Switching Power Converter Energy Storage for Input Power Limiting

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Solution Overview

Problem

Existing power converter systems face challenges in directly controlling maximum current during switching cycles due to unknown errors in slope compensation, leading to sub-harmonic behavior and inaccuracies in peak current limitation, especially when trying to manage the difference between peak and average inductor currents.

Innovation Solution

A power converter system with an energy storage element and control circuitry that manages excess energy by selectively coupling the bottom plate of the energy storage element to the power source, allowing the system to maintain positive voltage headroom and regulate voltage when input power exceeds the maximum allowable input power, while generating multiple supply voltages to track output signal envelopes and control inductor current.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If slope compensation circuitry is used to avoid sub-harmonic behavior, then stability is improved, but measurement precision deteriorates due to unknown errors in analog slope compensation

Engineering Contradiction:

ImprovestabilityVSAvoidmeasurement precision

Core Design Contradiction:

Stability of the object's compositionVSMeasurement precision

Solution Approach 1:

The patent replaces the analog slope compensation mechanism with a digital slope compensation approach. Instead of using analog circuitry that introduces unknown errors, the system uses digital signal processing to calculate and apply slope compensation, thereby eliminating the measurement precision deterioration while maintaining stability.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces a digital processor as an intermediary between the current measurement and the control decision. This intermediary digitally processes the current signal and applies precise slope compensation, avoiding the direct analog compensation path that causes measurement errors.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Power

If peak current control is implemented to limit maximum current, then power is improved, but measurement precision deteriorates due to inability to directly control maximum current

Engineering Contradiction:

ImprovepowerVSAvoidmeasurement precision

Core Design Contradiction:

PowerVSMeasurement precision

Solution Approach 1:

The patent replaces the analog peak current control mechanism with a digital control system. The digital processor directly measures and controls the peak current with high precision, eliminating the inaccuracies inherent in analog comparison circuits and slope compensation.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent creates a digital copy of the current waveform and processes this copy to determine peak current values. This digital copying allows for precise measurement and control of peak current without the limitations of analog measurement circuits.

Inventive Principle:

Principle #26Copying

3Use of energy by moving object

If average current control is used to manage energy, then energy utilization is improved, but device complexity increases due to additional control loops

Engineering Contradiction:

Improveenergy utilizationVSAvoiddevice complexity

Core Design Contradiction:

Use of energy by moving objectVSDevice complexity

Solution Approach 1:

The patent merges the peak current control and average current control functions into a single digital processor. By combining these control loops in software rather than implementing them as separate analog circuits, the system achieves improved energy utilization without proportionally increasing device complexity.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The digital processor is designed to perform multiple functions: it handles both peak current control and average current control, as well as slope compensation and protection functions. This multi-functionality reduces the need for separate dedicated circuits, thereby managing complexity while improving energy utilization.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Data Source

PatentUS11909317B2Efficient use of energy in a switching power converter

Publication Date: 2024.02.20 CIRRUS LOGIC INC

AI summary

A system may include a power converter having a maximum allowable input power drawn from a power source, an energy storage element coupled to an output of the power converter at a top plate of the energy storage element, wherein the energy storage element is configured to store excess energy, and control circuitry configured to, when an input power of the power converter exceeds the maximum allowable input power, cause excess energy stored in the energy storage element to be consumed by circuitry coupled to the output of the power converter, and in order to maintain positive voltage headroom for the circuitry coupled to the output of the power converter, selectively couple a bottom plate of the energy storage element to the power source such that excess energy stored by the circuitry coupled to the output of the power converter is consumed from the energy storage device when the input power of the power converter exceeds the maximum allowable input power.