A PWM signal generator circuit includes a multiphase clock generator that generates a number n of phase-shifted clock phases having the same clock period and being phase shifted by a time corresponding to a fraction 1/n of the clock period. The PWM signal generator circuit determines for each switch-on duration first and second integer numbers, and for each switch-off duration third and fourth integer numbers. The first integer number is indicative of the integer number of clock periods of the switch-on duration and the second integer number is indicative of the integer number of the additional fractions 1/n of the clock period of the switch-on duration. The third integer number is indicative of the integer number of clock periods of the switch-off duration, and the fourth integer number is indicative of the integer number of the additional fractions 1/n of the clock period of the switch-off duration.

A PWM signal generator circuit includes a multiphase clock generator that generates a number n of phase-shifted clock phases having the same clock period and being phase shifted by a time corresponding to a fraction 1/n of the clock period. The PWM signal generator circuit determines for each switch-on duration first and second integer numbers, and for each switch-off duration third and fourth integer numbers. The first integer number is indicative of the integer number of clock periods of the switch-on duration and the second integer number is indicative of the integer number of the additional fractions 1/n of the clock period of the switch-on duration. The third integer number is indicative of the integer number of clock periods of the switch-off duration, and the fourth integer number is indicative of the integer number of the additional fractions 1/n of the clock period of the switch-off duration.

A clock signal delay path unit includes a first delay cell including a first root signal line for delaying and transmitting a clock signal, a first repeater to transmit the clock signal transmitted through the first root signal line without signal attenuation, and a second root signal line for delaying and transmitting the clock signal output from the first repeater, a second delay cell including a first inverting circuit configured to invert the clock signal provided from the first delay cell to generate an inverted clock signal, and a third delay cell including a first branch signal line for delaying and transmitting the inverted clock signal provided from the second delay cell, a second repeater to transmit the inverted clock signal transmitted through the first branch signal line, and a second branch signal line for delaying and transmitting the inverted clock signal output from the second repeater.

A clock signal delay path unit includes a first delay cell including a first root signal line for delaying and transmitting a clock signal, a first repeater to transmit the clock signal transmitted through the first root signal line without signal attenuation, and a second root signal line for delaying and transmitting the clock signal output from the first repeater, a second delay cell including a first inverting circuit configured to invert the clock signal provided from the first delay cell to generate an inverted clock signal, and a third delay cell including a first branch signal line for delaying and transmitting the inverted clock signal provided from the second delay cell, a second repeater to transmit the inverted clock signal transmitted through the first branch signal line, and a second branch signal line for delaying and transmitting the inverted clock signal output from the second repeater.

A voltage regulator receives an input voltage and produces a regulated output voltage. A first feedback network compares a feedback signal to a reference signal to assert/de-assert a first pulsed control signal when the reference signal is higher/lower than the feedback signal. A second feedback network compares the output voltage to a threshold signal to assert/de-assert a second control signal when the threshold signal is higher/lower than the output voltage. A charge pump is enabled if the second control signal is de-asserted and is clocked by the first pulsed control signal to produce a supply voltage higher than the input voltage. A first pass element is enabled when the second control signal is asserted and is selectively activated when the first pulsed control signal is asserted. A second pass element is selectively activated when the second control signal is de-asserted.

A voltage regulator receives an input voltage and produces a regulated output voltage. A first feedback network compares a feedback signal to a reference signal to assert/de-assert a first pulsed control signal when the reference signal is higher/lower than the feedback signal. A second feedback network compares the output voltage to a threshold signal to assert/de-assert a second control signal when the threshold signal is higher/lower than the output voltage. A charge pump is enabled if the second control signal is de-asserted and is clocked by the first pulsed control signal to produce a supply voltage higher than the input voltage. A first pass element is enabled when the second control signal is asserted and is selectively activated when the first pulsed control signal is asserted. A second pass element is selectively activated when the second control signal is de-asserted.

A system includes a mixer of a phase interpolator. The mixer includes a dynamic load whose output signal is coupled to a subsequent stage of the phase interpolator. The dynamic load is configured to provide an alternating current (AC) signal to the subsequent stage of the phase interpolator as input clock signals. The mixer further includes a static load whose output signal is coupled to the subsequent stage of the phase interpolator in parallel with the respective output signal line of the dynamic load. The static load configured to provide a direct current (DC) signal to the phase interpolator temporarily in replacement of the respective AC signals to prevent output signals of the subsequent stage of the phase interpolator from being unpredictable.

A system includes a mixer of a phase interpolator. The mixer includes a dynamic load whose output signal is coupled to a subsequent stage of the phase interpolator. The dynamic load is configured to provide an alternating current (AC) signal to the subsequent stage of the phase interpolator as input clock signals. The mixer further includes a static load whose output signal is coupled to the subsequent stage of the phase interpolator in parallel with the respective output signal line of the dynamic load. The static load configured to provide a direct current (DC) signal to the phase interpolator temporarily in replacement of the respective AC signals to prevent output signals of the subsequent stage of the phase interpolator from being unpredictable.

Systems and methods for frequency reference generation are described. In an embodiment, a frequency reference circuit, includes: a bandgap proportional to temperature (PTAT) generator circuit that generates a bandgap PTAT current; a resistor complementary to temperature (CTAT) generator circuit that generates a resistor CTAT current; an adder that adds the PTAT current and the CTAT current to generate a constant current I.sub.cons; a switched-resistor (switched-R) circuit that receives the constant current I.sub.cons and a previously generated output clock and generates an output; a bandgap voltage reference generator circuit that generates a bandgap voltage V.sub.BG; an integrator circuit that receives the output of the switched-R circuit and the bandgap voltage V.sub.BG and generates an output; and a voltage-controlled oscillator (VCO) circuit that receives the output of the integrator circuit and generates a frequency reference.

Systems and methods for frequency reference generation are described. In an embodiment, a frequency reference circuit, includes: a bandgap proportional to temperature (PTAT) generator circuit that generates a bandgap PTAT current; a resistor complementary to temperature (CTAT) generator circuit that generates a resistor CTAT current; an adder that adds the PTAT current and the CTAT current to generate a constant current I.sub.cons; a switched-resistor (switched-R) circuit that receives the constant current I.sub.cons and a previously generated output clock and generates an output; a bandgap voltage reference generator circuit that generates a bandgap voltage V.sub.BG; an integrator circuit that receives the output of the switched-R circuit and the bandgap voltage V.sub.BG and generates an output; and a voltage-controlled oscillator (VCO) circuit that receives the output of the integrator circuit and generates a frequency reference.