Patent ID: 8378736

Claim:
Charge pump apparatus for generating an output voltage supply within a circuit, comprising: a) a transfer capacitor; b) a plurality of transfer capacitor coupling switches, each switchable between a conducting state and a nonconducting state under control of at least one charge pump clock output; and c) a charge pump clock generating circuit including a ring oscillator comprising an odd number of not more than three inverting driver sections cascaded sequentially in a ring such that each driver section has an output coupled to a next driver section input, wherein a first driver section is next after a last driver section and one of the driver section outputs constitutes a particular charge pump clock output from among the at least one charge pump clock output controlling at least one of the transfer capacitor coupling switches, and wherein each driver section includes i) circuitry configured as an active current limit to limit a rate of rise of voltage at the driver section output, and ii) circuitry configured as an active current limit to limit a rate of fall of voltage at the driver section output, wherein the charge pump clock output from among the at least one charge pump clock output is substantially sine-like; d) wherein the plurality of transfer capacitor coupling switches are coupled to the transfer capacitor, and are controlled so as to couple the transfer capacitor to a voltage source during periodic first times, and to couple the transfer capacitor to the output voltage supply during periodic second times that are not concurrent with the first times.