Shoot-Through Detection Circuit for Voltage Regulators
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Solution Overview
Problem
Existing methods for detecting shoot-through events in information handling systems, particularly in voltage regulators, are prone to false positives and mis-triggering due to variations in MOSFET gate capacitances and propagation delays, leading to potential damage from undesired current flow during simultaneous conduction of low-side and high-side MOSFETs.
Innovation Solution
A method that involves detecting the assertion of a low-side gate driver signal, obtaining a reference voltage, comparing it to the local high-side positive supply voltage, and providing a warning of cross-conduction detection before failure occurs, using a circuit that includes comparators and logic gates to validate the voltage drop as a shoot-through event, thus avoiding false indications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If existing methods are used to detect shoot-through events, then detection capability is provided, but false positives and mis-triggering occur due to variations in MOSFET gate capacitances and propagation delays
Solution Approach 1:
The patent changes the detection parameter from direct gate signal timing comparison to voltage level measurement at the switching node. By monitoring voltage drops at the switching node during dead time, the system achieves more reliable shoot-through detection that is insensitive to variations in gate capacitance and propagation delay, thereby reducing false positives while maintaining detection accuracy
Solution Approach 2:
The patent introduces an intermediary measurement approach by using the switching node voltage as an intermediate indicator of shoot-through conditions. Instead of directly comparing gate signals, the system measures the voltage at the switching node, which serves as an intermediary that reflects the actual conduction state of the MOSFETs and provides more accurate detection
2Reliability
If simultaneous conduction of low-side and high-side MOSFETs is detected, then shoot-through detection is achieved, but component damage occurs from undesired current flow
Solution Approach 1:
The patent implements preliminary detection by monitoring the switching node voltage during the dead time period before the next MOSFET switching action. By detecting voltage drops that indicate simultaneous conduction during this critical window, the system can identify shoot-through conditions early and trigger protective measures before damaging current levels develop, thereby preventing component damage
Solution Approach 2:
The patent employs feedback by continuously monitoring the switching node voltage and using this information to detect abnormal conduction states. The detection circuit provides feedback about the actual voltage conditions at the switching node, enabling real-time identification of shoot-through events and allowing the control system to respond by disabling affected MOSFETs to prevent damage
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Effectively detects shoot-through events with reduced false positives, providing ample warning to prevent component damage and system failure, allowing for timely remedial actions such as swapping out VR modules or adjusting driver timing to prevent further occurrences.
Implementation Method 1
to compare the local high side positive supply voltage to the reference voltage value to provide an indication of a cross-conduction detection
Data Source
AI summary
A method, circuit, and information handling system detect an assertion of a low side gate driver signal of a low side gate driver coupled to a low side gate of a low side selectively conductive device, to obtain a reference voltage value, to detect a local high side positive supply voltage at a high side positive supply voltage terminal of a high side selectively conductive device, to compare the local high side positive supply voltage to the reference voltage value to provide an indication of a cross-conduction detection, and to provide a warning of the cross-conduction detection before occurrence of a failure of a selectively conductive device selected from a group consisting of the low side selectively conductive device and the high side selectively conductive device.