Silicon Integrated Systems Corporation

M31 Technology Corporation

Tze-hsiang Chao

Chia-hao Yang

Chia-jung Liu

Ming-yen Tsai

An impedance calibration circuit includes a variable impedance circuit, a detection circuit and a control circuit. The variable impedance circuit includes conduction paths connected in parallel between an output terminal and a supply terminal coupled to a first supply voltage. The variable impedance circuit is configured to adjust an impedance at the output terminal by enabling one or more of the conduction paths according to a calibration code. The detection circuit is configured to detect a change in impedance of the conduction paths by applying a second supply voltage to a reference terminal through a detection path, and accordingly generate an input voltage at the reference terminal. An electric potential of the second supply voltage is equal to an electric potential of the first supply voltage. The control circuit is configured to compare the input voltage with reference voltages to generate the calibration code.

Impedance calibration circuit and method

A system for clock-switching applied in the field of integrated circuits is described. A phase interpolator converts an input clock signal into a clock_A and a clock_B having a phase difference therebetween and transmitting the clock_A and the clock_B. A switch command unit connected to the phase interpolator receives either the clock_A or the clock_B serving as a triggering signal for triggering the switch command unit to transform an input switching signal into an output switching signal when the output switching signal is located in either a rising or a falling edge. A selecting device connected to the phase interpolator and the switch command unit, selects either clock_A or clock_B according to the output switching signal from the switch command unit to output a clock-switching signal composed of clock_A and clock_B.

System and method for clock switching

An apparatus and a method of controlling and tuning clock phase alignment with a dual loop of a hybrid phase and time domain for clock source synchronization in electronic devices are described. The coarse calibration unit generates a plurality of output signals, the output signals having a plurality of fixed phase intervals therebetween. At least one of the fixed phase intervals is equal to complete 360 degrees which are divided by the number of the output signals to cover the phase range of complete 360 degrees. The first fine calibration unit connected to the coarse calibration unit delays the output signals generated from the coarse calibration unit by coupling a programmable delay circuit to adjust the phase of a feedback signal toward the phase of a reference signal. The phase detector connected to the first fine calibration unit is used to detect a phase difference between the reference and the feedback signals and outputting an indicating signal corresponding to the phase difference between the reference and the feedback signals. The controller controls the coarse calibration unit and the first fine calibration unit to align the feedback signal to the reference signal according to the indicating signal generated from the phase detector. The rotating detector rapidly tunes the phase difference between the feedback signal and the reference signal by adding a number of time delays to the feedback signal when the feedback signal and the reference signal are miss-aligned.

Apparatus and method of controlling and tuning a fine calibration for clock source synchronization in dual loop of hybrid phase and time domain

An apparatus and a method of controlling clock phase alignment with a dual loop of a hybrid phase and time domain for clock source synchronization in electronic devices are described. The coarse calibration unit generates a plurality of output signals, the output signals having a plurality of phase intervals therebetween. A predetermined phase angle is divided by the number of the output signals to generate one of the phase intervals. The first fine calibration unit connected to the coarse calibration unit delays the output signals generated from the coarse calibration unit by coupling a programmable delay circuit to adjust the phase of a feedback signal toward the phase of a reference signal. The phase detector connected to the first fine calibration unit is used to detect a phase difference between the reference and the feedback signal and outputting an indicating signal corresponding to the phase difference between the reference and the feedback signal. The controller controls the coarse calibration unit and the first fine calibration unit to align the feedback signal to the reference signal according to the indicating signal generated from the phase detector.

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Hsinchu, Taiwan

Tze-hsiang Chao