Abstract: A special mode activation circuit is disclosed for activating a special mode circuit within a semiconductor integrated circuit when the voltage of an input signal at an input terminal of the integrated circuit reaches a special high voltage level that is substantially above a low voltage level range of signals normally associated with binary logic levels. The special mode activation circuit comprises a voltage reduction subcircuit, a voltage detection subcircuit, and an active pullup subcircuit. The voltage reduction subcircuit reduces the voltage of the input signal to generate a reduced voltage input signal. The voltage detection subcircuit is responsive to the reduced voltage signal to prevent activation of the special mode circuit when the reduced voltage input signal is less than a preset threshold value and to activate the special mode circuit when reduced voltage input signal exceeds the preset threshold value.

Abstract: A low current substrate bias generator for regulating the voltage of a substrate layer of an integrated circuit includes a sense circuit having an input for sensing the voltage of the substrate and an output that is coupled to an inverter for providing a control signal. The control signal controls a charge pump that is coupled to the substrate layer or well that is desired to be regulated. The sense circuit includes a load element and a level shifting circuit having a predetermined standing current requirement that flows directly into the substrate. The current requirement of the bias generator is reduced by increasing the value of the load element and a reasonable delay time is maintained by coupling a capacitor across the level shifting circuit. Since the voltage across the capacitor cannot be changed instantaneously, changes in the substrate voltage are directly coupled from the input to the output of the sense circuit, triggering the charge pump.

Abstract: An integrated circuit includes a charge pump to provide current at a potential which is greater than a supply potential. An oscillator provides an output to a pair of capacitors. Each capacitor is bypassed respectively by one of a pair of clamp circuits. An output transistor is gated by one of the clamp circuits to maintain a continuous output at an elevated potential, while reducing power loss caused by impedances within the charge pump circuit. By using the charge pump as a source of elevated potential, the circuit layout of the DRAM array is simplified and the potential boosting circuitry can be locataed outside of the array, on the periphery of the integrated circuit. When used with an integrated circuit device, such as a DRAM, the current from the charge pump may be supplied to nodes on isolation devices and nodes on word lines, thereby improving the performance of the DRAM without substantially changing the circuit configuration of the DRAM array.

Abstract: An integrated cirucuit is provided with a depletion mode filter capacitor, which reduces voltage spiking, while at the same time avoiding latchup problems caused by the capacitor. The depletion mode capacitor has a barrier layer which is doped to an opposite conductivity type as the integrated circuit's substrate, achieved by doping to provide an opposite difference from four valence electrons as the substrate. The barrier is formed as a part of a CMOS process, in a manner which avoids additional process steps. The capacitor is formed with one node connected to ground or substrate, and the other node directly to a power bus. The capacitor is located on open space available on the whole siliocn chip (memory as well as logic chip), particularly directly underneath the metal power bus to achieve an on-chip power bus decoupling capacitor wth capacitance in excess of 0.001 .mu.F.

Abstract: A CMOS intermediate potential generation circuit having a voltage reference state, an intermediate comparator stage and an output stage. The intermediate potential is also used as feedback to the comparator stage. The inventive circuit is characterized by low standby current consumption, quick correction to deviations in the output voltage due to load variations, and quick response to generate a new intermediate potential relative to transitions of voltage supplies.

Abstract: An integrated circuit device includes a charge pump to provide current at a potential which is greater than a supply potential. A potential maintenance circuit gates on when the potential at the output of the charge pump circuit drops to a level which is below V.sub.CC. The potential maintenance circuit permits the charge pump can be bypassed or designed to provide a minimum current output. An overvoltage shutoff circuit permits the charge pump to be effectively bypassed when supply voltage is sufficiently high to make bypass desireable.

Abstract: I/O lines on a CMOS circuit are precharged to preferred voltage levels in order to avoid latch up. The precharging is achieved by using N channel transistors to provide a precharge which is at a threshold voltage (V.sub.T) below bias voltage V.sub.CC, or (V.sub.CC -V.sub.T). This results in a lower forward bias when V.sub.CC bumps down after the I/O lines are floated. By lowering the precharge voltage by a level corresponding to a threshold voltage (V.sub.T), the allowed range of power supply voltage bumping is increased by this amount. This eliminmates the destructive effect of a negative bump of V.sub.BE, which would have presented a diode forward bias condition. Instead, the power supply may bump to (V.sub.BE +V.sub.T).

Abstract: A voltage sensing circuit is used to rapidly pull up a high potential node of a reference array to a value of a high potential source reduced by a threshold voltage (V.sub.CC -V.sub.T). During an enable cycle, the high potential node is precharged to a potential of V.sub.CC -V.sub.T, which turns on a transistor gated to the V.sub.CC potential. This pulls the high potential node as rapidly as possible to a high level in order to speed up the sensing process. A potential maintenance circuit provides sufficient current from the high potential source to maintain a desired potential at the high potential node.

Abstract: A memory array (e.g., DRAM) is provided with a potential maintenance circuit which provides sufficient current to maintain a high potential node of the memory array at a predetermined potential. The potential maintenance circuit is gated ON after receipt of a clock signal and gated OFF at the predetermined potential. This permits the high voltage node to be maintained, while reducing current requirements. The invention is particularly useful when used in conjunction with a circuit which rapidly pulls up the high node to a value of V.sub.CC -V.sub.T (where VT is a threshold voltage of a transistor).

Abstract: A pumpdown circuit uses voltage sensing to bring a low node to a potential of V.sub.SS +V.sub.T by first grounding the node and then floating the node to the V.sub.SS +V.sub.T potential. When a sensing node is at the V.sub.SS +V.sub.T potential, the sensing node is maintained at a level above ground by leakage current through a pump-up circuit. Biasing the digit and digit* lines to a potential V.sub.T above ground reduces current (amperage) requirement, because the digit and digit* lines do not have to be discharged completely to ground. The momentary discharge of the sense amp node to ground allows the sense amp to behave like a conventional sense amp during initial sensing, thereby allowing a minimum digit/digit* sensing potential to approximate ground plus V.sub.T.