LOW VOLTAGE CHARGE PUMP CIRCUIT, IN WHICH CHARGE PUMP EFFICIENCY IS NOT DECREASED AT LOW VOLTAGE

摘要

PURPOSE: A low voltage charge pump circuit is provided to prevent the decrease of efficiency at a low voltage and thus to assure low voltage operation reliability of several semiconductor chips. CONSTITUTION: Four clock signals(CLK11- CLK14) are inputted, and two clock signals(CLK12,CLK13) are connected to two pumping capacitors directly and generate a negative voltage to specific nodes in the circuit. Two clock signals(CLK11,CLK14) are connected to two bootstrap capacitors and bootstrap a gate voltage of transfer transistors when transferring the negative voltage to a negative voltage node together with bootstrap transistors. Bias circuits bias a voltage of a bulk part of the transfer transistors. Precharge transistors precharge the nodes.