Parallel PSU Current Balancing via Digital Load Share Signal
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Solution Overview
Problem
Existing methods for balancing supply currents from multiple power supply units are complex, costly, and suffer from low accuracy and instability, particularly in managing sudden load changes and avoiding overloading of individual power sources.
Innovation Solution
A method and device that utilize a load share digital signal to synchronize output currents among power supply units, employing a field-effect transistor and timer to control the timing of current output, requiring minimal additional hardware and enabling simultaneous digital communication among units.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional current sharing methods are used, then current balancing can be achieved, but the system becomes complex and costly with low accuracy and instability
Solution Approach 1:
The patent replaces complex analog current sensing and sharing circuits with a digital communication-based control system. Each power supply unit uses a microcontroller to digitally communicate its output current status to other units via a shared bus, eliminating the need for complex analog current sharing hardware and achieving more precise current balancing through digital processing.
Solution Approach 2:
The patent introduces a digital communication bus as an intermediary between power supply units. Instead of direct analog current sharing, each unit reports its status through the bus, and a master controller processes this information to generate appropriate control signals, simplifying the overall system architecture while improving reliability.
2Power
If multiple power supply units operate in parallel, then larger power output is achieved, but current imbalance causes overloading and reduced service life
Solution Approach 1:
The patent implements a feedback mechanism where each power supply unit continuously monitors its output current and communicates this information to a master controller via a digital bus. The master controller processes this feedback and adjusts the operating status of individual units to maintain balanced current distribution, preventing overloading and ensuring stable operation.
Solution Approach 2:
The patent enables dynamic adjustment of power supply unit operating statuses based on real-time current conditions. When load changes occur, the system dynamically recalculates and redistributes the current sharing ratios among units, allowing the system to adapt to varying load conditions while maintaining current balance and preventing any single unit from being overloaded.
3Reliability
If current sharing management is implemented, then current balance is maintained, but response time to load changes is delayed
Solution Approach 1:
The patent implements preliminary action by having each power supply unit continuously monitor and report its current status to the master controller before actual load changes occur. The master controller maintains an updated understanding of each unit's capability and operating state, allowing it to immediately redistribute load when changes occur, reducing response time while maintaining accuracy.
Data Source
AI summary
A method, device, and system for balancing a supply current in a Power Supply Units (PSUs). The system includes a plurality of PSUs connected in parallel to a power bus. The method includes detecting a falling edge in a common Load Share (LS) signal and, in response to detecting the falling edge of the LS signal, enabling a field effect transistor (FET) and starting a timer. Prior to starting the timer, a time trigger is determined for the timer based on a current output level of a power source in the PSU. The method includes outputting a current at the current output level for the duration of the time trigger and, at the time trigger, releasing the FET and resetting the timer. The PSU includes a processor that monitors the LS signal. The LS signal determines a timing for outputting current by the PSU.