A +/−25V Charge Pump with Switchable Polarity in 3.3V CMOS Technology

In this paper a scalable multiple-stage charge pump with switchable polarity constructed from low-voltage MOS transistors is demonstrated. A distinguished feature of the proposed circuit is a cross-switch integrated in each pumping unit, which configures the polarity of the respective pumping stage depending on the polarity of the preceding stage, thus implementing a daisychained control scheme. Such approach allows connecting any amount of stages in series, enabling a straightforward scalability of the circuit. A prototype switchable charge pump comprising 18 stages is implemented with 3.3 V MOSFET devices in 90 nm SOICMOS technology. The measured circuit generates output voltages exceeding +/−;25 V from a single 1.9 V supply source while consuming a current of 450μ A. The proposed charge pump can be used as a driver for switchable systems requiring high actuating voltages for high-ohmic inputs.