Abstract: In a preferred embodiment, a battery charging system in the form of an integrated circuit (IC), incorporated in a consumer electronic device, has a charging controller, a charging current generator, a junction temperature sensor, and a device current monitor. The junction temperature sensor provides to the charging controller a measured junction temperature of the IC. The charging current generator utilizes fractional synthesis, which involves regulating the duty cycles of multiple current sources, to achieve increased current resolution. The charging controller regulates the charging current provided by the charging current generator based on the relation of the measured junction temperature to three or more threshold temperatures.

Abstract: A phase-locked loop includes a variable frequency generator, a comparator and a counter. The variable frequency generator is configurable for generating an output signal having a frequency which varies based at least in part on at least first and second control signals presented thereto. The comparator is configurable for receiving a first signal and a second signal, the first signal being an input signal presented to the phase-locked loop and the second signal being representative of the output signal from the variable frequency generator. The comparator generates a difference signal representative of a difference between a phase and/or a frequency of the first and second signals, the difference signal comprising the first control signal. The counter is configurable for generating an output count based at least in part on the difference signal from the comparator. The output count is a digital representation of the difference signal, the output count comprising the second control signal.

Abstract: Disclosed is a circuit for testing a delay module. An output of a ring oscillator formed with the delay module is transmitted to a counter. The counter generates a plurality of counts, each count associated with a setting of control lines of the delay module. One of the plurality of counts is then compared with a previous one of the plurality of counts.

Abstract: A signal buffering and retiming (SBR) circuit for a plurality of memory devices. A PLL-based clock generator generates a set of phase-shifted clock signals from a received host clock signal. Each of a plurality of phase selectors independently selects a subset of contiguous clock signals from the set of phase-shifted clock signals. Each subset of contiguous clock signals is applied to a different set of one or more verniers, each vernier independently selecting one of the contiguous clock signals as its retiming clock signal for use in generating either (1) an output clock signal or a retimed bit of address or control data for one or more of the memory devices or (2) a feedback clock signal for the PLL-based clock generator. The SBR circuit can be designed to satisfy relatively stringent signal timing requirements related to skew and delay.

Abstract: A duty-cycle generator including, in one embodiment, a duty-cycle adjustment circuit and a delay processor. The duty-cycle adjustment circuit is adapted to receive an input clock signal having an input duty cycle, generate first and second versions of the input clock signal having different amounts of delay, and combine the first and second versions of the input clock signal to generate an output clock signal having an output duty cycle different from the input duty cycle. The delay processor is adapted to generate at least one control signal for controlling operations of the duty-cycle adjustment circuit based on a comparison of a characteristic of the output clock signal with a corresponding characteristic of a target output clock signal.

Abstract: A clock selector for selecting a set of candidate clock signals from among a plurality of input clock signals. The phase selector includes control logic adapted to generate a plurality of control signals and a plurality of muxes controlled by the control signals and arranged in two or more stages having at least a first stage and a last stage. The input to the first stage is the plurality of input clock signals. At least one stage is adapted to (i) receive a plurality of clock signals, (ii) drop at least the first or the last clock signal of the received plurality of clock signals, and (iii) output a reduced plurality of clock signals. The output of the last stage is the set of candidate clock signals.

Abstract: Techniques are presented for creating a second clock signal by using a first clock signal. For instance, an output is determined that corresponds to a phase relationship between the first and second clock signals. A value, corresponding to a given one of a plurality of delays, is selected based at least partially on the output. The given delay is created, by using the value, on the first clock signal to produce the second clock signal, whereby the given delay creates a phase shift between the first and second clock signals.

Abstract: Techniques are described for slewing a clock frequency of a clock signal from an initial clock frequency to a final clock frequency. An oscillator provides a number of phase outputs. A current frequency divider value is set to an initial frequency divider value, the initial frequency divider value corresponding to the initial clock frequency. A period of a feedback signal is modified through a number of periods from an initial period to a final period, utilizing one or more of the phase outputs. The current frequency divider value is changed when the period of the feedback signal reaches the final period. The modify and change operations are performed until the current frequency divider value reaches a final frequency divider value, where the final frequency divider value corresponds to the final clock frequency.

Abstract: A signal generator circuit includes a controller adapted to generate a divide value in accordance with at least a first control signal, and a divider adapted to divide an output signal of the signal generator circuit by the divisor value. The controller is selectively operable in at least one of a plurality of modes in accordance with at least a second control signal. The controller is configured to calculate each of one or more new divide values so as to vary a frequency of the output signal in accordance with at least one of the first and second control signals. The controller is configured to switch between operational modes and/or switch between divide values, the switching between operational modes and/or divide values being performed in such a manner so as to substantially eliminate discontinuities in the frequency of the output signal.

Abstract: Techniques are presented for creating a second clock signal by using a first clock signal. For instance, an output is determined that corresponds to a phase relationship between the first and second clock signals. A value, corresponding to a given one of a plurality of delays, is selected based at least partially on the output. The given delay is created, by using the value, on the first clock signal to produce the second clock signal, whereby the given delay creates a phase shift between the first and second clock signals.

Abstract: A phase-locked loop includes a variable frequency generator, a comparator and a counter. The variable frequency generator is configurable for generating an output signal having a frequency which varies based at least in part on at least first and second control signals presented thereto. The comparator is configurable for receiving a first signal and a second signal, the first signal being an input signal presented to the phase-locked loop and the second signal being representative of the output signal from the variable frequency generator. The comparator generates a difference signal representative of a difference between a phase and/or a frequency of the first and second signals, the difference signal comprising the first control signal. The counter is configurable for generating an output count based at least in part on the difference signal from the comparator. The output count is a digital representation of the difference signal, the output count comprising the second control signal.

Abstract: A signal generator circuit includes a controller adapted to generate a divide value in accordance with at least a first control signal, and a divider adapted to divide an output signal of the signal generator circuit by the divisor value. The controller is selectively operable in at least one of a plurality of modes in accordance with at least a second control signal. The controller is configured to calculate each of one or more new divide values so as to vary a frequency of the output signal in accordance with at least one of the first and second control signals. The controller is configured to switch between operational modes and/or switch between divide values, the switching between operational modes and/or divide values being performed in such a manner so as to substantially eliminate discontinuities in the frequency of the output signal.

Abstract: Techniques are described for slewing a clock frequency of a clock signal from an initial clock frequency to a final clock frequency. An oscillator provides a number of phase outputs. A current frequency divider value is set to an initial frequency divider value, the initial frequency divider value corresponding to the initial clock frequency. A period of a feedback signal is modified through a number of periods from an initial period to a final period, utilizing one or more of the phase outputs. The current frequency divider value is changed when the period of the feedback signal reaches the final period. The modify and change operations are performed until the current frequency divider value reaches a final frequency divider value, where the final frequency divider value corresponds to the final clock frequency.

Abstract: Frequency spectrum spreading of a timing recovery circuit, such as a PLL, is controlled by periodically calculating each value for a divisor, M, of a fractional divider in the feedback path of the PLL. The fractional divider divides the output signal of a voltage-controlled oscillator (VCO) of the PLL by the divisor, M, and the value for divisor, M, is periodically updated based on a spreading profile. The output of the fractional divider and a reference clock signal are provided to a phase detector of the PLL so as to cause the PLL to slew the output frequency of the PLL in accordance with the spreading profile.