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Current regulator

N

nescafe

Jan 1, 1970
0
Hi.
I need to create some kind of charger.
The "charger" will be powered from dc source ( 1,5 AA battery ).

The voltage should stay the same but the current should be regulated
like this:
- charge time: 1 day --> 1,5 / 50mA
- charge time: 2 hours --> 1,5 / 100mA
- charge time: 4 hours --> 1,5 / 200mA
- charge time: 4 hours --> 1,5 / 500mA
- charge time: 7 hours --> 1,5 / 1A
--------------------------------------------
For now i will switch the charge with some micro switch but in future
this should be done with ne555 timer.
Is there any schematics how to make this pcb ?

One input, with multiple regulated current outputs, controlled per micro
switch.

Thnx in advance
 
N

nescafe

Jan 1, 1970
0
You would need to use the CMOS version of the 555 timer to operate at
that low of voltage.

Using a buck boost switch you can generate higher voltages at lower
currents, great for charging I guess.

Unless I miss understood your posting, I assume you're using a single
cell as your DC source ? Or do you mean you want to charge a single cell
from some other DC source?

Jamie ---------------------------
Yes , i did not describe it well...
I want to charge one homemade cell with AA battery.
 
R

Roberto Waltman

Jan 1, 1970
0
The "charger" will be powered from dc source ( 1,5 AA battery ).

The voltage should stay the same but the current should be regulated
like this:
- charge time: 1 day --> 1,5 / 50mA
- charge time: 2 hours --> 1,5 / 100mA
- charge time: 4 hours --> 1,5 / 200mA
- charge time: 4 hours --> 1,5 / 500mA
- charge time: 7 hours --> 1,5 / 1A

Assuming the load is a battery, that is, something whose internal
chemistry you have no control over, you can control the voltage, or
the current, but not both.
(I think the guy's name was Georg Ohm)
 
J

Jamie

Jan 1, 1970
0
nescafe said:
Hi.
I need to create some kind of charger.
The "charger" will be powered from dc source ( 1,5 AA battery ).

The voltage should stay the same but the current should be regulated
like this:
- charge time: 1 day --> 1,5 / 50mA
- charge time: 2 hours --> 1,5 / 100mA
- charge time: 4 hours --> 1,5 / 200mA
- charge time: 4 hours --> 1,5 / 500mA
- charge time: 7 hours --> 1,5 / 1A
--------------------------------------------
For now i will switch the charge with some micro switch but in future
this should be done with ne555 timer.
Is there any schematics how to make this pcb ?

One input, with multiple regulated current outputs, controlled per micro
switch.

Thnx in advance
You would need to use the CMOS version of the 555 timer to operate at
that low of voltage.

Using a buck boost switch you can generate higher voltages at lower
currents, great for charging I guess.

Unless I miss understood your posting, I assume you're using a single
cell as your DC source ? Or do you mean you want to charge a single cell
from some other DC source?

Jamie
 
J

Jamie

Jan 1, 1970
0
nescafe said:
You would need to use the CMOS version of the 555 timer to operate at
that low of voltage.

Using a buck boost switch you can generate higher voltages at lower
currents, great for charging I guess.

Unless I miss understood your posting, I assume you're using a single
cell as your DC source ? Or do you mean you want to charge a single cell
from some other DC source?

Jamie
How many of these AA cells were you planing on using? Depending on the
chemistry, lets say a basic carbon type is ~ 900 mAH, that is, you can
expect 900 m-amps to be supplied up to an hour. AFter that, it's all
down hill until dead! ALso, the batter voltage is going to drop so you
most likely will lose it before that as your loaded device will fail,
due to lack of proper operating voltage. SO you can scale that back
according to the voltage drop, too.

So looking at your figures above, I can't see how you plan on getting
7 hours at 1 amp for example?

Jamie
 
P

Phil Allison

Jan 1, 1970
0
"nescafe"
I need to create some kind of charger.
The "charger" will be powered from dc source ( 1,5 AA battery ).


** Better use two ( in series) - cos using just one is never gonna work.

The voltage of a 1.5V cell drops steadily during discharge.



.... Phil
 
N

nescafe

Jan 1, 1970
0
One homemade cell can be charged up to 1A (max) and standard voltage is
around 0.75
But to get to this 1A i have to charge the cell on the way i described
before.
 
J

Jasen Betts

Jan 1, 1970
0
Hi.
I need to create some kind of charger.
The "charger" will be powered from dc source ( 1,5 AA battery ).

The voltage should stay the same but the current should be regulated
like this:
- charge time: 1 day --> 1,5 / 50mA
- charge time: 2 hours --> 1,5 / 100mA
- charge time: 4 hours --> 1,5 / 200mA
- charge time: 4 hours --> 1,5 / 500mA
- charge time: 7 hours --> 1,5 / 1A
--------------------------------------------
For now i will switch the charge with some micro switch but in future
this should be done with ne555 timer.
Is there any schematics how to make this pcb ?

One input, with multiple regulated current outputs, controlled per micro
switch.

555 is too fast. try CD4060
you won't get 7 hours at 1A from an AA
 
J

Jamie

Jan 1, 1970
0
nescafe said:
One homemade cell can be charged up to 1A (max) and standard voltage is
around 0.75
But to get to this 1A i have to charge the cell on the way i described
before.
----------------------------------
Maybe there is one other solution to make this.
I can connect 15 cells in series and charge it with 12/7Ah battery or
car battery.
I think that this is far better option.

+---------------+-----++
| 2N3904 | |
12 Volt in | ___ |/ |
+-+-------+-+|___|--+--+| |
+ | |> +
- 4.7K | + |/ 2N3055
--- | +--+-|
| | |> 0.25 Ohm
+--------++ | ___ Cell Load
GND | | +---+--+-|___|-+-------+
+ | | | |
V | | .-. |
- + U1 | | |<--+--+
| | 470k /|| | | 10k POT
1N914 Types V \| ___ /+|+ '-' Current Limit
- 2N3904|--|___|--< | |
| <| \-|+---------+|
V | \| .-.
- + LM741 | |
| | Or like it | | 220k
| | '-'
=== === |
GND GND ===
GND


U1 Vee (-) = GND
U1 VCC(+)= 12V
(created by AACircuit v1.28.6 beta 04/19/05 www.tech-chat.de)

That is a voltage limited adjustable current 0..1 amp.
The Max output voltage should be around 1 volt.

As for the timer, in your case, why not use one of those wind up
mechanical timers that has a switch on it? You can get them to extend
to a lot of hours. You find them on car battery chargers etc..

I tried to do that all with transistors, but it was getting messy..
Too many parts. So I through in the OP-AMP as the current sense.

Jamie
 
J

Jamie

Jan 1, 1970
0
John said:
One homemade cell can be charged up to 1A (max) and standard voltage is
around 0.75
But to get to this 1A i have to charge the cell on the way i described
before.
----------------------------------
Maybe there is one other solution to make this.
I can connect 15 cells in series and charge it with 12/7Ah battery or
car battery.
I think that this is far better option.


---
You could use a buck regulator.

http://www.onsemi.com/pub_link/Collateral/NCP3065.PDF


View using a fixed-pitch font:

. +-------------+
. | +---------+ |
.+12--+-[Rs]-+-|IpK SWC|-+ S1 A
. | | SWE|-------+-[L]-+->>-[+AA]-<<-+-O-->O-[R1]-+
. +--------|Vin | | | | C B |
. | | CT|-+-[R]-+ | | O-[R2]-+
. |+ | | | | | | C |
. [Cin] | | | | | | O-[R3]-+
. | +-|GND COMP|-|-----|-----|------------ + D |
. | | +---------+ | | | O-[R4]-+
. | | NCP1365 [Ct] |K [Cout] E |
. | | | [D] | O-[R5]-+
. | | | | | |
.GND>-+------+-------------+-----+-----+--------------------------+

S1 is a single pole 5 throw break-before-make switch used to switch
between the various charging currents you want, and if 5% tolerances
in charging currents are acceptable, then the values of the resistors
will be:

LABEL CURRENT RESISTANCE
Ma OHMS
-----------------------------
R1 50 4.7
R2 100 2.4
R3 200 1.2
R4 500 0.47
R5 1000 0.24
Where is the voltage limiting control? That is needed since he is
only looking for charge around 0.75 volts, unless he made some mistake
or I did?

I don't know exactly what he is doing , but as cell charge
comes up the current usually drops back, in this circuit here, the
voltage is just going to raise and raise.

The one I showed only goes up to ~ 1.0 Volt.

Did I missed something ?

Jamie
 
N

nescafe

Jan 1, 1970
0
You could use a buck regulator.

http://www.onsemi.com/pub_link/Collateral/NCP3065.PDF


View using a fixed-pitch font:

. +-------------+
. | +---------+ |
.+12--+-[Rs]-+-|IpK SWC|-+ S1 A
. | | SWE|-------+-[L]-+->>-[+AA]-<<-+-O-->O-[R1]-+
. +--------|Vin | | | | C B |
. | | CT|-+-[R]-+ | | O-[R2]-+
. |+ | | | | | | C |
. [Cin] | | | | | | O-[R3]-+
. | +-|GND COMP|-|-----|-----|------------ + D |
. | | +---------+ | | | O-[R4]-+
. | | NCP1365 [Ct] |K [Cout] E |
. | | | [D] | O-[R5]-+
. | | | | | |
.GND>-+------+-------------+-----+-----+--------------------------+

S1 is a single pole 5 throw break-before-make switch used to switch
between the various charging currents you want, and if 5% tolerances
in charging currents are acceptable, then the values of the resistors
will be:

LABEL CURRENT RESISTANCE
Ma OHMS
-----------------------------
R1 50 4.7
R2 100 2.4
R3 200 1.2
R4 500 0.47
R5 1000 0.24
 
J

Jamie

Jan 1, 1970
0
John said:
John Fields wrote:

One homemade cell can be charged up to 1A (max) and standard voltage is
around 0.75
But to get to this 1A i have to charge the cell on the way i described
before.
----------------------------------
Maybe there is one other solution to make this.
I can connect 15 cells in series and charge it with 12/7Ah battery or
car battery.
I think that this is far better option.
-----------------------------------
OK. How to make this charge process with some 12/7ah or stronger battery ?
Any link to some schematics ?


---
You could use a buck regulator.

http://www.onsemi.com/pub_link/Collateral/NCP3065.PDF


View using a fixed-pitch font:

. +-------------+
. | +---------+ |
.+12--+-[Rs]-+-|IpK SWC|-+ S1 A
. | | SWE|-------+-[L]-+->>-[+AA]-<<-+-O-->O-[R1]-+
. +--------|Vin | | | | C B |
. | | CT|-+-[R]-+ | | O-[R2]-+
. |+ | | | | | | C |
. [Cin] | | | | | | O-[R3]-+
. | +-|GND COMP|-|-----|-----|------------ + D |
. | | +---------+ | | | O-[R4]-+
. | | NCP1365 [Ct] |K [Cout] E |
. | | | [D] | O-[R5]-+
. | | | | | |
.GND>-+------+-------------+-----+-----+--------------------------+

S1 is a single pole 5 throw break-before-make switch used to switch
between the various charging currents you want, and if 5% tolerances
in charging currents are acceptable, then the values of the resistors
will be:

LABEL CURRENT RESISTANCE
Ma OHMS
-----------------------------
R1 50 4.7
R2 100 2.4
R3 200 1.2
R4 500 0.47
R5 1000 0.24

Where is the voltage limiting control? That is needed since he is
only looking for charge around 0.75 volts, unless he made some mistake
or I did?


---
You did, since you assumed that the terminal voltage of the load was
relevant.

The OP stated that his goal was to push a fixed current through a load
for a specific amount of time, which makes the terminal voltage of the
load unimportant except in the context of the compliance of the
source.
---

I don't know exactly what he is doing , but as cell charge
comes up the current usually drops back, in this circuit here, the
voltage is just going to raise and raise.


---
As it should, but it'll be limited to whatever current causes the drop
across the current sensing resistor to be 0.235V.
---

The one I showed only goes up to ~ 1.0 Volt.

Did I missed something ?


---
Yes.

BTW, "+AA" on the schematic should read: "DUC" (Device/s Under Charge)
and there should have been a note to the effect that the DUC could be
a series string of as many of his cells of the same capacity as the
compliance of the source could handle.
that's fine, I'll stick with limiting the voltage.

As a cell increases with voltage, the current drops back. if you are
attempting to maintain current, the voltage will just keep raising until
at some point, the cell could get damaged. A little over is fine, which
is needed, but really, using 12 volt source to charge a .75 volt cell?

Oh, so much for that. I hope you don't get into the charging business.


Jamie
 
J

Jamie

Jan 1, 1970
0
nescafe said:
You could use a buck regulator.

http://www.onsemi.com/pub_link/Collateral/NCP3065.PDF


View using a fixed-pitch font:

. +-------------+
. | +---------+ |
.+12--+-[Rs]-+-|IpK SWC|-+ S1 A
. | | SWE|-------+-[L]-+->>-[+AA]-<<-+-O-->O-[R1]-+
. +--------|Vin | | | | C B |
. | | CT|-+-[R]-+ | | O-[R2]-+
. |+ | | | | | | C |
. [Cin] | | | | | | O-[R3]-+
. | +-|GND COMP|-|-----|-----|------------ + D |
. | | +---------+ | | | O-[R4]-+
. | | NCP1365 [Ct] |K [Cout] E |
. | | | [D] | O-[R5]-+
. | | | | | |
.GND>-+------+-------------+-----+-----+--------------------------+

S1 is a single pole 5 throw break-before-make switch used to switch
between the various charging currents you want, and if 5% tolerances
in charging currents are acceptable, then the values of the resistors
will be:
LABEL CURRENT RESISTANCE
Ma OHMS
-----------------------------
R1 50 4.7
R2 100 2.4
R3 200 1.2
R4 500 0.47
R5 1000 0.24

----
Thank you guys !.
This is exactly what i need.

Regards !
Good luck. Wouldn't of been my choice.

Jamie
 
J

Jamie

Jan 1, 1970
0
John said:
nescafe wrote:

On 16.09.12 23:24, John Fields wrote:


You could use a buck regulator.

http://www.onsemi.com/pub_link/Collateral/NCP3065.PDF


View using a fixed-pitch font:

. +-------------+
. | +---------+ |
.+12--+-[Rs]-+-|IpK SWC|-+ S1 A
. | | SWE|-------+-[L]-+->>-[+AA]-<<-+-O-->O-[R1]-+
. +--------|Vin | | | | C B |
. | | CT|-+-[R]-+ | | O-[R2]-+
. |+ | | | | | | C |
. [Cin] | | | | | | O-[R3]-+
. | +-|GND COMP|-|-----|-----|------------ + D |
. | | +---------+ | | | O-[R4]-+
. | | NCP1365 [Ct] |K [Cout] E |
. | | | [D] | O-[R5]-+
. | | | | | |
.GND>-+------+-------------+-----+-----+--------------------------+

S1 is a single pole 5 throw break-before-make switch used to switch
between the various charging currents you want, and if 5% tolerances
in charging currents are acceptable, then the values of the resistors
will be:
LABEL CURRENT RESISTANCE
Ma OHMS
-----------------------------
R1 50 4.7
R2 100 2.4
R3 200 1.2
R4 500 0.47
R5 1000 0.24

----
Thank you guys !.
This is exactly what i need.

Regards !

Good luck. Wouldn't of been my choice.

Jamie
Nope, absolutely not. I wouldn't use your circuit for a charger of such
nature.. I was only trying to be nice to the originator asking for a
sensible circuit that would fit properly and safely, for their needs.

I think you flatter yourself a little too much, you really should
think of others and instead of passing on what you would like to ignore.

We have charging stations at work and none and I mean none of the
chargers are allowed to exceed 10% of the battery voltage, regardless of
condition. You on the other hand, would think it's ok to boil the
battery off, even after its has reached the peak voltage.

Personally, I don't care what you do with your own cells, you can do
what ever and take a chance of generating undesirable effects if you
wish. It's your choice, but to give others advise with out taking that
into consideration, thinking that maybe they don't care any more than
you do is pure foolishness.

BTW, that circuit you posted can be modified very simply to add
limiting voltage function, but since you're so self centered I'll allow
you the honor or making a mess out of it.

Jamie
 
J

Jamie

Jan 1, 1970
0
John said:
John Fields wrote:

On Mon, 17 Sep 2012 17:55:45 -0400, Jamie



nescafe wrote:



On 16.09.12 23:24, John Fields wrote:



You could use a buck regulator.

http://www.onsemi.com/pub_link/Collateral/NCP3065.PDF


View using a fixed-pitch font:

. +-------------+
. | +---------+ |
.+12--+-[Rs]-+-|IpK SWC|-+ S1 A
. | | SWE|-------+-[L]-+->>-[+AA]-<<-+-O-->O-[R1]-+
. +--------|Vin | | | | C B |
. | | CT|-+-[R]-+ | | O-[R2]-+
. |+ | | | | | | C |
. [Cin] | | | | | | O-[R3]-+
. | +-|GND COMP|-|-----|-----|------------ + D |
. | | +---------+ | | | O-[R4]-+
. | | NCP1365 [Ct] |K [Cout] E |
. | | | [D] | O-[R5]-+
. | | | | | |
.GND>-+------+-------------+-----+-----+--------------------------+

S1 is a single pole 5 throw break-before-make switch used to switch
between the various charging currents you want, and if 5% tolerances
in charging currents are acceptable, then the values of the resistors
will be:
LABEL CURRENT RESISTANCE
Ma OHMS
-----------------------------
R1 50 4.7
R2 100 2.4
R3 200 1.2
R4 500 0.47
R5 1000 0.24

----
Thank you guys !.
This is exactly what i need.

Regards !

Good luck. Wouldn't of been my choice.

Jamie

Nope, absolutely not. I wouldn't use your circuit for a charger of such
nature.. I was only trying to be nice to the originator asking for a
sensible circuit that would fit properly and safely, for their needs.

I think you flatter yourself a little too much, you really should
think of others and instead of passing on what you would like to ignore.

We have charging stations at work and none and I mean none of the
chargers are allowed to exceed 10% of the battery voltage, regardless of
condition. You on the other hand, would think it's ok to boil the
battery off, even after its has reached the peak voltage.

Personally, I don't care what you do with your own cells, you can do
what ever and take a chance of generating undesirable effects if you
wish. It's your choice, but to give others advise with out taking that
into consideration, thinking that maybe they don't care any more than
you do is pure foolishness.

BTW, that circuit you posted can be modified very simply to add
limiting voltage function, but since you're so self centered I'll allow
you the honor or making a mess out of it.

Jamie
You failed ! Grossly,... And don't drag Jim in on your failures, he's
getting old and can't help what he does..

Jamie
 
J

Jamie

Jan 1, 1970
0
John said:
---
KA1LPA means you're registered with the government as an amateur,
right?

My story's a little different:
I never asked for your story nore do I care to hear it.

As for me being a registered radio operator, I have no idea what that
has to do with you throwing a tantrum.

The radio part is just a hobby to take me away from my regular duties.

I can't help it if you get all teary eyed when some one calls
you out on the advise you give out.

You better get used to people pointing out your design failures. It
happens to the best of them, even though at times don't want to
fess up to it.


Jamie
 
J

Jamie

Jan 1, 1970
0
Jim said:
KA1LPA == Registered boot licker, and thumb sucker.

...Jim Thompson
Such a miss informed performer, what do you do for encores?

Jamie
 
J

Jamie

Jan 1, 1970
0
Jim said:
Maynard has a website?? I didn't know that was allowed in the
Democratic Peoples' Republic of Connecticut.

...Jim Thompson
Yeah, Maynard has a web sight. If you are a window licking drooler with
both eyes going in opposite directions, you can get what ever you want,
sunshine!

Jamie
 
J

Jamie

Jan 1, 1970
0
Jim said:
Yay! Maynard has a web "sight".... BWAHAHAHAHAHAHAHA!

If Massa2shits is the asshole of the nation that must mean that
Connecticut is the butt crack ?:)

...Jim Thompson
It's sad to see what age can do to some. Mental degeneration must
be common among the elderly.

Jamie
 
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