Abstract: An I/O driver comprising: a circuit adapted to be powered by a first power supply. The circuit is adapted to receive a first signal referenced to the voltage of a second power supply and is adapted to convert the first signal to a second signal of the same logical value as the first signal and referenced to the voltage of the first power supply. The circuit is adapted to maintain the second signal on an output of the I/O driver when the second power supply is powered off.

Abstract: An I/O driver comprising: a circuit adapted to be powered by a first power supply. The circuit is adapted to receive a first signal referenced to the voltage of a second power supply and is adapted to convert the first signal to a second signal of the same logical value as the first signal and referenced to the voltage of the first power supply. The circuit is adapted to maintain the second signal on an output of the I/O driver when the second power supply is powered off.

Abstract: A method for enhancing power bus for I/O libraries in ASIC designs is disclosed. An I/O assignment for I/O circuits to be utilized in an ASIC design is initially generated. Each I/O circuit may obtain power from either a primary I/O power bus or a secondary I/O power bus. A determination is then made as to whether or not the I/O assignment meets certain predetermined power distribution requirements. In a determination that the I/O assignment does not meet the predetermined power bus distribution requirements, a power enhancement cell is added. The power enhancement circuit includes at least one metal line for connecting the primary I/O power bus to the secondary I/O power bus in order for the I/O assignment to meet the power bus distribution requirements.

Abstract: A method for enhancing power bus for I/O libraries in ASIC designs is disclosed. An I/O assignment for I/O circuits to be utilized in an ASIC design is initially generated. Each I/O circuit may obtain power from either a primary I/O power bus or a secondary I/O power bus. A determination is then made as to whether or not the I/O assignment meets certain predetermined power distribution requirements. In a determination that the I/O assignment does not meet the predetermined power bus distribution requirements, a power enhancement cell is added. The power enhancement circuit includes at least one metal line for connecting the primary I/O power bus to the secondary I/O power bus in order for the I/O assignment to meet the power bus distribution requirements.

Abstract: A method and apparatus for implementing a dual voltage driver circuit having two predrive circuits for driving the supported voltages. The driver circuit automatically senses the operating voltage and selects the appropriate predrive circuitry while isolating the non-selected predrive circuitry from the sensed voltage.

Abstract: An enhanced 2.5V LVDS driver with 1.8V technology for 1.25 GHz provides high speed performance for off chip drivers. Level shifting is accomplished in predriver circuits with buffer amplifier circuits operating at the on chip operating voltage level driving differential amplifiers operating at the higher driver circuit operating voltage level. An enhancement circuit is interposed between the level shifting circuits and the output stage, and this enhancement circuit speeds up the switching times of the signals input to the output stage. The enhancement circuit comprises first and second complementary transistors connected in cascode between the higher driver circuit operating voltage and a third transistor connected between the node of a predriver circuit and the higher supply voltage. The gate of the third transistor is connected to a common node between the first and second transistors.

Abstract: A method and apparatus for implementing a dual voltage driver circuit having two predrive circuits for driving the supported voltages. The driver circuit automatically senses the operating voltage and selects the appropriate predrive circuitry while isolating the non-selected predrive circuitry from the sensed voltage.

Abstract: A method and apparatus for enhancing reliability of a high voltage input/output (I/O) driver/receiver reduces voltage stress on transistors forming part of a logic I/O driver/receiver. The driver/receiver is designed to handle voltages greater than the power supply rails and a bias circuit reduces the voltage stress present on the output stage when a power supply voltage is removed from the circuit. The bias circuit is driven by I/O pin voltage to control a transistor within the I/O logic ladder.

Abstract: A driver circuit has an input terminal at which a first signal having a first voltage swing is applied, and an output terminal at which: (i) a second signal having a second voltage swing is provided to external circuitry, and (ii) a third signal having a third voltage swing is received from the external circuitry. A level shifter circuit is coupled to the input terminal and translates the first signal to the second signal. The level shifter circuit includes circuitry which regulates the switching rate of the driver circuit. An output circuit is coupled between the level shifter circuit and the output terminal which drives the external circuitry with the second signal received from the level shifter circuit. The output circuit has a floating well, and a bias circuit is coupled between the output terminal and the well of the output circuit. The bias circuit biases the well proportional to the third voltage swing when the third signal is received at the output terminal.

Abstract: An off-chip driver (OCD) circuit including a clamp circuit to limit overdrive is provided. The circuit comprises an input signal which is inverted to provide an output signal. The driver circuit is comprised of a source-follower transistor to pull-down the output signal. The clamp circuit actively feeds back the source-follower potential to slow down the OCD and minimize ground bounce and noise that causes circuits to fail and signal integrity to be corrupted. The simple drive and clamp circuit is comprised of three transistors, one resistor, and one capacitor. The OCD slew rate is controlled by a current source and provides an output that changes between a positive voltage and ground. The circuit limits dv/dt without using a large resistor as a source follower, hence minimizing the adverse effect on performance.

Abstract: A dual stage voltage level predrive circuit for an integrated circuit chip including two level shifter stages in series. The voltage level shifting circuit uses single dielectric layer devices and three bias supply circuits each providing a different DC bias voltage for distributing bias voltages among the devices such that dielectric voltage stress across single dielectric layers is reduced. The first stage of the level shifting circuit receives a first input signal having a first voltage swing, converts the first voltage swing to a second voltage swing and provides a first output signal corresponding to the first input signal and having the second voltage swing. The second stage of the level shifting circuit receives the first output signal from the first stage, converts the second voltage swing to a third voltage swing and provides a final output signal having the third voltage swing.

Abstract: Disclosed is an improved push-pull off-chip driver circuit. The circuit includes a push-pull amplifier including a pull-up transistor and a pull-down transistor, each provided with independent inputs and connected at the output node. The input to the pull-up transistor is provided by a transmission gate having an n-channel transistor connected in parallel with a p-channel transistor. A control transistor is coupled between the output node and the gate of the pull-up transistor to provide a protective bias. A feedback override circuit is coupled between the output node and the gate of the p-channel transmission gate transistor to selectively provide either Vout or a low level potential to that gate. The feedback override circuit improves the response time and noise immunity of a prior art off-chip driver in the active mode in a manner consistent with the objectives of protecting the gate oxides from high voltage stress and prevent leakage currents during the high-impedance mode.

Abstract: A bipolar push-pull driver in which the input transistor is biased so that it does not saturate and the base of its associated output transistor is pulled down to shut off compeletely by a transistor switch controlled by the complimentary output of the other input transistor.

Abstract: A low power push pull off chip driver for differential cascode current circuitry is described that includes the collectors of a differential pair directly coupled to bases of a push pull driver and level shifters coupled to the input of the differential pair to prevent saturation of the differential pair.