Parallel Power Converter Soft-Start Using Node Status Detection
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Solution Overview
Problem
In parallel power converters with directly coupled outputs, premature steady-state operation can lead to excessive in-rush current, switch over-stress, and thermal dissipation due to concurrent or sequential startup of power converters with mismatches in capacitor values, inductor values, and startup timing offsets, as well as faulty components.
Innovation Solution
The introduction of node status detectors and output status detectors to monitor voltage and current, ensuring that both pump capacitors and output capacitors are adequately charged during the soft-start period before allowing full power steady-state operation, with a StartUpOK signal generated only when all detectors indicate target charge levels are reached, synchronizing the transition to full power operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple power converters are started up concurrently or sequentially without synchronization, then the system can provide power faster, but excessive in-rush current and switch over-stress occur due to startup timing offsets and component mismatches
Solution Approach 1:
The patent applies preliminary action by implementing a soft-start period during which power converters operate in a controlled manner before transitioning to full power steady-state operation. During this soft-start period, the converters gradually establish proper voltage levels and synchronize their operation, preventing premature full-power operation that would cause in-rush current and switch over-stress. This preliminary controlled operation ensures that all converters are properly synchronized before full power delivery begins.
2Productivity
If power converters operate in steady-state prematurely, then full power delivery is achieved faster, but thermal dissipation and energy loss increase due to unsynchronized operation
Solution Approach 1:
The patent implements feedback mechanisms through status detectors that continuously monitor the operation state of each power converter. These detectors provide feedback signals to the control logic, enabling the system to detect when converters have completed their soft-start period and are ready for full power operation. This feedback ensures that power converters only transition to steady-state when properly synchronized, preventing energy loss and thermal dissipation that would result from premature or unsynchronized full-power operation.
3Device complexity
If startup detection is simplified without node status detectors, then device complexity is reduced, but measurement precision of capacitor charge levels and startup status deteriorates
Solution Approach 1:
The patent applies segmentation by dividing the startup detection function into multiple specialized status detectors, each monitoring specific nodes within the power converter circuit. Rather than using a single complex detector, the system employs multiple simpler detectors that each check specific conditions (such as capacitor charge levels at different nodes). This segmentation maintains measurement precision while keeping individual detector circuits relatively simple and modular.
Data Source
AI summary
Circuits/methods for controlling the startup of multiple parallel power converters that avoid inrush current or switch overstress in an added power converter or a power converter having fault conditions. Embodiments include node status detectors coupled to nodes within parallel-connected power converters to monitor voltage/current and configured in some embodiments to work in parallel with an output status detector measuring the startup output voltage of a power converter. With charge pump-based power converters, the node status detectors ensure that the power converter pump capacitors are charged while the output capacitor is charged as well. For such embodiments, a softstart period of startup may be considered finished if both the shared output capacitors and the power converter pump capacitors are charged to target values. Embodiments may also be used for fault detection during steady-state operation.