Chopper Amplifier Mode Switching for Low-Ripple DC Sensing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional chopper amplifiers suffer from chopper ripples due to voltage offsets, which are costly to mitigate and consume excessive current, limiting their effectiveness across various applications.
Innovation Solution
The proposed amplifier circuit employs a modulator and demodulator at a chopper frequency, coupled with capacitors and a discharge resistor circuit, to convert DC input voltage into AC and back to DC, effectively reducing chopper ripples through energy-saving modes and continuous operation, utilizing switched-capacitor or pseudo-resistor configurations for efficient charge equalization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional chopper amplifiers are used to amplify DC signals, then the zero-point error and 1/f noise are shifted to higher frequency bands, but chopper ripples are generated due to voltage offsets which consume excessive current and require costly mitigation
Solution Approach 1:
The patent employs periodic switching of the modulator circuit at a chopper frequency to convert DC input voltage into AC voltage, enabling the amplifier to operate in an optimized mode while maintaining offset compensation benefits. This periodic action allows the system to achieve low offset error without continuous high current consumption
Solution Approach 2:
The patent changes the operating parameters by switching between different modes (first operating mode with capacitive coupling for energy saving, second operating mode with discharge resistor for continuous operation). This parameter change allows the system to adapt current consumption levels while maintaining measurement precision across different application scenarios
2Measurement precision
If conventional chopper amplifiers are used to amplify DC signals, then the zero-point error and 1/f noise are shifted to higher frequency bands, but chopper ripples are generated due to voltage offsets which require costly mitigation
Solution Approach 1:
The patent merges the modulator, amplifier, and demodulator into a single integrated chopper amplifier circuit. By combining these functions and using capacitive coupling between stages, the design achieves offset compensation without requiring separate complex mitigation circuits for chopper ripples
Solution Approach 2:
The patent introduces capacitors as intermediary elements between the modulator output and amplifier input, and between amplifier output and demodulator input. These capacitors couple the stages while blocking DC offsets, thereby reducing chopper ripples without adding complex active compensation circuits
3Productivity
If the amplifier circuit operates in continuous mode, then signal processing is uninterrupted, but energy consumption increases
Solution Approach 1:
The patent implements dynamic operation by allowing the circuit to switch between two operating modes based on application requirements. The first mode uses capacitive coupling for energy-saving operation with sampled signal processing, while the second mode uses discharge resistor coupling for continuous signal processing. This dynamic adaptability optimizes the balance between productivity and energy consumption
Solution Approach 2:
In the first operating mode, the patent uses periodic switching at the chopper frequency to process signals in discrete phases (first switching phase for sampling, second switching phase for processing). This periodic action enables energy-saving operation while maintaining essential signal processing functionality
4Stability of the object's composition
If capacitors are used for coupling in the amplifier circuit, then charge equalization is needed between capacitors, but this requires additional circuit elements
Solution Approach 1:
The patent introduces a discharge resistor circuit as an intermediary element that provides a controlled path for charge equalization between the first and second capacitors. This simple passive component achieves charge balance stability without requiring complex active control circuits or additional switching elements
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 solution provides an offset-compensated chopper amplifier with reduced chopper ripple noise, low jitter, and low chip area, while enabling energy-efficient operation and adaptive mode switching based on signal changes.
Implementation Method 1
a modulator circuit that is switched at a chopper frequency and that is configured to convert a DC (direct current) input voltage into an AC (alternating current) input voltage in accordance with the chopper frequency
Implementation Method 2
The output terminals of the first and second capacitors are coupled to the output amplifier via a demodulator circuit switchable at the chopper frequency. The demodulator circuit is configured to convert the amplified AC voltage back into an amplified DC voltage.
Implementation Method 3
In a first switching phase of the modulator circuit in the first operating mode, an output terminal of the first capacitor and an output terminal of the second capacitor are connected to a joint common-mode potential, or DC potential. As a result, the (amplified) input voltage can be stored on the capacitors.
Implementation Method 4
In the second operating mode, a discharge resistor circuit is coupled between the output terminals of the first and second capacitors, through which a charge equalization can take place between the capacitors during a pair of sequential switching phases.
Data Source
AI summary
The present disclosure relates to chopper amplifier circuits with inherent chopper ripple suppression. Example implementations can realize a doubly utilized chopper amplifier circuit that is a current-saving circuit with a wake-up function that is capable of providing a self-wake signal in order to change into a fast, low-jitter/low-latency mode, and to provide a wake-up signal for a sleeping microprocessor or a system in response to signal changes.