Apparatuses and methods for adjusting a phase mixer circuit are disclosed. An example method includes providing data values stored by a plurality of first registers and a plurality of second registers. The method includes: during a first mode of operation, receiving the data values by groups of first registers of the plurality of the first registers and holding the data values by the plurality of second registers; during a second mode of operation, inverting a data value by one first register of the plurality of first registers at a time and holding the data values by the plurality of second registers; and during a third mode of operation, either inverting the data value by one first register of the plurality of first registers while holding the data values by the plurality of second registers or inverting a data value by one second register of the plurality of second registers while holding the data values by the plurality of first registers.

A data interface circuit wherein calibration adjustments for data bit capture are made without disturbing normal system operation, is described. A plurality of DLL capture and delay circuits for sampling a trained optimal sampling point as well as leading and trailing sampling points are defined. A first stream of data bits is input to the data interface circuit and using a first calibration method, a first optimal sampling point for sampling the data bits input is established. A second stream of data bits is input to the data interface circuit during normal system operation. A second calibration method is performed that is different from the first, the second calibration method being performed whereby: at least one reference data path is established for sampling transition edges of the second stream of data bits input to the data interface during normal system operation.

A delay measurement circuit includes a first skew circuit disposed proximate to a first bonding pad configured to receive a first clock signal having a first frequency. The delay measurement circuit includes a second skew circuit disposed proximate to a second bonding pad configured to receive a second clock signal having a second frequency. The first and second skew circuits each have a first mode of operation as zero-delay-return path and a second mode of operation as a synchronized pass path. The delay measurement circuit includes a pair of conductive traces coupled to the first skew circuit, another pair of conductive traces coupled to the second skew circuit, a time-to-digital converter circuit, and a switch circuit configured to selectively couple the time-to-digital converter circuit to the first skew circuit via the pair of conductive traces and the second skew circuit via the other pair of conductive traces.

An inverted group delay circuit is provided. The inverted group delay circuit can offset a group delay between a pair of signals. In a non-limiting example, the inverted group delay circuit can be configured to offset a group delay (e.g., negative group delay) between a time-variant voltage and a time-variant envelope of an analog signal. More specifically, the inverted group delay circuit can output an inverted time-variant voltage having an opposing phase and time-adjusted relative to the time-variant voltage to thereby offset the group delay between the time-variant voltage and the time-variant envelope. As such, the inverted group delay circuit can be provided in a power management integrated circuit (PMIC) to improve timing alignment between a time-variant voltage(s) and a time-variant analog signal(s) at a power amplifier(s), thus helping to reduce potential amplitude distortion when the analog signal(s) is amplified by the power amplifier(s).

In accordance with an embodiment, a method includes: receiving, by an adjustable frequency doubling circuit, a first clock signal having a first clock frequency; using the adjustable frequency doubling circuit, generating a second clock signal having a second clock frequency that is twice the first clock frequency; measuring a duty cycle parameter of the second clock signal, where the duty cycle parameter is dependent on a duty cycle of the first clock signal or a duty cycle of the second clock signal; and using the adjustable frequency doubling circuit, adjusting the duty cycle of the first clock signal or the second clock signal based on the measuring.

A clock transfer circuit includes a first stage circuit configured to produce an output signal that uses a second signaling technology from an input signal that uses a first signaling technology; and a second stage circuit configured to produce a clock signal by delaying the output signal; wherein the first stage circuit includes a semiconductor device configured to compensate for delay fluctuation caused by fluctuation of power supply voltage between a first power source and a second power source.

A skew sensor for detecting skew between two input signals is provided. The skew sensor includes at least two skew detectors. The first skew detector receives either a first clock signal or a second clock signal as a first input signal, and the other one of the first clock signal and the second clock signal delayed by a first delay difference induced by one or more delay elements as a second input signal. The second skew detector receives either the first clock signal or the second clock signal as the first input signal, and the other one of the first clock signal and the second clock signal optionally delayed by a second delay difference induced by one more delay elements, wherein the second delay difference is different from the first delay difference, as the second input signal. Skew is measured between the first clock signal and the second clock signal.

Circuits and systems for generating counter signals are provided herein. A circuit may comprise a shift register having a series of flip-flops. Each of the flip-flops of the series may be coupled to a clock. The shift register may generate a borrowing clock signal using an output of a flip-flop of the shift register, and a transition of the borrowing clock signal may be advanced by a number of clock cycles based on a position of the flip-flop of the shift register. The circuit may further comprise a clock divider circuit having a number of divide-by-N counters and a number of flip-flops. A divide-by-N counter may be coupled to a flip-flop of the shift register, and a flip-flop of the clock divider circuit may be coupled to one of the divide-by-N counters and to the clock.

A clock delay circuit includes an output to provide an output clock signal which is a delayed version of an input clock signal. The clock delay circuit includes a latch whose output provides the output clock signal. A delay control circuit provides a third clock signal. The latch includes a first input to receive the input clock signal and a second input to receive the third clock signal. The amount of delay provided by the latch is dependent upon the duty cycle of the third clock signal.

A buffer circuit, a frequency dividing circuit, and a communications device are disclosed. The buffer circuit includes a buffer, a first control circuit, and a second control circuit. The buffer is coupled to a frequency divider, and the buffer is configured to receive a first signal output by the frequency divider, and output a fourth signal by using an output terminal of the buffer circuit when driven by the first signal, where the first signal is obtained by the frequency divider by performing frequency division on a group of differential signals, and the differential signals include a second signal and a third signal. The first control circuit is configured to perform delay control on a rising edge of the fourth signal based on the second signal. The second control circuit is configured to perform delay control on a falling edge of the fourth signal based on the third signal.