[EE} Am I carrying KISS too far?

[David C Brown]

Power supply for a circuit with a handful of CD400 chips.

12vdc from wall-wort charges a 9volt NiMH through a series resistor. CMOS
runs of battery.
Just the two components. What have I overlooked?

__________________________________________
David C Brown
43 Bings Road
Whaley Bridge
High Peak Phone: [phone]
Derbyshire eMail: ***@gmail.com
SK23 7ND web: www.bings-knowle.co.uk/dcb
<http://www.jb.man.ac.uk/~dcb>



*Sent from my etch-a-sketch*

[David Van Horn]

Long term damage to the NIMH cell.
Possible issues with logic level shift as battery voltage changes.
What if the battery is disconnected?
Ripple?


-----Original Message-----
From: piclist-***@mit.edu <piclist-***@mit.edu> On Behalf Of David C Brown
Sent: Tuesday, October 30, 2018 8:49 AM
To: Microcontroller discussion list - Public. <***@mit.edu>
Subject: [EE} Am I carrying KISS too far?

Power supply for a circuit with a handful of CD400 chips.

12vdc from wall-wort charges a 9volt NiMH through a series resistor. CMOS runs of battery.
Just the two components. What have I overlooked?

__________________________________________
David C Brown
43 Bings Road
Whaley Bridge
High Peak Phone: [phone]
Derbyshire eMail: ***@gmail.com
SK23 7ND web: www.bings-knowle.co.uk/dcb
<http://www.jb.man.ac.uk/~dcb>



*Sent from my etch-a-sketch*
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[Steve Smith]

You need two resistors one is in series with the led (across the charging
resistor) to indicate its working...!

S

-----Original Message-----
From: piclist-***@mit.edu <piclist-***@mit.edu> On Behalf Of David C
Brown
Sent: 30 October 2018 14:49
To: Microcontroller discussion list - Public. <***@mit.edu>
Subject: [EE} Am I carrying KISS too far?

Power supply for a circuit with a handful of CD400 chips.

12vdc from wall-wort charges a 9volt NiMH through a series resistor. CMOS
runs of battery.
Just the two components. What have I overlooked?

__________________________________________
David C Brown
43 Bings Road
Whaley Bridge
High Peak Phone: [phone]
Derbyshire eMail: ***@gmail.com
SK23 7ND web: www.bings-knowle.co.uk/dcb
<http://www.jb.man.ac.uk/~dcb>



*Sent from my etch-a-sketch*
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[Art]

I like the etch-a-sketch David!! The new models must have wifi-what will
they think of next??!!

Seriously though...I think you still need to decouple each cmos chip
with a .1uF as close to the Vcc and Ground terminals as possible.

Happy soldering.

Art

Post by David C Brown
Power supply for a circuit with a handful of CD400 chips.
12vdc from wall-wort charges a 9volt NiMH through a series resistor. CMOS
runs of battery.
Just the two components. What have I overlooked?
__________________________________________
David C Brown
43 Bings Road
Whaley Bridge
High Peak Phone: [phone]
SK23 7ND web: www.bings-knowle.co.uk/dcb
<http://www.jb.man.ac.uk/~dcb>
*Sent from my etch-a-sketch*

[Forrest Christian (List Account)]

The fact that NiMH doesn't like to be float/trickle charged, perhaps?

Post by David C Brown
Power supply for a circuit with a handful of CD400 chips.
12vdc from wall-wort charges a 9volt NiMH through a series resistor. CMOS
runs of battery.
Just the two components. What have I overlooked?
__________________________________________
David C Brown
43 Bings Road
Whaley Bridge
High Peak Phone: [phone]
SK23 7ND web: www.bings-knowle.co.uk/dcb
<http://www.jb.man.ac.uk/~dcb>
*Sent from my etch-a-sketch*
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Tel: [phone] | Address: 3577 Countryside Road, Helena, MT 59602
***@imach.com | http://www.packetflux.com
<http://www.linkedin.com/in/fwchristian> <http://facebook.com/packetflux>
<http://twitter.com/@packetflux>

[AB Pearce - UKRI STFC]

Several things, apart from (as already noted) NiMH don't like float charge.

You don't have any cut out mechanism when the battery reaches full charge.
You don't have any temperature monitoring of the battery - rolls into the previous point.

Check out the Linear technology devices at Analog Devices.
The LTC4060 does NiMH up to 4 cells, which won't be enough, and you would need to limit the input voltage as it doesn't go to 12V input.

The LTC4079 looks like it will be right up your street though, 4 resistors, 1 capacitor and 1 thermistor, 2.7V to 60V input range, 1.2V to 60V output range, 10mA to 250mA charge current.
https://www.analog.com/media/en/technical-documentation/data-sheets/4079f.pdf
Biggest hassle is it is in a DFN package.

Then in the switching battery chargers there are LT1512, LT1513 and LT1513-2 that would look hopeful. These use more components though.





-----Original Message-----
From: piclist-***@mit.edu <piclist-***@mit.edu> On Behalf Of David C Brown
Sent: 30 October 2018 14:49
To: Microcontroller discussion list - Public. <***@mit.edu>
Subject: [EE} Am I carrying KISS too far?

Power supply for a circuit with a handful of CD400 chips.

12vdc from wall-wort charges a 9volt NiMH through a series resistor. CMOS runs of battery.
Just the two components. What have I overlooked?

__________________________________________
David C Brown
43 Bings Road
Whaley Bridge
High Peak Phone: [phone]
Derbyshire eMail: ***@gmail.com
SK23 7ND web: www.bings-knowle.co.uk/dcb
<http://www.jb.man.ac.uk/~dcb>



*Sent from my etch-a-sketch*
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[David C Brown]

Thank y'all for your comments

First to Art: My etch-a-sketch has been customised by a man in the back of
Glossop market. It has 802.11.ac wi-fi,, 4G connectivity and satellite
connectivity. It is powered by a small water turbine so can be used
anywhere a faucet is available. One bug, that answers Dave's comment, is
that it cannot sustain runs zeros longer than two. For that reason I have
had to negotiate a cut in pay of a penny to avoid a run of six zeros in my
salary advice. :-)

Seriously. I should have specified a NiCad battery since this is part of
my retro 1978 clock and NiMH were not around back them. And it is my
recollection that NiCads can be safely trickled at C/20 albeit with some
degradation.

And on further reflection it might be simpler to use a non rechargeable
battery. A good PP9 will supply about 400mAH which will cover a lot of
short outages.
__________________________________________
David C Brown
43 Bings Road
Whaley Bridge
High Peak Phone: [phone]
Derbyshire eMail: ***@gmail.com
SK23 7ND web: www.bings-knowle.co.uk/dcb
<http://www.jb.man.ac.uk/~dcb>



*Sent from my etch-a-sketch*


On Tue, 30 Oct 2018 at 16:52, AB Pearce - UKRI STFC <

Post by AB Pearce - UKRI STFC
Several things, apart from (as already noted) NiMH don't like float charge.
You don't have any cut out mechanism when the battery reaches full charge.
You don't have any temperature monitoring of the battery - rolls into the previous point.
Check out the Linear technology devices at Analog Devices.
The LTC4060 does NiMH up to 4 cells, which won't be enough, and you would
need to limit the input voltage as it doesn't go to 12V input.
The LTC4079 looks like it will be right up your street though, 4
resistors, 1 capacitor and 1 thermistor, 2.7V to 60V input range, 1.2V to
60V output range, 10mA to 250mA charge current.
https://www.analog.com/media/en/technical-documentation/data-sheets/4079f.pdf
Biggest hassle is it is in a DFN package.
Then in the switching battery chargers there are LT1512, LT1513 and
LT1513-2 that would look hopeful. These use more components though.
-----Original Message-----
Sent: 30 October 2018 14:49
Subject: [EE} Am I carrying KISS too far?
Power supply for a circuit with a handful of CD400 chips.
12vdc from wall-wort charges a 9volt NiMH through a series resistor. CMOS runs of battery.
Just the two components. What have I overlooked?
__________________________________________
David C Brown
43 Bings Road
Whaley Bridge
High Peak Phone: [phone]
SK23 7ND web: www.bings-knowle.co.uk/dcb
<http://www.jb.man.ac.uk/~dcb>
*Sent from my etch-a-sketch*
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View/change your membership options at
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[David Van Horn]

Some NIMH will "Tolerate" low current overcharge. This requires more catalyst to recombine the hydrogen and oxygen, and these cells usually aren't the highest capacity. Most NIMH cells specify ZERO float current.

Nicad is better in this regard, as well as working over a wider temperature range.

-----Original Message-----
From: piclist-***@mit.edu <piclist-***@mit.edu> On Behalf Of David C Brown
Sent: Tuesday, October 30, 2018 12:00 PM
To: Microcontroller discussion list - Public. <***@mit.edu>
Subject: Re: [EE} Am I carrying KISS too far?

Thank y'all for your comments

First to Art: My etch-a-sketch has been customised by a man in the back of Glossop market. It has 802.11.ac wi-fi,, 4G connectivity and satellite
connectivity. It is powered by a small water turbine so can be used
anywhere a faucet is available. One bug, that answers Dave's comment, is
that it cannot sustain runs zeros longer than two. For that reason I have had to negotiate a cut in pay of a penny to avoid a run of six zeros in my salary advice. :-)

Seriously. I should have specified a NiCad battery since this is part of
my retro 1978 clock and NiMH were not around back them. And it is my
recollection that NiCads can be safely trickled at C/20 albeit with some degradation.

And on further reflection it might be simpler to use a non rechargeable battery. A good PP9 will supply about 400mAH which will cover a lot of short outages.
__________________________________________
David C Brown
43 Bings Road
Whaley Bridge
High Peak Phone: [phone]
Derbyshire eMail: ***@gmail.com
SK23 7ND web: www.bings-knowle.co.uk/dcb
<http://www.jb.man.ac.uk/~dcb>



*Sent from my etch-a-sketch*

Post by AB Pearce - UKRI STFC
Several things, apart from (as already noted) NiMH don't like float charge.
You don't have any cut out mechanism when the battery reaches full charge.
You don't have any temperature monitoring of the battery - rolls into the previous point.
Check out the Linear technology devices at Analog Devices.
The LTC4060 does NiMH up to 4 cells, which won't be enough, and you
would need to limit the input voltage as it doesn't go to 12V input.
The LTC4079 looks like it will be right up your street though, 4
resistors, 1 capacitor and 1 thermistor, 2.7V to 60V input range, 1.2V
to 60V output range, 10mA to 250mA charge current.
https://www.analog.com/media/en/technical-documentation/data-sheets/40
79f.pdf Biggest hassle is it is in a DFN package.
Then in the switching battery chargers there are LT1512, LT1513 and
LT1513-2 that would look hopeful. These use more components though.
-----Original Message-----
Sent: 30 October 2018 14:49
Subject: [EE} Am I carrying KISS too far?
Power supply for a circuit with a handful of CD400 chips.
12vdc from wall-wort charges a 9volt NiMH through a series resistor.
CMOS runs of battery.
Just the two components. What have I overlooked?
__________________________________________
David C Brown
43 Bings Road
Whaley Bridge
High Peak Phone: [phone]
SK23 7ND web: www.bings-knowle.co.uk/dcb
<http://www.jb.man.ac.uk/~dcb>
*Sent from my etch-a-sketch*
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[RussellMc]

On Wed, 31 Oct 2018 at 08:05, David Van Horn <

Post by David Van Horn
Some NIMH will "Tolerate" low current overcharge. This requires more
catalyst to recombine the hydrogen and oxygen, and these cells usually
aren't the highest capacity. Most NIMH cells specify ZERO float current.
Nicad is better in this regard, as well as working over a wider temperature range.
NimH can (could) be trickled at up to about 1600 mAh in AA size. Above

that the recombination material is removed and by about 2000 mAh the
ability to trickle is usually ~~~= zero.

NimH can be clamped at 1.45V usually and 1.4V is safer at <= C/10 charge
rate and be "safe enough" in not too extreme temperatures in most cases
[tm].
(ie the clamp absorbs the current when 1.45V is reached.
Higher charge rates increase the likelihood that the cell will run through
the voltage limit and accept charge indefinitely.
I specify that voltage based on my tests some years ago with as many brands
of rechargeable NimH AA cells as I could obtain and tests from 'room
temperature' to about 50 C.
Capacity is < 100% possible but good enough to be worth the simplicity.


Russell

[Harold Hallikainen]

Post by David C Brown
And on further reflection it might be simpler to use a non rechargeable
battery. A good PP9 will supply about 400mAH which will cover a lot of
short outages.

If you don't power the display, will a supercap hold you over during outages?

Harold

[David C Brown]

I don't think that super caps meet my retro criterion. Components that
were avaialable in 1978
__________________________________________
David C Brown
43 Bings Road
Whaley Bridge
High Peak Phone: [phone]
Derbyshire eMail: ***@gmail.com
SK23 7ND web: www.bings-knowle.co.uk/dcb
<http://www.jb.man.ac.uk/~dcb>



*Sent from my etch-a-sketch*

Post by Harold Hallikainen

Post by David C Brown
And on further reflection it might be simpler to use a non rechargeable
battery. A good PP9 will supply about 400mAH which will cover a lot of
short outages.

If you don't power the display, will a supercap hold you over during outages?
Harold
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[John Gardner]

How about a RTG? (Radioisotope Thermal Generator).

They were around in 1978... "8)

...

Post by David C Brown
I don't think that super caps meet my retro criterion. Components that
were avaialable in 1978
__________________________________________
David C Brown
43 Bings Road
Whaley Bridge
High Peak Phone: [phone]
SK23 7ND web: www.bings-knowle.co.uk/dcb
<http://www.jb.man.ac.uk/~dcb>
*Sent from my etch-a-sketch*
On Tue, 30 Oct 2018 at 19:07, Harold Hallikainen

Post by Harold Hallikainen

Post by David C Brown
And on further reflection it might be simpler to use a non rechargeable
battery. A good PP9 will supply about 400mAH which will cover a lot of
short outages.

If you don't power the display, will a supercap hold you over during outages?
Harold
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[David C Brown]

Or a small windmill or water-wheel?
They were around in 1078 :-)
__________________________________________
David C Brown
43 Bings Road
Whaley Bridge
High Peak Phone: [phone]
Derbyshire eMail: ***@gmail.com
SK23 7ND web: www.bings-knowle.co.uk/dcb
<http://www.jb.man.ac.uk/~dcb>



*Sent from my etch-a-sketch*

Post by John Gardner
How about a RTG? (Radioisotope Thermal Generator).
They were around in 1978... "8)
...

Post by David C Brown
I don't think that super caps meet my retro criterion. Components that
were avaialable in 1978
__________________________________________
David C Brown
43 Bings Road
Whaley Bridge
High Peak Phone: [phone]
SK23 7ND web: www.bings-knowle.co.uk/dcb
<http://www.jb.man.ac.uk/~dcb>
*Sent from my etch-a-sketch*
On Tue, 30 Oct 2018 at 19:07, Harold Hallikainen

Post by Harold Hallikainen

Post by David C Brown
And on further reflection it might be simpler to use a non

rechargeable

Post by David C Brown

Post by Harold Hallikainen

Post by David C Brown
battery. A good PP9 will supply about 400mAH which will cover a lot

of

Post by David C Brown

Post by Harold Hallikainen

Post by David C Brown
short outages.

If you don't power the display, will a supercap hold you over during outages?
Harold
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