Dynamic linking of banks in configurable content addressable memory systems
Granted: May 30, 2006
Patent Number:
7054995
A content addressable memory (CAM) system includes CAM banks that can be linked together in a series to form a CAM module. Each CAM bank includes a CAM array with rows. In a lookup operation, each row asserts a field-match signal when a field from a key matches the field of a CAM entry held in the row. Each CAM bank receives a link-control signal, each received from the preceding CAM bank match-in signals for the rows, and each generates match-out signals for the rows. Some embodiments…
Prefix match search scheme
Granted: August 9, 2005
Patent Number:
6928430
A search scheme (10) in which a controller (14) provides a search key (16) to a search engine (18, 36). In one variation, the search engine (18) provides a match address (20) based on prefix matching to an associate content (AC) memory (22) and the AC memory provides a search result (24) back to the controller. In an other variation the search engine (36) effectively may include the AC and itself provide the search result (24). Within the search engine (18, 36) every possible prefix for…
Associated content storage system
Granted: August 2, 2005
Patent Number:
6925524
A relocation system to associatively search a database lookup table with a search key to addressably retrieve a corresponding associate content table record as a search result. The relocation system is implemented in search engine devices having associative memory (e.g., CAM) having one or more sections. The search engine devices employ relocation values when calculating addresses, one per section per device, with the relocation values optionally pre-calculated and stored in relocation…
Search engine for large database search using hash pointers
Granted: July 12, 2005
Patent Number:
6917934
A search engine (100) having a controller (112), a memory (114), and a hash pointer unit (110). The memory (114) includes a database of search data and associate content, and the controller (112) uses individual search values to access the memory (114) to obtain individual search results. The controller (112) includes a hash function (116) that generates a hash value from a, typically large, search value into a, typically smaller, hash value that may be a hash collision. The controller…
Large database search using content addressable memory and hash
Granted: May 3, 2005
Patent Number:
6889225
A hash-CAM (H-CAM) which may work with a controller and a memory containing a database of either search values and associate content or associate content by itself The H-CAM includes at least one set of paired hash units and CAM units and at least one logic unit. The CAM units hold values known to cause hash collisions in the respectively paired hash units, and the logic unit prioritizes the hash and CAM unit outputs to a single address value usable to access the memory and obtain a…
Fast aging scheme for search engine databases using a linear feedback shift register
Granted: August 3, 2004
Patent Number:
6772301
A fast aging system (10) which may work with a memory (12) in which data words (16) having aging words (18) are stored. An aging address counter (20) selects an aging word (18) for updating based on a state change in a linear feedback shift register (LFSR) (24). Optionally, in the aging word (18) a zero value (52) may represent a permanent data words (16), a predefined non-zero value (56) may represent data words (16) which are available for replacement, and other zero values may…
Dual match-line, twin-cell, binary-ternary CAM
Granted: March 9, 2004
Patent Number:
6704216
A content addressable memory (CAM)(10, 102) and method having a data-in sub-circuit (44), memory cells (16, 18), a match-high line (36), a match-low line (38), and pre-charge devices (40, 42). Input lines (30, 32, 48, 50) from the data-in sub-circuit (44) are not necessarily discharged to ground in every cycle of a clock signal (62) used by the memory cells (16, 18). Further, the pre-charge devices (40, 42) may be operated at one half of the rate of the clock signal (62). Yet further,…
Paralleled content addressable memory search engine
Granted: September 30, 2003
Patent Number:
6629099
A parallel search engine able to receive commands via a search instruction input and data words via a search data input. The commands received, which are optionally programmable, control operation of a data dispatch unit and a result dispatch unit. The data words received are sent by the data dispatch unit as search data to a CAM module array made up of CAM modules interconnected by a cascade information bus for comparison against pre-stored comparand databases. The CAM modules of the…
System and method for combining integrated circuit final test and marking
Granted: May 28, 2002
Patent Number:
6396295
A testing station tests integrated circuits and determines if the integrated circuits pass or fail predefined tests. The integrated circuits are placed in a pass bin if the integrated circuits passed the tests, or a fail bin if the integrated circuits failed the tests. A marking station marks identification information on the integrated circuits in the pass bin. The testing and marking stations are both included in a single, integrated tester-marker system.
Pulse delay circuit with stable delay
Granted: March 5, 2002
Patent Number:
6353349
A pulse delay circuit that provides a delay for a pulsed input signal that does not vary significantly under changing temperature, power supply voltage or process conditions. The delay provided by the pulse delay circuit is not significantly limited in duration. The pulse delay circuit includes a pulse detector, an RC delay circuit and a pulsed signal generator. The delay is primarily determined by the RC time constant of the RC delay circuit.
Method for fabricating stacked capacitor for a dynamic random access memory
Granted: February 6, 2001
Patent Number:
6184152
A method is provided for fabricating an array of memory cells for a dynamic random access memory. Each memory cell has an associated capacitor. An array of memory cell transistors is formed and each memory cell transistor has a source, a drain and a gate. The source is coupled to a bit line, and the gate is coupled to a word line. A lower conductive layer is formed over the array of memory cell transistors. The lower conductive layer is electrically coupled to the source of the memory…
Insertble and removable digital memory apparatus
Granted: January 16, 2001
Patent Number:
6175517
Each device of a family of removable digital media devices (310, 320, 330, 340, 350 and 360) may be plugged into a host to permits the host to store data in it or to retrieve data from it. The form factors of the digital media devices in the family and the connector system used by the digital media devices are compact for minimizing the volume of space occupied in portable devices and for easy storage. Some embodiments (310, 320, 330, 350 and 360) provide an elongated compact form factor…
Apparatus and method for preventing accidental writes from occurring due to simultaneous address and write enable transitions
Granted: August 8, 2000
Patent Number:
6101133
A Random Access Memory (RAM) with improved memory access time supporting simultaneous transitions of an address signal and a write enable signal while preventing accidental writes. The RAM includes a memory array, an address transition detector and a race detector. Operation of the memory array is controlled by the address signal and a write clock signal. In response to the write clock's read state the memory array reads data from an address represented by the address signal, while the…
High density self-aligned antifuse
Granted: July 11, 2000
Patent Number:
6087677
The present invention is an antifuse structure comprising an insulation layer between a top conductor and a bottom conductor. The insulation layer has a via. A resistive layer is adjacent the via and a plug is adjacent the resistive layer. The plug is in the via and is also adjacent the top conductor.The present invention also provides a method for fabricating the antifuse on a base. A bottom conductor is deposited on the base. An insulation layer are deposited adjacent the bottom…
Self-aligned storage node definition in a DRAM that exceeds the photolithography limit
Granted: June 13, 2000
Patent Number:
6074910
A method is provided for fabricating a stacked capacitor in a storage node (memory cell) of a dynamic random access memory (DRAM) that exceeds the photolithography limit. A DRAM has an array of memory cells and each memory cell has an associated capacitor. An array of memory cell transistors is formed and each memory cell transistor has a source, drain and gate. The drain is coupled to a bit line, and the gate coupled to a word line. A lower conductive layer is formed over the array of…
Leakage improved charge pump for nonvolatile memory device
Granted: May 30, 2000
Patent Number:
6069519
A distribution charge pump is disclosed that reduces leakage from a VPP node where a programming voltage (VPP) is provided. The distribution charge pump includes a pump section and a biasing network. The pump section, in response to input signals at 0V or VCC, generates corresponding output signals at 0V or VPP, respectively. Typically, VCC can be between 2V and 5V and VPP can be between 11V and 15V. The pump section includes two n-channel transistors that bootstrap each other to…
System and method for a low voltage charge pump with large output voltage range
Granted: May 16, 2000
Patent Number:
6064251
A low voltage charge pump system with a large output voltage range is described. The charge pump system comprises eight charge pump stages, an output stage, and a four phase clock generator. The clock generator generates two sets of four phase shifted signals. The first set of four clock signals are coupled to the first four charge pump stages and have a logic high level of VCC. The second set of clock signals are coupled to the second four charge pump stages and have a logic high level…
DRAM repair apparatus and method
Granted: April 4, 2000
Patent Number:
6046945
An apparatus and method for minimizing the access time incurred when accessing redundant columns of a dynamic random access memory (DRAM) is herein disclosed. A pair of redundant columns is associated with a defective column. Each pair of redundant columns has a single redundant column decoder that provides access to the column data in the pair of redundant columns. The redundant column decoder is enabled by the column repair circuitry when it receives a column address signal indicating…
Fast on-chip current measurement circuit and method for use with memory array circuits
Granted: February 29, 2000
Patent Number:
6031777
A high speed memory cell current measurement circuit uses an on-chip reference current circuit that generates a reference current Iref. The reference current circuit includes a first current source transistor. An on-chip current comparison circuit has a second current source transistor that is coupled to the first current source transistor so as to mirror the reference current Iref at a fixed current ratio WR. The current comparison circuit has a current connection path connecting the…
Guaranteed dynamic pulse generator
Granted: February 22, 2000
Patent Number:
6028814
The present invention is dynamic pulse generator for generating an output pulse from a first input pulse and a second input pulse, where the output pulse is guaranteed to have a pulse width of at least the pulse width of whichever of the two input pulses has a delayed leading edge with respect to the other. The first input pulse has a first leading edge and a first trailing edge. The second input pulse has a second leading edge and a second trailing edge. The second leading edge is…
