Power Supply Slope Adjustment for Inductance Variation

Solution Overview

Problem

Recent DC-DC converters face challenges in miniaturization and high-frequency characteristics due to the poor direct-current superposition characteristics of multilayer chip coils, leading to variations in inductance values and frequency characteristics, which affect phase margin and stability.

Innovation Solution

A power supply device with a switch circuit, a voltage adding circuit, and a control unit that differentiates the current flowing in the coil to adjust the slope of the reference voltage based on the inductance value, maintaining a constant crossover frequency and phase margin.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If a multilayer chip coil is used to meet miniaturization requirements, then the device size is reduced, but the inductance value varies due to poor direct-current superposition characteristics

Engineering Contradiction:

Improvedevice sizeVSAvoidinductance value

Core Design Contradiction:

Volume of moving objectVSStability of the object's composition

Solution Approach 1:

The patent applies dynamics by making the slope voltage adjustable based on operating conditions. The control circuit dynamically changes the slope voltage in response to variations in output current, which compensates for inductance changes in the multilayer chip coil. This dynamic adjustment maintains stable frequency characteristics despite the inherent inductance variations caused by DC superposition effects in miniaturized coils.

Inventive Principle:

Principle #15Dynamics

2Power

If the output current increases, then the power delivery capability is improved, but the inductance value decreases and phase margin is reduced

Engineering Contradiction:

Improvepower delivery capabilityVSAvoidphase margin

Core Design Contradiction:

PowerVSReliability

Solution Approach 1:

The patent implements feedback by monitoring the output current and using this information to adjust the slope voltage. The control circuit detects changes in operating conditions and modifies the slope voltage accordingly, creating a closed-loop system that maintains stable phase margin even when power delivery capability increases and inductance value decreases.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The patent applies parameter changes by varying the slope voltage based on output current levels. When output current increases causing inductance to decrease, the control circuit adjusts the slope voltage to compensate, thereby maintaining constant phase margin and stable frequency characteristics across different power delivery conditions.

Inventive Principle:

Principle #35Parameter changes

3Speed

If the inductance value decreases at high current, then the frequency band spreads to high-frequency side, but the phase margin is reduced causing potential oscillation

Engineering Contradiction:

Improvefrequency bandVSAvoidphase margin

Core Design Contradiction:

SpeedVSStability of the object's composition

Solution Approach 1:

The patent applies dynamics by making the slope voltage adjustable based on operating conditions. The control circuit dynamically changes the slope voltage in response to variations in output current, which compensates for inductance changes in the multilayer chip coil. This dynamic adjustment maintains stable frequency characteristics despite the inherent inductance variations caused by DC superposition effects in miniaturized coils.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent applies parameter changes by varying the slope voltage based on output current levels. When output current increases causing inductance to decrease, the control circuit adjusts the slope voltage to compensate, thereby maintaining constant phase margin and stable frequency characteristics across different power delivery conditions.

Inventive Principle:

Principle #35Parameter changes

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This approach stabilizes the frequency characteristics and phase margin, ensuring a wider bandwidth and preventing oscillation, even with variations in output current, by adjusting the slope of the reference voltage in response to inductance changes.

Implementation Method 1

a voltage adding circuit to which the differentiated signal is inputted and that adds a slope voltage to a reference voltage

Methodology Applied

Scientific EffectVoltage addition:

Implementation Method 2

a control unit that compares a feedback voltage corresponding to an output voltage and the reference voltage and switches the switch circuit at a timing corresponding to a comparison result

Methodology Applied

Scientific EffectVoltage comparison:

Implementation Method 3

A slope adjustment circuit differentiates a current flowing in the coil and adjusts a slope amount of the slope based on a differentiation result of the current

Methodology Applied

Scientific EffectCurrent differentiation:

Data Source

PatentUS9325239B2Power supply device, control circuit, electronic device and control method for power supply

Publication Date: 2016.04.26 INFINEON TECHNOLOGIES AMERICAS CORP

AI summary

A power supply device that includes a switch circuit to which an input voltage is supplied, a coil coupled between the switch circuit and an output terminal from which an output voltage is outputted. A voltage adding circuit adds a slope voltage to a reference voltage. A control unit compares a feedback voltage corresponding to the output voltage and the reference voltage and switches the switch circuit at a timing corresponding to a comparison result of the feedback voltage and the reference voltage. A slope adjustment circuit differentiates a current flowing in the coil and adjusts a slope amount of the slope based on a differentiation result of the current.