Voltage Detection Circuit With Chopper-Based Noise Suppression
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing voltage detection circuits struggle to accurately detect voltages while simultaneously detecting disconnections in AD converters due to noise and offset voltages, leading to inaccurate measurements and potential false detections.
Innovation Solution
A voltage detection circuit incorporating an AD converter, input and output chopper circuits, current chopper circuits, and a digital low-pass filter, which modulates low-frequency noise and offset voltages to high frequencies for removal, allowing accurate voltage measurement and disconnection detection in parallel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If voltage detection is performed using an AD converter, then voltage measurement capability is achieved, but noise and offset voltages cause measurement inaccuracies
Solution Approach 1:
The patent applies periodic chopping action to modulate the input voltage signal to a higher frequency. The chopper circuit periodically switches the input voltage, converting it to an AC signal that can be processed by the AD converter. This periodic modulation moves the signal away from low-frequency noise and DC offset voltages, improving measurement accuracy.
Solution Approach 2:
The patent converts the harmful low-frequency noise and offset voltages into a beneficial form by modulating them to high frequencies through chopping. The harmful DC offset and low-frequency noise are transformed into high-frequency components that can be easily filtered out by the low-pass filter, turning the harmful factors into removable artifacts.
2Adaptability or versatility
If disconnection detection is added to voltage detection, then both functions can be performed, but measurement accuracy deteriorates due to interference
Solution Approach 1:
The patent segments the detection process into two distinct frequency domains: voltage detection operates in the high-frequency chopped domain, while disconnection detection operates in the low-frequency domain by monitoring the chopping signal itself. This segmentation allows both functions to coexist without interfering with each other's accuracy.
Solution Approach 2:
The patent uses periodic chopping action to separate the two detection functions in time and frequency. During the chopping periods, voltage measurement is performed on the modulated signal. During non-chopping or transition periods, disconnection detection is performed by monitoring the chopping signal integrity. This periodic separation enables both functions to operate accurately.
3Object-affected harmful factors
If chopper circuits and current sources are added, then noise suppression is achieved, but device complexity increases
Solution Approach 1:
The chopper circuit serves multiple functions simultaneously: it modulates the input voltage for accurate ADC conversion, enables disconnection detection through its switching signal, and suppresses DC offset voltages. The current sources also serve dual purposes by providing bias currents for the chopper operation and contributing to the overall signal conditioning. This multi-functionality reduces the need for separate dedicated circuits.
Data Source
AI summary
A voltage detection circuit includes an AD converter, an input chopper circuit, an output chopper circuit, a digital low-pass filter, and a current chopper circuit. The chopper circuit switch a connection state of each input terminal of the AD converter, first and second input wirings at a first frequency. The output chopper circuit alternately execute inverting and non-inverting operations for an output value of the AD converter. The digital low-pass filter removes a high-frequency component from the output value of the output chopper circuit and operates at an output frequency. The current chopper circuit switches the connection state of a first current source, the first input wiring, a second current source and the second input wiring at a second frequency.