Isolated Signal Processing Circuit for Reference Voltage Stability
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Solution Overview
Problem
Signal processing circuits with isolators face destabilization due to discontinuous reference voltages between the input and output sides, leading to unstable signal processing.
Innovation Solution
A signal processing circuit configuration that includes an isolator with voltage setting circuits on both sides, a variable gain amplifier circuit, a DC offset adjustment circuit, and a control circuit to maintain stable signal processing by comparing and adjusting reference voltages and gains.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an isolator is used to electrically insulate the input side and output side, then isolation between high voltage side and low voltage side is improved, but reference voltage continuity deteriorates causing signal processing instability
Solution Approach 1:
A control circuit is introduced as an intermediary between the input and output sides of the isolator. This control circuit receives a control signal from the output side, converts it to a corresponding control voltage, and outputs it to the input side, thereby mediating the reference voltage discontinuity caused by the isolator and maintaining signal processing stability.
2Stability of the object's composition
If voltage setting circuits are provided on both input and output sides of the isolator, then reference voltage stability is improved, but device complexity increases
Solution Approach 1:
The control circuit serves multiple functions: it acts as a voltage setting circuit on the output side by generating a control signal, functions as a voltage converter by transforming the control signal to a corresponding control voltage, and operates as a feedback mechanism by receiving signals from the output side and adjusting the input side accordingly. This multi-functionality reduces the need for separate dedicated circuits for each function.
3Stability of the object's composition
If a control circuit is added to convert control signals to control voltages, then signal processing stability is improved, but device complexity and power consumption increase
Solution Approach 1:
The control circuit combines the functions of voltage setting, signal conversion, and feedback control into a single integrated unit. By merging these previously separate functions into one circuit block, the overall device complexity is reduced while maintaining the stability benefits of having both voltage setting circuits and active control.
Data Source
AI summary
According to one embodiment, a signal processing circuit includes a first voltage setting circuit that sets a reference voltage on an input side of an isolator, a variable gain amplifier circuit that amplifies an output signal of the isolator, a DC offset adjustment circuit that adjusts an offset of the variable gain amplifier circuit, a second voltage setting circuit that sets a reference voltage on an output side of the isolator, and a control circuit that controls the DC offset adjustment circuit in response to a result of comparison of an output voltage of the variable gain amplifier circuit with an output voltage of the second voltage setting circuit.