Power Converter Reference Voltage Adjustment for Load Stability
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In power converter systems, a fixed load-line setting leads to insufficient reference voltage variation at low input voltages, causing over-reaction in the control loop and increased peak-to-peak output voltage amplitude, resulting in unstable output during load changes.
Innovation Solution
A control circuit for power converters that includes a sensing circuit, reference voltage generation circuit, error amplifying circuit, and PWM circuit, which adjusts the reference voltage ratio based on error amplification signals, increasing the reference voltage variation when necessary and gradually restoring it to default values, related to input voltage and load stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a fixed load-line setting is used, then the reference voltage variation amount is consistent under the same output current, but the control loop over-reacts at low input voltage causing large output voltage variation amplitude
Solution Approach 1:
The patent implements dynamic load-line adjustment by modifying the reference voltage generation circuit to automatically adapt the load-line ratio based on operating conditions. The circuit transitions from a fixed resistor-based load-line to a dynamically adjustable configuration that responds to input voltage and load changes, ensuring optimal reference voltage variation across different operating points without manual intervention
Solution Approach 2:
The patent changes the load-line ratio parameter dynamically based on input voltage levels and load conditions. By adjusting the reference voltage variation amount proportionally to output current with a variable ratio rather than a fixed value, the system adapts reference voltage characteristics to match operating conditions, preventing over-reaction at low input voltage while maintaining stability at high input voltage
2Device complexity
If the load-line setting for high input voltage is applied to low input voltage condition, then the circuit structure remains simple, but the reference voltage variation amount is insufficient causing control loop over-reaction
Solution Approach 1:
The patent introduces dynamic adjustment capability into the reference voltage generation circuit by adding control logic that monitors input voltage and load conditions. This allows the load-line ratio to automatically transition between different settings based on operating point, achieving high input voltage performance at low input voltage without requiring completely separate circuit configurations
Solution Approach 2:
The patent modifies the load-line ratio parameter based on detected operating conditions. When low input voltage is detected, the circuit adjusts the reference voltage variation amount to provide sufficient control authority, whereas at high input voltage it maintains the original load-line setting, thereby optimizing performance across different voltage conditions with a single unified circuit
Data Source
AI summary
A control circuit of a power converter includes a first sensing circuit, a reference voltage generation circuit, an error amplifying circuit and a PWM circuit. The first sensing circuit, coupled to a first output circuit, provides a first current sensing signal. The reference voltage generation circuit, coupled to the first sensing circuit, provides a reference voltage according to the first current sensing signal. The error amplifying circuit, coupled to the reference voltage generation circuit, receives the reference voltage and an output feedback voltage of the power converter to provide an error amplifying signal. The PWM circuit, coupled between the error amplifying circuit and the first output circuit, receives the error amplifying signal and provides a control signal to control the first output circuit. The reference voltage generation circuit further receives the error amplifying signal and adjusts the reference voltage it generates according to the error amplifying signal.