, NTE 956 voltage regulators
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Hi all,
I am trying to control a 5v Mabuchi motor with an NTE956 voltage
regulator(1.5A rating from 1.2V to 37V).
Trouble is I can't tell from the data sheet how to control the output
voltage, e.g. for X volts applied to the adjustment pin what do I get for
output voltage.
Are voltage regulators controlled by voltage or current?
Anyway, the code below cycles the motor RPMs pretty well, I just wish I
could understand these voltage regulators a little better.
The hook up uses the PWM output circuit shown on p294 of manual v1.9
connected to the adjustment pin of the voltage regulator. The output of the
voltage regulator is then connected to the Mabuchi with an IN4001 with the
band toward positive connected across the Mabuchi as well. Also, with the
diode the motor runs faster for some reason.
'1 cycle=approx 1mS of PWM e.g. 100/255 duty=approx 1.96v
'duty 25 = .5, 50 =.98v, 100 = 1.96v, 200 = 3.92v, etc
duty var byte
top:
duty = 0
again:
PWM 0,duty,2000
pause 200
duty = duty + 25
if duty = 250 then top
goto again
Thanks,
Mark
I am trying to control a 5v Mabuchi motor with an NTE956 voltage
regulator(1.5A rating from 1.2V to 37V).
Trouble is I can't tell from the data sheet how to control the output
voltage, e.g. for X volts applied to the adjustment pin what do I get for
output voltage.
Are voltage regulators controlled by voltage or current?
Anyway, the code below cycles the motor RPMs pretty well, I just wish I
could understand these voltage regulators a little better.
The hook up uses the PWM output circuit shown on p294 of manual v1.9
connected to the adjustment pin of the voltage regulator. The output of the
voltage regulator is then connected to the Mabuchi with an IN4001 with the
band toward positive connected across the Mabuchi as well. Also, with the
diode the motor runs faster for some reason.
'1 cycle=approx 1mS of PWM e.g. 100/255 duty=approx 1.96v
'duty 25 = .5, 50 =.98v, 100 = 1.96v, 200 = 3.92v, etc
duty var byte
top:
duty = 0
again:
PWM 0,duty,2000
pause 200
duty = duty + 25
if duty = 250 then top
goto again
Thanks,
Mark
Comments
Hmmm... I don't think a voltage regulator is quite the right approach.
As I understand how a voltage regulator works, the control pin is connected
to the center of a resistive network whose values determine the output
voltage.
To me, it would be simpler to bias a power transistor with the output
described on P. 294 to drive the motor.
The idea is that the transistor is rapidly switched on and off with the
change in the pulse duration providing the speed control. The wider the
pulse or higher the percentage of the 'on state' during the cycle, the
'faster' the motor turns. This process is used regularly in model railroad
power controllers. For an example of the process using a Stamp I (easily
converted for use with a Stamp II), see page 171 of the programming manual.
In this example, the track load is driven by a ULN 2803 which is an array
of darlington drivers. Hmmm. that IC seems familiar.....
Hope this helps!
Jim Cambron
NEH Technologies
Original Message
From: "techno_masai" <plunkettm@e...>
To: <basicstamps@egroups.com>
Sent: Sunday, August 20, 2000 6:03 PM
Subject: [noparse][[/noparse]basicstamps], NTE 956 voltage regulators
> Hi all,
>
> I am trying to control a 5v Mabuchi motor with an NTE956 voltage
> regulator(1.5A rating from 1.2V to 37V).
>
> Trouble is I can't tell from the data sheet how to control the output
> voltage, e.g. for X volts applied to the adjustment pin what do I get for
> output voltage.
>
> Are voltage regulators controlled by voltage or current?
>
> Anyway, the code below cycles the motor RPMs pretty well, I just wish I
> could understand these voltage regulators a little better.
>
> The hook up uses the PWM output circuit shown on p294 of manual v1.9
> connected to the adjustment pin of the voltage regulator. The output of
the
> voltage regulator is then connected to the Mabuchi with an IN4001 with the
> band toward positive connected across the Mabuchi as well. Also, with the
> diode the motor runs faster for some reason.
>
> '1 cycle=approx 1mS of PWM e.g. 100/255 duty=approx 1.96v
> 'duty 25 = .5, 50 =.98v, 100 = 1.96v, 200 = 3.92v, etc
>
> duty var byte
>
> top:
>
> duty = 0
>
> again:
>
> PWM 0,duty,2000
>
> pause 200
>
> duty = duty + 25
>
> if duty = 250 then top
>
> goto again
>
> Thanks,
>
> Mark
>
>
>
>
So it seems like a voltage regulator just gets set to a fixed value and
stays there, just like the one on the Stamp.
I had the NTE956 sitting around so I was just trying to figure out something
to do with it.
Mark
Original Message
From: nehsoft <nehsoft@h...>
To: basicstamps@egroups.com <basicstamps@egroups.com>
Date: Sunday, August 20, 2000 5:24 PM
Subject: Re: [noparse][[/noparse]basicstamps], NTE 956 voltage regulators
>Mark:
>
>Hmmm... I don't think a voltage regulator is quite the right approach.
>
>As I understand how a voltage regulator works, the control pin is connected
>to the center of a resistive network whose values determine the output
>voltage.
>
>To me, it would be simpler to bias a power transistor with the output
>described on P. 294 to drive the motor.
>
>The idea is that the transistor is rapidly switched on and off with the
>change in the pulse duration providing the speed control. The wider the
>pulse or higher the percentage of the 'on state' during the cycle, the
>'faster' the motor turns. This process is used regularly in model railroad
>power controllers. For an example of the process using a Stamp I (easily
>converted for use with a Stamp II), see page 171 of the programming manual.
>
>In this example, the track load is driven by a ULN 2803 which is an array
>of darlington drivers. Hmmm. that IC seems familiar.....
>
>Hope this helps!
>
>Jim Cambron
>NEH Technologies
>
>
Original Message
>From: "techno_masai" <plunkettm@e...>
>To: <basicstamps@egroups.com>
>Sent: Sunday, August 20, 2000 6:03 PM
>Subject: [noparse][[/noparse]basicstamps], NTE 956 voltage regulators
>
>
>> Hi all,
>>
>> I am trying to control a 5v Mabuchi motor with an NTE956 voltage
>> regulator(1.5A rating from 1.2V to 37V).
>>
>> Trouble is I can't tell from the data sheet how to control the output
>> voltage, e.g. for X volts applied to the adjustment pin what do I get for
>> output voltage.
>>
>> Are voltage regulators controlled by voltage or current?
>>
>> Anyway, the code below cycles the motor RPMs pretty well, I just wish I
>> could understand these voltage regulators a little better.
>>
>> The hook up uses the PWM output circuit shown on p294 of manual v1.9
>> connected to the adjustment pin of the voltage regulator. The output of
>the
>> voltage regulator is then connected to the Mabuchi with an IN4001 with
the
>> band toward positive connected across the Mabuchi as well. Also, with the
>> diode the motor runs faster for some reason.
>>
>> '1 cycle=approx 1mS of PWM e.g. 100/255 duty=approx 1.96v
>> 'duty 25 = .5, 50 =.98v, 100 = 1.96v, 200 = 3.92v, etc
>>
>> duty var byte
>>
>> top:
>>
>> duty = 0
>>
>> again:
>>
>> PWM 0,duty,2000
>>
>> pause 200
>>
>> duty = duty + 25
>>
>> if duty = 250 then top
>>
>> goto again
>>
>> Thanks,
>>
>> Mark
>>
>>
>>
>>
>
>
>
>
>