Abstract: A power supply includes a first DC-DC converter coupled to receive power from a first power source, a second DC-DC converter coupled to receive power from a second power source, and a control block. The first DC-DC converter is operable to generate a regulated power supply voltage on an output node of the power supply. The first power source has a maximum output current limit. The second DC-DC converter is also operable to generate a regulated power supply voltage on the output node. The control block is designed to generate the regulated power supply voltage based on both of the first DC-DC converter and the second DC-DC converter.

Abstract: A phase locked loop (PLL) includes a phase detector, a first low-pass filter, an oscillator, a feedback divider and a cycle slip detector. The cycle slip detector is operable to detect at a first time instance, a cycle slip between an input clock and a feedback clock of the PLL. Upon detection of the cycle slip, the cycle slip detector is operable to increase a loop BW of the PLL. As a result, faster relocking of the PLL is achieved upon occurrence of an abrupt and large frequency difference between the input clock and the feedback clock.

Abstract: A frequency divider includes a set of frequency-dividing units coupled in series in a sequential order, with the sequence of frequency-dividing units including a lowest unit and a highest unit, with the remaining units being disposed in series between the lowest unit and the highest unit. The lowest unit is coupled to receive an input clock whose frequency is to be divided and provided as an output clock. Each frequency-dividing unit in the set is coupled to receive a corresponding first clock as an input and is operable to generate a corresponding second clock as an output. The frequency divider includes a logic block to generate a first set of edges of the output clock synchronous with the input clock. The logic block is designed to generate a second set of edges of the output clock synchronous with the output clock of a highest operative frequency-dividing unit in the set.

Abstract: A phase locked loop (PLL) includes a multiplexer (MUX), a phase detector, a filter block, an oscillator, a frequency divider, and a clock switch controller, and achieves hitless switching between a primary clock and a redundant clock. The clock switch controller, upon detecting a condition requiring switching from the primary clock to the redundant clock, is operable to restart the feedback divider synchronously with respect to the redundant clock, and derive the output of the PLL from the redundant clock. The PLL further includes a delay block to process delayed phase error signals generated by the phase detector. The PLL performs hitless clock switching in the event of input clock loss or in response to a command to switch input clocks. The PLL further includes circuitry for estimating and cancelling residual phase errors.

Abstract: A phase locked loop (PLL) includes a multiplexer (MUX), a phase detector, a filter block, an oscillator, a frequency divider, and a clock switch controller, and achieves hitless switching between a primary clock and a redundant clock. The clock switch controller, upon detecting a condition requiring switching from the primary clock to the redundant clock, is operable to restart the feedback divider synchronously with respect to the redundant clock, and derive the output of the PLL from the redundant clock. The PLL further includes a delay block to process delayed phase error signals generated by the phase detector. The PLL performs hitless clock switching in the event of input clock loss or in response to a command to switch input clocks. The PLL further includes circuitry for estimating and cancelling residual phase errors.

Abstract: A DC-DC converter includes an inductor, and generates a regulated voltage from a power source. The current flow through the inductor is increased at a first rate in a first interval. In a second interval, the current flow through the inductor is either increased at a second rate or decreased at a third rate depending on whether the regulated voltage is required to be respectively less than or greater than a voltage of the power source. The current flow through the inductor is decreased at a fourth rate in a third interval. The sequence formed by the first interval, the second interval and the third interval is repeated, and followed for all values of the regulated voltage from a lower threshold to higher threshold. The higher threshold has a value greater than the voltage of the power source. The lower threshold is zero volts.

Abstract: A fully differential amplifier includes a first feedback resistance, a second feedback resistance, a first input resistance and a second input resistance. A first ratio of the first feedback resistance to the first input resistance is equalized with that of a reference ratio of a pair of reference resistances. Similarly a second ratio of the second feedback resistance to the second input resistance is also equalized with that of the reference ratio. Such equalization operations may be performed during a calibration phase prior to normal operation of the fully differential amplifier. Accordingly, when a common mode voltage present on each of the first output terminal and the second output terminal varies during normal operation, contribution of an erroneous differential signal component across the pair of differential output terminals is prevented.

Abstract: Shoot-through condition in a component containing an amplifier with a push-pull output stage is managed. A first current in a first transistor of the output stage is mirrored to generate a first mirrored current. A second current in a second transistor of the output stage is mirrored to generate a second mirrored current. A sum of the first mirrored current and said second mirrored current is generated. When a magnitude of the sum exceeds a first pre-determined threshold, a respective control voltage of the first transistor and the second transistor is adjusted to reduce the first current and the second current at least until the sum falls below a second pre-determined threshold. In an embodiment, the first pre-determined threshold equals the second pre-determined threshold. In an embodiment, the component is a class-L power amplifier.

Abstract: Shoot-through condition in a component containing an amplifier with a push-pull output stage is managed. A first current in a first transistor of the output stage is mirrored to generate a first mirrored current. A second current in a second transistor of the output stage is mirrored to generate a second mirrored current. A sum of the first mirrored current and said second mirrored current is generated. When a magnitude of the sum exceeds a first pre-determined threshold, a respective control voltage of the first transistor and the second transistor is adjusted to reduce the first current and the second current at least until the sum falls below a second pre-determined threshold. In an embodiment, the first pre-determined threshold equals the second pre-determined threshold. In an embodiment, the component is a class-L power amplifier.

Abstract: A phase frequency detector (PFD) includes a first circuit portion and a second circuit portion. The first circuit portion receives a reference signal and activates a first error signal if the phase of the reference frequency leads the phase of a feedback signal. The second circuit portion receives the reference and activates a second error signal if the phase of the reference frequency lags the phase of the feedback signal. The first circuit portion is powered by a first power supply, and the second circuit portion is powered by a second power supply. A PLL implemented using the PFD generates a frequency output with minimized jitter.

Abstract: A divider circuit determines whether an input factor (N) is an even number or an odd number. If N is an even number then the input clock is divided by N/2 to generate an intermediate clock. The intermediate clock is further divided by two to generate a div-by-2 clock, which is provided as the output clock with fifty percent duty cycle. If N is an odd number, the input clock is divided by (N/2?0.5) in a first duration and by (N/2+0.5) in a second duration to generate the intermediate clock, which is then divided by two to generate the div-by-2 clock. A delayed clock is generated from the div-by-2 clock, wherein the delayed clock lags the div-by-2 clock by half cycle duration of the input clock. The div-by-2 clock and the delayed clock are combined to generate the output clock with fifty percent duty cycle.

Abstract: A programmable frequency divider includes a cascade of frequency-dividing units, each capable of dividing by a first or a second factor. Each unit receives an input clock and generates a divided output clock. Each unit receives a mode control signal that specifies when to divide its input clock by the second factor if a control input allows it, otherwise dividing the input clock by the first factor. The frequency divider is designed to support a range of divide ratios that requires one or more of the units to be non-operative or unused in some intervals. The final divided clock is generated using the mode control signal of the lowest unit in the cascade and the mode control signal of the highest unit that is never set to be non-operative or unused in supporting the range. As a result, duty-cycle variations of the final divided clock are minimized.

Abstract: A power amplifier containing a DC-DC converter, a linear amplifier and a control block. The DC-DC converter receives power from a power source and generates a regulated power supply voltage whose magnitude is controlled by the magnitude of a control signal provided to the DC-DC converter. The linear amplifier receives an input signal and generates a power-amplified output signal, and receives the regulated power supply voltage for operation. The control block is coupled to receive the input signal, and generates the control signal with a magnitude based on the amplitude of the input signal. The regulated power supply voltage is modulated based on the amplitude of the input signal, for peak-to-peak amplitudes of the power-amplified output greater than or less than or equal to the magnitude of the power source. High efficiency for the power amplifier is thereby obtained.