Noise Filter Circuit With Controllable Off-Resistance for Faster Settling

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing noise filter circuits face issues with high power consumption, large area consumption, and slow settling time due to large transistor off-resistance, which are not suitable for low-voltage applications and cause undesired voltage mismatches.

Innovation Solution

A noise filter circuit with a transistor off-resistance control circuit that includes a first transistor and a charge storage component, where the control terminal is not directly tied to a reference voltage, allowing for controllable off-resistance through a transistor off-resistance control circuit.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If large resistance/capacitance is used in the low-pass filter to achieve low corner frequency, then noise filtering performance is improved, but settling time increases and area consumption increases

Engineering Contradiction:
Improvenoise filtering performanceVSAvoidsettling time
Core Design Contradiction:
Object-affected harmful factorsVSLoss of time

Solution Approach 1:

The patent applies dynamics by making the transistor off-resistance controllable and adjustable rather than fixed. The control circuit dynamically adjusts the off-resistance of the transistor based on operational requirements, allowing the filter to adapt between high resistance (for better noise filtering) and lower resistance (for faster settling), thus resolving the contradiction between noise filtering performance and settling time

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the resistance parameter of the transistor by controlling its off-resistance through a dedicated control circuit. By adjusting the control voltage applied to the transistor, the off-resistance can be varied to optimize both noise filtering and settling time performance, directly addressing the contradiction between these two parameters

Inventive Principle:
Principle #35Parameter changes

2Object-affected harmful factors

If large resistance/capacitance is used in the low-pass filter to achieve low corner frequency, then noise filtering performance is improved, but area consumption increases

Engineering Contradiction:
Improvenoise filtering performanceVSAvoidarea consumption
Core Design Contradiction:
Object-affected harmful factorsVSArea of stationary object

Solution Approach 1:

The patent changes the resistance parameter of the transistor by controlling its off-resistance through a dedicated control circuit. By adjusting the control voltage applied to the transistor, the off-resistance can be varied to optimize both noise filtering and settling time performance, directly addressing the contradiction between these two parameters

Inventive Principle:
Principle #35Parameter changes

3Object-affected harmful factors

If transistor off-resistance is large, then noise filtering is improved, but settling time increases

Engineering Contradiction:
Improvenoise filteringVSAvoidsettling time
Core Design Contradiction:
Object-affected harmful factorsVSLoss of time

Solution Approach 1:

The patent applies dynamics by making the transistor off-resistance controllable and adjustable rather than fixed. The control circuit dynamically adjusts the off-resistance of the transistor based on operational requirements, allowing the filter to adapt between high resistance (for better noise filtering) and lower resistance (for faster settling), thus resolving the contradiction between noise filtering performance and settling time

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

The solution reduces transistor off-resistance, improving settling time, reducing operational amplifier output voltage, and minimizing voltage mismatches, making it suitable for low-voltage applications.

Implementation Method 1

The filter includes a first transistor and a charge storage component

Methodology Applied
Scientific EffectCapacitance: Capacitance

Implementation Method 2

The first transistor is arranged to have off-resistance when turned off or operated under sub-threshold region

Methodology Applied
Scientific EffectElectrical Resistance: Electrical Resistance

Data Source

PatentUS12388420B2Noise filter circuit with controllable transistor off-resistance and associated noise filtering method
Publication Date: 2025.08.12 MEDIATEK INC
  • US12388420B2 patent drawing
  • US12388420B2 patent drawing
  • US12388420B2 patent drawing

AI summary

A noise filter circuit includes a filter and a transistor off-resistance control circuit. The filter includes a first transistor and a charge storage component. The first transistor has off-resistance when turned off or operated under sub-threshold region. A control terminal of the first transistor is not directly tied to a reference voltage, and is used to receive a first control voltage. The charge storage component has one terminal coupled to a connection terminal of the first transistor. The transistor off-resistance control circuit is coupled to the first transistor, and arranged to set the first control voltage for controlling the off-resistance of the first transistor.