Power Converter Dynamic I-V Control via Feedback
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Solution Overview
Problem
Conventional power supply converters have limited output current-voltage (I-V) characteristics, which are not suited for various applications requiring more flexible I-V relationships, particularly in scenarios where current consumption changes with output voltage.
Innovation Solution
The method involves modifying the current sense signal and conduction duty ratio using feedback voltage signals to control the output current, allowing it to vary with output voltage, with specific configurations to increase current at lower voltages and reduce it at higher voltages, achieved through circuits that include resistors, Zener devices, and transistors within a single integrated circuit chip or discrete components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional fixed I-V characteristic power supply is used, then the power supply structure is simple, but the adaptability to different applications is poor
Solution Approach 1:
The patent implements dynamic I-V characteristic control by making the current limit value variable based on output voltage through feedback circuits. The control circuit dynamically adjusts the current limit according to the relationship I_limit = f(V_out), transforming the fixed characteristic into a flexible, application-specific characteristic without requiring complete redesign for different uses.
Solution Approach 2:
The patent changes the control parameter from fixed current limit to variable current limit that depends on output voltage. By modifying the current sense signal through feedback voltage signals and Zener devices, the system achieves different I-V characteristics (constant voltage, constant current, or customized curves) by adjusting the relationship between voltage and current limit parameters.
2Power
If constant current mode is used at low voltage, then current output is high, but power consumption increases
Solution Approach 1:
The patent employs feedback mechanisms where the output voltage is sensed and fed back to adjust the current limit. Through the feedback voltage signal and Zener device configuration, the system automatically reduces current output when voltage drops, preventing excessive power consumption while maintaining adequate output power for the load.
Solution Approach 2:
The system dynamically adjusts the operating point on the I-V curve based on actual output voltage conditions. Instead of maintaining constant current regardless of voltage, the control circuit modifies the current limit in real-time to optimize the balance between output power and power consumption, achieving energy efficiency while meeting power requirements.
Data Source
AI summary
A power converter includes a primary winding for providing a primary current, a secondary winding for providing an output current and an output voltage, and a current sense node for receiving a current sense signal related to the primary current. The power converter also includes a control circuit configured to limit the current sense signal to be lower than or equal to a predetermined reference peak current. Moreover, the power converter includes a first circuit configured to modify the current sense signal using a first signal related to the output voltage to cause an variation in the output current.