Chopper-Stabilized Switched Capacitor Circuit for Low-Power Offset Removal

Solution Overview

Problem

Switched capacitor circuits in semiconductor circuits face challenges with high power consumption and large area occupation, particularly due to the use of operational amplifiers, which limits their integration and application range.

Innovation Solution

The implementation of an inverting amplifier with chopper stabilization circuits to reduce power consumption and area, incorporating differential inverters, chopper stabilization units, sampling units, and feedback capacitors, which periodically invert signals to minimize offset and flicker noise, replacing traditional operational amplifiers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If an operational amplifier is used in the switched capacitor circuit, then the circuit performance is improved, but the power consumption increases and the area occupied increases

Engineering Contradiction:

Improvecircuit performanceVSAvoidpower consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent changes the operating parameters by using periodic switching of capacitors to simulate resistance, replacing the continuous operation of operational amplifiers with discrete switching operations. This parameter change enables the circuit to achieve similar functionality with lower power consumption and reduced area occupation.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent extracts the essential function of the operational amplifier (signal amplification and integration) and implements it separately using switched capacitor networks and timing control, eliminating the need for the complex operational amplifier structure and reducing both power consumption and area.

Inventive Principle:

Principle #2Taking out (Extraction)

2Reliability

If an operational amplifier is used in the switched capacitor circuit, then the circuit performance is improved, but the area occupied increases

Engineering Contradiction:

Improvecircuit performanceVSAvoidarea occupied

Core Design Contradiction:

ReliabilityVSArea of stationary object

Solution Approach 1:

The patent changes the operating parameters by using periodic switching of capacitors to simulate resistance, replacing the continuous operation of operational amplifiers with discrete switching operations. This parameter change enables the circuit to achieve similar functionality with lower power consumption and reduced area occupation.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent extracts the essential function of the operational amplifier (signal amplification and integration) and implements it separately using switched capacitor networks and timing control, eliminating the need for the complex operational amplifier structure and reducing both power consumption and area.

Inventive Principle:

Principle #2Taking out (Extraction)

3Use of energy by moving object

If traditional operational amplifiers are replaced with inverting amplifiers, then power consumption and area are reduced, but offset and flicker noise must be addressed

Engineering Contradiction:

Improvepower consumptionVSAvoidoffset and flicker noise

Core Design Contradiction:

Use of energy by moving objectVSObject-generated harmful factors

Solution Approach 1:

The patent applies periodic switching action to the capacitor networks, using clocked switching to periodically charge, hold, and discharge capacitors. This periodic action enables the inverting amplifier to achieve stable operation and reduces the impact of offset and flicker noise through timing-controlled signal processing.

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The patent implements feedback mechanisms using switched capacitor networks that periodically feed back signals to correct for offset and reduce flicker noise. The feedback is achieved through controlled capacitor charging and discharging cycles that stabilize the amplifier output.

Inventive Principle:

Principle #23Feedback

Data Source

PatentUS8723597B2Switched capacitor circuit

Publication Date: 2014.05.13 XO SEMICONDUCTOR INC

AI summary

According to the present invention, a switched capacitor circuit comprises: an inverting amplifier for removing the offset by using a chopper stabilization circuit; a sampling unit which is connected between an input terminal and the inverting amplifier; and a feedback unit which is connected to the inverting amplifier in parallel.