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Old June 21st 04, 12:52 PM
Hans Summers
 
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Default Low current crystal oscillator


Hello

I have built 2 very simple 2-chip frequency counters with 8 LED binary
readout see http://www.hanssummers.com/radio/sfreq/index.htm . My Mk2
counter is extremely small (just 25 x 16 x 16mm) and consumes a low current
of 5mA max.

The question relates to the 4.096MHz oscillator which uses the internal
oscillator of the 74HC4060. Of the 5mA current consumption, 1.2mA is used by
the LED's when max 7 are on at any one time. About 0.8mA by the
diode-resistor gate logic, transistor switch, 74HC4040 and the voltage
regulator. Fully 3mA is wasted on the 74HC4060 crystal oscillator + divider.
It seems wrong to spend 60% of your current consumption on an oscillator,
compared to less than 25% on the LED's.

In the pursuit of excellence in this design, I would like to cut the current
consumption of the oscillator section. Does anyone know of a better
arrangement that will cut current consumption? Increasing the series
resistor wasn't the solution. I put a 100K variable in here in place of the
original 2K2. Initially as the resistor was increased the current
consumption fell, but at higher resistances the current consumption
increased quite dramatically. The optimum was at close to 4K7.

73 Hans G0UPL
http://www.HansSummers.com



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Old June 21st 04, 03:16 PM
Michael Dunn
 
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Default

regulator. Fully 3mA is wasted on the 74HC4060 crystal oscillator + divider.
It seems wrong to spend 60% of your current consumption on an oscillator,
compared to less than 25% on the LED's.


Try a plain 4060.
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Old June 21st 04, 03:31 PM
Reg Edwards
 
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Each sub-circuit in an equipment should be considered seperately, on its own
merits, in respect of minimisation of power consumption.

It is essential for the future of the human race that electronic design
engineers are familiar with the basic principles involved. Energy
consumption has to be paid for throughout life of the equipment. It's a
part of the cost of ownwership.

At present much of the world's energy requirements come from oil, gas and
coal. Ordinary food is the principal source of energy of course and is
always in short supply. Oil is also used to make plastics for the packaging
industries, etc.

World war has been in progress for many years about control of food
supplies, the oil fields and pipelines. It is becoming daily more intense
and building up towards Armageddon. Fundamentally it is a war involving the
Multi-nationals, Wall Sreet Bankers and giant Insurance Companies, etc.,
completely beyond control of World Governments.

Sooner or later the World MUST concentrate on atomic energy. The sensible
French already have 90% of their energy requirements provided by atomic
power stations. The remainder by hydro-electric and tidal power. The
Japanese, having no natural biological energy resources, are also quietly
well on their way. Iranians, oil producers themselves, are busy building
there own atomic power stations in anticipation of a World oil shortage, but
their efforts are sabotaged by multi-national legal and political warfare
about who gets the development, investment and construction contracts.

When the World is mainly on atomic energy, electronic circuit designers can
feel free to enjoy themselves and exercise their unrestrained imaginations.
----
Optimistic Reg.


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Old June 21st 04, 04:01 PM
Bill Janssen
 
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Default

Hans Summers wrote:

Hello

I have built 2 very simple 2-chip frequency counters with 8 LED binary
readout see http://www.hanssummers.com/radio/sfreq/index.htm . My Mk2
counter is extremely small (just 25 x 16 x 16mm) and consumes a low current
of 5mA max.

The question relates to the 4.096MHz oscillator which uses the internal
oscillator of the 74HC4060. Of the 5mA current consumption, 1.2mA is used by
the LED's when max 7 are on at any one time. About 0.8mA by the
diode-resistor gate logic, transistor switch, 74HC4040 and the voltage
regulator. Fully 3mA is wasted on the 74HC4060 crystal oscillator + divider.
It seems wrong to spend 60% of your current consumption on an oscillator,
compared to less than 25% on the LED's.

In the pursuit of excellence in this design, I would like to cut the current
consumption of the oscillator section. Does anyone know of a better
arrangement that will cut current consumption? Increasing the series
resistor wasn't the solution. I put a 100K variable in here in place of the
original 2K2. Initially as the resistor was increased the current
consumption fell, but at higher resistances the current consumption
increased quite dramatically. The optimum was at close to 4K7.

73 Hans G0UPL
http://www.HansSummers.com





Not familiar with the chips you are using but you should use the lowest
frequency oscillator possible.
Maybe try the 32 + KHz crystal

A lot of the current is used to charge and discharge internal capacity
so doing that less often helps.

Bill K7NOM

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Old June 21st 04, 04:58 PM
Paul Burridge
 
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On Mon, 21 Jun 2004 14:31:12 +0000 (UTC), "Reg Edwards"
wrote:

Sooner or later the World MUST concentrate on atomic energy.


Absolutely right, Reg. Even good old fission if necessary. Yeah, it's
dirty but so what? Outer space has a limitless capacity for our
radioactive garbage. Instead of encasing it in concrete and burying
it, we should be just firing away in rockets. Way to go!
--

"What is now proved was once only imagin'd." - William Blake, 1793.


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Old June 21st 04, 05:23 PM
Tim Wescott
 
Posts: n/a
Default

Hans Summers wrote:
Hello

I have built 2 very simple 2-chip frequency counters with 8 LED binary
readout see http://www.hanssummers.com/radio/sfreq/index.htm . My Mk2
counter is extremely small (just 25 x 16 x 16mm) and consumes a low current
of 5mA max.

The question relates to the 4.096MHz oscillator which uses the internal
oscillator of the 74HC4060. Of the 5mA current consumption, 1.2mA is used by
the LED's when max 7 are on at any one time. About 0.8mA by the
diode-resistor gate logic, transistor switch, 74HC4040 and the voltage
regulator. Fully 3mA is wasted on the 74HC4060 crystal oscillator + divider.
It seems wrong to spend 60% of your current consumption on an oscillator,
compared to less than 25% on the LED's.

In the pursuit of excellence in this design, I would like to cut the current
consumption of the oscillator section. Does anyone know of a better
arrangement that will cut current consumption? Increasing the series
resistor wasn't the solution. I put a 100K variable in here in place of the
original 2K2. Initially as the resistor was increased the current
consumption fell, but at higher resistances the current consumption
increased quite dramatically. The optimum was at close to 4K7.

73 Hans G0UPL
http://www.HansSummers.com




On the other hand, you can always console yourself with the fact that
60% of your power budget is going toward making the thing accurate...

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com
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Old June 21st 04, 05:25 PM
Hans Summers
 
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Default


"Bill Janssen" wrote in message
...
Hans Summers wrote:

[snip]



Not familiar with the chips you are using but you should use the lowest
frequency oscillator possible.
Maybe try the 32 + KHz crystal


Bill, I am aware that CMOS current consumption is dependant on operating
frequency. However the simplicity of the design demands a clock frequency
which is a power-of-two multiple of 1KHz. Otherwise the counting range would
have to be other than 0 to 99.5KHz. This counting range is perfect for
amateur bands, the offset off the band edge or next multiples of 100KHz.

In any case the counting frequency of the 74HC4040 in my tests was very
similar to the 74HC4060 timebase since I was using an 80m VFO. But the
current consumption of the 74HC4040 was negligble. Therefore there must be
something about the oscillator configuration which is causing the high
current consumption.

That's why I'm wondering if there are other, more power-efficient ways of
making an oscillator. Bear in mind that a 32768Hz watch crystal is only 125
times slower than my 4096KHz crystal. Assuming proportionality that's about
25uA. Isn't this rather large for a watch? What sort of capacity are we
looking at in a watch battery... 25mAh or less? In this case a watch battery
would only last 6 weeks, and that's just powering the oscillator on its own
not even worrying about the watch hands.

73 Hans G0UPL
http://www.HansSummers.com


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Old June 21st 04, 05:31 PM
Reg Edwards
 
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The problems of how to get rid of relatively minute quantities of mildly
radioactive waste materials have been exaggerated by the oil conglomerates
and the other multi-national companies in the control of world governments.
They do it for obvious reasons via the international media which they also
own and control. Whoever owns and controls the Internet will ruthlessly
rule the Earth. Only the Chinese can prevent it.
----
Reg.

======================================

"Paul Burridge" wrote -

Absolutely right, Reg. Even good old fission if necessary. Yeah, it's
dirty but so what? Outer space has a limitless capacity for our
radioactive garbage. Instead of encasing it in concrete and burying
it, we should be just firing away in rockets. Way to go!



  #9   Report Post  
Old June 21st 04, 05:34 PM
Hans Summers
 
Posts: n/a
Default


Sooner or later the World MUST concentrate on atomic energy. The sensible
French already have 90% of their energy requirements provided by atomic
power stations. The remainder by hydro-electric and tidal power. The
Japanese, having no natural biological energy resources, are also quietly
well on their way. Iranians, oil producers themselves, are busy building
there own atomic power stations in anticipation of a World oil shortage,

but
their efforts are sabotaged by multi-national legal and political warfare
about who gets the development, investment and construction contracts.


What about renewable sources providing all of it, and sensibly conserving
energy with energy efficient appliances, homes, transport etc so that less
of it is required in the first place? Nuclear fission of current fuels
(Uranium) is in any case only a postponement of the problem since eventually
Uranium supplies will be burnt up just the same as fossil fuels.

The real costs of the nuclear alternatives have never been properly
considered, since nuclear programs have always been subsidised by
governments interested in the defence (or offence) applications of the
technology and byproducts. Once the full lifecycle cost of the power
stations is taken into account they become rather uneconomic in comparison
to other forms of energy such as renewable sources. The latter would have
become much much cheaper long ago had they received the same degree of
subsidised research and development as nuclear.

When the World is mainly on atomic energy, electronic circuit designers

can
feel free to enjoy themselves and exercise their unrestrained

imaginations.

At the moment my imagination concentrates itself on the unimaginably tiny
and simple frequency counter with tiny current consumption. Forget nuclear,
this thing could even run off solar power recharged batteries ;-)

So please, indulge my fancy for an even lower current frequency counter
containing just 2 IC's,, and tell me if there's a way!

73 Hans G0UPL
http://www.HansSummers.com


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Old June 21st 04, 05:35 PM
Hans Summers
 
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Default


"Reg Edwards" wrote in message
...

The problems of how to get rid of relatively minute quantities of mildly
radioactive waste materials have been exaggerated by the oil conglomerates
and the other multi-national companies in the control of world

governments.
They do it for obvious reasons via the international media which they also
own and control. Whoever owns and controls the Internet will ruthlessly
rule the Earth. Only the Chinese can prevent it.


To get rid of even a relatively minute quantity of radioactive material into
space requires the expenditure of rather huge amounts of fuels. Fossil fuels
that is. Ooops


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