Atmel Corporation

Cypress Semiconductor Corporation

Saroj Pathak

James E Payne

Glen Arnold Rosendale

Nianglamching Hangzo

Jagdish Pathak

Harry H Kuo

David L Hoff

Victor V Nguyen

Bruce Prickett

A programmable logic device (PLD) architecture includes a plurality of PLD single-bit logic cells. Each single bit logic cell is comprised of all CMOS logic devices including a programmable cell unit, a settable latch, a signal path with inverter, and an output logic gate. The single path is coupled to the cell unit, the settable latch, and the output logic gate to create a positive feedback loop to improve speed and noise immunity. Each single bit logic gate is a basic building block for a modular low power consumption, high speed, zero DC current, high noise immunity programmable logic device (PLD) which includes an array of word lines and bit lines arranged in rows and columns for addressing, an array of OR gates, and a plurality of output logic circuits.

High speed zero DC power programmable logic device (PLD) architecture

A bit/column latch comprising a pair of first and second cross-coupled CMOS inverters. Each inverter of the pair comprises an NMOS transistor and a PMOS transistor. The first CMOS inverter has the source of its NMOS transistor coupled to ground via a control transistor and has its output connected to the associated bit line. When low voltage data intended for the associated memory cell appears on the bit line, the control transistor is barely turned on to weaken the NMOS transistor of the first inverter. This makes it easier for the data on the bit line to turn on the NMOS transistor of the second inverter so as to switch the bit latch from storing a 'low' to storing a 'high'. In other words, the data bit from the bit line is loaded into the bit latch. After that, the control transistor is strongly turned on and therefore it becomes transparent to the latch. As a result, the latch is stable when the bit line later ramps up to a high programming level.

High voltage bit/column latch for Vcc operation

A driver circuit for use in an array of picture elements in a liquid crystal display is capable of displaying one set of image data while receiving a second set of image data. A first select switch transistor responsive to a first select signal controls the coupling of a first image to a first storage capacitor. A second select switch transistor responsive to a second select signal controls the coupling of a second image to a second storage capacitor. The first storage capacitor may be selectively coupled to an output node by means of a first enable switch transistor responsive to a first enable signal. The second storage capacitor may be selectively coupled to the same output node by means of a second enable switch transistor responsive to a second enable signal. By proper manipulation of the switch transistors, one storage capacitor may be coupled to the output node while the other storage capacitor is isolated from the output node and receiving new image data.

Drive circuit for liquid crystal display cell

A reference cell for use in a high speed sensing circuit includes a first sub-circuit and a second sub-circuit. The first sub-circuit has a structure similar to memory cells within odd number rows of a main memory array. The second sub-circuit has a structure similar to memory cells within even numbered rows of the main memory array. If a target cell within the main memory array lies within an odd numbered row, then the first sub-circuit is selected, and if the target cell lies within an even numbered row, then second sub-circuit is selected. Both of the first and second sub-circuits include a reference transistors having its control gate broken into two parts. A first part is a poly layer and is separated from the channel region by a tunneling oxide. A second part is a metal or poly layer over the first part and separated from the first part by a gate oxide. A via is used to connect the first part to the second part.

Reference cell for high speed sensing in non-volatile memories

A voltage regulator circuit that receives an input signal and provides an output signal that is clamped at a specified voltage desired for an internal circuit. The disclosed voltage regulator circuit includes a plurality of subcircuits including a voltage tracking subcircuit in which the output voltage tracks the input voltage with no voltage drop when the input voltage starts to rise from zero volts. If the input voltage increases to a desired voltage level for the internal circuit, the voltage tracking subcircuit clamps the output voltage to remain at that voltage. If the input voltage further increases to a higher voltage, the voltage tracking subcircuit is disabled and one of a plurality of voltage maintaining subcircuit takes control so that the output voltage remains at the desired voltage for the internal circuit.

Low power voltage regulator circuit for use in an integrated circuit device

A circuit for transferring high voltage analog video signals while enabling the use of conventional low voltage logic levels includes a first transistor powered by a high voltage power source to bias a pass transistor at a high voltage level. The pass transistor receives a high voltage video signal and because of the high voltage bias is able to pass the video signal without attenuation of the signal due to feedthrough effects, thus preserving the fidelity of the video signal. A second transistor provides a ground potential which operates to turn OFF the pass transistor, thus disabling the transfer of the video signal therethrough. A third transistor operatively coupled to the first transistor operates to turn OFF the first transistor when the second transistor is in operation.

Circuit for transferring high voltage video signal without signal loss

A video chip includes test circuitry for detecting opens and shorts. The circuitry includes a series-connected chain of transistors and a test register. There is a circuit for the column lines and for the row lines. A bit pattern is driven onto the column or the row lines and received in the corresponding test circuitry. The pattern is read out and compared against the input pattern to detect faulty lines.

Method and apparatus for testing a video display chip

A fuse circuit includes a fusible element and a feedback path which causes the circuit to behave as if the fusible element is fully blown even though the fusible element in fact is partially intact. While a partially intact fuse normally would result in a continuous drain of power, the feedback path cuts off the current flow through the partially intact fusible element.

Fuse circuit having zero power draw for partially blown condition

A sense amplifier for use in a serial configuration memory includes multiple stages which are enabled and disabled in a controller manner, in response to a control pulse. The control pulse is produced every Nth period of an externally provided clock signal, the clock being used to clock out a bitstream representing the contents of the memory device. In a preferred embodiment, N such sense amps are utilized to read out in parallel fashion the N memory cells (bits) that constitute an accessed memory location. The sense amps are therefore active only of a period of time sufficient to read out a memory cell.

Sense amplifier with zero power idle mode

A serial configuration memory device comprises an architecture wherein the reading out of data and the outputting of the bitstream are performed in pipeline fashion. As a result, the device is capable of outputting a bitstream based solely on the frequency of an externally provided clock, and is not limited by the slower operating speed of the sense amp circuitry. A caching scheme is provided which allows the first byte to be pre-loaded during a reset cycle so that the device can immediately begin outputting the bitstream as soon as the reset cycle completes. In a preferred embodiment of the invention, the bitstream consists of serially accessed memory locations starting from memory location zero. In one variation, the bitstream can begin from a memory location other than memory location zero.

Zero power high speed configuration memory

A power-on-reset circuit includes a first charging stage for building up a charge during power up. The rising voltage of the first charging stage is sensed and used to control means for charging up a second charging stage. When the second charging stage reaches a first voltage level, a circuit is tripped to pull the potential of the first to ground. The grounding of the first charging stage is fed back to the charging means which shuts off its power burning components and maintains the first voltage level at the second charging stage.

Zero power power-on reset circuit

A memory device includes a memory cell whose data state is sensed by a sense amplifier. A balance amplifier having the same construction as the sense amplifier is utilized to sense a balance cell having the same construction as the memory cell. The balance cell is maintained in an erased (conductive) state. The balance cell is gated by the output of the sense amplifier. Such a device operates in a way to consume the same amount of power regardless of the data state of the memory cell. In one embodiment of the invention, a memory device consisting of a memory array includes a balance circuit associated with each of the sense amplifiers in the memory device. In another embodiment of the invention, a trim circuit is used to adjust the conductivity of the of the balance circuit. This allows the balance circuit to be fine tuned during manufacture to compensate for process variations, thus allowing the balance circuit to be matched to the memory cells.

Semiconductor memory having a current balancing circuit

An SRAM configures its bitline load structure to implement one of three different precharge schemes, none of which use an ATD circuit. The SRAM monitors its WRITE/READ pin and initiates a first precharging scheme when the SRAM is in a read mode. In the first precharging scheme, every complementary bitline pair is directly coupled to Vcc via a first pmos transistor which is permanently turned on, regardless of whether a memory cell is being read or not. Additionally, both true and false bitlines in every complementary bitline pair are coupled together via a pmos transistor as long as the SRAM remains in a read mode. When in a write mode, the second precharging scheme is initiated causing the second pmos transistor to be turned off and only the first pmos transistors remain active. Thus, all complementary bitline pairs which are not selected for a write operation are pulled up to Vcc by the first pmos transistors. The termination of the write mode activates the third precharging scheme which causes all the bitlines, both true and false, within the memory array to be momentarily shorted together. The cumulative equivalent capacitance of the complementary bitlines pairs which were not selected for a write operation help to pull up the few complementary bitlines pairs which were pull down during the previous write operation.

Bitline load and precharge structure for an SRAM memory

A zero power fuse circuit includes a latch means having two inputs, a first input being latched to ground and a second input being latched to V.sub.cc. The latch means is triggered either by a momentary contact of the first input to ground or by the momentary contact of the second input to V.sub.cc. A first embodiment includes two fuse element/capacitor pairs each coupled to one of the two inputs of the latch means. A second embodiment includes a pull-up transistor and a fuse element/capacitor pair, coupled to the first and second inputs respectively. A third embodiment includes a pull-down transistor and a fuse element/capacitor pair respectively coupled to the second and first inputs of the latch means.

Zero power fuse circuit

A non-volatile programmable circuit having programming and read bitlines, a non-volatile memory cell, and a read select transistor, and a method for its operation. The non-volatile memory cell is programmable through the programming bitline. The read select transistor is connected between the non-volatile memory cell and the read bitline. During read operation, the programming bitline is grounded and programmed information is readable onto the read bitline. During programming operation, the read bitline is grounded, and programmed information is programmable into the non-volatile memory cell for storage and retention.

Growing community of inventors

Los Altos Hills, CA, United States of America

Saroj Pathak