Cypress Semiconductor Corporation

Crystal Semiconductor Corporation

Mohammad J Navabi

Michael L Duffy

Kamal Dalmia

Bertrand Jeffery Williams

Baker P Scott, Iii

Stephen F Bily

A parallel sampling phase detector with linear output response. The parallel sampling phase detector for use in data recovery. The device includes a voltage controlled oscillator (VCO) that generates ten separate phase signals using a five stage ring oscillator. Five linear phase detectors are employed in the device, each operating during one of five &ldquo;window&rdquo; intervals. The &ldquo;window&rdquo; intervals are non-overlapping, and are generated using preselected ones of the VCO output phases. The linear phase detectors each generate, respectively, a variable pulsewidth pump up signal wherein the pulsewidth of the pump up signal is proportional to a phase difference between the input data signal applied to the phase detector, and the output phase signals of the VCO. Each phase detector also generates a pump down signal that has a fixed pulsewidth. A loop filter determines the difference between the pump up and pump down signals and develops a control signal to vary the output frequency and phase of the VCO in accordance therewith. Each phase detector also operates as a deserializer, capturing, during the interval when the respective &ldquo;window&rdquo; signal is active, the data signal from the input data stream. The plurality of sampled data signals are captured by a data register, which then outputs an n-bit (5-bit) parallel format data word. The linear phase detector includes means for generating the pump down signal in response to the generation of the pump up signal.

Phase locked loop (PLL) with linear parallel sampling phase detector

A circuit comprising a plurality of input devices, a plurality of select devices and a selector device. The plurality of inputs may each be configured to receive an input. The plurality of select devices may each be configured to present an output in response (i) one of said plurality of inputs and (ii) one of a plurality of select signals. The selector device may be configured to present the plurality of select signals, where only one of the select signals is active at a time.

High-speed, multiple-input multiplexer scheme

A circuit comprising a pump-up circuit and a pump-down circuit. The pump-up circuit may be configured to generate a pump-up signal in response to (i) a data signal and a clock signal. The pump-down circuit may be configured to generate a pump-down signal in response to (i) the data signal, (ii) the clock signal, and (iii) a quadrature of the clock signal.

Phase detector

A circuit comprising a pump-up circuit and a pump-down circuit. The pump-up circuit may be configured to generate a pump-up signal in response to (i) a data signal and a clock signal. The pump-down circuit may be configured to generate a pump-down signal in response to (i) the data signal, (ii) the clock signal, and (iii) a quadrature of the clock signal. The pump-down circuit and the pump-up circuit are generally independent circuits.

A parallel sampling phase detector with linear output response is disclosed. The parallel sampling phase detector for use in data recovery. The device includes a voltage controlled oscillator (VCO) that generates ten separate phase signals using a five stage ring oscillator. Five linear phase detectors are employed in the device, each operating during one of five 'window' intervals. The 'window' intervals are non-overlapping, and are generated using preselected ones of the VCO output phases. The linear phase detectors each generate, respectively, a variable pulsewidth pump up signal wherein the pulsewidth of the pump up signal is proportional to a phase difference between the input data signal applied to the phase detector, and the output phase signals of the VCO. Each phase detector also generates a pump down signal that has a fixed pulsewidth. A loop filter determines the difference between the pump up and pump down signals and develops a control signal to vary the output frequency and phase of the VCO in accordance therewith. Each phase detector also operates as a deserializer, capturing, during the interval when the respective 'window' signal is active, the data signal from the input data stream. The plurality of sampled data signals are captured by a data register, which then outputs an n-bit (5-bit) parallel format data word. The linear phase detector includes means for generating the pump down signal in response to the generation of the pump up signal.

A driver circuit is presented which can transition between output voltage levels at a high switching speed. The preferred output driver is a PECL driver having both a correction circuit portion and a drive circuit portion. The correction circuit senses changes in the base-to-emitter forward bias voltage V.sub.BE of drive transistors within the drive circuit. Thus, any change in performance of those drive transistors is replicated in the correction circuit, which then produces a compensating current. The compensating current is modulated by a reference voltage value, and mirrored to the drive circuit. The drive circuit includes not only differential input transistors and differential drive transistors, but also a resistor coupled to the base terminal of each drive transistor. The resistor receives the compensating current which then offsets any change in voltage level (V.sub.OH or V.sub.OL) produced at the output of the drive transistors. The compensating current and specifically the compensating current as reflected upon the drive transistor outputs offset any dependence upon the forward bias voltage of the drive transistor caused by, for example, temperature or fabrication skews.

Correctable output driver and method of using the same

A parallel sampling phase detector with linear output response is disclosed. The parallel sampling phase detector is disclosed for use in data recovery. The device includes a voltage controlled oscillator (VCO) that generates ten separate phase signals using a five stage ring oscillator. Five linear phase detectors are employed in the device, each operating during one of five 'window' intervals. The 'window' intervals are non-overlapping, and are generated using preselected ones of the VCO output phases. The linear phase detectors each generate, respectively, a variable pulsewidth pump up signal wherein the pulsewidth of the pump up signal is proportional to a phase difference between the input data signal applied to the phase detector, and the output phase signals of the VCO. Each phase detector also generates a pump down signal that has a fixed pulsewidth. A loop filter determines the difference between the pump up and pump down signals and develops a control signal to vary the output frequency and phase of the VCO in accordance therewith. Each phase detector also operates as a deserializer, capturing, during the interval when the respective 'window' signal is active, the data signal from the input data stream. The plurality of sampled data signals are captured by a data register, which then outputs an n-bit (5-bit) parallel format data word. The linear phase detector includes means for generating the pump down signal in response to the generation of the pump up signal.

Phase detector with linear output response

An amplifier having an inverting and a non-inverting input and at least one output is compensated by dynamically varying the transconductance of a gain stage in accordance with the gain of the output stage of the amplifier. The amplifier comprises a gain section having at least one output, where a gm of the gain section varies with a transconductance control signal. The amplifier further comprises an output stage comprising a output drive device controlled by an output of the gain section. A bias control circuit is coupled to drive the transconductance control input of the gain section, the bias control circuit increasing a differential mode transconductance of the first gain stage when the active pullup or pulldown output drive device has low gain.

Amplifier having frequency compensation by gain degeneration

An amplifier with controlled output impedance utilizing current and voltage feedback to set gain and output impedance is disclosed. The voltage feedback is provided by feedback resistor connected from the output to the inverting input. The current feedback is provided by feeding a current proportional to the output current directly to the inverting input of the amplifier. An error amplifier is used to maintain the proper ratio of the current feedback to the output current and to cancel the effects of the output device impedance on the overall output impedance. Two such amplifiers driven by complimentary signals form a differential amplifier with controlled output impedance. Because the output impedance is a function of the voltage feedback resistance and the current feedback ratio, it is possible to digitally control the output impedance by changing the feedback resistance and/or the current feedback ratio.

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Austin, TX, United States of America

Mohammad J Navabi