Simple CPU voltage regulator:

With the introduction of the AMD K6, Cyrix 6x86 and Pentium MMX processors, a second supply voltage is required on the motherboard in addition to the primary voltage of 3.3 to 3.5 V. This additional voltage can be generated using a special voltage regulator, but there is an easier approach. The circuits presented here solve the problem in an especially simple and inexpensive manner.