Microsoft Technology Licensing, LLC

Level One Communications, Inc.

Cambridge Display Technology Limited

Stefan M Wurster

Barry Thompson

Haim Shafir

Dane Snow

Richard McCauley

David T Chan

Joseph E Heideman

Euan Christopher Smith

Daniel L Ray

Ralph E Andersson

Lawrence Albert Prather

David S Wong

Mustansir Y Mukadam

Richard Alan Page

Shaun M McCarthy

Cecil Aswell

David S Warren

Cheng-chung Shih

A clocking system disclosed herein includes a delay locked loop (DLL) circuit with a plurality of delay elements, where the DLL circuit is configured to receive a clock input signal and generate a plurality of clock output signals. The clocking system also includes a feed-forward system configured to increase the speed of the clock signal transmission through the delay elements and to enforce symmetric zero crossings of the clock signal at each of the plurality of delay elements.

Scaleable DLL clocking system

A voltage mode laser diode driver selectively turns on and off a laser diode. An output stage has an output node configured to be connected to one of the terminals of the laser diode. Depending upon implementation, an active swing controller drives the output stage in a manner that substantially prevents inductive kickback from causing the output node voltage to swinging above the voltage level at the voltage output of the power supply, or swing below ground. The output stage provides a discharge path around the laser diode to shunt current associated with the inductive kickback, and substantially eliminates ringing on the output node of the output stage while the laser diode is off. A power supply controller adjusts the voltage level of the voltage output of the power supply so that current through the laser diode when on and emitting light is substantially equal to a predetermined desired current.

Power efficient laser diode driver circuit and method

Two transistors are connected between a power source and separate current references. The base of the first transistor is connected to a bias voltage, and the base of the second transistor is connected to the output of a differential amplifier. The amplifier inputs are connected to the nodes where the transistors are connected to the current references. The transistors and the current references may be of different sizes, such that the output voltage of the amplifier is a function of temperature and of the product of the ratios of the transistors and the current references. A number of switches may be employed such that, in alternative modes of operation, the amplifier is used to buffer the bias voltage, the offset of the amplifier, the output of the first transistor, and/or a stored sample of the temperature output voltage, which are combined to arrive at an adjusted temperature reading.

High accuracy voltage references

A transducer such as a translinear proportional-to-absolute-temperature sensor uses two amplifiers, where each amplifier is used in a variety of modes. The first amplifier generates a measurement voltage though feedback in an analog circuit. The second amplifier samples and integrates the measurement in a switched-capacitor mode, and the output is stored on a capacitor. Then the first amplifier is set to measure its offset. The offset is sampled and integrated by the second amplifier, and the output is stored on a second capacitor. Then the first and second amplifiers are set to buffer the voltages stored on the capacitors. The measurement can then be offset-adjusted by digital or analog means. The adjusted measurement is then available to be used for calibration of, e.g., an image sensor. Other transducers, such as pressure sensors, strain sensors, gyroscopes, magnetometers, accelerometers, and xyz positioning sensors may employ the same dual amplifier approach.

Transducer measurement

A method of driving an electro-optic display comprising providing a current source, digitally modulating the current source and generating a modulated digital signal, and converting the modulated digital signal into an effective analog drive signal so that the display pixels receive an effective analog drive current, wherein the internal capacitance of the electro-optic display smooths the digitally modulated signal and generates the effective analog drive signal.

Method of driving an electro-optic display utilizing internal capacitance to smooth a digitally modulated signal

A current matching control apparatus for matching a plurality of current sources and a plurality of current sinks, the plurality of current sinks having a drive current value controlled by a drive processor in accordance with a reference control current and wherein each output of the plurality of current sinks are connected to a common output node; a feedback circuit having an input connected to the common output node and an output connected to the drive processor, wherein the feedback circuit is arranged to match a voltage at the common output node to a reference voltage by communicating a signal to the drive processor to adjust the reference control current.

Matching current source/sink apparatus

An inter-repeater backplane that allows seamless integration of multiple repeaters into a single hub and wherein each repeater may be swapped out without causing the backplane to crash, hang-up or pass error messages. The mixed signal state machines operate in conjunction with the dual analog, digital collision signaling scheme so that repeaters can be removed from the hub without causing the remaining repeaters in the hub to malfunction. Additional drivers or external glue logic are not needed for arbitration because PORTN and PORTM information is embedded within the backplane signals. Thus, the backplane scheme according to the present invention is completely seamless. The present invention provides a bus of electrically conductive signal lines coupled between repeaters for communicating electrical signals therebetween, collision signaling scheme that uses both analog and digital signals to convey state machine information to adjacent repeaters over the bus, collision force scheme for indicating transmit collision over the bus, monitor scheme for determining when transmit collision and PORTM conditions occur and mixed signal state machines for implementing the functions of the repeaters and controlling the transitions on the backplane. Thus, the unique analog digital backplane combination in conjunction with the repeater/IRB state machine makes bus arbitration unnecessary.

Inter-repeater backplane for allowing hot-swapping of individual

An inter-repeater backplane employs both analog and digital circuitry to convey state machine information to adjacent repeaters thereby allowing seamless integration of multiple repeaters into a single hub without requiring additional drivers or external glue logic. A data path allows the passage of data between multiple repeaters on the inter-repeater backplane and an inter-repeater backplane enable allows individual repeaters to take control of the inter-repeater backplane data bus. An inter-repeater backplane driver enables external bus drivers which may be required in synchronous systems with large backplanes. An inter-repeater backplane clock is used to synchronize multiple repeaters on the inter-repeater backplane. Only two leads (IRCOL and IRCFS) are used to provide transmit and receive collision information. These two leads in conjunction with IRENA also indicate which repeater is receiving data. The transmit and receive collision information is presented on the backplane in a manner that is both analog and digital in nature.

Inter-repeater backplane with mixed signal state machine interconnect

A pair of electrical display elements, LEDs, is driven by a three-state buffer driver circuit. The LEDs have associated current-limiting resistors. The driver circuit applies different selected voltage levels at different selected predetermined frequencies to the LEDs. By having two predetermined frequencies to a pair of LEDs, there can be exhibited at least five different display conditions from the pair of LEDs.

Electrical display elements for displaying multiple different conditions

An inter-repeater backplane that allows either synchronous or asynchronous data transmission between multiple repeaters integrated into a single hub and enables any repeater to be swapped out without causing the backplane to crash, hang-up, or pass error messages. A dual analog, digital collision signaling scheme is utilized to obviate the need for additional drivers or external glue logic for arbitration. 'the specific port of a hub receiving data (PORTN)'. and The one port left state (PORTM) information is embedded within the backplane signals. Thus, the backplane scheme according to the present invention is completely seamless. Unique state machines enable the repeater to transmit data either synchronously or asynchronously. In the synchronous mode of data transmission, the data is synchronized with the system clock. When the asynchronous mode of data transmission is selected, the recovered data is synchronized with a clock signal associated with the transmitting repeater. Mixed signal state machines operate in conjunction with the dual analog, digital collision signaling scheme to prevent malfunctions when individual repeaters are swapped or removed. The mixed signal state machines implement the functions of the repeaters and control the transitions on the backplane. Thus, the unique analog digital backplane combination in conjunction with the repeater inter-repeater blackplane (IRB) state machine makes bus arbitration unnecessary.

Inter-repeater backplane

A data communication system employing predetermined equalized waveforms for transmit equalization is disclosed. Serial NRZ data is received from a network controller and utilized to select from memory its equivalent as predistorted and filtered Manchester encoded data. Predetermined waveforms in memory are representative of the analog waveform produced when predistorted digital Manchester encoded data is passed through a high order transmit filter. Data from memory drives a digital to analog converter (DAC) to reconstruct the waveforms into analog form. A line driver having an integrated single pole low pass filter impresses the equalized waveform on to the transmission line.

System and method employing predetermined waveforms for transmit

A two terminal line driver employing predistortion is disclosed, for driving data over a lossy transmission line such as a twisted pair cable at speeds on upwards of 10 Mbit/s. The driver is designed for voltage output operation wherein fullstep and halfstep information is actively encoded into a voltage level provided for at the output terminals. The driver provides a fullstep voltage spanning the supply rails and a halfstep voltage having a selectable controlled amplitude of a predetermined value. Fat bits resulting from the biphase encoding format are predistorted by dropping the amplitude to a predetermined value, equalizing the relative power content.

Growing community of inventors

Livermore, CA, United States of America

Stefan M Wurster