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Well...the price is sure right!!
The chip is manufactured on a bicadmium process technology, which integrates a bipolar transistor, CMOS FET and double-diffused MOS.Samples are due in September and will be priced at 81 cents.
Call (800) 879-4963 www.toshiba.com/taec
The chip is manufactured on a bicadmium process technology, which integrates a bipolar transistor, CMOS FET and double-diffused MOS.Samples are due in September and will be priced at 81 cents.
Call (800) 879-4963 www.toshiba.com/taec
MrAl
Flashlight Enthusiast
Looks pretty interesting.
Too bad minimum
input voltage is 3v dc, and maximum output
current is 20ma. Might need a driver
transistor in order to overdrive the led's
a little for increased brightness.
Maxim makes similar chips, but are priced
around $4 each. If that price of 81 cents
stands for normal production(as well as samples), they might be useful in 3 cell
flashlights. The 3v input requirement doesnt
impress me though. I think they could
have done better
It might be possible to use a simple switching supply to supply that chip.
That way it can get its 3v input.
I suspect that requirement is needed in order
to drive the output MOSFET gate, so its probably a low current requirement too.
If so, the output transistor might be able
to run from much lower voltages while the
main ic gets its 3v requirement. Of course
the circuit will be much more complex, but
it might be worth it after all. I guess
we will find out when they post some
application notes. Ill check back now and then.
--Al
Too bad minimum
input voltage is 3v dc, and maximum output
current is 20ma. Might need a driver
transistor in order to overdrive the led's
a little for increased brightness.
Maxim makes similar chips, but are priced
around $4 each. If that price of 81 cents
stands for normal production(as well as samples), they might be useful in 3 cell
flashlights. The 3v input requirement doesnt
impress me though. I think they could
have done better
It might be possible to use a simple switching supply to supply that chip.
That way it can get its 3v input.
I suspect that requirement is needed in order
to drive the output MOSFET gate, so its probably a low current requirement too.
If so, the output transistor might be able
to run from much lower voltages while the
main ic gets its 3v requirement. Of course
the circuit will be much more complex, but
it might be worth it after all. I guess
we will find out when they post some
application notes. Ill check back now and then.
--Al
D
**DONOTDELETE**
Guest
MrAl, as far as I understand, the typical setup is 6 LEDs in series with 20 mA through them; lets hope it is only typical.
I hope some flashlight manufacturers will give it a try
.
I hope some flashlight manufacturers will give it a try
D
**DONOTDELETE**
Guest
Speaking of the new Maxim chips:
This thing looked too good to be true from the first sight, but closer examination revealed revealed that it isn't.
This could be doable, but what's the fuss with the caps? ...and the DAC input too.
This chip looks VERY promising for driving LED arrays or Luxeon Stars. They even have an evaluation kit with 9 white LEDs.
In a regular parallel setup, an LED fails -> becomes a short circuit -> all the current flows though it, and not the LEDs. This chip, however, would provide the REAL guarantee that the light won't fail: an LED fails -> becomes a short circuit -> the voltage is adjusted to keep the current unchanged -> the array is still working. Plus the current regulation and high efficiency too.
This thing looked too good to be true from the first sight, but closer examination revealed revealed that it isn't.
This could be doable, but what's the fuss with the caps? ...and the DAC input too.
This chip looks VERY promising for driving LED arrays or Luxeon Stars. They even have an evaluation kit with 9 white LEDs.
In a regular parallel setup, an LED fails -> becomes a short circuit -> all the current flows though it, and not the LEDs. This chip, however, would provide the REAL guarantee that the light won't fail: an LED fails -> becomes a short circuit -> the voltage is adjusted to keep the current unchanged -> the array is still working. Plus the current regulation and high efficiency too.
Well....here goes another few bucks... I want this eval kit. Thanks MadScience man!
MAX1698EVKIT Evaluation Kit for the MAX1698
Each one of these is more fun than the one before. I really like the feature you pointed out..."the voltage is adjusted to keep the current unchanged"
======================================
I am finding that my interests are moving more toward application rather than making these lights from scratch. I don't mind throwing in 10 bucks or so for labor.
I think there is a niche for a company to be formed just selling these board solutions ( I hate that word) to hobby people. If you want a chip for a LS...then get xxx chip.
If you want a chip for longevity...then get xxx etc. etc.....sort of like what Eternalight is doing with their new board/light combo....and what Gadget is doing with his custom orders etc etc.
BTY, my LS night light is well into the second month with the original SINGLE C cell, used every night for 8 or so hours, still above 1.5 volts.
MAX1698EVKIT Evaluation Kit for the MAX1698
Each one of these is more fun than the one before. I really like the feature you pointed out..."the voltage is adjusted to keep the current unchanged"
======================================
I am finding that my interests are moving more toward application rather than making these lights from scratch. I don't mind throwing in 10 bucks or so for labor.
I think there is a niche for a company to be formed just selling these board solutions ( I hate that word) to hobby people. If you want a chip for a LS...then get xxx chip.
If you want a chip for longevity...then get xxx etc. etc.....sort of like what Eternalight is doing with their new board/light combo....and what Gadget is doing with his custom orders etc etc.
BTY, my LS night light is well into the second month with the original SINGLE C cell, used every night for 8 or so hours, still above 1.5 volts.
MrAl
Flashlight Enthusiast
Thanks for doing the reasearch mad_scientist.
The thing i dont like about most of
these kind of chips is the dropout voltage.
Even the Maxim chips are spec'ing 2.6v or
higher. Right now, my Brinkmann LED F.L.
is running on 2.35v at near full brightness.
According to the Maxim specs, if i were using
one of those chips it would not be running at all
on 2.35v battery input. I guess thats
why im sticking with the Brinkmann-like circuit for now,
as it can run down to just less then 1 volt and still
provide full output brightness (with a slight mod).
Kenbar: im doing a night light test too Mine has
been running now for about 2 weeks on a battery that was
otherwise too dead to use for anything else! I think these
things are the light of the future.
A friend an i are about ready to mod a standard EXIT sign also.
We think replacing the regular 120v night light bulbs with LED's
will eliminate the need to keep replacing the bulbs which run for
24 hours a day. Adjusting the current to 10ma should make the
LED's last for 20 years!
Good luck with your LED's,
--Al
The thing i dont like about most of
these kind of chips is the dropout voltage.
Even the Maxim chips are spec'ing 2.6v or
higher. Right now, my Brinkmann LED F.L.
is running on 2.35v at near full brightness.
According to the Maxim specs, if i were using
one of those chips it would not be running at all
on 2.35v battery input. I guess thats
why im sticking with the Brinkmann-like circuit for now,
as it can run down to just less then 1 volt and still
provide full output brightness (with a slight mod).
Kenbar: im doing a night light test too
Mine hasbeen running now for about 2 weeks on a battery that was
otherwise too dead to use for anything else! I think these
things are the light of the future.
A friend an i are about ready to mod a standard EXIT sign also.
We think replacing the regular 120v night light bulbs with LED's
will eliminate the need to keep replacing the bulbs which run for
24 hours a day. Adjusting the current to 10ma should make the
LED's last for 20 years!
Good luck with your LED's,
--Al
PeLu
Flashlight Enthusiast
<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by mad_scientist:
Speaking of the new Maxim chips:
In a regular parallel setup, an LED fails -> becomes a short circuit -> all the current flows though it, and not the LEDs. This chip, however, would provide the REAL guarantee that the light won't fail: <HR></BLOCKQUOTE>
The LED will not fail for the simple reason that it will not suffer from thermal runaway.
Speaking of the new Maxim chips:
In a regular parallel setup, an LED fails -> becomes a short circuit -> all the current flows though it, and not the LEDs. This chip, however, would provide the REAL guarantee that the light won't fail: <HR></BLOCKQUOTE>
The LED will not fail for the simple reason that it will not suffer from thermal runaway.
MrAl
Flashlight Enthusiast
<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by mad_scientist:
MrAl, as far as I understand, the typical setup is 6 LEDs in series with 20 mA through them; lets hope it is only typical.
<HR></BLOCKQUOTE>
Yeah he he, but im not nearly as worried
about the output current as the input
minimum voltage spec. Right now it looks
like the min is 3v, which would make it
hard to use in a standard two cell flashlight which barely puts out 3v most of
the time, but then im hard to please
I probably wont be satisfied even with a
2v min because i would like to see the
battery power used right down to 1v or less
(in a F.L. with two cells in series).
--Al
MrAl, as far as I understand, the typical setup is 6 LEDs in series with 20 mA through them; lets hope it is only typical.
<HR></BLOCKQUOTE>
Yeah he he, but im not nearly as worried
about the output current as the input
minimum voltage spec. Right now it looks
like the min is 3v, which would make it
hard to use in a standard two cell flashlight which barely puts out 3v most of
the time, but then im hard to please
I probably wont be satisfied even with a
2v min because i would like to see the
battery power used right down to 1v or less
(in a F.L. with two cells in series).
--Al
Adam S.
Newly Enlightened
Hi, I don't know hardly anything about electronics but I read the data sheets on the MAX1698 and MAX1698EVKIT and I had an interesting thought, if you used a small 3v lithium battery to power the IC then you could use any battery configuration between 0.8v and 7v to run the LEDs. It may not be very practical but it could be interesting.
I looked around for somewhere a regular guy could buy one (MAX1698) online and cameup empty, the MAX1698EVKIT Evaluation Kit cost $100.00 and thats more than I want to pay right now for something I would probably fry.
I've really enjoyed all the information on this board it has been very helpfull.
I looked around for somewhere a regular guy could buy one (MAX1698) online and cameup empty, the MAX1698EVKIT Evaluation Kit cost $100.00 and thats more than I want to pay right now for something I would probably fry.
I've really enjoyed all the information on this board it has been very helpfull.
PeLu
Flashlight Enthusiast
<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by MrAl:
Yeah he he, but im not nearly as worried
about the output current as the input
minimum voltage spec. Right now it looks
like the min is 3v, which would make it
hard to use in a standard two cell flashlight which barely puts out 3v most of
the time, but then im hard to please
[/QB]<HR></BLOCKQUOTE>
Two alkaline AA cells will put out 3V or above only for a fraction of a second (less that 0.1s) when loaded with 0.5A.
To get out most of the juice you need to rund down AAs to 0.9V and C and D cells down to 0.6V.
So it is good to design the circuits that way.
Yeah he he, but im not nearly as worried
about the output current as the input
minimum voltage spec. Right now it looks
like the min is 3v, which would make it
hard to use in a standard two cell flashlight which barely puts out 3v most of
the time, but then im hard to please
[/QB]<HR></BLOCKQUOTE>
Two alkaline AA cells will put out 3V or above only for a fraction of a second (less that 0.1s) when loaded with 0.5A.
To get out most of the juice you need to rund down AAs to 0.9V and C and D cells down to 0.6V.
So it is good to design the circuits that way.
