Shaoxing Yuanfang Semiconductor Co., Ltd.

Ningbo Aura Semiconductor Co., Limited

Sandeep Sasi

Raja Prabhu J

Ankit Seedher

Srinath Sridharan

Debasish Behera

Jeevabharathi G

Purva Choudhary

Akash Gupta

Harshavardhan Reddy

Bhupendra Sharma

Akash Kumar Gupta

Chandrashekar Bg

Venkata Krishna Mohan Panchireddi

Nandini Ganig Bs

An electronic block includes multiple independent Phase-Locked Loops (PLLs) and a switch matrix. Each PLL has an input path and an output path. The switch matrix is operable to concurrently connect a respective signal on the output path of each PLL to the input path of another PLL. In an embodiment, each of the respective signals on the output paths is a corresponding frequency-correction signal generated by a low-pass filter (LPF) in the corresponding PLL. In an embodiment, each PLL includes a frequency-correction signal combiner to combine the frequency-correction signals received from any of the other PLLs with its own frequency-correction signal to form a combined frequency-correction signal. The combined frequency-correction signal is provided to a controlled oscillator in the PLL to generate an output clock of the PLL based on the combined frequency-correction signal. The frequency-correction signals may be analog or digital signals.

Inter-PLL communication in a multi-PLL environment

A phase-locked loop (PLL) is implemented to have another (second) PLL in place of the controlled oscillator. When a known frequency change in the frequency of the output clock is desired, in addition to changing a configuration of the PLL (first PLL), the configuration of the second PLL is also changed to cause the frequency of the output clock to change quickly. In various embodiments, the configuration of the second PLL is changed by changing the divisor of the feedback divider of the second PLL, the divisor in a pre-scaler in the second PLL, the control voltage of a VCO used in the second PLL, and any other point of user control in the second PLL.

Fast switching of output frequency of a phase locked loop (PLL)

A fractional sampling-rate converter includes a first-in first-out (FIFO) buffer, a write logic, a read logic and a fractional interpolator. The write logic is designed to write input data samples into the FIFO at a first rate. The fractional interpolator is coupled to receive the input data samples from the FIFO and is designed to generate corresponding interpolated data samples as an output of the fractional sampling-rate converter at a second rate. The read logic is designed to cause input data samples in the FIFO buffer to be transferred to the fractional interpolator. A ratio of the second rate and the first rate is a fractional number greater than one.

Fractional sampling-rate converter to generate output samples at a higher rate from input samples

Enhancing the accuracy in compensating errors caused by a reference signal with unequal successive periods in a fractional-N phase locked loop (PLL). A compensation block generates a compensation factor, and is implemented based on a correction block and a filter. The correction block generates a correction signal containing a first frequency correction factor and a second frequency correction factor for a first period and a second period constituting each pair of successive periods, with the correction signal also containing a noise component at direct current (DC). The filter operates to remove the noise component at DC from the correction signal to generate a compensation factor containing the first frequency correction factor and the second frequency correction factor. The compensation factor thus generated may be provided as an input to a division factor generator of a frequency divider block of the PLL, potentially resulting in zero error frequency synthesis.

Reducing noise contribution in compensating for unequal successive time periods of a reference clock in a fractional-N phase locked loop

A division factor generator of a feedback divider block in a fractional-N phase locked loop (PLL). The division factor generator is enabled to operate with larger values of division factors without increased complexity of an internal modulator core implemented, for example, as a delta-sigma modulator (DSM) having a signal transfer function (STF), wherein the STF always generates only an integer value as an output in response to an integer value received as input.

Reduction of noise in output clock due to unequal successive time periods of a reference clock in a fractional-N phase locked loop

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Bengaluru, India

Sandeep Sasi