laptop power
Mr. Lag:
I suggest you better use the MV step up method to achieve a 24v then use 2 LM338 in parallel to regulate the output voltage to 16v, then add capacitors at both in /out side with 2 0.1uf 50v monolithic cap. in parallel with.
The MV step up cct, or DIY kit are supplied by one electronic firm
called " Master Electronic " in Hong Kong, You can enquire from him. This kit or assembled kit can deliver 5 amps.
If your supply voltage is 8v, then u will get exactly 16v. without regulation. therefore I recommend to use the former method.
Another thing is a laptop is a computer device, internal uses 5v+, 5v-, 12v+, or 12v-. therefore the 16v u supplied is only input to the another smps which was build inside or outside your laptop.
or to charge up the nickel cadmium batteries. It has it's regulator to provide for the IC circuitry
WE CONSIDER USE THINGS PRACTICAL
Mr. Lag:
I suggest you better use the MV step up method to achieve a 24v then use 2 LM338 in parallel to regulate the output voltage to 16v, then add capacitors at both in /out side with 2 0.1uf 50v monolithic cap. in parallel with.
The MV step up cct, or DIY kit are supplied by one electronic firm
called " Master Electronic " in Hong Kong, You can enquire from him. This kit or assembled kit can deliver 5 amps.
If your supply voltage is 8v, then u will get exactly 16v. without regulation. therefore I recommend to use the former method.
Another thing is a laptop is a computer device, internal uses 5v+, 5v-, 12v+, or 12v-. therefore the 16v u supplied is only input to the another smps which was build inside or outside your laptop.
or to charge up the nickel cadmium batteries. It has it's regulator to provide for the IC circuitry
WE CONSIDER USE THINGS PRACTICAL
I'm Back
Hi Laq-
Sorry for the absence. Out of town for a day. Can't believe the confusion here. I'm hearing alot of things like "step it up with a switcher from 12 to 24V, then use linear regulators (LM338s) down to 16V....." blah, blah, blah.
(Originally posted by mitwrong:
"I suggest you better use the MV step up method to achieve a 24v then use 2 LM338 in parallel to regulate the output voltage to 16v..."
This sounds unnecessarily complex. Also, I disagree with opinions like: " Circuit can be found on web, so i don't waste space to discuss here." That's the reason for this whole forum! To discuss the DIY approach to all things audio, video, and every circuit associated with them. to discourage them defeats the whole purpose of this fine forum.
Each stage of conversion you go through lessens the overall efficiency. If you're powering off the AC Mains, then this might not be a big concern. But if you're powering off 12V, either a battery, or your car, then circuit efficiency is everything.
OK, I'll get off the soapbox here and return to the subject at hand: You need 16V at 3A, or 48W (just an example). At 12V in, this is 4A (assuming 100% efficiency). Even at 80% efficiency (a more realistic figure), you will still be drawing 5A from the 12V source to get your needed power. The LM2588 will easily supply this.
Go to Nat. Semi's website to the LM2588 datasheet. This PWM chip is used for DC-DC step-up and DC-DC flyback applications.
Originally posted by mitwrong:
"A simpleswitcher just convert the input voltage into the desired voltage with least minimum component. It may not have feedback loop, noise filter, protect cct. It's basic theory is by switching, may not employ PWM method."
Incorrect! It's a complete chip containing all the basic elements for an SMPS: oscillator, PWM, and feedback section. Its simplest form requires only 2 caps, a diode and a coil. That's it! The datasheet covers the design and fabrication, and gives manufacturer's part numbers and places to acquire them......
Hi Laq-
Sorry for the absence. Out of town for a day. Can't believe the confusion here. I'm hearing alot of things like "step it up with a switcher from 12 to 24V, then use linear regulators (LM338s) down to 16V....." blah, blah, blah.
(Originally posted by mitwrong:
"I suggest you better use the MV step up method to achieve a 24v then use 2 LM338 in parallel to regulate the output voltage to 16v..."
This sounds unnecessarily complex. Also, I disagree with opinions like: " Circuit can be found on web, so i don't waste space to discuss here." That's the reason for this whole forum! To discuss the DIY approach to all things audio, video, and every circuit associated with them. to discourage them defeats the whole purpose of this fine forum.
Each stage of conversion you go through lessens the overall efficiency. If you're powering off the AC Mains, then this might not be a big concern. But if you're powering off 12V, either a battery, or your car, then circuit efficiency is everything.
OK, I'll get off the soapbox here and return to the subject at hand: You need 16V at 3A, or 48W (just an example). At 12V in, this is 4A (assuming 100% efficiency). Even at 80% efficiency (a more realistic figure), you will still be drawing 5A from the 12V source to get your needed power. The LM2588 will easily supply this.
Go to Nat. Semi's website to the LM2588 datasheet. This PWM chip is used for DC-DC step-up and DC-DC flyback applications.
Originally posted by mitwrong:
"A simpleswitcher just convert the input voltage into the desired voltage with least minimum component. It may not have feedback loop, noise filter, protect cct. It's basic theory is by switching, may not employ PWM method."
Incorrect! It's a complete chip containing all the basic elements for an SMPS: oscillator, PWM, and feedback section. Its simplest form requires only 2 caps, a diode and a coil. That's it! The datasheet covers the design and fabrication, and gives manufacturer's part numbers and places to acquire them......
Part Two.....
..... so go and read, in detail, this datasheet before you do anything.
Next, I need to ask you, are you at all comfortable with experimenting with any kind of SMPSs? If not, then please let us know. If so, then read on......
Assuming you want to still power some of these things from your 220V mains, then I would recommend a half-bridge converter (using all the basic elements: two big electrolytic caps rated for 250V, two 500V MOSFETs, your TL598 PWM IC, a gate-drive transformer (to drive the high-side and low-side MOSFETs), a power transformer designed for SMPS operation, two output Schottky diodes, filter capacitors, and all the associated components) outputting 12V at, say, 10A, fow 120W. This will give you all the power you need, with room to spare.
From there, you could do a DC-DC boost circuit (using the LM2588) to get you from the +12V regulated output from your 220-12v converter to the +16V you said your laptop will need, and any individual step-up, or step-down DC-DC SMPS converters for whatever other circuits you will need to power.
For a more in-depth look at designing switch-mode power supplies, get any of the following three books, because they are the Holy Grail of SMPS design:
1) George Chryssis' book "High Frequency Switching Power Supplies" (c) 1989 (most recent edition);
2) Abraham Pressman's "Switching Power Supply Design" (c) 1998;
3) Marty Brown's book entitled: Power Supply Cookbook", (c) ????about Switchers from the EDN series of design books.
I will stop for now, because I have been writing for well over two hours now, but will be back in the morning.
Steve
..... so go and read, in detail, this datasheet before you do anything.
Next, I need to ask you, are you at all comfortable with experimenting with any kind of SMPSs? If not, then please let us know. If so, then read on......
Assuming you want to still power some of these things from your 220V mains, then I would recommend a half-bridge converter (using all the basic elements: two big electrolytic caps rated for 250V, two 500V MOSFETs, your TL598 PWM IC, a gate-drive transformer (to drive the high-side and low-side MOSFETs), a power transformer designed for SMPS operation, two output Schottky diodes, filter capacitors, and all the associated components) outputting 12V at, say, 10A, fow 120W. This will give you all the power you need, with room to spare.
From there, you could do a DC-DC boost circuit (using the LM2588) to get you from the +12V regulated output from your 220-12v converter to the +16V you said your laptop will need, and any individual step-up, or step-down DC-DC SMPS converters for whatever other circuits you will need to power.
For a more in-depth look at designing switch-mode power supplies, get any of the following three books, because they are the Holy Grail of SMPS design:
1) George Chryssis' book "High Frequency Switching Power Supplies" (c) 1989 (most recent edition);
2) Abraham Pressman's "Switching Power Supply Design" (c) 1998;
3) Marty Brown's book entitled: Power Supply Cookbook", (c) ????about Switchers from the EDN series of design books.
I will stop for now, because I have been writing for well over two hours now, but will be back in the morning.
Steve
I´ll be confortable building the 12V to 16V for the laptop, if this will improve the noise problem of my actual converter, so I hope the problem will be only there. But you told I´ll have no ground loop problem with the SMPS, and if it´s that way, so I´ll go.
Regarting to the 220V to 12V power supply, I would prefer buy one really. I just have one that seems to be some type of swtich type, and has a high frequency noise, I would like to avoid. Anyway, maybe buying a linear 220-12V would be more simple and would work, I think. Do you agree?
I like electronics, but just have to make a balance between needs, time, work, money, and so save some time to make some music, at least will be no much, since I have to work 40 hours a week.
So I´ll want to build want I don´t find. This case the 12-16 laptop noise-free converter.
Very thanked N-Channel. Go on..
Regarting to the 220V to 12V power supply, I would prefer buy one really. I just have one that seems to be some type of swtich type, and has a high frequency noise, I would like to avoid. Anyway, maybe buying a linear 220-12V would be more simple and would work, I think. Do you agree?
I like electronics, but just have to make a balance between needs, time, work, money, and so save some time to make some music, at least will be no much, since I have to work 40 hours a week.
So I´ll want to build want I don´t find. This case the 12-16 laptop noise-free converter.
Very thanked N-Channel. Go on..
Part Three
..... I think you asked if I had any A/D conversion experience. No, I have not had any, sorry. I have read from many Forum members that have done that, that if they power their A/D converter by an SMPS, they usually synchronize the SMPS's clock to the A/D's clock to vastly reduce noise and eliminate beat frequencies.
Synch'ing two SMPSs together is really alot easier than it might seem, and many SMPS chips have dedicated pins for this. Even for those that don't, like the TL494 & TL598, synch'ing them together is easy, and is covered in the TI datasheet for the TL494, which the TL598 is a totem-pole output version of.
I believe you also asked if the adapter you had was an SMPS or not, even if it wasn't a SimpleSwitcher. Yes, It is. Anything using any of the following chips is an SMSP: UC3842 thru '3846, UC3806, UCC3808, UCC3802 thru '3805, SG3525, UC3525, MC33025/34025, UC3825, TL494, TL594, TL598, SG3524, etc.
The datasheet for the TL494 shows a schemcatic for a non-isolated DC-DC buck regulator, using a PNP transistor as the switching element. Re-arranging this, you could use the TL598 to control an NPN bipolar, or N-Channel MOSFET, in a step-up configuration. Again, your current would be limited only by the current rating of the chosen NPN or N-Channel, boost diode and coil. The diodes used in SMPS are either fast-recovery, ultrafast-recovery, hyperfast-recovery, soft-recovery, or Schottky Barrier rectifiers. Each of these types has their advantages and disadvantages. Schottkys have a lower forward voltage drop (0.3-0.7), but have lower peak inverse voltage (PIV) ratings. Ultrafasts have shorter switching times, higher PIV ratings. but create some noise, and have higher forward voltage drop (1.0-1.2V). Since you would be going from 12V to 16V, Schottkys area good choice.
If how you get +12V from the AC mains is irrelevant, then you could separate the 220VAC-12VDC section from the 12-16V DC-DC step-up section, and use DC-DC to plug into both the AC-DC converter, and the cigar-lighter plug of your car, making it the portable part of the whole circuit. Just a thought.....
I believe you also asked if you could convert the +12V to +/-15, or +/-32Vdc. The short answer is, yes, you can.
You could use your TL598 to do this, driving two N-Channels through a center-tap transformer, outputting the (+) and (-) voltages thru an ultrafast diode bridge, or use the LM2588 in a flyback configuration to get the desired +/- outputs.
..... I think you asked if I had any A/D conversion experience. No, I have not had any, sorry. I have read from many Forum members that have done that, that if they power their A/D converter by an SMPS, they usually synchronize the SMPS's clock to the A/D's clock to vastly reduce noise and eliminate beat frequencies.
Synch'ing two SMPSs together is really alot easier than it might seem, and many SMPS chips have dedicated pins for this. Even for those that don't, like the TL494 & TL598, synch'ing them together is easy, and is covered in the TI datasheet for the TL494, which the TL598 is a totem-pole output version of.
I believe you also asked if the adapter you had was an SMPS or not, even if it wasn't a SimpleSwitcher. Yes, It is. Anything using any of the following chips is an SMSP: UC3842 thru '3846, UC3806, UCC3808, UCC3802 thru '3805, SG3525, UC3525, MC33025/34025, UC3825, TL494, TL594, TL598, SG3524, etc.
The datasheet for the TL494 shows a schemcatic for a non-isolated DC-DC buck regulator, using a PNP transistor as the switching element. Re-arranging this, you could use the TL598 to control an NPN bipolar, or N-Channel MOSFET, in a step-up configuration. Again, your current would be limited only by the current rating of the chosen NPN or N-Channel, boost diode and coil. The diodes used in SMPS are either fast-recovery, ultrafast-recovery, hyperfast-recovery, soft-recovery, or Schottky Barrier rectifiers. Each of these types has their advantages and disadvantages. Schottkys have a lower forward voltage drop (0.3-0.7), but have lower peak inverse voltage (PIV) ratings. Ultrafasts have shorter switching times, higher PIV ratings. but create some noise, and have higher forward voltage drop (1.0-1.2V). Since you would be going from 12V to 16V, Schottkys area good choice.
If how you get +12V from the AC mains is irrelevant, then you could separate the 220VAC-12VDC section from the 12-16V DC-DC step-up section, and use DC-DC to plug into both the AC-DC converter, and the cigar-lighter plug of your car, making it the portable part of the whole circuit. Just a thought.....
I believe you also asked if you could convert the +12V to +/-15, or +/-32Vdc. The short answer is, yes, you can.
You could use your TL598 to do this, driving two N-Channels through a center-tap transformer, outputting the (+) and (-) voltages thru an ultrafast diode bridge, or use the LM2588 in a flyback configuration to get the desired +/- outputs.
I´m forgeting this issue for one reason. The desinger of JLM preamps told me that they have tried over 50 SMPS AC-DC power supplies to can one, that works really "fine" for subtle high-end preamps, and have tried another 50 SMPS DC-DC ones and have found one that works subtle for this, So I think I´ll better follow their sugestions there, since they know much about preamps, and have gear to can test low level noise floor etc etc.
I didn´t understand this ok. What do you mean?
When I´ll use on the car, I´ll not use any AC at all.
About the converter I have, it seems have mosfet, (the three leg diode), so maybe replacing or adding some components could do the job?
I´ll make some pics and upload here, with the components it has
lagoausente said:
Sorry, I mistakenly thought you wanted to power these things from 220VAC, using 12VDC as your universal DC low voltage, while retaining the capability of taking the laptop portably on the road, which means powering it from +12V. Please clarify your needs.
lagoausente said:
OK, most probably, the three-legged TO-220 device is your MOSFET. Can you make out any of the markings on it?
After going back and re-reading your original post (#1) I now understand that you already have the 12V to16V DC-DC Converter, and that all you really need is to know how to power the other things from the same power source as the laptop. Since they will ALL work off +12V directly, your only remaining issue is the noise created by the 12-16V Converter. Am I correct? OK, since we want to get rid of this noise, we need to put a PI filter in line with the +12V input of this laptop DC-DC converter. Also, manufacturers of such DC-DC devices are notorious for using the absolutely minimum size parts to get the job done. I'm amazed that you were able to get inside the converter, as now adays, most manufacturers seal the enclosure with epoxy or ther industry equivalent of krazy glue, to keep wondering noses out.
So, to get rid of the noise in the other components created by the laptop SMPS, I would recommend experimenting with various inductors and capacitors for the PI filter, until the noise is either gone, or below detectable limits. Since you have opened the converter, if it's a plastic case, I would line it with either tinfoil or copper sheeting in a roll. Both available in most electronics & hobby stores.
Hi lago,
In your case, it seems using an inverter is ideal. So that u can
plug different adapters independently and power all respective devices. Since u power the inverter from a car battery, the power supply seem to be not a problem at all. This method also helps in plugging other devices to your inverter like TV,stereo etc. Here is one schematic of a inverter which is quite easy to build. You may have to calculate the total power rating and select an apt tranformer for that.
Good Luck!
In your case, it seems using an inverter is ideal. So that u can
plug different adapters independently and power all respective devices. Since u power the inverter from a car battery, the power supply seem to be not a problem at all. This method also helps in plugging other devices to your inverter like TV,stereo etc. Here is one schematic of a inverter which is quite easy to build. You may have to calculate the total power rating and select an apt tranformer for that.
Good Luck!
Attachments
First of all, sorry for so late reply but have been out for a while.
Yes, correct.
The converter is partially sealed, I needed to use a light to can read the letters of the IC from one side. It has a metal cover soldered to the mainboard, but could see something for the lateral hole .
Outside is plastic. Inside have a metal cover over the main IC, even doesn´t cover all components.
But this would me another type of isolation, isn´t? I think the mainly noise is traveling over the wires.
Yes, correct.
Ok, but what capacity, and coil? Need to analize the noise frequency?
The converter is partially sealed, I needed to use a light to can read the letters of the IC from one side. It has a metal cover soldered to the mainboard, but could see something for the lateral hole .
Outside is plastic. Inside have a metal cover over the main IC, even doesn´t cover all components.
But this would me another type of isolation, isn´t? I think the mainly noise is traveling over the wires.
rejithcv said:
Yes, but there are two issues here. One is that going from 12V to 220V and then then again down for preamp or converter would be a waste of energy, probably.
Second, I would need a "pure sine wave" inverter. Most inverters out there are modified sine wave, what are quite bad for audio
Is that shematic you linked a "pure sine wave inverter"?
I´m guessing if maybe could be better option, to change the output transformer to get for example +/- 18 V?
I´m thinking about an inverter like this: 12VDC- oscilator 50hz- 12V AC- transformer- +/- 18V AC. Then just apply this after the preamp power supply transformer, and let work it´s own filter/recified filter. Do you think would work? and less noise than a smps?
Would I save energy comparing to going to 220 first?
Note: N-Channel, I still have most devices at 12V DC, so I still need the noise isolation. Even I have sold the preamp/AD converter that worked at 12VDC, I´ll get a another converter that has 12V input, and if I´ll try to get a preamp also with the 12V dc input, or build the inverter I´m talking about.
There are two diferent issues here, the noise isolation and the inverter or smps supply, but I need both in my system now.
For now, I´m avoiding the laptop noise, using the laptop battery. But could be fine to isolate the converter anyway, for can use it when need it.
Thanks for your patiente with me.
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