Voltage Regulation using diodes
Russell McMahon email (remove spam text)
> I wanted to be sure that I can use 3 diodes to drop the voltage from a 5v
> rail down to around 3v to drive an EPROM requiring 1.8v - 3.6. I was
> an LM317T but seems a little overboard as the EPROM uses very little
> It 'seems' to work ok, just wandered if there were any pitfalls and if I
> should use a particular sized resistor to provide a load to get the diodes
> to do their thing and perhaps a capacitor to smooth things out a little.
- Aways use same diodes once you have it right.
- Don't go too light on current (say mA's at least.)
- Check EPROM allowable voltage range spec.
- Do use filter cap
- Rail will vary if 5V rail does.
- A zener and resistpr would probably be as good.
(Either through Z with R to gtound or through R with z to ground !
:-) )(different Z in each case though)
- If EPROM doesn't mind what supply is then aim for middle of range to
ensure lots of margin.
- Many 3v regs available at lowish cost. As one offs why not use them?. In
volume they may be cheaper.
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