Abstract: The present invention provides a tunable circuit for quickly optimizing an electrical field generated by the F-N tunneling operation. To optimize this electrical field, the charging of a positive charge pump is begun after the charging of a negative charge pump. The tunable circuit of the present invention provides a means to detect the optimal negative voltage at which pumping of the positive voltage should begin. The tunable circuit includes a resistor chain coupled between a first reference voltage and a negative voltage from the negative charge pump. When charging of the negative charge pump begins, a comparator compares the voltage at a node within the resistor chain to a second reference voltage. In accordance with the present invention, the node voltage within the resistor chain is equal to the second reference voltage when the negative voltage is equal to the voltage to be detected. Thus, the comparator generates a trigger signal when the voltage at the node decreases to the second reference voltage.

Abstract: The present invention provides a tunable circuit for quickly optimizing an electrical field generated by the F-N tunneling operation. To optimize this electrical field, the charging of a positive charge pump is begun after the charging of a negative charge pump. The tunable circuit of the present invention provides a means to detect the optimal negative voltage at which pumping of the positive voltage should begin. The tunable circuit includes a resistor chain coupled between a first reference voltage and a negative voltage from the negative charge pump. When charging of the negative charge pump begins, a comparator compares the voltage at a node within the resistor chain to a second reference voltage. In accordance with the present invention, the node voltage within the resistor chain is equal to the second reference voltage when the negative voltage is equal to the voltage to be detected. Thus, the comparator generates a trigger signal when the voltage at the node decreases to the second reference voltage.

Abstract: A shift register system is disclosed wherein shift registers buffering memory data perform shift operations in response to a set of sub-clock signals. The set of sub-clock signals comprise nested sub-clock signals having non-overlapping transitions formed from a system clock signal or power on reset signal. Each shift register (or bank of shift registers) responds to a different sub-clock signal. As a result, shift operations are spread out over a period of time rather than occurring simultaneously. Thus, the current drawn during each shift operation is similarly spread out over a period of time. The maximum current drawn during any one shift operation is inversely proportional to the number of non-overlapping sub-clock signal. Therefore, the maximum current drawn (i.e., current spike) drawn during memory operations is minimized.

Abstract: A floating gate memory device that includes a switching circuit for selectively transferring two or more negative voltages to a common node (e.g., to the negative pole of a driver circuit). The switching circuit includes two switches respectively connected between the two negative voltages and the common node. Each of the switches includes series-connected triple-well NMOS transistors that provide a dual-isolation structure between the common node the negative voltage sources. An optional triple P-well resistor is provided between the series-connected triple-well NMOS transistors in each of the switches that includes a deep N-well region biased by a system voltage source (e.g., VCC) to reverse bias the central P-well region.

Abstract: A pseudo-differential sense amplifier for sensing the state of an array memory cell by reference to a reference cell in a predetermined state. The sense amplifier has an input stage coupled to the array memory cell, which provides signals to a differential stage from which an output is generated. The input stage has reference and array side cascode circuits in which the components are matched on each side so as to eliminate process, temperature, and other extraneous variations from influencing the differential output. An enabling signal to the array side of the input stage is delayed with respect to the reference side such that voltage fluctuations externally introduced into the signals passed from the input stage to the differential stage do not cause erroneous switching and/or glitches to appear at the sense amplifier output.