Abstract: According to an aspect of one or more exemplary embodiments, there is provided a constant on-time buck converter with calibrated ripple injection having improved light load transient response and reduced output capacitor size.

Abstract: According to an aspect of one or more exemplary embodiments, there is provided a constant on-time buck converter with calibrated ripple injection having improved light load transient response and reduced output capacitor size.

Abstract: According to an aspect of one or more exemplary embodiments, there is provided a constant on-time controller for a buck converter with calibrated ripple injection in continuous conduction mode. The constant on-time controller may include a pulse width modulator (PWM) comparator that generates an on-time request, an error amplifier that regulates an average feedback voltage to an internal reference voltage, and passes a feedback node ripple signal to an input of the PWM comparator, an on-time generator that outputs an on-time signal that controls an on-time of the buck converter based on the on-time request, a MOSFET driver that drives the buck converter based on the output of the on-time generator, and an injection signal generator coupled to the on-time generator, wherein the injection signal generator may include a first switch and a second switch, a fixed signal generator, and a bias current source.

Abstract: A step-down hysteretic current LED driver circuit implements frequency regulation to adjust the hysteresis levels of a hysteretic comparator in the control circuit of the LED driver to keep the switching frequency of the inductor current constant. More specifically, the switching frequency of the inductor current is kept constant by increasing or decreasing the hysteresis window of the hysteretic comparator. In this manner, the switching frequency of the LED driver is kept constant or predictable. In one embodiment, the control circuit of the LED driver includes a frequency regulator to monitor the switching frequency and adjusts the hysteresis window accordingly to maintain a constant switching frequency.

Abstract: A step-down hysteretic current LED driver circuit implements frequency regulation to adjust the hysteresis levels of a hysteretic comparator in the control circuit of the LED driver to keep the switching frequency of the inductor current constant. More specifically, the switching frequency of the inductor current is kept constant by increasing or decreasing the hysteresis window of the hysteretic comparator. In this manner, the switching frequency of the LED driver is kept constant or predictable. In one embodiment, the control circuit of the LED driver includes a frequency regulator to monitor the switching frequency and adjusts the hysteresis window accordingly to maintain a constant switching frequency.

Abstract: A voltage regulation system is provided including detecting a feedback voltage less than a reference voltage; asserting a current source gate output by the feedback voltage less than the reference voltage; activating a gated current source by the current source gate output; and waiting a delay interval before negating the current source gate output for turning off the gated current source.

Abstract: A method for providing adaptive compensation for an electrical circuit where the electrical circuit includes an inductor-capacitor network connected in a feedback loop being compensated by a first compensation capacitance value and a second compensation capacitance value defining the frequency locations of two compensation zeros includes: measuring the inductance value of the inductor; when the inductance value is greater than a first threshold value, increasing the first and second compensation capacitance values so that the frequency locations of the two compensation zeros are adjusted for compensating the poles introduced by the first inductor and the first capacitor; and when the inductance value is less than the first threshold value, decreasing the first and second compensation capacitance values so that the frequency locations of the two compensation zeros are adjusted for compensating the poles introduced by the first inductor and the first capacitor.

Abstract: A method for providing adaptive compensation for an electrical circuit where the electrical circuit includes an inductor-capacitor network connected in a feedback loop being compensated by a first compensation capacitance value and a second compensation capacitance value defining the frequency locations of two compensation zeros includes: measuring the inductance value of the inductor; when the inductance value is greater than a first threshold value, increasing the first and second compensation capacitance values so that the frequency locations of the two compensation zeros are adjusted for compensating the poles introduced by the first inductor and the first capacitor; and when the inductance value is less than the first threshold value, decreasing the first and second compensation capacitance values so that the frequency locations of the two compensation zeros are adjusted for compensating the poles introduced by the first inductor and the first capacitor.

Abstract: An integrated circuit system is provided including forming a differential pair; reducing a mismatch in the differential pair by: coupling an amplifier to the differential pair; and coupling a local feedback network to the amplifier in which referencing the local feedback network includes coupling a first voltage; and driving an output transistor by the amplifier.

Abstract: A buck switching regulator formed on an integrated circuit receives an input voltage and provides a switching output voltage on a switch output node using a constant on-time, variable off-time feedback control loop. The buck switching regulator includes an amplifier comparing a feedback voltage to a reference voltage and generating an output voltage on an output terminal, a first capacitor and a first resistor connected in series between the switch output node and the output terminal of the amplifier, and a second capacitor coupled between the DC output voltage node and the output terminal of the amplifier. The first capacitor and the first resistor generate a ripple voltage signal which is injected onto the output terminal of the amplifier for use in the constant on-time, variable off-time feedback control scheme. The magnitude of the ripple voltage signal is a function of the capacitance value of the second capacitor.

Abstract: An integrated circuit system is provided including forming a differential pair; reducing a mismatch in the differential pair by: coupling an amplifier to the differential pair; and coupling a local feedback network to the amplifier in which referencing the local feedback network includes coupling a first voltage; and driving an output transistor by the amplifier.

Abstract: A voltage regulation system is provided including detecting a feedback voltage less than a reference voltage; asserting a current source gate output by the feedback voltage less than the reference voltage; activating a gated current source by the current source gate output; and waiting a delay interval before negating the current source gate output for turning off the gated current source.

Abstract: A buck switching regulator receives an input voltage and provides a switching output voltage on a switch output node using a minimum on-time, variable off-time feedback control loop. The buck switching regulator includes an on-time control circuit for generating a first signal for turning off the high-side switch at the expiration of a first on-time duration or at the expiration of a maximum on-time. The first on-time duration is at least a minimum on-time and is allowed to expand to a maximum on-time when the feedback voltage remains less than a reference voltage. The maximum on-time includes a first maximum on-time and a second, extended maximum on-time. The second maximum on-time is applied when a minimum off-time was used for the high-side switch during the previous switching cycle. In another embodiment, the second maximum on-time is applied only when the switching regulator is not being current limited.

Abstract: A buck switching regulator formed on an integrated circuit receives an input voltage and provides a switching output voltage on a switch output node using a constant on-time, variable off-time feedback control loop. The buck switching regulator includes an amplifier comparing a feedback voltage to a reference voltage and generating an output voltage on an output terminal, a first capacitor and a first resistor connected in series between the switch output node and the output terminal of the amplifier, and a second capacitor coupled between the DC output voltage node and the output terminal of the amplifier. The first capacitor and the first resistor generate a ripple voltage signal which is injected onto the output terminal of the amplifier for use in the constant on-time, variable off-time feedback control scheme. The magnitude of the ripple voltage signal is a function of the capacitance value of the second capacitor.

Abstract: A buck switching regulator receives an input voltage and provides a switching output voltage on a switch output node using a minimum on-time, variable off-time feedback control loop. The buck switching regulator includes an on-time control circuit for generating a first signal for turning off the high-side switch at the expiration of a first on-time duration or at the expiration of a maximum on-time. The first on-time duration is at least a minimum on-time and is allowed to expand to a maximum on-time when the feedback voltage remains less than a reference voltage. The maximum on-time includes a first maximum on-time and a second, extended maximum on-time. The second maximum on-time is applied when a minimum off-time was used for the high-side switch during the previous switching cycle. In another embodiment, the second maximum on-time is applied only when the switching regulator is not being current limited.

Abstract: For load currents greater than a threshold current, the voltage regulator operates in a conventional manner by fully turning on and off one or more switching transistors at a duty cycle necessary to maintain the output voltage a regulated voltage. Upon a load current below a threshold being detected, a controller stops the switching of the transistor(s) and applies a reduced drive signal to the high side transistor so as to apply a constant trickle current to the load. Unnecessary components are shut down to save power. When the output voltage falls below a threshold, the normal switching routine is resumed to recharge the regulator's output capacitor to a certain level, and the regulator once again enters the light load current mode. By not completely shutting down the transistors at light load currents, as in done in a conventional intermittent-operation mode, there is lower power loss by less frequent switching of the transistor(s).

Abstract: For load currents greater than a threshold current, the voltage regulator operates in a conventional manner by fully turning on and off one or more switching transistors at a duty cycle necessary to maintain the output voltage a regulated voltage. Upon a load current below a threshold being detected, a controller stops the switching of the transistor(s) and applies a reduced drive signal to the high side transistor so as to apply a constant trickle current to the load. Unnecessary components are shut down to save power. When the output voltage falls below a threshold, the normal switching routine is resumed to recharge the regulator's output capacitor to a certain level, and the regulator once again enters the light load current mode. By not completely shutting down the transistors at light load currents, as in done in a conventional intermittent-operation mode, there is lower power loss by less frequent switching of the transistor(s).

Abstract: A comparator circuit having improved operational characteristics. A predetermined voltage drop device is provided, such as an exemplary embodiment Schottky diode, having an anode connected to circuit power supply voltage and an output stage of the comparator and a cathode connected to an input stage of the comparator. The predetermined voltage drop device effects a lowering of the power supply voltage for the output stage bias between said power supply voltage and said common voltage. This reduces the required swing of the output stage drivers during a comparator input signal transition and reduces propagation delay of said comparator.

Abstract: A switching regulator integrated circuit for controlling first and second switches in a hysteretic mode using a zero or very low equivalent series resistance (ESR) capacitor includes an integrated circuit package housing a switching regulator semiconductor chip, a first package lead on the integrated circuit package receiving the regulated output voltage and a second package lead to be coupled to a zero or low ESR capacitor of the LC filter. The first package lead may be connected to a first bond pad of the semiconductor chip using a first bond wire. A second bond wire connects the second package lead to the first package lead, or to the first bond pad, or to a second bond pad electrically shorted to the first bond pad. The capacitor is thus electrically coupled to the regulated output voltage and the second bond wire provides series resistance to the capacitor.

Abstract: A comparator circuit having improved operational characteristics. A predetermined voltage drop device is provided, such as an exemplary embodiment Schottky diode, having an anode connected to circuit power supply voltage and an output stage of the comparator and a cathode connected to an input stage of the comparator. The predetermined voltage drop device effects a lowering of the power supply voltage for the output stage bias between said power supply voltage and said common voltage. This reduces the required swing of the output stage drivers during a comparator input signal transition and reduces propagation delay of said comparator.