Capacitance Multiplier Topology for Low-Voltage Noise Decoupling

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Solution Overview

Problem

Conventional capacitance multiplier circuits are unsuitable for low voltage applications due to voltage drop, require high impedance, and consume large amounts of power, making them inefficient for providing effective noise suppression in integrated circuits.

Innovation Solution

The implementation of a capacitance multiplier circuitry that includes a capacitor, an adjustable resistance, and a transconductance circuit, allowing for a large adjustable capacitance without voltage drop and low power consumption, using a transistor with source-drain terminals coupled to power and ground lines, and optional resistors and electrical components to enhance capacitance multiplication.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional capacitance multiplier circuits are used to provide large capacitance values, then noise suppression is improved, but voltage drop occurs making them unsuitable for low voltage applications

Engineering Contradiction:
Improvenoise suppressionVSAvoidvoltage drop
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent changes the operating parameters of the capacitance multiplier circuit by using a transconductance circuit with high gain to achieve large capacitance multiplication (greater than 100x) without the traditional voltage drop. The circuit operates in a regime where the transconductance parameter dominates, allowing low-voltage operation while maintaining noise suppression effectiveness.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If conventional capacitance multiplier circuits are used to provide large capacitance values, then noise suppression is improved, but power consumption increases

Engineering Contradiction:
Improvenoise suppressionVSAvoidpower consumption
Core Design Contradiction:
ReliabilityVSUse of energy by stationary object

Solution Approach 1:

The patent optimizes the power consumption parameter by designing a transconductance circuit that achieves high capacitance multiplication with minimal current draw. The circuit uses high-impedance nodes and carefully selected transistor dimensions to minimize static power consumption while maintaining the ability to suppress power supply noise effectively.

Inventive Principle:
Principle #35Parameter changes

3Reliability

If conventional capacitance multiplier circuits are used, then fixed capacitance values are provided, but adaptability to different impedance requirements is reduced

Engineering Contradiction:
Improvecapacitance provisionVSAvoidimpedance compatibility
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent introduces dynamic adaptability by making the capacitance multiplier circuit's output impedance controllable through the transconductance parameter. The circuit can adapt to different load impedance requirements by adjusting the transconductance gain, allowing it to interface with various circuit configurations while maintaining its noise suppression function.

Inventive Principle:
Principle #15Dynamics

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 configuration provides a capacitance value greater than a hundred times the original capacitor value, effectively suppressing power supply noise without increasing circuit area or power consumption, enabling its use in low voltage systems.

Implementation Method 1

a capacitor having a first terminal coupled to the power supply line and having a second terminal

Methodology Applied
Scientific EffectCapacitance: Capacitance

Implementation Method 2

a transconductance circuit coupled to the capacitor and the adjustable resistance. The transconductance circuit can include a current source coupled between the second source-drain terminal of the transistor and the ground line

Methodology Applied
Scientific EffectTransconductance:

Implementation Method 3

an adjustable resistance having a first terminal coupled to the second terminal of the capacitor and having a second terminal. The capacitance multiplier circuitry has a capacitance value that can be elevated by increasing a resistance value of the adjustable resistance

Methodology Applied
Scientific EffectElectrical Resistance: Electrical Resistance

Data Source

PatentEP4216435A1Capacitance multiplier for decoupling capacitor
Publication Date: 2023.07.26 APPLE INC
  • EP4216435A1 patent drawingFigure 1
  • EP4216435A1 patent drawingFigure 2
  • EP4216435A1 patent drawingFigure 3

AI summary

An integrated circuit may include one or more circuits coupled to capacitance multiplier circuitry. The capacitance multiplier circuitry may include a capacitor, fixed and tunable resistances, and a transconductance circuit. The tunable resistance can be adjusted to control the overall capacitance of the capacitance multiplier circuitry. The transconductance circuit may include a transistor having a drain terminal coupled to a first electrical component and a source terminal coupled to a second electrical component. The first electrical component may be a diode-connected transistor, a direct shorting wire, a resistor, an inductor, or a current source. The second electrical component may be a current source, a direct shorting wire, a resistor, an inductor, or another diode-connected device. Configured in this way, the capacitance multiplier circuitry can provide a large adjustable amount of capacitance without a voltage drop and without consuming a large amount of power.