Variable Current Limiter for Non-Isolated Voltage Converters
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Solution Overview
Problem
Fixed output current limits in non-isolated voltage converters constrain power delivery at higher output voltages, leading to inefficient use of package size and power capability across a wide voltage range.
Innovation Solution
Implementing a variable current limiter that inversely varies with output voltage, allowing the output current limit to adjust based on the output voltage, thereby maintaining a more constant power output across different voltage levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a fixed output current limit is implemented to protect non-isolated voltage converters from overcurrent, then converter protection is improved, but power delivery capability at higher output voltages is constrained
Solution Approach 1:
The patent implements a dynamic current limit that varies with output voltage. The current limit circuit adjusts the maximum output current based on the actual output voltage level, transitioning from a static fixed limit to a dynamic adaptive limit. This allows the system to maintain constant power delivery across different voltage levels while still providing overcurrent protection.
Solution Approach 2:
The patent changes the parameter of current limit from a fixed value to a variable value that depends on output voltage. By making the current limit parameter dynamic and voltage-dependent, the system optimizes both protection and power delivery capabilities across the full operating voltage range.
2Device complexity
If a fixed output current limit is used to simplify the control circuit, then device complexity is reduced, but power delivery efficiency across wide voltage range deteriorates
Solution Approach 1:
The patent integrates multiple functions into the current limit circuit: it provides both overcurrent protection and power delivery optimization. The same circuit that limits current also dynamically adjusts the limit based on voltage to maintain constant power, making the circuit multi-functional rather than requiring separate protection and power management circuits.
Solution Approach 2:
The patent implements a feedback mechanism where the output voltage is sensed and fed back to the current limit circuit. This feedback allows the current limit to automatically adjust based on the actual operating conditions, optimizing power delivery without requiring complex external control.
3Reliability
If a fixed current limit is implemented to prevent overcurrent damage, then converter reliability is improved, but package size utilization deteriorates
Solution Approach 1:
The patent makes the current limit dynamic rather than fixed, allowing the system to fully utilize the package's power capability across different operating conditions. By adapting the current limit to the output voltage, the system maximizes the use of available package resources without compromising reliability.
Data Source
AI summary
A variable current limiter, a power supply and a method of operating a non-isolated voltage converter are disclosed herein. In one embodiment, the variable current limiter includes: (1) a converter controller configured to regulate an output voltage of a non-isolated voltage converter and limit an output current thereof and (2) a limit provider configured to provide a variable output current limit that inversely varies with the output voltage, the converter controller configured to employ the variable output current limit to limit the output current.