The floating capacitor is a key factor to determine the output characteristics of a charge pump.In order to overcome the difficulty in fabrication of the large capacitors in monolithic integrated circuits

a technique of replacing the floating capacitor by an active capacitance multiplier is proposed in this paper.Equivalent capacitance value of the active capacitance multiplier can be enlarged in 1~3 orders of magnitude.PSPICE simulations of the output characteristics were carried out for charge pump doublers and charge pump inverters for the different designs of adopting the capacitance multiplier and a normal capacitor

respectively.The simulation results show that the same output characteristics can be obtained from the new charge pump with a capacitor much smaller than that adopted in the normal charge pump products.For example

100 pF in the new is equivalent to 50nF normally in this work.Employing the active capacitance multiplier

therefore

the new charge pump is much easier to be fabricated in fully integrated realizations with on-chip capacitor.