Low swing CMOS current mode charge pump

Abstract

This article present the CMOS charge pump circuit which is operated in current mode. MOS transistors in this circuit act as the switches (charge transfer switch) and current source for store the charge from the supply voltage into the fly capacitor and transfer charge from the fly capacitor to the output (output capacitor and resistive load). All of the MOSFET which act as switch operated in saturation and cutoff region. Then the output voltage can be increase because of charge at the fly capacitor which is already pumped up the voltage transfer to output node. This circuit is test in SPICE simulation program by using BSIM3v3 MOSIS 0.35micron model. The supply voltage is 5V. The charge can transfer into fly capacitor (Cfly) or discharge to load and Cout by using clock reference to switch the charge transfer switch on/off the MOSFET. Output voltage of this circuit can be increase from the input supply voltage.