internal 2-bit DAC
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Harrkev
Enlightened
A "DAC" is a "Digital to Analog Converter."
2-bit implies that it has a reslution of two bits, which translates to four levels (2^2).
Such circuits are commonly used by digial controllers to read or control analog circuitry. As a simple example, if you had a 2-bit converter, and wanted to read a voltage between 0 and 40V, you would have the following ranges:
1) 0-10V
2) 10-20V
3) 20-30V
4) 30-40V
You would be able to tell which "range" the voltage was in, but no more than that.
Quite honestly, two bits seems to be quite miniscule. I would prefer at least eight bits myself, but this depends upon the application.
Where did you read this?
2-bit implies that it has a reslution of two bits, which translates to four levels (2^2).
Such circuits are commonly used by digial controllers to read or control analog circuitry. As a simple example, if you had a 2-bit converter, and wanted to read a voltage between 0 and 40V, you would have the following ranges:
1) 0-10V
2) 10-20V
3) 20-30V
4) 30-40V
You would be able to tell which "range" the voltage was in, but no more than that.
Quite honestly, two bits seems to be quite miniscule. I would prefer at least eight bits myself, but this depends upon the application.
Where did you read this?
Thanks Harrkev..
I was looking into a charge pump..I am trying to find something under 5 bucks. This 20 bucks a pop for evaluation boards is straining the bank account
! I am still trying to make a "poor man's Arc". I could have bought a DOZEN for the money I have spent...LOL!
Charge pump application
I was looking into a charge pump..I am trying to find something under 5 bucks. This 20 bucks a pop for evaluation boards is straining the bank account
Charge pump application
Harrkev
Enlightened
Seems like a nice chip, except for the narrow (and high) input voltage range (2.7v-4v). The 4V means that you could not use 3-cells, and the 2.7 means that you could not use 1-cell.
So, you will be using two cells. However, because 2.7 is the minum voltage, you will not get much battery life. The ARC is a wonderful light because it appears to suck the battery almost completely dry before dying. With this chip, you would be lucky to get 1/2 of the battery's power.
My guess is that this chip is intended to be used on a cell phone or PDA where there is already a regulated 3.3V supply. It is probably not intended to operate directly off of a battery.
I posted another thread about a regulator IC (http://www.candlepowerforums.com/cgi-bin/ultimatebb.cgi?ubb=get_topic&f=3&t=000901). If you can handle surface-mount stuff, this seems quite promising.
Unfortunately, doing switching power supply stuff is not easy. Even though I have a Master's degree in Electrical Engineering, I do not understand where the "minimum" voltage specification comes from on various boost circuits. Perhaps this could have something to do with the fact that I focused on ditigal technology and avoided analog stuff like the plague.
So, you will be using two cells. However, because 2.7 is the minum voltage, you will not get much battery life. The ARC is a wonderful light because it appears to suck the battery almost completely dry before dying. With this chip, you would be lucky to get 1/2 of the battery's power.
My guess is that this chip is intended to be used on a cell phone or PDA where there is already a regulated 3.3V supply. It is probably not intended to operate directly off of a battery.
I posted another thread about a regulator IC (http://www.candlepowerforums.com/cgi-bin/ultimatebb.cgi?ubb=get_topic&f=3&t=000901). If you can handle surface-mount stuff, this seems quite promising.
Unfortunately, doing switching power supply stuff is not easy. Even though I have a Master's degree in Electrical Engineering, I do not understand where the "minimum" voltage specification comes from on various boost circuits. Perhaps this could have something to do with the fact that I focused on ditigal technology and avoided analog stuff like the plague.
PeLu
Flashlight Enthusiast
<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by Harrkev:
Seems like a nice chip, except for the narrow (and high) input voltage range (2.7v-4v). The 4V means that you could not use 3-cells, and the 2.7 means that you could not use 1-cell.<HR></BLOCKQUOTE>
It's maximum input is 4.5V, so it is good for a 3-cell application (and that is what it is intended IMHO). Also a single Li Ion will be suitable.
Seems like a nice chip, except for the narrow (and high) input voltage range (2.7v-4v). The 4V means that you could not use 3-cells, and the 2.7 means that you could not use 1-cell.<HR></BLOCKQUOTE>
It's maximum input is 4.5V, so it is good for a 3-cell application (and that is what it is intended IMHO). Also a single Li Ion will be suitable.
MrAl
Flashlight Enthusiast
<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by KenBar:
Thanks Harrkev..
I was looking into a charge pump..I am trying to find something under 5 bucks. This 20 bucks a pop for evaluation boards is straining the bank account
! I am still trying to make a "poor man's Arc". I could have bought a DOZEN for the money I have spent...LOL!
<HR></BLOCKQUOTE>
How many LED's do you have to drive?
I might be able to make up boards for you
guys and sell them for $5 or less in
small quantities.
Probably be easier then trying to explain
the design procedures
Let me know if your interested.
Al
[email protected]
Thanks Harrkev..
I was looking into a charge pump..I am trying to find something under 5 bucks. This 20 bucks a pop for evaluation boards is straining the bank account
<HR></BLOCKQUOTE>
How many LED's do you have to drive?
I might be able to make up boards for you
guys and sell them for $5 or less in
small quantities.
Probably be easier then trying to explain
the design procedures
Let me know if your interested.
Al
[email protected]
Mr Al
I am not sure of how many led's...Probably 1-3. Any suggestions?
Since getting the Versalux from Eternalight, I am sort of getting hooked on lots of light. My regular eternalights are not getting used quite as much. I sort of am gravitating from either a few LED's or as many as I can fit ( like Gadget makes)
Mike...YES! I would love one of the modules for the ARC. I have been waiting for the LS to settle out as well. The thing I like about the VersaLux is that using 4 batteries, I can suck the life out of them. I would like that opportuinty on just one D cell with the ARC module.
I am not sure of how many led's...Probably 1-3. Any suggestions?
Since getting the Versalux from Eternalight, I am sort of getting hooked on lots of light. My regular eternalights are not getting used quite as much. I sort of am gravitating from either a few LED's or as many as I can fit ( like Gadget makes)
Mike...YES! I would love one of the modules for the ARC. I have been waiting for the LS to settle out as well. The thing I like about the VersaLux is that using 4 batteries, I can suck the life out of them. I would like that opportuinty on just one D cell with the ARC module.
MrAl
Flashlight Enthusiast
<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by KenBar:
Mr Al
I am not sure of how many led's...Probably 1-3. Any suggestions?
<HR></BLOCKQUOTE>
Sure Ken. Do you do your own electronic
assembly, like soldering transistors and
resistors and stuff?
--Al
Mr Al
I am not sure of how many led's...Probably 1-3. Any suggestions?
<HR></BLOCKQUOTE>
Sure Ken. Do you do your own electronic
assembly, like soldering transistors and
resistors and stuff?
--Al
MrAl
Flashlight Enthusiast
<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by KenBar:
Regular stuff no problem.
Ken<HR></BLOCKQUOTE>
I guess i could post a schematic that will
drive 4 white led's then, if you want to build it yourself. Im in the process of
building a 4 led now myself, and plan to use
the simplest possible circuit, with parts that anyone can get almost anywhere. I really like a lot of chips i saw out there on the web as well as one i got to test out firsthand, but sometimes they are a little hard to get ahold of.
The main problem i have is finding small "project" boxes that are just the right size...anyone know where to find these?
If you want to build up your own circuit, i'll post a 4 led circuit that will drive
say 2 to 4 led's, ok? I'll use very common parts if possible. I'll assume you can get
parts like 2N4401 transistors, 1A Schottky diodes, standard capacitors, and at least one inductor around 200uH or so, but if you need parts, just let me know.
I think i found a fairly simple way to
add LED constant current control to a simple
circuit, but it does add one more transistor to the total parts count, although its a 25 cent transistor
--Al
Regular stuff no problem.
Ken<HR></BLOCKQUOTE>
I guess i could post a schematic that will
drive 4 white led's then, if you want to build it yourself. Im in the process of
building a 4 led now myself, and plan to use
the simplest possible circuit, with parts that anyone can get almost anywhere. I really like a lot of chips i saw out there on the web as well as one i got to test out firsthand, but sometimes they are a little hard to get ahold of.
The main problem i have is finding small "project" boxes that are just the right size...anyone know where to find these?
If you want to build up your own circuit, i'll post a 4 led circuit that will drive
say 2 to 4 led's, ok? I'll use very common parts if possible. I'll assume you can get
parts like 2N4401 transistors, 1A Schottky diodes, standard capacitors, and at least one inductor around 200uH or so, but if you need parts, just let me know.
I think i found a fairly simple way to
add LED constant current control to a simple
circuit, but it does add one more transistor to the total parts count, although its a 25 cent transistor
--Al
<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>MrAl but if you need parts, just let me know.
<HR></BLOCKQUOTE>
===================================================================
That would be something I would be interested in.
It would help as I live east of Egypt and stores are not found very much out here. Add a few extra bucks for your trouble and 3 bucks for mailing and I would still be ahead of trying to order parts that would not possibly work. Shipping kills me as it is usually most of the cost of what I order. My usual Hosfelt order is about $50...most of which I don't immediately need but I don't want to pay the shipping.
I still think a person could start a small home business selling kits in the USA. I would do it but I truly don't have the time.
<HR></BLOCKQUOTE>
===================================================================
That would be something I would be interested in.
It would help as I live east of Egypt and stores are not found very much out here. Add a few extra bucks for your trouble and 3 bucks for mailing and I would still be ahead of trying to order parts that would not possibly work. Shipping kills me as it is usually most of the cost of what I order. My usual Hosfelt order is about $50...most of which I don't immediately need but I don't want to pay the shipping.
I still think a person could start a small home business selling kits in the USA. I would do it but I truly don't have the time.
Steelwolf
Flashlight Enthusiast
I would also be very interested in a good 4 LED circuit. I've been doing the SatCure circuit for quite a while now and have given away several lights using that, but the downside is always its inability to maintain a constant brightness until the batteries die.
I wish Gransee could soon release the hobby modules of the Arc-AAA and LS power supplies, or a schematic using discrete components (ie no surface mounted stuff). Till then, I'm stuck with the SatCure and several unsuccessful experimental circuits.
I wish Gransee could soon release the hobby modules of the Arc-AAA and LS power supplies, or a schematic using discrete components (ie no surface mounted stuff). Till then, I'm stuck with the SatCure and several unsuccessful experimental circuits.
<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by MrAl:
The main problem i have is finding small "project" boxes that are just the right size...anyone know where to find these?
<HR></BLOCKQUOTE>
Current Hosfelt Electronics catalog has a bunch of project boxes on pages 132-134 http://www.hosfelt.com
(888)264-6464 or (800) 524-6464
The main problem i have is finding small "project" boxes that are just the right size...anyone know where to find these?
<HR></BLOCKQUOTE>
Current Hosfelt Electronics catalog has a bunch of project boxes on pages 132-134 http://www.hosfelt.com
(888)264-6464 or (800) 524-6464
I use Hosfelt quite a bit also. I used to use Radio Shack ones but I like the Hosfelt better. They have more boxes in their catalog than these. Enclosures
They have one that has 4 AA built in that you can wire to have the exact voltage you want...a strong 1.5, 3, 6 volts etc. It is about the size and thickness of a small pocket novel. I have one ordered for the Versalux I have. Radio shack has a really nice TINY one however. It has enough room for one 9 volt battery and a few led's. ALL radio shacks do not carry it however.
A small Hosfelt I like is the LMB#401
It is:
Width 2.25 inches
Length 3.6 inches
Height 1.5 inches
It is made by "Heeger".
Here is a pic of the Radio Shack one.
They have one that has 4 AA built in that you can wire to have the exact voltage you want...a strong 1.5, 3, 6 volts etc. It is about the size and thickness of a small pocket novel. I have one ordered for the Versalux I have. Radio shack has a really nice TINY one however. It has enough room for one 9 volt battery and a few led's. ALL radio shacks do not carry it however.
A small Hosfelt I like is the LMB#401
It is:
Width 2.25 inches
Length 3.6 inches
Height 1.5 inches
It is made by "Heeger".
Here is a pic of the Radio Shack one.
Here is a site that may keep you busy for awhile....LOTS of enclosures.
Lots of Enclosures..Project boxes Many stocked by Hosfelt.
FYI...
LMB plastic products use UL rated 94 high-impact ABS. Waterproof gaskets (perimeter seals) are made of Elastomer to provide flexibility for outdoor weather environments. Gaskets can be used on both the 400 and 500 series. (On 500 series battery compartment is not sealed.)
These are high quality boxes and use things like "special" Plastite® screwsscrews for the plastic cases that don't strip out like many...as many of you know this is a hot point with me...
The PLASTITE® screw's Trilobular™ design reduces dangerous hoop stress and the friction of root interference, which can frequently cause the bursting of thin-walled bosses.
Fewer torque problems.
The unusually high drive-to-strip ratio of PLASTITE® screws permits a wider span of torque settings to be safely used with automatic drivers. Strip out is virtually eliminated.
"Better quality" screws used in Heeger project boxes
If Gadget could go into business with his quality workmanship, using these boxes, and his retina ripping led arrangements, he could probably sell a few.
Lots of Enclosures..Project boxes Many stocked by Hosfelt.
FYI...
LMB plastic products use UL rated 94 high-impact ABS. Waterproof gaskets (perimeter seals) are made of Elastomer to provide flexibility for outdoor weather environments. Gaskets can be used on both the 400 and 500 series. (On 500 series battery compartment is not sealed.)
These are high quality boxes and use things like "special" Plastite® screwsscrews for the plastic cases that don't strip out like many...as many of you know this is a hot point with me...
The PLASTITE® screw's Trilobular™ design reduces dangerous hoop stress and the friction of root interference, which can frequently cause the bursting of thin-walled bosses.
Fewer torque problems.
The unusually high drive-to-strip ratio of PLASTITE® screws permits a wider span of torque settings to be safely used with automatic drivers. Strip out is virtually eliminated.
"Better quality" screws used in Heeger project boxes
If Gadget could go into business with his quality workmanship, using these boxes, and his retina ripping led arrangements, he could probably sell a few.
MrAl
Flashlight Enthusiast
Thanks to Jeff and Ken, i'll look into those boxes, that's exactly the kind i was looking for.
I should have a circuit running by the end of next week that can drive up to say 4 led's
from one or two AA cells. I'll post a note on here as soon as i have it up and running.
If you need parts you'll have to email me, and i'll look into getting a lot of the parts that goes into the circuit.
Ken: how much is it to send a regular first class letter to your area from the USA ?
Small quantities dont weigh all that much
Steel: i'll post the circuit hopefully by the end of next week that will drive up to 4 led's.
--Al
I should have a circuit running by the end of next week that can drive up to say 4 led's
from one or two AA cells. I'll post a note on here as soon as i have it up and running.
If you need parts you'll have to email me, and i'll look into getting a lot of the parts that goes into the circuit.
Ken: how much is it to send a regular first class letter to your area from the USA ?
Small quantities dont weigh all that much
Steel: i'll post the circuit hopefully by the end of next week that will drive up to 4 led's.
--Al
