PWM Modulated Output Adjustment Circuit for Power Converters
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Solution Overview
Problem
Conventional power conversion systems face complexity and high costs due to their dependency on accurate digital-to-analog converters (DACs) for dynamic output voltage control, particularly in AC/DC and DC/DC converters.
Innovation Solution
A power converter circuit with a feedback network using a combined resistive voltage divider and a PWM modulated control signal, where the modulation node is switchable between a floating and grounded state, allowing for dynamic output voltage adjustment without relying on DAC accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a digital-to-analog converter (DAC) is used for dynamic output voltage control, then the output voltage can be controlled and changed dynamically, but the circuit complexity increases and the output voltage resolution becomes highly dependent on DAC accuracy
Solution Approach 1:
The patent extracts and eliminates the DAC component from the conventional power conversion system. Instead of using a DAC to generate analog control signals, the invention directly uses a PWM signal from a microcontroller to control the power stage, thereby removing the source of complexity and accuracy dependency while maintaining dynamic voltage control capability
Solution Approach 2:
The patent substitutes the electronic DAC-based control mechanism with a PWM-based control mechanism. The PWM signal, being a digital signal that can be directly generated by microcontrollers, replaces the analog voltage generation approach, simplifying the overall system architecture and reducing component count
2Measurement precision
If a digital-to-analog converter (DAC) is used for dynamic output voltage control, then the output voltage can be adjusted with high resolution, but the system becomes more costly and complex
Solution Approach 1:
The patent employs a PWM signal that can be generated by standard, low-cost microcontrollers without requiring expensive high-precision DAC components. The PWM approach uses inexpensive digital logic and timing circuits to achieve accurate voltage control, replacing costly analog components with affordable digital alternatives
3Stability of the object's composition
If conventional feedback control is used, then the output voltage is stable, but the ability to dynamically adjust output voltage is limited
Solution Approach 1:
The patent introduces dynamic control capability by using a PWM signal with variable duty cycle to control the power stage. This allows the system to dynamically adjust the output voltage in response to changing load conditions or control commands, transforming a static feedback system into a dynamic, adaptable control system while maintaining stability through proper PWM frequency selection and feedback loop design
Data Source
AI summary
A circuit includes a first voltage divider coupled between an output node and a ground voltage, and a second voltage divider coupled between the output node and a modulation node. The first voltage divider includes the modulation node. The modulation node is configured to receive a pulse width modulation (PWM) modulated control signal having an open drain configuration. The modulation node is switchable by the PWM modulated control signal between a floating state and a grounded state. The modulation node experiences a high impedance with respect to a ground connection while in the floating state and experiences a low impedance with respect to the ground connection while in the grounded state.