Parallel Linear Regulator Control for Stable Current Sharing
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Solution Overview
Problem
Conventional power supply devices with parallel-connected linear regulators suffer from unstable control systems due to crossed feedback control loops, leading to oscillation and imbalance in current distribution, which can result in inadequate load current satisfaction and reduced reliability.
Innovation Solution
A power supply device configuration where a voltage controller and current controllers are connected in parallel, each with separate control systems, including a reference voltage circuit, voltage control circuit, and current detection circuits, allowing for independent control of output currents to achieve balanced and stable operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If multiple linear regulators are connected in parallel to increase output current capacity, then the load current requirement can be satisfied, but the control system becomes unstable and oscillation occurs due to crossed feedback loops
Solution Approach 1:
The patent divides the control system into separate independent control loops for each linear regulator. Each regulator has its own error amplifier and feedback path, preventing crossed feedback loops. This segmentation maintains control stability while allowing multiple regulators to operate in parallel and share the load current.
Solution Approach 2:
The patent implements individual feedback paths from each regulator's output to its own error amplifier. This feedback mechanism allows each regulator to independently sense and adjust its output voltage, ensuring stable operation and preventing oscillation caused by interconnected feedback loops.
2Power
If linear regulators with different output voltages are connected in parallel, then current can be dispersed among multiple regulators, but uneven current distribution occurs causing some regulators to carry excessive current
Solution Approach 1:
The patent dynamically adjusts the reference voltage or feedback ratio of each linear regulator to equalize their output voltages. By changing these parameters, all regulators operate at the same voltage level, ensuring uniform current distribution and preventing any single regulator from being overloaded.
3Ease of operation
If the common output voltage is fixed higher than individual regulator voltages, then the system can initialize properly, but regulators with lower voltages cannot contribute to current supply
Solution Approach 1:
The patent makes the output voltage of each linear regulator dynamically adjustable rather than fixed. During initialization, voltages can be set higher for proper startup, but during normal operation, the voltages are dynamically adjusted to match, allowing all regulators to actively participate in current supply based on load requirements.
Data Source
AI summary
In a power supply device, a voltage controller includes: a reference voltage circuit that generates a reference voltage based on an input voltage; a voltage control circuit that generates an output voltage of the voltage controller based on the input voltage by controlling an output current of the voltage controller so that the output voltage of the voltage controller corresponds to the reference voltage; and a first current detector circuit that detects the output current of the voltage controller, and generates a first current detection signal corresponding to the output current thereof. A current controller includes: a second current detector circuit that detects an output current of the current controller, and generates a second current detection signal corresponding to the output current thereof; and a current control circuit controls the output current of the current controller so that the second current detection signal corresponds to the first current detection signal.