Re: "Goosing" with a higher voltage


eromlignod wrote:
Hi guys:

I have an application where I'm driving a device with 5 volts DC.
From time to time it is necessary to give it a short pulse of 24 Vdc
then revert back to 5V.

I have a power supply that has both 5V and 24V outputs.  Can I just
pulse the 24V right onto the 5V line (with a power transistor or
relay) as long as I include a diode on the 5V output to avoid back
current?  Or is this foolish?

OR control, latest version:

              24v
               |
               +-----+----,
               |     |    |
               |     |    |
            |\ |    6k2   |
     ,------|+\|     |    |
     |      |  \     |    |
     | LM393|   >----+    |
     |      |  /     |    o|
     |   ,--|-/|     |     |--power
     |   |  |/ |     |    o|  switch
    10k 10k   gnd    |    |
     |   |           |    |
     |   '-----------|----+
     |               |    |
     |     gnd--15k--+    |
     |             |    |
     |   5v     |_   |
     |   |    __   |
     |    |         ||   |
     | +----------''---+--load
     |    |         s  d
     |    |   n-channel mosfet
     |    \       SPP80N03
     |    /
     '--->\1k
          /
          \
          |
          |
         500k
          |
          |
         gnd

.