Nabble - PIC - [EE]

Re: Freescale Coldfire...

2008-09-05T23:14:09Z

On Sat, Sep 6, 2008 at 10:52 AM, William Chops Westfield
<billw@...> wrote:

>
>
>> Some of the Freescale ColdFire V1 (and a few V2) MCUs start to look
>> interesting here even though the choices are still very limited. But
>> they seem to be very competitive against PIC24/PIC32, especially
>> on the higher end (Ethernet, USB, etc).
>>
>>
>>> From the product summary brocure:
>>>
>> 10k SRP of MCF51QE32/64/128 is US$1.94/3.30/3.80. LQFP64
>> 10k SPR of MCF51JM128 is US$3.65 with 44LQFP option.
>>
>>
>
> Wow. I had no idea that the Coldfire CPUs had crept so far down in
> price! That's ... REALLY interesting (IMO) and worth thinking about
> vs the ARM and MIPS cored "large" MCUs.

The downside is that Coldfire is only from Freescale. But so far the
only MIPS based real generic MCU is the PIC32 from Microchip.
ARM is still the king. From the website, Freescale starts to license
the Coldfire core.

> "Freescale" has the CPUs that used to be Motorola. Coldfire is
> essentially a re-design (?) of the motorola 68000 core. To me,
> that means two important things:
>
> 1) development tools, including gnu compilers, are pretty mature
> and don't have the issues that seem to plague ARM ("oh, the Cortex
> M3 core WILL be in gcc, but right now you have to download the
> SPECIAL version from compiler vendor XXXX.")

It is said the V1/V2/V3/V4 core are all using the same instruction
sets and GCC support is pretty good (bare metal or with Linux).
3rd party commercial compiler and RTOS support are also pretty
good but tend to be expensive.

> 2) The coldfire architecture is "elegant" compared to nearly anything
> developed in the last 20 years. You can write assembly language
> code without warping your brain.
>
> The old motorola 683xx chips (their first foray into putting a 68k
> core on the same die with peripherals (but not memory)) were pretty
> sweet chips, aside from being relatively big, expensive, and hard to
> obtain except in professional quantitites. If that's changed, it opens
> up all sorts of interesting possibilities!

Many Coldfire chips are still big and pretty expensive. Not so sure
about the sample policy. But it is said that Freescale is now
pushing hard on the MCU front so maybe the situation is changed.

Actually the only reason that I looked at ColdFire is that Freescale is
now the recommended 32bit MCU vendor in the company.

Xiaofan
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Freescale Coldfire...

2008-09-05T19:52:54Z

> Some of the Freescale ColdFire V1 (and a few V2) MCUs start to look
> interesting here even though the choices are still very limited. But
> they seem to be very competitive against PIC24/PIC32, especially
> on the higher end (Ethernet, USB, etc).
>
>
>> From the product summary brocure:
>>
> 10k SRP of MCF51QE32/64/128 is US$1.94/3.30/3.80. LQFP64
> 10k SPR of MCF51JM128 is US$3.65 with 44LQFP option.
>
>

Wow. I had no idea that the Coldfire CPUs had crept so far down in
price!
That's ... REALLY interesting (IMO) and worth thinking about vs the
ARM and
MIPS cored "large" MCUs.

The only Hitachi/Freescale parts I've ever used have been the
HC11 and
H8S, so I'm not really up to speed on them. Do the Coldfire
devices have
any significant advantages over ARM based ones?

Note that "Renesas" has the CPUs that used to be Hitachi (and
mitsubishi).
"Freescale" has the CPUs that used to be Motorola. Coldfire is
essentially
a re-design (?) of the motorola 68000 core. To me, that means two
important
things:

1) development tools, including gnu compilers, are pretty mature
and don't
have the issues that seem to plague ARM ("oh, the Cortex M3 core
WILL be
in gcc, but right now you have to download the SPECIAL version from
compiler vendor XXXX.")
2) The coldfire architecture is "elegant" compared to nearly anything
developed in the last 20 years. You can write assembly language
code without warping your brain.

The old motorola 683xx chips (their first foray into putting a 68k
core on
the same die with peripherals (but not memory)) were pretty sweet chips,
aside from being relatively big, expensive, and hard to obtain except in
professional quantitites. If that's changed, it opens up all sorts of
interesting possibilities!

BillW

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Re: RF Transceiver w/ antenna for $10

2008-09-05T16:58:54Z

See this at http://i.cmpnet.com/edtn/ccellar/e032pdf1.pdf

--- El vie 5-sep-08, Marcel Duchamp <marcel.duchamp@...> escribió:

De: Marcel Duchamp <marcel.duchamp@...>
Asunto: Re: [EE] RF Transceiver w/ antenna for $10
A: "Microcontroller discussion list - Public." <piclist@...>
Fecha: viernes, 5 septiembre, 2008, 5:33 pm

Peter Loron wrote:

>> Microchip has similar products, I think:
>> http://www.microchip.com/wwwproducts/Devices.aspx?dDocName=en027752
>> http://www.microchip.com/wwwproducts/Devices.aspx?dDocName=en535967
>
> Yes. I have recently gotten some of the complete modules in and they
> look very nice. They are already FCC certified, so if you build
> something with them, I believe only need to go through the much
> cheaper device tests, rather than the intentional radiator tests.
>
> Now I'm trying to flog up some SPI libraries to use with my Arduino
> boards.
>
> -Pete

I could not resist either so I bought a pair of them. Haven't had time
to do anything with them yet...
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Re: RF Transceiver w/ antenna for $10

2008-09-05T15:33:38Z

Peter Loron wrote:

Re: RF Transceiver w/ antenna for $10

2008-09-05T14:59:14Z

On Sep 5, 2008, at 2:24 PM, Marcel Duchamp wrote:

> Vitaliy wrote:
>> Sounds too good to be true.. what's the catch?
>>
>> http://circuitspecialists.com/search.itml?icQuery=cc1100b
>>
>> Does "license free" mean "doesn't need FCC certification"?
>>
>> Vitaliy
>
> Microchip has similar products, I think:
> http://www.microchip.com/wwwproducts/Devices.aspx?dDocName=en027752
> http://www.microchip.com/wwwproducts/Devices.aspx?dDocName=en535967

Yes. I have recently gotten some of the complete modules in and they
look very nice. They are already FCC certified, so if you build
something with them, I believe only need to go through the much
cheaper device tests, rather than the intentional radiator tests.

Now I'm trying to flog up some SPI libraries to use with my Arduino
boards.

-Pete
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Re: RF Transceiver w/ antenna for $10

2008-09-05T14:24:55Z

Vitaliy wrote:
> Sounds too good to be true.. what's the catch?
>
> http://circuitspecialists.com/search.itml?icQuery=cc1100b
>
> Does "license free" mean "doesn't need FCC certification"?
>
> Vitaliy

Microchip has similar products, I think:
http://www.microchip.com/wwwproducts/Devices.aspx?dDocName=en027752
http://www.microchip.com/wwwproducts/Devices.aspx?dDocName=en535967
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Re: RF Transceiver w/ antenna for $10

2008-09-05T14:23:17Z

It means it's operating in the ISM bands. AFAIK, if you build it into a
product you need an FCC mark/certification.

-marc

On Fri, Sep 5, 2008 at 4:50 PM, Vitaliy <spam@...> wrote:

> Sounds too good to be true.. what's the catch?
>
> http://circuitspecialists.com/search.itml?icQuery=cc1100b
>
> Does "license free" mean "doesn't need FCC certification"?
>
> Vitaliy
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Re: Ethernet to RS232 adapters

2008-09-05T14:19:07Z

Looking through the ads in electronics magazines...

SitePlayer.com
http://www.siteplayer.com/
$80 ($100 for RoHS compliant)

Saelig
<http://www.saelig.com/miva/merchant.mvc?Screen=PROD&Product_Code=ETH012>
$89.00

GridConnect
http://www.gridconnect.com/wi232.html
$200

Lemos
<http://lemosint.com/device_servers/device_servers_details.php?itemID=178>
$70

NetBurner
<http://www.netburner.com/products/serial_to_ethernet/sb72ex.html>
$179

Saelig's seems like the best choice due to the form factor and the fact that
it can be powered from pin 9 of the DB9. Any other ideas?

Best regards,

Vitaliy

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Re: RF Transceiver w/ antenna for $10

2008-09-05T14:12:00Z

On Fri, 5 Sep 2008 13:50:58 -0700, "Vitaliy" <spam@...> said:
> Sounds too good to be true.. what's the catch?
>
> http://circuitspecialists.com/search.itml?icQuery=cc1100b
>
> Does "license free" mean "doesn't need FCC certification"?

Any products that use it will require FCC certification. But the users
will not require licenses.

Cheerful regards,

Bob

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RF Transceiver w/ antenna for $10

2008-09-05T13:50:58Z

Sounds too good to be true.. what's the catch?

http://circuitspecialists.com/search.itml?icQuery=cc1100b

Does "license free" mean "doesn't need FCC certification"?

Vitaliy
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Re: WiFi to RS232 adapters

2008-09-05T13:37:03Z

2008/9/5 Vitaliy <spam@...>:

> Jon Baker wrote:
>> For $100 you can buy a second hand linksys router on eBay or alike, it
>> comes with ethernet, wireless and one or two onboard serial ports +
>> JTAG. Check out www.openwrt.org for the linux OS to run on it and it
>> seems like an ideal solution. After that, an IP to serial port
>> redirector, with ssl encryption or not is a one-liner, alternatively,
>> if it is for a remote programmer, download the hex file to the box
>> wirelessly and then initiate the programming sequence to avoid timing
>> or buffering problems.
>
> Jon, this may work for a hobby project, but we really need something
> off-the-shelf that we can use right away. Something like this:
>
> http://www.rovingnetworks.com/index_files/image014.jpg

Sorry, I thought it was just an in house toy of some kind..

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Re: WiFi to RS232 adapters

2008-09-05T13:23:53Z

Harold Hallikainen wrote:
> I'm designing a module from Connect One into a couple products. They also
> have "serial servers" that appear to be one of the modules with a TTL to
> RS232 interface. They can be set up to listen on a particular TCP port and
> then connect the RS232 when a TCP connection comes in. They also have an
> interesting internal web server.

Do you have experience with the Mini Socket iWiFi?

http://www.connectone.com/products.asp?did=73&pid=73

It's not exactly what I was looking for (we need an external adapter that
plugs into the DB9F), but we may want to build it into one of our future
products.

Their external device server has a lead time of 9 weeks (and it's way bigger
than I would like):

http://www.connectone.com/products.asp?did=39&pid=31

This is what I envisioned originally:

http://www.rovingnetworks.com/index_files/image014.jpg

Vitaliy

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Re: WiFi to RS232 adapters

2008-09-05T13:09:06Z

Jon Baker wrote:
> For $100 you can buy a second hand linksys router on eBay or alike, it
> comes with ethernet, wireless and one or two onboard serial ports +
> JTAG. Check out www.openwrt.org for the linux OS to run on it and it
> seems like an ideal solution. After that, an IP to serial port
> redirector, with ssl encryption or not is a one-liner, alternatively,
> if it is for a remote programmer, download the hex file to the box
> wirelessly and then initiate the programming sequence to avoid timing
> or buffering problems.

Jon, this may work for a hobby project, but we really need something
off-the-shelf that we can use right away. Something like this:

http://www.rovingnetworks.com/index_files/image014.jpg

Vitaliy

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Re: WiFi to RS232 adapters

2008-09-05T13:03:30Z

William "Chops" Westfield wrote:
> The Lantronix "wiport" modules seem to be generally well respected; I
> haven't used them myself. There are modules that are pin-compatible
> with wired adapters, which is sort of nice. Prices seem to range
> from about $55 for a bare module (no antenna, logic-level outputs) to
> about $250 for a two-port packaged solution ("WiBox")

$250 is unfortunately way out of our price range.

>> What would be really cool (but not required), is to be able to
>> connect to
>> the serial device over the internet: serial device --- wifi router ---
>> internet --- PC.
>
> I don't quite understand. Once you have wifi, and and IP stack, this
> sort of thing tends to come "for free", and is more dependent on your
> network infrastructure than on the Wifi/rs232 adapter (in fact, you
> may have more problems finding a module that allows the sort of
> device->device "ad hoc" wifi direct from phones/etc than a module
> that works with a standard wireless network (to wireless AP.)

I figured that may be the case.

> As for TCP/IP to serial in general, it's a pretty mature technology,
> with enough history and standardization that there are "standard"
> 'com port redirectors' that should work with nearly any device (using
> "telnet" as protocol.) Things get less compatible if you need secure
> (ssh) access, and/or serious programatic manipulation of rs232
> signals. I would expect major problems trying to operate a JDM-style
> PIC programmer over SSH...

We're just getting our feet wet, I wanted to get people's feedback, then
order the top candidates and play with them.

Vitaliy

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Re: WiFi to RS232 adapters

2008-09-05T12:40:47Z

Justin Richards
> Bluetooth serial adapter perhaps, I know you mentioned WiFi but
> thought I would mention it

We use Bluetooth already -- in fact, we recently launched a site to sell
various Bluetooth adapters:

http://www.btdongles.com

The STM4100 module is something we build in-house, for use in our scan
tools:

http://tinyurl.com/6x8aoe

The WiFi modules have a different purpose.

Vitaliy

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Re: WiFi to RS232 adapters

2008-09-05T12:07:58Z

2008/9/5 William Chops Westfield <westfw@...>:
>
> On Sep 4, 2008, at 4:12 PM, Vitaliy wrote:
>
>> I'm seeking recommendations on 802.11 to RS232 adapters. Basically,
>> we need
>> to be able to connect to a serial device wirelessly, from a device
>> equipped
>> with WiFi (e.g., an iPhone, a WiFi equipped laptop, etc).
>

For $100 you can buy a second hand linksys router on eBay or alike, it
comes with ethernet, wireless and one or two onboard serial ports +
JTAG. Check out www.openwrt.org for the linux OS to run on it and it
seems like an ideal solution. After that, an IP to serial port
redirector, with ssl encryption or not is a one-liner, alternatively,
if it is for a remote programmer, download the hex file to the box
wirelessly and then initiate the programming sequence to avoid timing
or buffering problems.

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Re: Best step up 1.5V->5V?

2008-09-05T09:03:41Z

On Fri, 05 Sep 2008 10:16:18 -0400, "Brian B. Riley" <brianbr@...>
said:
> Bob, in the higher current less efficient one, is R4 correct as "22 R"
> or should it also be "220 R" like R1 ?

It's 22 ohms (needs the extra current to drive the base of the next
transistor).

Cheers,

Bob

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Re: WiFi to RS232 adapters

2008-09-05T08:38:15Z

On Sep 4, 2008, at 4:12 PM, Vitaliy wrote:

> I'm seeking recommendations on 802.11 to RS232 adapters. Basically,
> we need
> to be able to connect to a serial device wirelessly, from a device
> equipped
> with WiFi (e.g., an iPhone, a WiFi equipped laptop, etc).

The Lantronix "wiport" modules seem to be generally well respected; I
haven't used them myself. There are modules that are pin-compatible
with wired adapters, which is sort of nice. Prices seem to range
from about $55 for a bare module (no antenna, logic-level outputs) to
about $250 for a two-port packaged solution ("WiBox")

> What would be really cool (but not required), is to be able to
> connect to
> the serial device over the internet: serial device --- wifi router ---
> internet --- PC.

I don't quite understand. Once you have wifi, and and IP stack, this
sort of thing tends to come "for free", and is more dependent on your
network infrastructure than on the Wifi/rs232 adapter (in fact, you
may have more problems finding a module that allows the sort of
device->device "ad hoc" wifi direct from phones/etc than a module
that works with a standard wireless network (to wireless AP.)

As for TCP/IP to serial in general, it's a pretty mature technology,
with enough history and standardization that there are "standard"
'com port redirectors' that should work with nearly any device (using
"telnet" as protocol.) Things get less compatible if you need secure
(ssh) access, and/or serious programatic manipulation of rs232
signals. I would expect major problems trying to operate a JDM-style
PIC programmer over SSH...

BillW

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Re: Best step up 1.5V->5V?

2008-09-05T07:16:18Z

Bob, in the higher current less efficient one, is R4 correct as "22 R"
or should it also be "220 R" like R1 ?

On Sep 4, 2008, at 11:29 PM, Bob Blick wrote:

> 500 mA and 80% efficiency. Ouch. I don't think those two will be so
> easy.
>
> Attached is a converter that meets neither spec but does decent
> amounts
> of current. Next email will be one with good efficiency.
>
> Cheers, Bob
>
> Mike Hagen wrote:
>> Good Luck on that shopping list!
>>
>> Bob Blick has a really cheap and neat switcher, it has been on the
>> Pic
>> List before. May not go down to one input cell?
>>
>> Maybe he will chime in here or you can Google it?
>>
>>
>>
>>
>> Bob Ammerman wrote:
>>> I am looking for step-up switcher with following characteristics:
>>>
>>> 1: Input voltage: 1 alkaline cell, the lower the starting voltage
>>> and sustain voltage the better.
>>>
>>> 2: Output voltage: 5V
>>>
>>> 3: Current: max of 500ma (yes, I know this will kill the input
>>> cell pretty quickly)
>>>
>>> 4: Efficiency: not critical, 80% nice
>>>
>>> 5: Through hole mounting
>>>
>>> 6: Reasonable cost: In 100's total cost of circuit, including
>>> switcher, inductor, cap(s), diode under $2.00 if possible
>>>
>>> 7: Soft failure would be nice: ie: if it can't produce a full 5V
>>> on output given the source impedence then generate what it can.
>>>
>>> Can be IC or discrete solution.
>>>
> <1_cell_up_pwm.gif>--
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Re: Best step up 1.5V->5V?

2008-09-05T06:51:34Z

>> IF you can find an acceptable way to start

> That's the tricky part. I originally was trying to create something that
> would run from a single cell. If I remember right, I got this topology
> with
> maybe different value to run from around 900mV. Since I wanted it to work
> from rechargable batteries, I didn't think 900mV was acceptable. In the
> end
> I used two batteries in series. But Bob specifically said alkaline, which
> start at around 1.5V with very little of the total energy left at 1V.

I'm using the AN6601D which i've mentioned before in several made-in-China
products (not the BOGO light).
It starts on 0.6V. Runs down to 0.3V or so. Costs about $US0.08 in 10k. DIP
8 and SOIC 8.
Only 40 mA output and only about 5V- output - designed for 1 White LED or
several in parallel. It's big brother is the AN6201 but it is in SOT89? and
SOT23. The former is high current but a 3 pin brain dead topology. The
latter has a sense pin of sorts. 6201 5 pin and 6601D can be voltage or
current regulated with 1 external transistor.

One of these as a boot strap and drive rail supply for something else would
allow 1 cell operation, <<1 V startup and more.
Minimum configuration is IC, 0.1 uF, inductor. Add 1R and 1Q for current
regulation. Add 2R and 1Q for voltage regulation.
eg this plus an MC34063 and a small amount of glue would be very very useful
and still very cheap.

Using the An6601D and current regulation and a white LD I can maintain
current to within about 5% for 1.1V to 1.5V Vin.
Cuts off at 1.1V for rechargeable battery protection BUT would go lower with
much the same results.

Don't know of a western supplier, alas. Shenzhen knows them well.

Russell

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Re: Best step up 1.5V->5V?

2008-09-05T06:09:08Z

Apptech wrote:
> It's interesting that it both output voltage and output current
> limits.

This is really a regulated current supply since it's job was to drive a
string of LEDs. The output voltage limit was only to prevent damage in case
the output was ever left open circuit.

Since Bob wants voltage regulation, he can dispense with the current limit
altogether and make the voltage limit more accurate. Something like a 4.3V
zener into transistor base with a little resistance to ground is probably
good enough, and will be a lot less temperature sensitive and more accurate
than what I had. My voltage limit was only there to keep the voltage below
damaging levels, so it didn't need much accuracy.

> IF you can find an acceptable way to start

That's the tricky part. I originally was trying to create something that
would run from a single cell. If I remember right, I got this topology with
maybe different value to run from around 900mV. Since I wanted it to work
from rechargable batteries, I didn't think 900mV was acceptable. In the end
I used two batteries in series. But Bob specifically said alkaline, which
start at around 1.5V with very little of the total energy left at 1V.

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Re: Best step up 1.5V->5V?

2008-09-05T05:55:21Z

>For:
>
>5. Through hole mounting
>
>Read:
>
>5. Hand solderable by an old man who drinks too much coffee.

OK, under those conditions I would say that any 1206 and larger SM
components, and SO- ICs are viable (although a head mounted magnifier is
advisable). I certainly have little trouble with these. Doing closer pitch
ICs than SO- series ones I do find awkward. having suitable tweezer
soldering iron certainly helps removal of passive components during
development.

So, for 1206 sized components, you can all R & non-polar C values, tantalums
come in packages that start at around 1206 (I think the A size might be
closer to 0804, but really you only get these in low value/low voltage) and
get larger as value*voltage climbs, over a range of 5 or 6 packages.
Inductors vary depending on just what you require, but people like Coilcraft
have ranges that correspond to 1206 type sizing, which would probably be
satisfactory for what you want, but if you need real low R in the L then you
will end up with larger packages where they can wind them with thicker gauge
wire.

Transistors in SOT-23 I find satisfactory to solder as they have well spaced
leads. You can get a whole heap of jelly bean types in this size package
that would be well suited to Bob Blicks circuits.

You may be able to find a suitable IC in an SO-8 package, but IIRC most of
the ones designed to operate off of a well run down single cell are in tiny
packages, designed for cell phone type mass market use, or putting in LED
torches where space is a real premium. It is probably worth working your way
through the selector guide at Linear Technology to see if something comes
into the right package and price range. Maxim also have a selector guide.

Have fun.

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Re: Best step up 1.5V->5V?

2008-09-05T05:21:57Z

> Anyway, I put the schematic of the 20mA LED driver circuit at
> http://www.embedinc.com/pic/light2/light2.pdf. Parts of this circuit are
> overkill for a 20mA output, but when you want up to 500mA input the extra
> gain stages and the like are probably a good idea. You will need a
> different switching element that can take the higher current. Figure peak
> currents will be in the 1 to 1.5A range.

It's interesting that it both output voltage and output current limits.
Note that the output current limit adds about 50/Vout % inefficincy and
should be byassed if not needed.
(eg for a 5V vout the current sense takes ~~ 50/5 = 10% of the output
energy.

IF you can find an acceptable way to start it you can use a packet of HC
gates to do most of what Olin is doing here with discretes. (Q4 still needed
and Q5/6 may be). HC family operate down to 2 volts and run off their own
boosted output.(eg HC series Schmitt). Not as compact as discrete but much
easier to get OK results.Starting with one cell can be by start button
bootstrapping a capacitor to 2 volts or, as some do, pulsing a start
inductor to provide initial Vdd.

Russell McMahon

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Re: 3-phase conditioning (was CCP range and limiting)

2008-09-05T05:13:11Z

Richard Prosser wrote:
> Re the capacitance, as a rough estimate I'd look at 0.1uF/Amp or even
> less for full wave rectified 3 phase. I guess you could also compare
> the charge situation with an automotive alternator. No capacitors used
> here at all, but the charger is a rectified three phase source. Might
> also be a good source of diodes / 3 phase diode bridge??

If the turbine is producing 3 phase AC natively, then you should really
consider power factor correction. It not so much a efficiency issue, but
with a constant resistive load on all 3 phases the generator torque remains
constant.

With full wave bridge front ends and no PFC, the generator will be free
wheeling between the waveform peaks and feeling a sudden hit in torque at
the peaks. When you factor out the constant rotation speed as DC, this is
essentially putting a nasty spiked AC load on the rotor and generator. You
definitely don't want this to occur at any of the resonant frequencies of
the rotor blades, unless you can arrange the wind to blow at only the right
speeds. A little PFC sounds rather easier.

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(978) 742-9014. Gold level PIC consultants since 2000.
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Re: Best step up 1.5V->5V?

2008-09-05T05:11:58Z

For:

5. Through hole mounting

Read:

5. Hand solderable by an old man who drinks too much coffee.

Also, for

6: Reasonable cost: In 100's total cost of circuit, including switcher,
inductor, cap(s), diode under $2.00 if possible

Read:

6: Reasonable cost: In 100's total cost of circuit, including switcher,
inductor, cap(s), diode under $4.00 if possible

Does that help open up the possibilities??

-- Bob Ammerman

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Re: Best step up 1.5V->5V?

2008-09-05T04:49:09Z

Bob Ammerman wrote:

> I am looking for step-up switcher with following characteristics:
>
> 1: Input voltage: 1 alkaline cell, the lower the starting voltage and
> sustain voltage the better.
>
> 2: Output voltage: 5V
>
> 3: Current: max of 500ma (yes, I know this will kill the input cell
> pretty quickly)
>
> 4: Efficiency: not critical, 80% nice
>
> 5: Through hole mounting
>
> 6: Reasonable cost: In 100's total cost of circuit, including
> switcher, inductor, cap(s), diode under $2.00 if possible
>
> 7: Soft failure would be nice: ie: if it can't produce a full 5V on
> output given the source impedence then generate what it can.

A long time ago I did a discrete circuit for running a string of LEDs from
two AA batteries. This was really a boost switcher with the feedback coming
from a low side current sense. It would be a voltage regulator if the
feedback came from the output voltage instead.

It is basically a free running oscillator with the feedback killing the
oscillation when the output gets above the regulation threshold. The
accuracy isn't that tight since the reference is a B-E junction, but this
could be changed of course.

I sortof remember this circuit or versions of it with different values
working down to 900mV. There is very little left in a alkaline battery when
it gets down to 900mV. Still, you'd have a easier time if you can use two
batteries in series. If it's a space issue, how about two AAA in series
instead of a single AA?

Anyway, I put the schematic of the 20mA LED driver circuit at
http://www.embedinc.com/pic/light2/light2.pdf. Parts of this circuit are
overkill for a 20mA output, but when you want up to 500mA input the extra
gain stages and the like are probably a good idea. You will need a
different switching element that can take the higher current. Figure peak
currents will be in the 1 to 1.5A range.

I did make boards of this circuit a long time ago, and can probably find a
few left over ones if you want. This was meant for others build easily and
is all thru hole. I can send you some if I can find them.

I just looked around and found 2 blank boards, and 2 where someone had
installed the parts. If I remember right, one of those never worked (the
guy barely knew which end of a soldering iron to hold), and the other I
think worked fine. I'd be happy to send you the whole mess if you want to
experiment with them.

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Re: Anyone familiar with Quad, Juki, Mann, etc PnP machines?

2008-09-05T03:10:39Z

> Looking into purchasing an SMD Pick and Place system soon, and wondering if
> someone can advise me on any of these machines. The more I investigate the
> more things I discover, such as some companies charging $15K to re-register
> the machine before they discuss any support issue. Also looking for
> practical info, such as I heard from a few sources that Quad machines have
> electronic feeders that are unreliable.
>
> These are the machines I'm considering so far, but other recommendations
> appreciated...
> - Quad IV-C
> - Juki/Zevatech -- 460, 710, 720, etc
> - Phillips CSM66
> - Panasonic (various)
> - Manncorp

I can only talk about Juki - I am quite satisfied with ours but you
should avoid older models with mechanical centering like the ones you
mentioned. It's not that they don't work but for a bit more you can buy
better.

http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=270272223135

This one seems great - it has contactless centering, top and bottom
vision and you get the manuals and some feeders. It has three heads so
you have spares if one head is worn out/defective. It is reasonably fast
and you have feeder bays from both sides.

The only thing to check is if there are nozzles and feeders available on
the market but I'm sure there are. These guys have feeders and also the
machine for sale http://www.getsmtglobal.com/pickandplace.htm

Djula
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Re: Best step up 1.5V->5V?

2008-09-05T02:18:32Z

> But I am wondering how well Bob Blicks circuits would meet the budget.
> There
> is a reasonable number of components on those.

Around $US0.20 in China in 10ks for his PFM boost converter.

Digikey in 100's, somewhat more..

Still under $2 by quite a long way I think.

The boost converter could drive an arbitrarily large through hole FET with a
bit more playing. A D-Pak is probably essentially through hole for this
application - ie can be easily hand soldered. Failing that a TO220 FET. Use
output to provide gate drive voltage and it should work well enough. FET
needs to switch after a fashion at Vgs= 1 volt for startup, but need not run
well there.

Russell

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Re: Best step up 1.5V->5V?

2008-09-05T01:27:38Z

>The CES2310 FEt that I have mentioned previously would work OK there.
>Zetex do some very low Vgson (low gate voltage ) FETs.
>There aren't a vast number that are happy at 1 volt.

But do they come as TH parts (requirement 5 from the OPs list)?

>A good trick is to use Vout to provide the gate drive voltage
>thereby allowing a far wider range of FETs to be used.

I guess a couple of bootstrap components are not going to eat into the
couple bucks budget he gave, that much.

But I am wondering how well Bob Blicks circuits would meet the budget. There
is a reasonable number of components on those.

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Re: 3-phase conditioning (was CCP range and limiting)

2008-09-05T01:21:36Z

>As it turns out, I'm told the frequency of interest from the turbine
>is > 450Hz, and switch-over frequency (star-delta) is ~ 650Hz,
...
>Now I'm trying to help him with the rectification.

You may need to look at recovery time of the rectifiers at that sort of
frequency. I know older 1N400x series diodes have visible reverse recovery
time on an oscilloscope at 50Hz, so it is probably worth at least checking
the RRT rating on whatever you choose, otherwise your diodes may become a
significant heat loss point affecting the overall efficiency.

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Re: 3-phase conditioning (was CCP range and limiting)

2008-09-05T01:21:36Z

Re: Best step up 1.5V->5V?

2008-09-05T01:16:25Z

>5: Through hole mounting

I believe this one will kill your search. Most such chips come in the micro
miniature packages.

Linear Technology and Maxim both make suitable chips, but none in a TH
package that I am aware of.

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Re: Best step up 1.5V->5V?

2008-09-04T21:24:16Z

> Here's one with good efficiency but not much current, maybe 50 mA.

Bob knows all this. Others may find it useful:

Add a suitable FET and a bit of gate waveform shaping and you can get as
much power as desired.

The CES2310 FEt that I have mentioned previously would work OK there.
Zetex do some very low Vgson (low gate voltage ) FETs.
There aren't a vast number that are happy at 1 volt.
A good trick is to use Vout to provide the gate drive voltage thereby
allowing a far wider range of FETs to be used.

Russell

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Re: Best step up 1.5V->5V?

2008-09-04T20:30:30Z

Here's one with good efficiency but not much current, maybe 50 mA.

Cheers,

Bob

Mike Hagen wrote:

> Good Luck on that shopping list!
>
> Bob Blick has a really cheap and neat switcher, it has been on the Pic
> List before. May not go down to one input cell?
>
> Maybe he will chime in here or you can Google it?
>
>
>
>
> Bob Ammerman wrote:
>> I am looking for step-up switcher with following characteristics:
>>
>> 1: Input voltage: 1 alkaline cell, the lower the starting voltage and sustain voltage the better.
>>
>> 2: Output voltage: 5V
>>
>> 3: Current: max of 500ma (yes, I know this will kill the input cell pretty quickly)
>>
>> 4: Efficiency: not critical, 80% nice
>>
>> 5: Through hole mounting
>>
>> 6: Reasonable cost: In 100's total cost of circuit, including switcher, inductor, cap(s), diode under $2.00 if possible
>>
>> 7: Soft failure would be nice: ie: if it can't produce a full 5V on output given the source impedence then generate what it can.
>>
>> Can be IC or discrete solution.
>>

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Re: Best step up 1.5V->5V?

2008-09-04T20:29:30Z

500 mA and 80% efficiency. Ouch. I don't think those two will be so easy.

Attached is a converter that meets neither spec but does decent amounts
of current. Next email will be one with good efficiency.

Cheers, Bob

Mike Hagen wrote:

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