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D.2 Adiabatic CMOS

Despite the fact that (high-Q) inductors are not available in a CMOS technology they can be realized, e.g., on an MCM substrate or be simply included in the package. This limits adiabatic switching with inductors to designs which use only a few external inductors, such as pulsed power supply or adiabatic clocking [12, p210]. Yet, this means that at least parts of the logic circuitry can operate quasi adiabatically (with respect to (D.1)), although the overhead can be quite considerable [58, pp65-97].

Another approach proposes the stepwise charging of a capacitance through a series of N MOSFETs and voltages as shown in Fig. D.3, reducing the dissipated energy by a factor of N. The voltages $V_1\ldots V_{N-1}$ at the tank capacitors will assume approximately the values $V_N/N\ldots (N-1)V_N/N$.

Figure D.3: Quasi-adiabatic stepwise charging

Despite the large overhead this method can be used for slow driving of large external capacitances (e.g., LCDs) [12, p204].

G. Schrom