Buffer a signals to SSRs??

Archiver

I'm trying to drive SSRs with my Stamp2. When I drive the 4th one (at
the same time), the stamp goes to reset. Is there a way around this
like buffering. Can someone point me to a basic cuircut?
rheine@m...

Archiver

Rick,

Your reset problem may be caused by excessive currents on the Stamp's outputs
used to drive the SSRs, or the Stamp's power supply voltage is dropping to an
unacceptable level because of SSR drive and/or load demands. Individual BS2
in/out pin currents should not exceed 20 mA source, or 25 mA sink. Combined
pin current for all pins should not exceed 40 mA source, or 50 mA sink. If
the combined current needed to drive all SSRs does not exceed the Stramp's
pin load requirements, the combined SSR drive or output loads may be causing
the Stamps power supply voltage to drop.

If pin load is the issue, you can use one Texas Instrument's ULN2003AN to
buffer and sink SSR drive current on as many as 7 Stamp outputs. The part is
available at http://www.digi-key.com/. If the problem is caused by Stamp
power supply voltage drop under SSR load, you will need a heftier supply.

marc_reynolds1@h...



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