Simple charge-pump circuit with variable conduction path for changing boosting ratio and step-up circuit using the same

摘要

A pattern generator is responsive to a control signal so as to change a pulse signal pattern selectively supplied through a level-shift circuit to switching elements of a charge-pump circuit, and the switching elements cause boosting capacitors to be differently charged depending upon the pulse signal pattern so that all the boosting capacitors participate in the boosting operation regardless of the target ratio between the input potential and the output potential.