Texas Instruments Corporation

Ngai H Hong

Lionel S White, Jr

Edmund A Reese

Donald J Redwine

Chitranjan N Reddy

Tadashi Tachibana

A semiconductor dynamic read/write memory of the multiplexed-address type employs an on-chip refresh counter which is activated by CAS-before-RAS sequence. This counter is made up of stages almost identical to the row address buffers so the same clocks can be used. Either the address input buffers or the refresh counter stages are gated into second-stage row address buffers, and carry feedback from these second stage buffers to the counter stages is used to increment the counter. The access time of the memory for normal read or write is not degraded by the refresh circuitry.

Self refresh circuitry for dynamic memory

A random access read/write MOS memory device or the like employs a delay circuit in clock generators to produce small increments of delay. The delay circuit consists of a field effect transistor connected as a transfer device with its gate precharged and the gate-to-source capacitance much larger than the parasitics of the gate node. A larger transistor may be connected to the output node to improve the output waveform by holding down the output voltage at the beginning of a cycle.

Delay circuit used in semiconductor memory device

A semiconductor memory device forming a static type memory cell uses three field effect transistors. One is connected between a storage node and a bit line so it functions as an access transistor. The storage node is connected to a refresh node through a second transistor having its gate shorted to drain, and the third transistor connects the refresh node to a supply voltage. A voltage dependent capacitor connects the refresh node to a refresh clock. A logic 1 on the storage node turns on the third transistor and charges the refresh node, which turns on the capacitor so the refresh clock is coupled through to turn on the second transistor and refresh the storage node. When a logic 0 is stored, this will not happen.

Low power quasi-static storage cell

A clock generator for producing internal waveforms for an MOS dynamic RAM or the like provides a preselected delay period between input and output clocks. A pair-delay circuit including two transistor stages produces the desired delay; a driver circuit provides the necessary high level output. A pair of series transistors in the output of the pair-delay, with the node between the series transistors being precharged, provides a more precise control of the delay over a wide range, and the waveshape of the input to the driver is improved.

Clock voltage generator for semiconductor memory

A clock generator for producing internal waveforms for an MOS dynamic RAM or the like provides a preselected delay period between input and output clocks. A pair-delay circuit including two transistor stages produces the desired delay, a driver circuit provides the necessary high level output. A pair of series transistors in the output of the pair-delay, with the node between the series transistors being precharged, provides precise control of the delay over a wide range. Power dissipation is reduced in the driver circuit by avoiding the possibility of d.c. current paths when the reset clock goes high.

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Ngai H Hong