Re: [CAD_CAM_EDM_DRO] Re: FS: New 4 axis microstepping driver $45.00 USD

In figure 10 (Circuit for Increasing Output Voltage), the voltage from
the regulator's ground to it's input is the difference between the
junction of R1R2 and the input voltage, not the full input voltage.

In figure 13 (High Output Current with Short Circuit Protection), a
TIP42 is used to up the maximum current. The TIP42 is rated at 6A.

Regards,
JJ

On Monday, Mar 22, 2004, at 05:23 US/Eastern, Fred Smith wrote:

> --- In CAD_CAM_EDM_DRO@yahoogroups.com, John Johnson <johnatl@m...>
> wrote:
>> Using a couple of the circuits in the LM78xx datasheet available
> here:
>> http://www.fairchildsemi.com/pf/LM/LM7805.html
>> It would be possible to build a regulator with short circuit
> protection.
>> See figures 10 & 13.
>
> JJ,
>
> I would think that the LM317 would be a better solution.
>
> http://www.fairchildsemi.com/pf/LM%2FLM317.html
>
> It is rated for 1.5 amps and *** 40 volts ***. Since a desktop
> machine only needs about 4 amps @ 30 volts for a power supply, 3 of
> these would seem to be a very interesting solution to the issue of
> the 35 volt supply limit of the A3977. Pretty inexpensive too.
>
> Anyone ever play with creating a power supply with 3 LM317's in
> parallel?
>
> Since we are going interesting places with this discussion, anybody
> ever run any tests on the A3977 to see if the same overvoltage limits
> were applicable at 1-2 amps (the limits on our board) instead of max
> current draw?
>
> Fred Smith - IMService
>
>> On Wednesday, Mar 17, 2004, at 17:40 US/Eastern, Fred Smith wrote:
>>>> --- In CAD_CAM_EDM_DRO@yahoogroups.com, "Fred Smith"
> <imserv@v... wrote:
>>>>>> We have a limited edition, 4 axis, microstepping driver
> available.Based
>>>>> on
>>>>>> the Allegro A3977 chip. The board is rated at 2 amps per axis
>>> and
>>>>>> maximum of 35vdc. This is a promotional item and is subject to
>>>>> prior
>>>>>> sale. Quantities are very limited.
>>>
>>> Info at: http://www.cadcamcadcam.com
>
>
>
>
>
>
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