.43;-5092.584;1;1;45.15;3048;3020;3046;0
2/10/2010 5:28:01 PM;9032;-3070;0;-56293.9;-5101.111;0;0;45.35;3019;2989;3018;0

Discharge begin(12.606V): 3:46:31
Discharge End(9.032V): 5:28:01
Discharge current: 3.070A+/-1% maximum 3.1A, minimum 3.04A

Time elapsed: 1:41:30 (1hour41minutes30seconds)

Maximum Discharged Capacity (+1% error): 5208mAH (2604mAH per cell)

Minimum Discharged Capacity (-1% error): 5107mAH (2554mAH per cell)

End of Discharge Temperature: 45.35 Degree Celsius

Ambient Temperature: ~30 Degree Celsius

Please note that it is done at fast discharge for testing purpose, to show these battery cell is capable of doing high current discharge and have lower impedance which suitable for notebook battery pack. Most notebook by default only draw less than 2A current when automatic power management turn on, which usually last up to double the runtime as tested figure.

------------------------------------------------------

*Please check your battery original capacity to comfirm will it perform better than your original battery! For example if your battery is 6 cell and labeled 40Whr, this cell will perform 56/40=140%, 40% extra runtime compare to your original battery! *6 cell battery that have original runtime (mean at the time when you just bought a new laptop) of less than 1 hour is not recomanded to do any upgrade of capacity. As the gain is not significant and battery can getting too hot because these high energy density cell have lower power density, i.e.it is designed to discharge at more than 2 hours.

*For a 6 cells battery pack, with power saving feature turn on, most user can get 3-4hours runtime in centrino system, 4-8hours in Atom system, 2-3hours in core2duo, Pentium mobile CPU, AMD mobile CPU or other common and less than 17inch laptop. Laptop that using destop CPU usually come with 8 cell battery and it runtime is usually 1-2hours only. Any laptop that have screen size of 17inch or bigger will also not having long battery runtime.

*Results above showing the result for the first time used only, any subsequences cycle will not degrade the cell more than 1Whr per cycle if the cycle interval is less than 1 months and rest time is more than 1 hour before charge it back. Conclusion is made base on basic test of cell under room temperature. There is however, the rate of degrade per cycle become more obvious if the cell is keep fully-charged or full-discharged for a long period such as few months or years, which could make it degrade more than 10Whr per cycle.

*Battery will not longer learn meaningful capacity that can report the real runtime after the impedance become too high, because the battery discharge dv/dt rate will never reach qualified learning rate anymore. Battery that have it crystallize structure damaged usually show this symptom due to increasing of cell impedance. Cheaper cell have the crystal link break faster.

*Under lower temperature, any Li-ion cell generally release/store less energy that it actually capable as if under room temperature.

*All of the informations above is given based on my previous knowledges and experiences, may contain mistakes or may not up to date. Shall you have any question kindly contact me by the following email: mail.altbattery@gmail.com.

Do water-fueled cell exist?

Under normal condition, I can tell, water-fueled battery cell do not exist! But please read the full story below. Please refer to perpetual motion machine why it do not exist.

Yes water can store energy, there are currently two commonly known ways how water can store energy. First, one give it force to rise it to higher ground, to use the energy store, just release it, it will flow to lower ground, everthing that have mass will do this! Secondly, split it into hydrogen and oxigen by electrolysis. Then burn it to get back the energy stored!

Picture below show a conceptual idea about a power generator that store solar or wind kinectic energy in the form of potential energy, people have built similar water fall generator but the cost is way too high to built it at sea. The pieces of this generator have to be built on land and assembly it at the shallow sea. Black color retangle show the hole for water out to drive electric generator, and the white color show the hole for water intake with pump, water is pump into the tower and store as potential energy by using the power supply by the solar cell or wind turbine when there are extra energy unused.
Please note that I have no study where is the best place for pump and generation gate is placed, the picture posted just to give reader some idea about what is it. This thing can also work the other way round, i.e. pump the water out from tower, if power is needed, open the valve and let water flow into the tower.

According to conservation law of energy, energy can not be created or destroy by human being. We can only store it or convert it!

In our natural, water is a stable sustances, mean that it will not produce energy by it-self. Please note that the different between word 'produce' and 'create'. Create mean from non exist to exist here, produce mean from unseen to be seen!

By using electrolisis, the amount of energy can be stored is actually lower than the amount of energy it required to split the water, some energy will lost as heat!

What happen if we can produce more hydrogen and oxigen with lesser energy? This is not something imposible, but that just do not occur under normal circumstances! The real secret is the catalyst use in the system.

It just similar to uranium do not produce energy by it-self, but with the added of other reactant that produce neutron, it then produce heat!

What is the different between catalyst and reactant? Reactant is something that directly join the response, just like oxigen is reactant to any chemical fuel but not a catalyst. We do know that with existance of catalyst, any chemical response than initailly will occur, will become faster, from undetectable rate to become detectable.

Catalyst is something widely use in China medicine making, there is a say that herbal(s) will not produce it function effectively if lack of some other herbal function as catalyst, but if you use only the catalyst itself it have not particular function at all. Just similar to people add salt to apple or watermelon, the fruits become more delicious after adding salt.

That mean in a water-fueled cell, the catalyst have the most important role there! It can be something that add into the water, or something that built up the electrode.

The problem remain to me is that, even the best catalyst used, let say 100% efficiency of energy used to split the water, it still gonna lost the energy at the output, therefore the energy slowly reduce and eventually the machine stop.

The only reason I can think of, it is not catalyst that playing the role, it is reactant that been used, reactant store the energy needed to split the water effectively.

But please note that reactant is something that can be exhausted! If we consume up all the reactant on the earth, it is similar to the result of comsuming all petroleum!

This reactant do work for a period of time, and then it can die off. There are just no free lunch in the world! You got to pay for it once a while. You can not expect your water fueled cell power you for too many years. Once the reactant wear out, it stop working! Everthing converges! Nothing diverges! That is what make human being can not be seen as 'thing'. Thing that do not converges must have life. And a reactant do not have life I believe.

If the petroleum price is more expansive than the reactant price, then it may be good to use water fueled cell. Otherwise not.

There are currently two type of water fueled cell is claimed have been invented, first type is currently master by advanced country, with the help of catalyst or perhap reactant, they can directly produce electricity, which is the world most efficient water fueled cell. The second type is those spliting water to hydrogen and oxigen, and then burn it back to produce energy. Internal combustion engine will not produce energy with more than 50% energy store inside it since my last access to the related data, may not up to date, you can try to check it out yourself.

There are two main reasons why the water-fueled cell is not so good to use it in internal combustion engine or car. First you need to pay for the reactant, the benefit is actually very hard to be calculated. If the reactant is built into the electrode itself may give you more problem, as the efficency decrease with time untill all the reactant stop functioning, the system will not give you any benefit at all! How many water the system can split bacome the key to how much petrol you can save. It may actually more expansive than the petrol you can save depending on the price of the reactant or the whole system.

Secondly the engine block, piston, valve and any other part involve, must be anti-stain or must have good lubricating system. As a product of combustion hydrogen and oxigen will produce water, will make the internal of the engine rusted more obvious and reduce the life of a car, especialy the exhaust pipe.

And stain can spread, as water is only some sort of catalyst to oxidation, oxigen inside engine block will be suficient to make it rusted and become unususable in months if the car leave unuse, after the lubricating oil become too thin or at the part the oil do not reach. Some say engine block can be make of hi-tech ceramic such as those invented by Kyocera (Tokyo Ceramic), but I have never see it for myself yet.

Therefore, solar energy is still considered the best long term energy for earth currently! A good solar cell will at least function more than 10 years. Untill we can use solar energy to produce reactant for electrolisis, it is not safe to say that water-fueled cell is a good source of energy. And I believe thing that can store or contain large amount of energy, must be radioactive! As the energy will slowly leaking althought the reactant do not exist.

Hydrofuel

I come across with some article about the title today, something regarding Malaysian claim have design some device that save fuel for a car!

I never use it before, so this article is just for a purpose of expressing my thoughts, not to critisize or praise it.

Firstly, why we need this system? Because the oxigen concentration in the air, is about 1/5 in ratio, this is far more than enough for a car at lo speed. But at high speed, the petrol intake may be more than the amount of oxigen it can be reacted(burned) with, therefore result in imcomplete combustion.

Of course a car can be fine turned to allow it carbureter or fuel injection system or whatever to limit the amount of maximum petrol intake, so at full pedal, the amount of air mixed with petrol, is in perfect ratio to conduct complete combustion. But that is an ideal case, in real life that seem imposible due to how the mixture mix up and their condition, there are some randomize activity in the particle due to its size that prevent complete combustion in short period. Therefore, we can always expect some carbon or carbon monoxide produced at the exhaust.

Please note that I am not expert in this matter, therefore I know very little. If we can use some electricity to split the water and get some oxigen from it, we should be able to increase the oxigen density of air intake so that we can fully utilize the potential of the petrol, if the fuel is fully burned, it will give more output. In ideal case, if we can put in pure oxigen into the engine block, it will be excellent. But in real life, the cost of put in pure oxigen into a car is far too higher than the petrol you can actually save, this is not pratical to be applied in automotive industry.

Pure oxigen will not only give full combustion, but it also give speed! The speed of the petrol burn! Expanding the volume of gas mixture in short period, will result in largest force being produced acording to the Newton second law. Because the burned mixture particle expand at higher acceleration. That is similar to gun catton explosive, people damp catton into liquid oxigen, it can become explosive! It burn too fast untill explosion can occur! Therefore the engine block must be design to hold this kind of force, otherwise one is actually making a bomb.

But also note that the inertial force will limit how fast the engine can response to the explosion force! Every car have a most efficient cycling frequency that can give you higher efficiency, beyond that point, it simply use more petrol for same kilometer. And it varying with age. Therefore maintain the RPM of a car is also a good way to save petrol. The sweet spot is usually judged by experiences especially for those car with fuel per km meter!

Therefore, it required some sort of control, that control the rate of the oxigen being produced, the oxigen should be produced when the car is under high speed such as on a high way. So it do not utilize battery power when the car is under lo speed. I expect this kind of system is effective. But just theoritically. The only problem in this kind of system is the cost per liter oxigen you pay for. For example if you pay RM0.90 for oxigen but you get extra kilometer that worth RM1, it is consider you earn RM0.10.

But if you only use less than RM50 petrol per month, and you install a system that cost few thousands which only last you for let say 3 years, this is absolutely undesirable, paying extra for nothing. But if you use few hundreds RM petrol each month, this device may be useful. Consider you drive in high way, not in city.

In a city, it is better to use a hybrid car, cause electric motor is more energy effective at start moving a car. In a city, always car jammed, one moving and stop frequently, a electric petrol hybrid car will save you some petrol. But sometime this kind of not so well established rules is not always right, consider the cost of battery replacement corespond to the wear and tear and the initial cost of purchase, there are trade off point where petrol car is actually save more money for someone. You must use the car at certain kilometer, then you earn the benefit. Besides, in Malaysia, do not park a hybrid car under sky, the radiation from sun may easilly kill the battery inside faster due to heating. Those battery can not be expected cheap, it is specially built, limited edition!

Ok, after so many talking, there are nothing related to hydrofuel, I apologise for that. I believe they try to put in both hydrogen and oxigen into the air intake of the car. I doubt if this is a scientific way to do it correctly. This thing may be good, if you like to play with car, but, burning hydrogen with oxigen together will produce water right? That is not a good idea for engine block, does it speed up the rate of the component inside the engine block become rusted? I am not sure if an engine block and piston is make of stainless steel, but I guess that is imposible. Besides, even stainless steel can become rusted under hot environment! Saving few hundreds or even thousands a years and result in damaging a few ten thousands car is just not worth it sometime!

Different

Peoples ask me, what is the different between original battery pack and third party battery pack? Honestly, I do not like to answer this question, that is strictly depand on the price you pay for, it is a matter of demand and supply.

Today I open one Dell D620 replacement battery that cost you around RM230 to let you examine it youself, I know consumer do not or never open it and see it for yourself.


Picture below show, the red retangle is the protection board of third party battery, only one controller inside! The blue retangle in original battery, there are 3 integrated circuit inside, one fuel gauge, one analog font end and one second level back up protection!

Some people may ask, why we need three while we can only use one? At the begining, the largest fuel gauge company actually try design the protection board with only one IC, but many manufacturer found that it is not safe enough, as IC can fail to operate under some circustances, such as aging, power surge, high tempereture or others reasons. Therefore, everyone design the protection with more than one layer of protection for long term safety.


Picture below, original battery use 3 pin fuse, the third party battery use 2 pin, 3 pin fuse can be cut off by the small second level protection ic, the small eight leg ic work independent not rely on the main circuit. Therefore if something wrong with the main circuit, it do not sense any dangerous critical operation, the second level protection will cut the fuse to shut the circuit down so no more current flowing into or out from the battery pack. This fuse will also melt when the mosfet is overheat, mean that there are over current(usually short on the output) but the main circuit and second level protection circuit do not shut it down.

Picture below show that the cell use inside original(LG chemical, Korea) battery and third party battery, both last 1.5years, but the original battery have been discharge more cycles then the third party one, in this customer usage, the third party only been discharged 37cycles and last only half an hours currently.

While my repacked battery is using ORIGINAL PROTECTION BOARD plus HI QUALITY BRANDED CELL which are purposely design for notebook battery pack! At the same price you pay, you get some thing twice or triple time lasting!!!

Fixed!

Recently get quite some amount of the item below, model number is not a problem for this up to date of this post. All can be fixed, 100% done so far!
Please note that even the same note book may use differ model number, or even the difference notebook model may use the same battery, so before you send a battery to repair, better let me know it battery model instead of notebook model, so I can tell you if the particular battery model can be done!

And this one (picture below) I deny to recieve quite many customer before this, proven can be fixed also. So far have done 2 pieces, no problem.

Altbattery fix more battery than you was told "Can not be fixed!" Try it now, it is excellent in performance! Or your money back!

Hybrid battery architecture

Having long time didn't update this blog, today I will sharing some interesting story in battery recell. Hopefully this topic is not too bored to whoever that may read this.

Any one in the field of li-ion battery pack for long enough, will notice that there are 2 cells (2s), 3 cells(3s), 4 cells(4s), 6 cells(3s2p, 2s3p), 9 cells(3s3p), 12cells(3s4p, 4s3p) battery pack, is there any possible that we could have 5cells, 7 cells, 10 cells, 11 cells? 's' mean series, 'p' mean parellel.

By parellel up cell, one can expect to get more power surge from the cell, it simply mean more current can be supplied by the cells. By series it up, it simply mean more voltage. It is not very pratical to assemble 6 cell in series, it will produce up to 4.2x6=25.2V from the battery pack, which is way too high for high current flow power mosfet to operate at greatest efficiency, or there will be some compromise at the filter side of PWM.

Lenovo is the very first company that adopt 7 cell battery, manufacture by OEM of Sanyo, many people have no sense of what is OEM, OEM mean original equipment manufacturer, it simply mean Lenovo make an custom order from Sanyo, other manufacturer that clone the battery thus can not be called OEM, cause Lenove didn't make an order from them.

I have no idea how they call this type of battery pack, but I call it "hybrid battery archetecture". It is basically 2 pieces of battery of 3 cells and 4 cells combine in one. There are three reasons I can think of why they must do this.

1. There are only room for 7 cells left for particular model (this is very unlikely).
2. The bussiness machine company do not want other clone battery company follow their design, 6 cells design is easilly duplicated, 7 cell is harder and cost is higher (please note that the protection board use extra component(higher cost), it is 2 battery in one, remember?) What make it so dificuit to other clone manufacturer is that the two battery automatically shift at certain preset voltage level, from one to another. This reasons is very close to be truth, but also not very likely.
3. This battery is best in cell balancing performance. In other word, the controller board will balance the cell in series better as too many cooks spoil the broth, because the current flow through series cells is same in all cell, there will not be a particular one higher than another. There is however, there are some trade off point, i.e. this battery must not be used in system that are power hungry, since it is only three or four cell in series at one time (parellel can suppy higher current remember?). This reason make those third party lo quality cell imposible to be used for this battery, because three or four cell in series make them not enough for the output, it will be very hot and tend to terminate discharge before it able to deliver 100% of it energy. In fact I guess third party lower quality will only output less than 80% of energy that it can store.
   

Picture above: There are one gas gauge(left, almost same price with one piece of Li-ion cell) and two analog front end voltage/current over limit protection. All component is doubled except the gas gauge which in charge communicate with system management.

This is an engineering perfect battery pack, obviously, with some extra cost .

Control a stepper motor with just one low cost IC

There are generally two type of motor that can do the amount of work you request, stepper and a servo motor. Stepper is usually more precise but slow (to prevent overturn or underturn), but those stepper in your hardrive is not slow at all, it can even go up to 10'000RPM, perhap it turn a large degree for every driving signal? Or it can be magnetized/demagnetized very fast, I just never have experience with it.

A stepper motor is the type of motor that usually use in printer, typewriter to roll the paper in the correct length one time a bit.

Custom stepper motor driver is expansive, usually around RM15 to RM25 each driver IC. If you burn one during development of your project, that mean you burn RM15 each time.

Alternatively, you can use 4 MOSFET or BJT and one microcontroller to drive your unipolar type stepper motor. If you need to drive a bipolar type stepper motor with only 4-pin as you found on most printer, you will need at least 6 transistor to form two individual switchable H-bridge.

A H-bridge is a transistor bridge that allow bipolar (two direction) current flowing. To cut the cost, one can actually get a ready available bidirectional motor drive IC on the market such as BA6238A.

Those IC are very famous last time, it is widely use in CD-player, tape-recorder and etch. As long as there are at least 2 bidirectional channel, you can use it to drive a stepper motor. Please note that those IC only cost less than RM3, but I doubt will you still get it from the market as it is obsoleted. Nowaday BJT is widely replace by the MOSFET due to it significant power saving benefit over BJT.

You can refer to code below to drive your BA6238A to bipolar stepper motor, please note that a unipolar stepper can be drive with bipolar driver, but a bipolar stepper motor won't work if drive with unipolar driver.

Last Pattern is global variable that store the last motor control patern. We only need to output 3 LSB pin from PC port or MCU port to the BA6238A. Pin 10 of BA6238 is common to both bipolar coil of the motor, Pin 2,3 is connected to the repective coil of different phase.

ACT_OP1=0x07; //Motor 1 mask 00000111, last 3 pin of port B
if (MTP1.Val>RELATIVE_POS1.Val && !FORCE_REVERSE)
{
switch (LAST_PATTERN1)
{
case 5: LAST_PATTERN1=3;break;
case 3: LAST_PATTERN1=4;break;
case 4: LAST_PATTERN1=2;break;
case 2: LAST_PATTERN1=5;break;
default: LAST_PATTERN1=5;
}
RELATIVE_POS1.Val++; //Change this to change direction??
}

Reverse drection is done with reversed pattern.

else if (FORCE_REVERSE)
{ //MASK=LAST_PATTERN1 & 0x07
switch (LAST_PATTERN1)
{
case 5: LAST_PATTERN1=2;break;
case 3: LAST_PATTERN1=5;break;
case 4: LAST_PATTERN1=3;break;
case 2: LAST_PATTERN1=4;break;
default: LAST_PATTERN1=5; }
RELATIVE_POS1.Val--;
}
else
{
ACT_OP1=0;
}

motor= LAST_PATTERN1 & ACT_OP1

'motor' is Port B in my case. I know it is dificuit with no photo here, but I am not too free to take the photo yet, will try to post it later if posible.

Please note that you should turn the active coil off for a while before you turn on another coil, you can do this with timer, alternatively, a current sense circuit can be used to sense the current across the motor. The best way is high side current sensing on BA driver, then chop the supply off when it over the limit. If you sense it at low side, the digital i/o signal will become too noisy.

Ok, I think that is enough for small piece of information, if you have problem kindly email to: mail.altbattery@gmail.com. May not be replied on this affair, but you can try your luck.

Drill-bit for sell

This tiny drill-bit is so difficuit to get from local hardware shop, therefore I buy some oversea, for some of my through hole old style PCB drilling work.

DIP8 through hole CNC result of my CNC project at year 2004:


Diameter available: 0.8mm, 0.9mm, 1mm, suitable for thru hole type PCB drilling, can be used on CNC(computer numerical control) machine, mini hand drill or dremel.

Price: RM10 each(Please specified the diameter you want), postage add RM3 for courier.

Item condition: New

Matching a MOSFET to a synchronous driver

Preface:
In power electronic, many time reader will come accross with this synchronous MOSFET driver. The most useful characteristic about synchronous driver is that, it save the energy drop across conventional diode approach (to conduct right after mosfet stop conduct).

A conventional diode can 'eat' around 0.7V to few Volt if current passed through it, a metal processed schottky diode can reduce the voltage drop to lesser, some newer process allow very low forward bias potential. Supposed current flow at 10A, a 0.5V drop accross diode will result in 5Watt dissipate through the diode. 5Watt is good for many conventional big component, but definitely not too good for those small size SMD component, it will getting overheat due to limited surface area to dissipate the energy.

When the MOSFET getting cheaper and the current required by electronic device getting bigger in number, engineers/circuit designers begin to adding another MOSFET into the DC-DC driver, which known as synchronous regulator. Voltage drop accross a MOSFET can be less than 0.05V, depending on it on state resistance and current pass through it. Considered a MOSFET on-state resistance is 0.005Ohm, at current 10A, it theoritically(without considered switching loses) will only generate 0.5Watt heat, which can be withstand by SOIC8 SMD packaging or any other similar IC packaging.

Supposing one circuit designer design the power regulator for a notebook central processing unit, the processor required 1V-15A peak power, a synchronous buck allow >90% convertion efficiency from your power adaptor. The processor are expected to consume 15W maximum, we expect a waste of less than 1.5W for the power management unit. Using asynchronous buck one will expect to waste more than 3W, even with very good diode used. Which, is not good for any battery powered device. The advantage of synchronous buck become especially obvious when we are dealing with desktop CPU where it can consume up to or even >50A in today PC environment. Circuit designer are dealing with more phase buck to ensure stable power supply to the central processor unit.

One good thing about synchronous drived MOSFET is that, it can be both boost or buck driver, driving current in get a buck configuration, reverse it or driving current out, one can expect to get a boost regulator.

15 years ago, we can hardly, if not imposible, to see high frequency MOSFET driver available on the market. Primary is due to market demand, many consumer electronics do not required such a big power, even Pentium at the time use less than 15Watt, even a series linear regulator can handle that rate without causing exceed power waste. Morever, it use 3.3V or 2.7V or something close to that.

15 years ago, we are still dealing with those large size and large scale electronic in our TV, Monitor, Mini HiFi and so on. 15 years ago, TV repair service have high demand in Malaysia. One of the problem of those large size component is inductance on it lead. Don't overlook or neglect these inductance, it is the killer that limit the frequency response of a system. In today electronic, few Megahertz power switching become possible, driving high current is like driving a big truck, it could hardly achieve high speed.


Choosing the correct mosfet:
To choose a MOSFET that match your schematic involve many technical detail, I hope that reader have learned that before.

But to choose a MOSFET that match a driver, there are three important criteria, first the Vgs(on) must match with the driver's driving potential and within the permited range.

Second, the driver must be able to supply maximum current that able to charge the MOSFET gate up for full achieveable conductance in a very short time, usually recomanded less that 1% of the period of switching signal (in decades nano second).

Third, must assure the Turn On Delay and Turn Off Delay time of a MOSFET match the Turn Off Propagation Delay set in the mosfet driver. If using a mosfet with a Turn Off Delay very much time larger than the Turn Off Propagation Delay of the driver, cross conduction may occur when low side MOSFET just turn on. Causing switching lose in the turning off high side MOSFET.

Fourth, let me know if I have missed something important here.

Table 1: Timing diagram of a MOSFET driver

Table 2: Fraction of datasheet of MOSFET.

Avoiding crossed-conduction:
Please note that a MOSFET with Turn-On Delay Time larger than Turn-Off Delay Time is suitable for synchronous driver, for example, without taking account of the Turn Off Propagation Delay of the driver, if we turning off high side MOSFET, as the condition specified above, it take 13+10=23ns to fully turn off. At the same time(simultaneously), we turn on low side MOSFET, typically, it take 15+12=27ns to fully turn on, that mean 27-23=5ns, there are 5 ns both MOSFET are in non-conduct condition, thus no crossed conduction is possible to occur.

*Refer to table 1, please don't forget that there are a minumum of 10ns Turn Off/ON Propagation Delay intoduce by the MOSFET driver, so over all there will have 5+10=15ns minimum where both MOSFET non-conducting. One can also use a MOSFET which have Turn-On Delay Time slightly smaller than Turn-Off Delay Time, but make sure that the difference do not exceed Turn Off/ON Propagation Delay intoduce by the MOSFET driver. Or else crossed-conduction may occur where both MOSFET conduct at the same time, which can cause MOSFETs failure or overheat.

There are some MOSFET, specially designed to have Turn-On Delay Time much smaller than Turn-Off Delay Time, this type of MOSFET usually used in aplication where switching is not required or in MOSFET and DIODE type of DC-DC, usually in lower frequency. Longer Turn-Off Fall Time reduce the current lose transiently built up of higher potential in the inductor or wire of any circuit, which is hazard to most component and therefore making it more robust.

FEB2010
By: David

DIY SMD Rework Hot Pencil (for small component)

What is a SMD rework station? A picture worth a thounsand words.

I recently doing new purchasing research online about the SMD rework. The cheapest one will cost us around RM270, while some company selling it increadibly expansive, price can go up to thousand Ringgit Malaysia. Interesting enough, I come across with some DIY article about SMD Rework Pencil or even DIY rework station, what? This thing also can be DIY? The question is not correct, what can not be DIY? It just need correct knowledge and action.

The good thing about DIY is that we can make use some stuff that we already have. The material required is roughly as the picture above, aquarium pump 3.5L/min maximum (RM10-30, there are some more powerful unit can go up to 30L/min), guitar string (B2 will do, RM1-5), some big fuse (RM1-10) and a big transformer is required (I am using a 12V, 10A unit from Maplin Electronic, around RM40-50, of course you can also use a PC power suply 5V or 12V rail, provided it can output enough current). 12V is recomended as smaller current required to heat up the guitar string, 24V is the best but you may need twice the guitar string length compare to 12V supply, unless if it capable to source twice the current rate compare to 12V supply.

Remove the cap of big fuse by using hand saw, cut the cap as the picture below and you will be able to remove it. Inside the fuse there are some processed(salt removed to prevent corrosion) sand, the porpuse of the sand is to prevent explosion of fuse as air can instantly increase in volume when temperature suddenly increase during fuse blowing, can result in fuse burst or even explode. Remove the sand to make it empty.

Measure the resistance of the guitar string with some precise multimeter, in my case I am using 12V, 10A power source, the resistance must not smaller than 12/10=1.2Ohm, Ohm's Law, remember? Wind the guitar string at correct dimension corespond to the inner diameter size of the fuse used, as what is show in the picture below.

It is done, pretty job isn't it? I fail at first two string, what a waste!!!

Put the guitar string into the fuse with cap removed as the picture below.

Get some wire interconnector copper tube from your local electrical shop, this thing are used for clamping two wire together without the need of using soldering iron, for fast work generally, but the most important idea is, sometime solder lead just don't work especially in the few hundred dergree Celcius environment, example inside a hair blower.

Assemble the copper tube and ceramic tube together such as show in picture below, use some copper foil to wrap the fuse, if you can not found copper foil, aluminium foil or even tin also aplicaple. Alternatively, you can use back the original cap if you able to take it off without scratched it, I guess damp the fuse into some oil or WD40 will help you in removing the cap, take two adjustable spanar, adjust to correct opening as wide as the fuse body and apply force apart toward the direction of the cap.

It is time for first testing, fire time (generally, this thing also can be used as igniter), show time. It took ~1-2minutes to heat up the ceramic chamber (the ceramic (body of fuse) will somehow store energy and the chamber will getting hotter and hotter) before it ready to solder/unsolder any SMD component, quite satisfy with the result.

It is not done yet, please wait for part 2 to come up, once I am free, I will proceed to part two later if have any add on.

Ok, thank for reading, any question please mail to mail.altbattery@gmail.com, I will try to answer it if I am free, thank you.


Note: This is not a long term solution for any other use, the heating element (guitar string) can become oxidation and eventually broken after some period of use. There is however, this is a good solution if you only need it to solder some small component once a while. It is cheap, you can use your old PC unused power supply, then the whole thing will not cost you more than RM50 I guess, of course, in the sacrifice of some of your time, but it can be interesting when you see your own built unit work!

Update 11thFreb2010:
It is time to show some result, it take 10-20s to remove bigger ic or D-Pak transistor, I don't know will that spoil the ic, but usually when you need to remove a ic mean that it is already spoiled. You can increase the power of heat element, it will shorthen the time needed to remove the ic, but the heat element will blow like fuse easily, sooner or later. The solution is use thicker wire and wind more turn, that will distribute heat over a bigger wire surface area and thus increase the life of the heating element.

One can also built a circuit to control the temperature of the heating element within a range, but the problem is that it is so difficult, if not imposible, to get a electronic temperature sensor that withstand 1000 degree Celcius or above. You can of course put the sensor on the exhaust or ceramic, but that sacrifice transient response measurement, i.e. you get information slower that what happen on the heating element. As a result, it is hard to limit the maximum temperature of the heating element. I suggest using some sort of metal strip thermo-couple which can be placed as close as possible to the heating element, I shall experiment on this once I am free.

The board still in perfect condition after ic removed, ready for next ic installation.

Some modification, I found out the the heat will going up and melt the silicone hose, therefore, I add another segment of 'fuse', this segment allow air preheat and prevent any heat reaching the handle. The whole thing is glued together using Araldite Rapid Steel Epoxy, which can withstand high temperature.

Suggestion:

1. Built a on/off switch for heating element, on the handle of the Pencil.

2. Built in a thermocoupler, it gain is control by a potential-meter, and then make the control available on the handle itself.

3. Built a tyristor control unit that control the duty cycle of the input voltage 230V, thus control the power output by big transformer.

*using a DC PWM control may result in great lost of power in the rectifier and mosfet, as the current involved is high 8-10A. Unless if 24V source is used for maximum efficiency.

4. Use thicker nichrome wire for longer life.

*Sorry for my poor English language, there must be a lot of grammer mistake...
*Do not attempt to do this DIY if you do not know what you are doing, AC240V use in main power is hazardous. Safety First, use insulated AC to DC. Hot air can burn skin, please proceed carefully.

Update 12thMarch2010:
The nichrome wire from hair dryer, this one is better choice and last longer, I get it from a stop working hair dryer. It resistance gradually increase as the element getting hotter and it getting red, so you need a lower resistance. Carban steel (guitar string) as heating element won't last long, the heat will consume the carban and eventually it will become iron, which have much lower resistance, high current then will pass through the iron and it will blow like a fuse.

Going smaller, going SMD

Resistor/Capacitor:

SMD for reparing job and Alternative Tools or other project development use.

Space tight for custom circuit? Go smaller with SMD! SMD component can be soldered by using tweezers and normal soldering iron.

Price: RM0.20 per pieces SMD resistor/capacitor

Zener Diode:

6.2V Zener diode to protect digital i/o port that have risk to expose to higher voltage, example 24V. By design always perfect, but sometime wrong connection, ESD, transient current or component failure can let you down. Protect the port will avoid damaging i/o port which cost higher to replace the main ic.

Price: RM0.30 each

*Please mail to mail.altbattery@gmail.com for inquiry about value available, shipping and handling RM10 within Malaysia for poslaju, RM5 for normal parcel pos or RM1 for envelope post.

Important

Alternative Battery.Ent promise to give most correct information about what cell using and it real tested capacity (or runtime after realt base on feedback of previous customers(if any)), not just a joke or a lie to you. Please refer to What our customer say? section or leave your comment there after you have make a deal with us. We offer 30 days not satisfy 100% money back and 6 months failsafe 80% money back if it turn out that serious damage occur which beyond repair. Once you try, you sure know that our battery is emphasize on quality. How we know it? Because many return customers use our service twice or few time for their friend, family or even company's laptop battery.

• Low Cost
• Quality Work and Product(Samsung cell with good reputation and low impedance)
• *Fast service cycle, it is ridiculous if you fail to get your battery in one week time. More than 80% of COD user get their battery back in 3 days, more than 50% in 1 days. Poslaju user usually get it back in 5days after they post it (exclude public holiday).

*Unless if Malaysia have logistic problem, too much public holiday or your battery need a chip replacement which the spare part order is in progress or delayed of your third party bank transfer or any other unspecified reason which will be discussed with customer earlier, such as workshop overload, technician outstation, stock finished. So make sure that you contact us every time before your battery posted to get us updated.

6 mojor reasons to realt your used battery(s)

What is realt?

-Availability of your battery on the Market
You can not found your battery elsewhere, it is too rare and no one selling it, or the battery model is discontinued.

-It is more cost effective than original
Considered the quality of our refilled battery, you are not likely to get equel energy at our price! We offer you half year warranty and 100% money back in one month if you are not satisfy with the performance of the battery.

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It is safer since original circuitry is use (original battery come with more level of protection, one fail, you have a back up protect unit), rather than some third party or oem circuitry with only one level of protection. We do not alter, modify or bypass the protection to force your battery work, instead, we look for the reasons why it fail and change the related component! We ensure that the protection is in working condition before passing it back to customers.

-This service is available in Malaysia
Many country do not have this service is because they do not have the techinical necessary available, some country, they are too rich and do not even need this service. Alternative Battery.Ent co-operate with customers to solve their mobile computing power need! We have great workmanship, trust able and reliable works and results, we repair most battery that fail to be repaired by other party, example IBM 40, 60 series, Hyundai/clevo M540BAT, Dell Inspiron 5000 BAT30WL, HP Series HSTNN-DB01, HP HSTNN-IB17, HP HSTNN-IB18, BAT30N3L, BATCL50L P and more. We work hard to ensure every battery work!

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Urgently need a working battery? It is faster to get a working battery by sending your battery to repair compare to order an obsolete model oversea.

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Recycle your old battery, reuse mean reduce the rate of rubbish being produced. Well, although we will change the contain inside, but we still use back the housing and the circuit board inside. The chip on the battery circuitboard itself cost around RM12-30 on global market. New plastic housing can cost RM5-15 in small volume trading.