Neomagic Corporation

Signetics

Cirrus Logic Inc.

North American Philips Corp, Signetics Division

Deepraj S Puar

Ravi Ranganathan

Adrian E Ong

A graphics controller system which has a graphics engine and video memory together with some interface blocks, a PCMCIA host adapter, an infrared interface for generating video images on a LCD or CRT display unit, and a video stream interface for receiving video signals, all in the form of a CMOS integrated circuit. The video memory is integrated on the same integrated circuit as the graphics controller; no package pins are required for the memory interface. Simultaneous performance improvement and power dissipation reduction is achieved because of the wide memory interface and the elimination of the large parasitic capacitances associated with a package pin connection.

Graphics controller integrated circuit without memory interface

A CMOS integrated circuit which has a graphics controller system that has a graphics engine and video memory together with some interface blocks, a PCMCIA host adapter, an infrared interface for generating video images on a LCD or CRT display unit, and a video stream interface for receiving video signals. Since the video memory is integrated on the same integrated circuit as the graphics controller, no package pins are required for the memory interface. The pins thus saved are used to provide access to an on-chip PCMCIA host adapter. The internal memory interface is 128 bits wide. Simultaneous performance improvement and power dissipation reduction is achieved because of the wide memory interface and the elimination of the large parasitic capacitances associated with package pin connections.

A graphics controller system which has a graphics engine and video memory together with some interface blocks, a PCMCIA host adapter, an infrared interface for generating video images on a LCD or CRT display unit, and a video stream interface for receiving video signals, all in the form of a CMOS integrated circuit. The video memory is integrated on the same integrated circuit as the graphics controller; no package pins are required for the memory interface. Simultaneous performance improvement and power dissipation reduction is achieved because of the wide memory interface and the elimination of the large parasitic capacitances associated with a package pin connection

A CMOS integrated circuit that comprises a graphics controller system that consists of a graphics engine and video memory together with some interface blocks, a PCMCIA host adapter, an infrared interface for generating video images on a LCD or CRT display unit, and a video stream interface for receiving video signals. Since the video memory is integrated on the same integrated circuit as the graphics controller, no package pins are required for the memory interface. The pins thus saved are used to provide access to an on-chip PCMCIA host adapter. The internal memory interface is 128 bits wide. Simultaneous performance improvement and power dissipation reduction is achieved because of the wide memory interface and the elimination of the large parasitic capacitances associated with a package pin connection.

A content-addressable memory (CAM) cell isolates the gate nodes of pass transistors during a write operation. Select transistors between the word line and the pass-transistor gates are driven high by a column-select signal. The bit lines are precharged low. The word line is driven high to Vcc, and the select transistors drive the pass-transistor gates to Vcc-Vtn. One of the bit lines is then driven high to Vcc while the other bit line is held low. As the bit line swings high, capacitive coupling drives one of the pass-transistor gate nodes higher, above Vcc-Vtn. The select transistor then isolates the gate node from the word line. As the bit line continues to swing high, more coupling drives the gate node above Vcc. The boosted gate-node voltage increases the current drive of the pass transistor, accelerating the write operation. When the word line drop to ground, the select transistors drain the gate nodes, disabling the pass transistors and dynamically storing charge on the gates of storage transistors. The drains of the storage transistors are connected to a match line through a pair of match transistors. The gates of the match transistors are connected to the bit lines. The match transistors and storage transistors form an exclusive-OR (XOR) function with two series connections to the match line. When both a match transistor and a storage transistor in series are on, the match line is discharged, indicating a mis-match.

NMOS dynamic content-addressable-memory CAM cell with self-booting pass

Graphics controller integrated circuit without memory interface pins and

A controller chip has dynamic logic which is driven by a suspendable clock. Power is reduced in a standby mode when the clock to the dynamic logic is stopped. However, power is still applied to the dynamic logic in standby mode so that the dynamic logic can be quickly resumed without the delay of re-charging the power-supply capacitances in the dynamic logic. Stopping the clock to dynamic logic can eventually cause loss of data. A more severe problem than data loss is power consumption. When the clock is stopped to dynamic logic, the isolated nodes leak and eventually their voltages change. When their voltages change by more than a transistor threshold voltage then both the p-channel and n-channel transistors in dynamic logic cells can turn on, forming a direct current paths between power and ground. Thus power consumption can increase dramatically in suspend mode. The isolated dynamic nodes of the dynamic logic are instead recharged periodically during suspend mode. A timer triggers generation of intermittent clock pulses which are applied to the clock to the dynamic logic, recharging the isolated nodes. When data loss can be tolerated, the intermittent pulses ensure that power consumption does not jump due to the voltage changes on the isolated dynamic nodes.

Dynamic logic having power-down mode with periodic clock refresh for a

Each touchdown of a probe card during wafer-sort testing of integrated circuits can leave a gouge in the pad metal. These gouges reduce the reliability of any wire bond to that pad as voids can be left in the bond where the gouges are. A second auxiliary test pad is adjacent to the primary bonding pad. This second auxiliary test pad is electrically connected to the primary bonding pad. Thus probes can land on the second auxiliary pad rather than the primary pad. Gouges are made on the second pad rather than the primary pad. This second test pad allows for multiple probing. Multiple probing is needed for testing large embedded memories on large logic chips such as video controllers. The yield of large memories is increased by laser repair. Probing and testing is required both before and after laser repair using a memory test machine. However, a logic test machine is used to test the logic controller portion of the IC, but cannot generate the millions of test vectors needed to fully test the embedded memory. Only the pins that are used for both memory testing and logic testing need the second auxiliary pads. Thus the probes can land on the second test pads multiple times while the wire bond is made to the primary bonding pad.

Multiple probing of an auxilary test pad which allows for reliable

A circuit is added to a complementary metal-oxide silicon (CMOS) integrated circuit (IC) to provide an intentional, non-reverse-biased VDD-to-VSS shunt path for transient currents such as electrostatic discharges (ESD). This circuit protects the IC from ESD damage by turning on before any other path, thus directing the ESD transient current away from easily damaged structures. Specifically, the ESD transient current is steered from the VDD rail to the VSS rail through the on conduction of a P-channel transistor whose source and drain are connected to VDD and VSS respectively. The voltage on the gate of this transistor follows the VDD supply rail because it is driven by a delay network formed by a second transistor and a capacitor. This VDD-tracking delay network turns the VDD-to-VSS transistor on during a transient and off during normal operation of the IC.

Shunt circuit for electrostatic discharge protection

A device (16) for preventing an input signal (V.sub.I) applied to a terminal (12) of an integrated circuit from damaging a section (18) of the circuit contains a regular enhancement-mode insulated-gate FET (Q1 or Q2), a resistor (R1 or R2) that enables the regular FET to act temporarily like a 'floating-gate' FET, and a thick-oxide insulated-gate FET (Q3).

Input protection device for integrated circuits

An on-chip regulated substrate bias voltage generator for an MOS integrated circuit includes a ring oscillator (10) for developing a true signal and its complement. The signals are applied to a charge pump (12) that includes two capacitors (C1 and C2) and a plurality of rectifiers (22, 24, and 26). The charge pump produces a substrate bias voltage (V.sub.BB) which is supplied to the gate of a depletion-mode field-effect transistor (28) whose source receives a reference voltage (V.sub.SS). The transistor forms part of a control circuit (14) coupled to the ring oscillator. In the N-channel case, the charge pumping action on the substrate drives the substrate bias negative until it reaches the sum of the reference voltage and threshold voltage of the depletion-mode transistor. This enables the control circuit to control the operation of the ring oscillator so as to regulate the substrate bias voltage.

Depletion-mode FET for the regulation of the on-chip generated substrate

An amplifier circuit for sensing and refreshing stored information, utilized with a voltage supply. The amplifier is of the type that is capable of assuming first and second conditions in response to signals at first and second input nodes. The circuit comprises first and second cross coupled devices each capable of assuming a high and low conduction state. Restore circuitry means is provided connected between the active devices and the voltage supply for selectively connecting the supply solely to the device assuming a low conduction state. In a dynamic random access memory embodiment means is further provided for alternately precharging the nodes to a predetermined state and applying stored information to the nodes to cause the amplifier to assume first and second conditions in response to stored information.

Sense and refresh amplifier circuit

An improved read-only memory arrangement for generating a differential output signal within the memory array itself incorporates a column of reference cell transistors and a single reference bit line within the same general area occupied by the memory cell transistors and memory main bit lines. Each word line is coupled to the gate of one of the reference cell transistors as well as to the gates of the memory cell transistors lying in the same row. The reference bit line voltage is maintained substantially midway between the high and low potential levels of the main bit lines to produce a differential output voltage for sensing purposes.

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Sunnyvale, CA, United States of America

Deepraj S Puar