This is probably a very basic question, but it is troubling me.

In my robot's design, I have a couple of daughterboards running PICs (or
maybe other uC's). I want to design a circuit for supplying power to the
daugherboards.

The main power source is a battery pack that supplies 12V. What I'm trying
to decide is whether I design one extra daughterboard for voltage regulation
or if I include voltage regulation in each one of the daughterboards. Here's
what I see as advantages and disadvantes of each method, please critique.

One VReg
========
Advantages:
- savings in real estate
- savings in power consumption
Disadvantages:
- If I install a diode or a bridge rectifier on the
  daughterboard, I won't have 5V for the electronics
  because of the v.drop of the diodes
- If one of the daughterboards needs 3.3V instead of 5V,
  I will need a vreg on the daughterboard anyway

Distributed VRegs
=================
Advantages:
- Each board is encapsulated, which means I can connect
  any voltage (in between vreg specified min and max) that it
  will work
- I can select a specific vreg for each board according to its
  characteristics (current and voltage needs)
- I may choose a vreg with overvoltage and overcurrent features
- I can implement the reverse polarity diode before the vreg,
  therefore the diode voltage drop won't affect the voltage
  available for the load
Disadvantages
- real estate
- power consumption

(cost is not really a problem... this is not going to production)


Cheers

Padu


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