Lsi Logic Corporation

Nec Electronics Corporation

Tzu-Wang Pan

Shih-Ming Shih

Sang-Soo Lee

Ravindra U Shenoy

Vishnu Balan

Richard A Contreras

Jenn-Gang Chern

A circuit controls an oscillation amplitude of a crystal oscillator including a crystal resonator, a current source supplying a bias current, and an output transistor coupled to the crystal resonator and the current source. The circuit includes a peak detector for detecting a peak voltage of an output signal of the crystal oscillator, and a controller coupled to the peak detector and to the current source for controlling the current source in accordance with a difference between the peak voltage and a target voltage, the target voltage being set to be substantially equal to 2V , where V is a threshold voltage of the output transistor. A frequency control circuit controls a first switched-capacitor array and a second switched-capacitor array coupled to the crystal resonator, and alternately switches a unit capacitor in the first switched-capacitor array and a unit capacitor in the second switched-capacitor array based on a frequency control signal.

Method and apparatus for controlling oscillation amplitude and oscillation frequency of crystal oscillator

A system and method are disclosed for equalizing a read signal from a data storage media is disclosed. An analog output signal is equalized by reading the data storage media using an analog equalization filter. The analog output of the analog equalization filter is converted to a raw digital output signal. The raw digital output signal is processed to detect and correct an error in the raw digital output signal. The error is detected and an adjustment is made to the boost of the analog equalization filter according to the error detected.

Method and apparatus for adapting the boost of a read channel filter

An initial phase control for an oscillator such as a differential ring voltage-controlled oscillator is disclosed. The initial phase control generally comprises a current source circuit coupled to a first node of the delay cell and a current provider. The current source circuit and current provider are preferably selectively and synchronously in an on or off state such that when the current source circuit and current provider are in an on state, the current source circuit draws a current through the first node of the delay cell and the current provider provides current through a second node of the delay cell. A method for controlling a delay cell and an initial phase control for a differential ring oscillator having a plurality of delay cells in a ring configuration are also disclosed.

Initial phase control of an oscillator

A system and method for reduced metastability errors in an analog-to-digital converter (&ldquo;ADC&rdquo;) are disclosed. The ADC comprises comparators configured to output a thermometer code and a thermometer-to-binary encoder for converting the thermometer code to a digital output. The thermometer-to-binary encoder includes a transition detection logic to generate a transition codeword having at least one transition bit corresponding to a transition point in the thermometer code, an intermediate encoding logic to encode the transition codeword into first intermediate signals, a converter logic to convert the first intermediate signals into converted intermediate signals such that same converted intermediate signals result from first intermediate signals corresponding to a transition codeword having more than one transition bit and first intermediate signals corresponding to another transition codeword having one of the more than one transition bit, and a converted signals mapper for mapping the converted signals to the digital output. The transition detection logic may include inverters and AND gates where a threshold voltage of each inverter is preferably greater than a threshold voltage of each corresponding AND gate to which the output of each inverter is input.

Architecture to reduce errors due to metastability in analog to digital converters

Analog-to-digital converter (ADC) output bits are partitioned in a way that simplifies the phase error calculations. The circuit architecture embeds the implementation of the phase error calculations in the analog-to digital-converter (ADC) to simplify the overall circuit implementation. Simplification of the phase error calculations allows a reduction in the complexity of the circuits needed to implement the phase-locked-loop (PLL) for recovering the sampling clock.

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San Jose, CA, United States of America

Tzu-Wang Pan