Abstract: An error amplifier circuit receives first and second input signals and provides an error amplifier output signal indicative of the difference between the first and second input signals. The error amplifier circuit implements a proportional-integrator-differentiator (PID) circuit having a differential input signal path and including a proportional amplifier circuit, an integrator amplifier circuit, and a differentiator amplifier circuit. The differentiator amplifier circuit receives an AC coupled input signal. The error amplifier circuit sums the output from the proportional amplifier circuit, the integrator amplifier circuit and the differentiator amplifier circuit to provide the error amplifier output signal where the error amplifier output signal is referenced to a first bias voltage.

Abstract: An error amplifier circuit receives first and second input signals and provides an error amplifier output signal indicative of the difference between the first and second input signals. The error amplifier circuit implements a proportional-integrator-differentiator (PID) circuit having a differential input signal path and including a proportional amplifier circuit, an integrator amplifier circuit, and a differentiator amplifier circuit. The differentiator amplifier circuit receives an AC coupled input signal. The error amplifier circuit sums the output from the proportional amplifier circuit, the integrator amplifier circuit and the differentiator amplifier circuit to provide the error amplifier output signal where the error amplifier output signal is referenced to a first bias voltage.

Abstract: An error amplifier circuit receives first and second input signals and provides an error amplifier output signal indicative of the difference between the first and second input signals. The error amplifier circuit implements a proportional-integrator-differentiator (PID) circuit having a differential input signal path and including a proportional amplifier circuit, an integrator amplifier circuit, and a differentiator amplifier circuit. The differentiator amplifier circuit receives an AC coupled input signal. The error amplifier circuit sums the output from the proportional amplifier circuit, the integrator amplifier circuit and the differentiator amplifier circuit to provide the error amplifier output signal where the error amplifier output signal is referenced to a first bias voltage.

Abstract: An error amplifier circuit receives first and second input signals and provides an error amplifier output signal indicative of the difference between the first and second input signals. The error amplifier circuit implements a proportional-integrator-differentiator (PID) circuit having a differential input signal path and including a proportional amplifier circuit, an integrator amplifier circuit, and a differentiator amplifier circuit. The differentiator amplifier circuit receives an AC coupled input signal. The error amplifier circuit sums the output from the proportional amplifier circuit, the integrator amplifier circuit and the differentiator amplifier circuit to provide the error amplifier output signal where the error amplifier output signal is referenced to a first bias voltage.

Abstract: A voltage-controlled oscillator (VCO) generates a clock signal in response to an input feedback signal by applying tuning to a control loop error signal related to the input feedback signal and generating the clock signal using a voltage ramp signal that is ground referenced. The VCO includes an input tuning circuit applying tuning to a difference signal to generate a tuned voltage signal, a comparator to compare the tuned voltage signal to the ground-based ramp signal, an one-shot circuit to generate an one-shot signal pulse in response to the ramp signal increasing to the tuned voltage signal. The one-shot signal pulse is the clock signal and is also used to reset the ramp signal. In some embodiments, the voltage-controlled oscillator of the present disclosure is incorporated in a current mode hysteretic modulator.

Abstract: A circuit for providing temperature compensation to a sense signal having a first temperature coefficient includes a temperature compensation circuit receiving a temperature sense signal indicative of a temperature associated with the sense signal where the temperature compensation circuit is digitally configurable by at least one digital signal to generate a compensating impedance signal having a second temperature coefficient. The compensating impedance signal provides an impedance value in response to the temperature sense signal. The compensating impedance signal is applied to modify the sense signal to provide a modified sense signal having substantially zero temperature coefficient over a first frequency range. The circuit further includes an amplifier circuit receiving the modified sense signal and generating an output signal indicative of the sense signal where the output signal has substantially zero temperature coefficient over the first frequency range.

Abstract: An embodiment of a power-supply controller includes a switching circuit and a transition circuit. The switching circuit is configured to generate a regulated output voltage by generating first current pulses at an approximately fixed frequency during a first mode, and generating second current pulses at a variable frequency during a second mode. And the transition circuit is configured to transition the switching circuitry from the first mode to the second mode in response to a length of one of the first current pulses. For example, a power supply may include such a power-supply controller to transition the supply from a PWM mode to a PFM mode under light-load conditions. To cause this transition at a predictable load point, the controller may monitor the lengths of the current pulses during the PWM mode, and may transition the supply to a PFM mode in response to the lengths being below a threshold.

Abstract: In an embodiment, an apparatus, such as a power-supply controller, includes a generator and an adjuster. The generator is configured to provide a switching signal that causes a power supply to generate a regulated output signal, and the adjuster is configured to impart a condition to the power supply while the power supply is operating in a first mode, the condition being approximately equal to a condition that the power supply would have if the power supply were operating in a second mode. For example, such an apparatus may be able to reduce or eliminate a transient on a regulated output signal (e.g., a regulated output voltage) when a power supply transitions from a first operating mode, such as a pulse-frequency-modulation (PFM) mode, to a second operating mode, such as a pulse-width-modulation (PWM) mode.

Abstract: An embodiment of a power-supply controller includes switching circuitry and an adjuster circuit. The switching circuitry is configured to cause a charging current to flow until the charging current has a predetermined relationship to a threshold, and to cause a discharging current to flow after the charging current. The adjuster circuit is configured to adjust the threshold in response to at least one of a charging period during which the charging current flows and a discharging period during which the discharging current flows. For example, a power supply may include such a power-supply controller to maintain a length of a current pulse, or of a portion thereof, within a particular range, such as approximately at a particular value, during a pulse-frequency-modulation (PFM) mode despite variations in one or more parameters such as input voltage, output voltage, filter capacitance, phase inductance, charging-current-sense impedance, and load, from their respective nominal values.

Abstract: In an embodiment, a power-supply controller includes switching circuitry and an adjuster circuit. The switching circuitry is configured to cause a charging current to flow until the charging current has a predetermined relationship to a threshold, and to cause a discharging current to flow to an output node that carries an output voltage after the charging current. And the adjuster circuit is configured to adjust the threshold such that a ripple voltage superimposed on the output voltage has an approximately constant magnitude. For example, a power supply may include such a power-supply controller to maintain the magnitude of the output ripple voltage within a particular range during a pulse-frequency-modulation (PFM) mode despite variations in one or more parameters such as input voltage, output voltage, filter capacitance, phase inductance, and charging-current-sense impedance, from their respective nominal values.

Abstract: In an embodiment, a power-supply controller includes switching circuitry and an adjuster circuit. The switching circuitry is configured to cause a charging current to flow until the charging current has a predetermined relationship to a threshold, and to cause a discharging current to flow to an output node that carries an output voltage after the charging current. And the adjuster circuit is configured to adjust the threshold such that a ripple voltage superimposed on the output voltage has an approximately constant magnitude. For example, a power supply may include such a power-supply controller to maintain the magnitude of the output ripple voltage within a particular range during a pulse-frequency-modulation (PFM) mode despite variations in one or more parameters such as input voltage, output voltage, filter capacitance, phase inductance, and charging-current-sense impedance, from their respective nominal values.

Abstract: An embodiment of a power-supply controller includes switching circuitry and an adjuster circuit. The switching circuitry is configured to cause a charging current to flow until the charging current has a predetermined relationship to a threshold, and to cause a discharging current to flow after the charging current. The adjuster circuit is configured to adjust the threshold in response to at least one of a charging period during which the charging current flows and a discharging period during which the discharging current flows. For example, a power supply may include such a power-supply controller to maintain a length of a current pulse, or of a portion thereof, within a particular range, such as approximately at a particular value, during a pulse-frequency-modulation (PFM) mode despite variations in one or more parameters such as input voltage, output voltage, filter capacitance, phase inductance, charging-current-sense impedance, and load, from their respective nominal values.

Abstract: An embodiment of a power-supply controller includes a switching circuit and a transition circuit. The switching circuit is configured to generate a regulated output voltage by generating first current pulses at an approximately fixed frequency during a first mode, and generating second current pulses at a variable frequency during a second mode. And the transition circuit is configured to transition the switching circuitry from the first mode to the second mode in response to a length of one of the first current pulses. For example, a power supply may include such a power-supply controller to transition the supply from a PWM mode to a PFM mode under light-load conditions. To cause this transition at a predictable load point, the controller may monitor the lengths of the current pulses during the PWM mode, and may transition the supply to a PFM mode in response to the lengths being below a threshold.

Abstract: In an embodiment, an apparatus, such as a power-supply controller, includes a generator and an adjuster. The generator is configured to provide a switching signal that causes a power supply to generate a regulated output signal, and the adjuster is configured to impart a condition to the power supply while the power supply is operating in a first mode, the condition being approximately equal to a condition that the power supply would have if the power supply were operating in a second mode. For example, such an apparatus may be able to reduce or eliminate a transient on a regulated output signal (e.g., a regulated output voltage) when a power supply transitions from a first operating mode, such as a pulse-frequency-modulation (PFM) mode, to a second operating mode, such as a pulse-width-modulation (PWM) mode.

Abstract: An optical instrument is provided for forming a viewable image of an object. The optical instrument includes an objective lens for forming the viewable image at an image plane, an eyepiece through which the user can view the viewable image, an eye sensor for sensing the direction of gaze of a user, and means for controlling a function of the optical instrument depending on the gaze direction. The eye sensor includes a light source for outputting light through the eyepiece towards the user's eye, a lens for causing the light from the source to be collimated when it exits the eyepiece, an imaging transducer for imaging the user's eye through the eyepiece and for generating an electrical image signal, and processing means for processing the image signal to determine the location of the user's pupil center and the location of a reflection of the light source to determine the gaze direction information.