Rick Mann wrote:
>
> I was going to use a voltage regulator from Toko America, what Digi-Key
> listed as a 260 ma 5.5 volt regulator (datasheet:
> http://207.208.84.9/semiconductors/pdf/tk112xxb.pdf).
>
> However, when it arrived and I started looking at the data sheet, it seemed
> to be only a 150 ma regulator. What I'd like to know is, can I safely put
> two of these together, both outputs tied to the same positive (circuit)
> supply rail? Will I then be able to get 300 ma out of the two regulators?
>
> If I can't tie them to the same supply rail, can I run some of my components
> off a separate rail? For example, can I have one regulator power the LCD in
> my circuit, and the other regulator power the MCU, but still have output
> pins of the MCU connected to input pins of the LCD, and everyone sharing a
> common ground?


Yes you can have 2 regulators, grounds connected, and
each supplying different chips/devices. There is enough
range in the logic in/out voltage thresholds that it
will work fine even if there is a 0.5v or more
difference in the two 5v rails. I have seen this done
in commercial devices. :o)

Another way is to parallel both the regulator inputs,
and grounds, and parallel the 5v outputs each through a
small resistor. Like the old emitter balance resistor
trick. At 150mA each try a 1.8ohm resistor, so you will
lose about 0.27v total from your 5v rail, but it will
happily supply the 300mA and they will balance equally.
Obviously your 5v rail regulation will vary from 5v to
4.73v from 0mA to 300mA.
-Roman

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