Triangular Wave Generator Feedback for Symmetry and Low Distortion
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Solution Overview
Problem
Conventional triangular wave generator circuits suffer from limited adjustability of charging and discharging currents, leading to non-constant slopes and asymmetrical triangular wave signals, resulting in distortion.
Innovation Solution
A low distortion triangular wave generator circuit that uses an integration circuit and an adjustment control circuit to generate symmetrical triangular waves by adjusting charging and discharging currents based on a common mode related signal and a predetermined DC level, ensuring equal time lengths for charging and discharging periods and maintaining an average voltage at a target DC level.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional triangular wave generator circuits use limited adjustability of charging and discharging currents, then the circuit structure is simple, but the triangular wave signal becomes distorted with non-constant slopes and asymmetry
Solution Approach 1:
The patent implements a feedback mechanism where the triangular wave signal is fed back to the current control circuit, which adjusts the charging and discharging currents based on the detected signal characteristics. This closed-loop feedback ensures the triangular wave maintains constant slopes and symmetry by automatically correcting deviations, thereby improving signal accuracy without requiring overly complex open-loop control structures.
Solution Approach 2:
The patent employs dynamic current adjustment where the charging and discharging currents are not fixed but are continuously adapted based on the triangular wave signal characteristics. The current control circuit dynamically modifies the current values to maintain constant slopes during both charging and discharging phases, resolving the contradiction between simple structure and signal accuracy by introducing controlled dynamics.
2Manufacturing precision
If the charging current and discharging current are not equal, then the circuit operation is simplified, but the rising period and falling period become unequal causing asymmetrical triangular wave and higher distortion
Solution Approach 1:
The feedback mechanism monitors the triangular wave signal and automatically adjusts the charging and discharging currents to ensure they are equal in magnitude. This feedback control eliminates the need for manual current matching and ensures symmetrical triangular wave output, improving ease of operation while maintaining high precision symmetry.
Solution Approach 2:
The patent creates an equipotential condition for the charging and discharging currents by designing the current control circuit to maintain equal current magnitudes during both phases. This equipotential approach ensures that the rising and falling periods are equal, achieving symmetrical triangular wave without complex differential control.
3Manufacturing precision
If the time period for adjusting charging and discharging currents is limited to part of the charging or discharging period, then the circuit response is faster, but the triangular wave signal becomes distorted with non-constant slopes
Solution Approach 1:
The patent ensures continuous current adjustment throughout the entire charging and discharging periods rather than limiting adjustment to only part of these periods. The feedback mechanism operates continuously, constantly monitoring and adjusting the currents to maintain constant slopes, thereby eliminating distortion while accepting the necessary time for complete-period adjustment.
Data Source
AI summary
A low distortion triangular wave generator circuit generates a triangular wave signal by performing integration on an integration capacitor via a charging current and a discharging current during a charging period and a discharging period within a switching period of an external clock signal. A time length of the charging period is identical to a time length of the discharging period. A common mode related signal related to a common mode characteristic of the triangular wave signal is generated. An adjusting signal is generated according to a difference between the common mode related signal and a predetermined DC (direct current) level. The adjusting signal adjusts at least one of the charging current and the discharging current via feedback mechanism such that the triangular wave signal is a symmetrical triangular wave, and an average voltage of the triangular wave signal is equal to a target DC level.