Abstract: Methods and apparatus are provided for implementing a receiver capable of receiving signals in simultaneous bi-directional current mode differential links. The receiver comprises a resistor-summing network and a differential amplifier. The resistor-summing network can also comprise capacitors for the purpose of attenuating high-frequency noise at the differential amplifier. The high-frequency noise can arise from impedance discontinuities in the signal paths or from differences in rising or falling transition times between the data driver and the replica driver in the links.

Abstract: Methods and apparatus are provided for implementing a CMOS low voltage current source. The current source embodies a voltage feedback mechanism with a low voltage gain. The current source controls a gate of an output driver FET such that a substantially constant current is maintained, even for a portion of the linear range of operation of the output FET. The current source is suitable for driving transmission lines on printed wiring boards, or other application where the load is relatively heavy or complex, and where operation near the power supply is required.

Abstract: Methods and apparatus are provided for implementing a CMOS low voltage current source. The current source embodies a voltage feedback mechanism with a low voltage gain. The current source controls a gate of an output driver FET such that a substantially constant current is maintained, even for a portion of the linear range of operation of the output FET. The current source is suitable for driving transmission lines on printed wiring boards, or other application where the load is relatively heavy or complex, and where operation near the power supply is required.

Abstract: A differential receiver-amplifier having reduced input distortion at differential input (positive and negative) terminals to the differential receiver-amplifier. The output from the differential receiver-amplifier is generated from a differential signal detector receiving each differential input from one of a pair of differential amplifiers.

Abstract: A differential receiver-amplifier having reduced input distortion at differential input (positive and negative) terminals to the differential receiver-amplifier. The output from the differential receiver-amplifier is generated from a differential signal detector receiving each differential input from one of a pair of differential amplifiers.

Abstract: A feedback mechanism is provided to a current mode differential driver by connecting the center tap of a terminator of the output of the driver through feedback resistors to the gates of a positive and a negative current source connected to the driver. Connecting the center tap between the feedback resistors, the average common mode voltage at the output of the differential driver is substantially constant which avoids variations and reflective noise in high speed data transmission that can occur because of manufacturing tolerances.

Abstract: Methods and apparatus are provided for implementing a receiver capable of receiving signals in simultaneous bi-directional current mode differential links. The receiver comprises a resistor-summing network and a differential amplifier. The resistor-summing network can also comprise capacitors for the purpose of attenuating high-frequency noise at the differential amplifier. The high-frequency noise can arise from impedance discontinuities in the signal paths or from differences in rising or falling transition times between the data driver and the replica driver in the links.

Abstract: A resistance circuit includes an off-chip resistor having a precision resistance; a plurality of on-chip switchable resistors, each of which is capable being switched so as to be coupled in parallel to a nominal resistor; and a resistance comparison unit. The resistance comparison unit compares a plurality of on-chip comparison resistors to the off-chip resistor and couples a number of the on-chip switchable resistors to the nominal resistor so that the combined resistance of the parallel combination of the nominal resistor and the coupled on-chip switchable resistors is within a predetermined range of the precision resistance.

Abstract: An echo cancellation circuit for neutralizing signal reflections in a differential link interface, and a method for achieving the same. The differential link interface includes a line driver that generates a line drive signal and a replica driver for generating a replica signal that mirrors the line drive signal within the differential link. The echo cancellation circuit includes a slope adjustment device within the replica driver for temporarily altering the slope of the replica line drive signal during a signal reflection at the output of the line driver, such that the amplitude of the replica signal corresponds to the amplitude of the line drive signal during the signal reflection.

Abstract: A Complementary Metal Oxide Semiconductor (CMOS) current mode differential link with precompensation is provided. The Complementary Metal Oxide Semiconductor (CMOS) bi-directional current mode differential link with precompensation includes a CMOS driver receiving a data input and having an output coupled to a transmission line. A CMOS replica driver receives the data input and provides a replica driver output substantially equal to the CMOS driver output. A CMOS receiver is coupled to both the transmission line and replica driver output. The CMOS receiver subtracts the replica driver output from a signal at the transmission line. The CMOS driver and the CMOS replica driver include a plurality of parallel current sources. Each of the current sources is arranged to send positive or negative current through a load responsive to an applied control signal. The use of the plurality of parallel current sources allows the CMOS driver to effectively implement precompensation.

Abstract: One phase of a multi-phase spindle motor, normally used to rotate the disk of a disk drive system when power is on, is used to supply power to a capacitor storage circuit when power is lost (turned off or otherwise interrupted). The capacitor storage circuit provides the power to the retract circuit, which retracts the head. The combination of the generator effect of the phase and the capacitor storage circuit provides power to the retract circuit for a time clearly sufficient to reliably retract and lock the head regardless of the bias of the head prior to power loss.Simultaneously with one phase being used to retract the head, the other phases are shorted together to provide regenerative braking. FET drivers, normally used to drive the spindle motor when power is supplied, are used to short out the remaining phases to brake the motor when power is lost.In the preferred embodiment, the capacitor storage circuit is used as a line filter circuit when power is on.