Loop-Voltage Clamping in Power Converters for Fast Current Limiting
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Solution Overview
Problem
Existing power converter circuitry is not fast enough to prevent overshoots in current and voltage during transient conditions, which can lead to damage to the converter and other system components.
Innovation Solution
A dynamic current limit circuitry that includes an inductor, switches, switch control circuitry, loop gain circuitry, and clamping circuitry to stabilize loop voltage and inductor current, thereby clamping input current and reducing peak current overshoot.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional power converter circuitry is used, then the circuit can operate and regulate voltage, but it cannot prevent overshoots in current and voltage during transient conditions fast enough, leading to potential damage
Solution Approach 1:
The clamping circuitry is configured to clamp the loop voltage before the overshoot can propagate to the input current. By acting preliminarily on the loop voltage signal, the circuit prevents the harmful effect (overshoot) from occurring in the first place, rather than attempting to correct it after it has already damaged components.
Solution Approach 2:
The loop voltage signal serves as an intermediary that the clamping circuitry monitors and restricts. By clamping this intermediate signal, the circuit indirectly controls and limits the input current, preventing overshoot without requiring direct sensing or control of the input current itself.
2Reliability
If the clamping circuitry restricts the loop voltage, then the input current overshoot is reduced by approximately 29%, but the circuit complexity increases due to additional components
Solution Approach 1:
The clamping circuitry is integrated into the existing power converter control architecture, where the loop voltage signal already exists as part of the standard control loop. This existing signal is repurposed to serve the additional function of overshoot protection, allowing one component to perform multiple functions without proportionally increasing complexity.
Solution Approach 2:
The power converter's own loop voltage signal is used to trigger the clamping action. The circuit monitors its own internal signal and automatically activates protection when needed, eliminating the need for external sensing circuits or additional control hardware to detect overshoot conditions.
Data Source
AI summary
Systems, apparatus, articles of manufacture, and methods are disclosed to dynamically limit current for power converters. An example switch control circuitry configured to control a plurality of switches based on a loop voltage to control inductor current through a inductor; loop gain circuitry configured to generate the loop voltage based on an input voltage and a reference voltage; and clamping circuitry configured to clamp the loop voltage after the loop voltage exceeds a threshold, the switch control circuitry configured to clamp the inductor current based on the clamping of the loop voltage, wherein the clamping of the inductor current clamps an input current.