Digital Power Converter Control With Slew Rate Detection

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Solution Overview

Problem

Existing power converter and voltage regulator circuits face challenges in maintaining stability and gain due to complex analog control loops, leading to issues like overshoots and voltage droops, especially in multi-phase systems.

Innovation Solution

Implementing a digital control loop with a slew rate detection circuit that adjusts control signals based on the rate of change of the voltage level, switching to a secondary control loop when the slew rate exceeds specified thresholds to stabilize the voltage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If complex analog control loops are used to maintain stability and gain in power converter circuits, then voltage regulation capability is improved, but circuit complexity increases and leads to overshoots and voltage droops

Engineering Contradiction:

Improvevoltage regulation stabilityVSAvoidcontrol loop complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces complex analog control loops with a digital control system that uses a microcontroller or digital signal processor to implement control algorithms. This substitution of mechanical/analog systems with digital systems reduces circuit complexity while maintaining or improving voltage regulation stability through programmable control logic that can adapt to different operating conditions.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent implements a slew rate detection mechanism that dynamically changes control parameters based on the rate of change of the output voltage. When the slew rate exceeds a threshold, the system adjusts the compensator parameters or control gain to prevent overshoots and voltage droops, thereby maintaining stability without requiring permanently complex circuitry.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If slew rate detection is implemented to prevent overshoots and voltage droops, then voltage stability is improved, but control system complexity increases

Engineering Contradiction:

Improvevoltage level stabilityVSAvoidcontrol loop structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent implements a slew rate detection circuit that continuously monitors the rate of change of the output voltage and provides feedback to the control system. When the slew rate exceeds a predetermined threshold, the feedback mechanism triggers adjustments in the control signals or compensator parameters, enabling the system to prevent overshoots and voltage droops through real-time monitoring and adaptive response.

Inventive Principle:

Principle #23Feedback

Data Source

PatentUS12476542B2Slew rate detection in power converter with digital current mode control

Publication Date: 2025.11.18 APPLE INC

AI summary

A power converter with slew rate detection is disclosed. A power converter comprises a plurality of phase circuits coupled to a regulated power supply line via corresponding ones of a plurality of inductors. A first control loop generates, using digital samples and based on comparisons of a reference voltage to a voltage on the regulated power supply line, a first plurality of control signals. A second control loop, using the digital samples, generates a second plurality of control signals based on a rate of change of the voltage of the regulated power supply line. The second control loop causes the first control loop to control the plurality of phase circuits in response to detecting that the rate of change is within a specified range, and causes the second control loop to control the plurality of phase circuits, in response to detecting that the rate of change exceeds the specified range.