Cirrus Logic Inc.

Cirrus Logic International Semiconductor Limited

Ullas Pazhayaveetil

Jeffrey Allen May

Sarang Vadnerkar

Gautham Devendra Kamath

Theodore M Burk

Christian Larsen

John Christopher Tucker

Eric Jerome King

Michael Allan Kost

Anu Chakravarty

Ku He

Umar J Lyles

A method may include operating a DC-DC switch converter in a forced continuous conduction mode in which for each switching cycle of the switch converter during the forced continuous conduction mode, the switch converter operates in a series of phases including: a first phase in which an inductor current flowing in an inductor of the switch converter increases from zero to a controlled positive current magnitude with respect to a first terminal and a second terminal of the inductor; a second phase in which the inductor current decreases from the controlled positive current magnitude to approximately zero; a third phase in which the inductor current decreases from approximately zero to a controlled negative current magnitude with respect to a first terminal and a second terminal of the inductor; and a fourth phase in which the inductor current increases from the controlled negative current magnitude to approximately zero.

Boost converter with forced continuous conduction mode

A method may include monitoring an input power supply, monitoring an inductance of an inductor of a boost converter, monitoring one or more other characteristics of the boost converter, and calculating a target peak inductor current based on the input power supply voltage, the inductance, the one or more other characteristics of the boost converter, and a target average current of the inductor during a switching cycle of the boost converter. A method may include monitoring an input power supply voltage, monitoring an inductance of an inductor of a boost converter, monitoring one or more other characteristics of the boost converter, and calculating an average current of the inductor during a switching cycle of the boost converter based on the input power supply voltage, the inductance, the one or more other characteristics of the boost converter, and a peak inductor current of the inductor.

Adjusting peak inductor current to limit supply input current

A DC-DC converter and a corresponding method for maintaining an output voltage of the DC-DC converter, wherein the DC-DC converter is configured to operate in a discontinuous conduction mode, within a predetermined voltage range. The method comprises adjusting a duty cycle of the DC-DC converter based on the output voltage to maintain the output voltage within a predetermined voltage range; wherein the duty cycle of the DC-DC converter is adjusted by switching between a first switching frequency to a second switching frequency, and the first switching frequency and the second switching frequency are selected such that the first switching frequency and the second switching frequency fall outside of at least one predefined disallowed frequency band.

Maintaining output voltage of DC-DC converter in discontinuous conduction mode

A DC-DC converter and corresponding method for transitioning between a discontinuous conduction mode, DCM, and a continuous conduction mode, CCM, wherein the DC-DC converter is configured to power a signal processing system within an integrated circuit, is provided. The method comprises receiving input data, wherein the input data is for inputting into the signal processing system; determining an amplitude of the input data; and transitioning between DCM and CCM based on the amplitude of the input data. A DC-DC converter and respective method for transitioning from CCM to DCM comprising determining an estimated current representative of an inductor current through an inductor of the DC-DC converter; and transitioning from CCM to DCM based on the estimated current, is provided. A DC-DC converter and respective method for transitioning from DCM to CCM comprising determining either an output voltage of the DC-DC converter or a duty cycle of the DC-DC converter; and transitioning from DCM to CCM based on the determined output voltage or duty cycle of the DC-DC converter, is provided.

DC-DC converter

A controller of a boost converter may be configured to dynamically adjust conditions within the boost converter by monitoring conditions in the boost converter. For example, the controller may determine an current inductance value for an inductor of the boost converter by monitoring a current through the inductor. When the inductance value of the inductor is known, a slope compensation value may be used in determining a transition time between charging the inductor of the boost converter and discharging the inductor.

Boost converter controller with inductance value determination

During operation of a boost converter conditions may exist that result in a reverse current through the boost converter, such as when a load drop from the boost converter occurs. During the reverse current period, inductance value determinations made during a forward current period may be used to estimate a magnitude of the reverse current and this estimate used by a controller to control the boost converter and return the boost converter to normal operation. The controller may control the boost converter by changing a ratio of charging and discharging time for an inductor of the boost converter, decreasing a bandwidth of the boost converter, and/or increasing a resistance of the boost converter.

Determination of inductor current during reverse current in a boost converter

A combination of inductor current thresholds and circuitry for controlling the inductor based on the thresholds may be implemented in a power converter. One or more of the inductor current thresholds may be variable. An inductor current threshold may be varied as part of a search algorithm for identifying a value resulting in full scale operation of the inductor without exceeding a safe limit. After each cycle of the power converter, circuitry may determine which current thresholds have been exceeded and which have not been exceeded and then generate indication signals for each of the thresholds. Control logic may receive the indication signals and adjust one of the inductor current thresholds used to determine timing for disconnecting and reconnecting current through the inductor of the power converter.

Peak current limiting in inductor-based power converter

Thermal levels in an inductor of a boost converter may be managed by implementing peak current limits for the boost converter. For example, an inductor may be allowed to conduct above a certain peak current limit for a certain period of time before the current is reduced by a controller to a low current limit. The controller may hold the low current limit in place for a certain period of time, after which the current through the inductor is allowed to again exceed the low current limit. However, if the high current limit is again exceeded or sustained for a certain period of time, the low current limit may be again imposed by the controller.

Controller for imposing current limits on a boost converter for managing thermal loads

Audio amplification may be improved by controlling an audio amplifier based on the audio signal being amplified. For example, when the audio signal level increases or decreases, a boost voltage provided to an audio amplifier by a boost converter may also be increased or decreased. In another example, when the audio signal level decrease below a certain level, the audio amplifier may be switched from amplifying the audio signal with a boost converter input to amplifying the audio signal with a low voltage input. Control of the audio amplifier may be implemented in a digital boost converter controller coupled to the boost converter and/or the audio amplifier.

Boost converter voltage controlled based on audio signal

Thermal levels in an inductor of a boost converter may be managed by controlling an average current through the inductor. For example, a switching frequency of the boost converter between charging and discharging the inductor may be increased or decreased. Increasing or decreasing the switching frequency results in a corresponding decrease or increase in the switching period for the boost converter. The controller may adjust the switching frequency to control the average current level while maintaining a peak-to-peak current level in the inductor by monitoring the inductance of the inductor and the peak current level in the inductor.

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Cedar Park, TX, United States of America

Ullas Pazhayaveetil