Converter Control Circuit Using Dual Oscillators for Low-Offset PWM
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Solution Overview
Problem
There is a need for an improved control device for PWM-driven electronic converters, such as buck or boost converters, that can efficiently regulate output voltage using a time-based control scheme, which combines the advantages of analog and digital controllers without the limitations of wide bandwidth amplifiers and high-speed comparators.
Innovation Solution
A control circuit for electronic converters is implemented, featuring a PWM signal generator with current-controlled oscillators, operational transconductance amplifiers, phase detectors, and delay lines to generate PWM signals based on feedback and reference voltages, enabling time-based PID regulation. This circuit includes bias current generators and switching circuits to ensure balanced operation and minimize output voltage offsets.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a time-based control scheme is used to regulate output voltage, then the complexity of wide bandwidth amplifiers and high-speed comparators is reduced, but the precision of voltage regulation may be compromised
Solution Approach 1:
The patent introduces a time-based control scheme that uses timing intervals and counter measurements as an intermediary mechanism between the PWM signal and the voltage regulation output. Instead of directly comparing voltages with high-speed comparators, the system measures time intervals proportional to voltage differences, thereby reducing hardware complexity while maintaining regulation precision through temporal measurement.
Solution Approach 2:
The patent replaces the traditional mechanical/electrical system of wide bandwidth amplifiers and high-speed comparators with a time-based measurement system using counters and timing circuits. This substitution eliminates the need for complex analog components by translating voltage comparison into time interval measurement, thereby reducing device complexity while preserving measurement precision.
2Measurement precision
If bias current generators are used to ensure balanced operation, then output voltage offsets are minimized, but the device complexity increases
Solution Approach 1:
The patent implements bias current generators that automatically adjust and balance the operation of the control circuit without requiring external calibration or complex control mechanisms. The bias currents self-regulate to minimize output voltage offsets, thereby achieving high precision with relatively simple circuitry by allowing the system to self-correct imbalances.
Solution Approach 2:
The patent uses bias current generators that dynamically adjust current parameters to maintain balanced operation across varying conditions. By changing the bias current parameters adaptively, the system minimizes output voltage offsets without requiring complex additional circuitry, as the parameter adjustment itself compensates for imbalances.
3Reliability
If a time-based PID regulation is implemented, then the dynamic performance is improved, but the device complexity increases due to additional components
Solution Approach 1:
The patent merges the PID regulation functions into a unified time-based control scheme where proportional, integral, and derivative actions are implemented through integrated timing and counting mechanisms rather than separate analog circuits. This consolidation achieves improved dynamic performance while avoiding the complexity of multiple discrete PID components by combining their functions into a cohesive time-based system.
Solution Approach 2:
The time-based control circuit is designed to perform multiple functions including PWM generation, PID regulation, and voltage measurement using a unified set of components. The same timing and counting mechanisms serve multiple purposes in the control algorithm, thereby achieving enhanced dynamic performance without proportionally increasing device complexity, as each component serves multiple roles in the system.
Data Source
AI summary
In a control circuit for a switching stage of an electronic converter, a phase detector generates a drive signal in response to a phase difference between first and second clock signals. The first and second clock signals are generated by first and second current-controlled oscillators, respectively. An operational transconductance amplifier generates first and second control currents in response to a difference between a reference and a feedback of the electronic converter, with the first and second currents applied to control the first and second current-controlled oscillators. In response to a switching clock having a first state, a switching circuit applies first and second bias currents to the control inputs of the first and second current-controlled oscillators, respectively. Conversely, in response to the switching clock having a second state, the switching circuit applies the second and first bias currents to the control inputs of the first and second current-controlled oscillators, respectively.