Boost Converter Startup Control for Low Inrush Current
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Solution Overview
Problem
DC-DC boost converters experience high instantaneous inrush currents during startup, requiring overcurrent protection and often leading to long operational delays in achieving stable output voltage.
Innovation Solution
A DC-DC boost converter design incorporating a control unit, sensor unit, and reference signal generation unit to control the semiconductor switch with a ramping reference voltage, gradually increasing from the initial output voltage to minimize inrush current and achieve stable output voltage quickly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the boost converter is switched on with high instantaneous input current, then the converter can start up quickly, but overcurrent protection is required and operational delays occur
Solution Approach 1:
The control unit performs preliminary action by detecting the initial output voltage at activation and setting the initial value of the ramped reference voltage accordingly. This preparation before the inrush current occurs allows the converter to start up quickly without triggering overcurrent protection, as the reference voltage already accounts for the initial conditions.
Solution Approach 2:
The patent applies parameter changes by implementing a ramped reference voltage that dynamically changes over time. The reference voltage starts at an initial value determined by the initial output voltage and increases continuously until reaching the target output voltage. This continuous parameter change allows the control signal to adapt to the converter's startup phase, enabling fast startup without overcurrent issues.
2Reliability
If overcurrent protection is implemented to prevent high instantaneous current, then component damage is prevented, but operational delays occur in achieving stable output voltage
Solution Approach 1:
The control unit continuously compares the actual output voltage with the ramped reference voltage and adjusts the control signal accordingly. This feedback mechanism ensures that the output voltage follows the reference trajectory, achieving stable output voltage quickly without requiring conservative overcurrent protection delays. The feedback loop maintains component safety while minimizing operational delays.
Solution Approach 2:
The patent implements dynamics by using a time-varying ramped reference voltage instead of a static reference. The reference voltage dynamically adapts to the converter's operational phase, starting from the initial output voltage and continuously increasing to the target voltage. This dynamic approach allows the system to operate safely without the delays associated with static overcurrent protection schemes.
3Device complexity
If a fixed reference voltage is used for control, then the control circuit is simple, but the converter cannot quickly adapt to initial output voltage conditions
Solution Approach 1:
The control unit performs preliminary detection of the initial output voltage at activation and uses this information to set the initial value of the ramped reference voltage. This preliminary action allows the reference voltage to be appropriately initialized without requiring complex adaptive algorithms during operation, maintaining relatively simple control circuitry while improving adaptability speed.
Solution Approach 2:
The patent changes the reference voltage parameter from a fixed value to a time-varying ramped signal. The reference voltage continuously changes from the initial output voltage to the target output voltage, enabling the converter to quickly adapt to initial conditions. This parameter change approach maintains reasonable circuit complexity while significantly improving the converter's response speed and adaptability.
Data Source
AI summary
The present invention relates to a DC-DC boost converter which ensures a fast start until the desired output voltage is reached without causing a high input current during the start phase. In particular, the limitation of the input current is influenced according to the initial output voltage. The invention also relates to a method for the boost converter.