Semiconductor Integrated Circuit Dynamic Phase Compensation for Power Supply Stability

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Solution Overview

Problem

The increase in equivalent series resistance (ESR) of aluminum electrolytic capacitors at low temperatures leads to instability and abnormal oscillation in stabilizing power supply circuits, making it difficult to maintain a stable output voltage and increasing the cost of external components like thermistors for temperature compensation.

Innovation Solution

A semiconductor integrated circuit with a detection control circuit that varies the phase compensation characteristics of the phase compensation circuit based on temperature variations of the electrolytic capacitor, reducing the number of external components needed by dynamically adjusting the time constant and pole frequency to maintain stability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If aluminum electrolytic capacitors are used in stabilizing power supply circuits, then cost is reduced and availability is improved, but equivalent series resistance (ESR) increases at low temperatures causing instability and abnormal oscillation

Engineering Contradiction:
Improvecost reductionVSAvoidcircuit stability
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent applies dynamics by making the phase compensation circuit adjustable through switching elements that can change the capacitance value dynamically. The detection control circuit detects temperature variations and controls the switching elements to adjust the capacitance, thereby adapting the phase compensation characteristics to different operating conditions and preventing oscillation at low temperatures while maintaining cost-effectiveness of aluminum electrolytic capacitors

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the capacitance parameter of the phase compensation circuit based on temperature detection. By switching between different capacitance values (e.g., from a smaller capacitance at high temperature to a larger capacitance at low temperature), the system optimizes the phase compensation characteristics for different temperature ranges, resolving the stability issue at low temperatures without requiring expensive temperature-compensated capacitors

Inventive Principle:
Principle #35Parameter changes

2Reliability

If thermistors are added for temperature compensation, then circuit stability at low temperatures is improved, but the number of external components and manufacturing cost increase

Engineering Contradiction:
Improvecircuit stabilityVSAvoidnumber of external components
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges the temperature compensation function with the existing phase compensation circuit by using the same capacitor and switching elements. The detection control circuit integrates temperature detection and switching control to adjust the phase compensation characteristics, eliminating the need for separate thermistor components while achieving temperature compensation

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The system performs self-service by using its own detection control circuit to monitor temperature and automatically adjust the phase compensation circuit parameters. This self-regulating mechanism eliminates the need for external thermistors or manual intervention, maintaining stability while reducing component count

Inventive Principle:
Principle #25Self-service

3Device complexity

If fixed phase compensation characteristics are used, then circuit design is simplified, but stability cannot be maintained across wide temperature ranges

Engineering Contradiction:
Improvecircuit design simplicityVSAvoidtemperature range adaptability
Core Design Contradiction:
Device complexityVSAdaptability or versatility

Solution Approach 1:

The patent transforms the fixed phase compensation circuit into a dynamic one by adding switching elements controlled by temperature detection. The capacitance value changes dynamically based on temperature, allowing the circuit to adapt to different temperature ranges while maintaining a relatively simple overall structure that builds upon the basic phase compensation topology

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP2897273B1Semiconductor integrated circuit and method for operating the same
Publication Date: 2019.12.25 RENESAS ELECTRONICS CORP
  • EP2897273B1 patent drawingFigure 1
  • EP2897273B1 patent drawingFigure 2~3
  • EP2897273B1 patent drawingFigure 4~6

AI summary

A semiconductor integrated circuit that is used for a stabilizing power supply circuit which supplies an output power supply voltage to a parallel connection of a smoothing capacitor and a load, from an input power supply voltage, includes an error amplifier that detects an error of the output power supply voltage, an output control circuit that is connected between the input terminal and the output terminal, a phase compensation circuit that is connected to the error amplifier, and a detection control circuit that is connected to the phase compensation circuit.