of fig8 in other embodiments it may be acceptable to have larger transistors at these points and thus a fast slew rate can be obtained for this later portion of the transition in the prior art the peak current taken from the boosted voltage source is 2 23 milliamps whilst the highest current taken from the boosted voltage source in any of the embodiments of the present invention is 927 micro amps this is significantly lower this is because the current for generating this change in voltage level is generated from the vddg source as this is required to power the rest of the circuitry it needs to be a large source and the grid connecting it to the circuitry is similarly large thus in the prior art a grid and boosted power supply sufficient to supply a peak current of 2 23 milliamps is required while embodiments of the current invention only require a peak current of 927 microamps or if a slow slew rate is acceptable 174 microamps the diagram also shows the difference in transition times and peak currents between the fast and the slow slew rates these are quite significant and thus in some embodiments where it is very important to have a small source the slow slew rates may prove to be advantageous fig9 shows a.