Capacitive charge pump, bicmos circuit for low supply voltage

摘要

A BiCMOS capacitive charge pump circuit for low supply voltage has a bipolar part, functionally reproducing a basic charge pump circuit and a CMOS part that comprises MOS transistors (M1, M2) functionally connected in parallel with the driving switch toward ground potential (T3) of the charge transfer capacitance (C1) and in parallel with the output diode (T7) for substantially nullifying voltage drops on the respective bipolar components (T3, T7). A special driving circuit (T8, R2, I2), powered at the boosted output voltage (VOUT) responds to the rise of the voltage on the output node above a minimum level, as ensured by the bipolar part of the charge pump circuit, to drive said MOS transistors (M1, M2), thus allowing the output voltage to reach a level that is substantially double the supply voltage (Vs), also when the latter is exceptionally low for reliably ensuring switching of the CMOS part of the circuit.