LED Driver Surge Protection via dv/dt Sensing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Electronic power supplies are vulnerable to high voltage surges, such as those caused by lightning strikes, which can damage semiconductor components like switches Q1 and Q2, even with existing surge protection, as they are designed for steady-state voltage and not surge conditions.
Innovation Solution
A fast triggering surge protection circuit that includes a dv/dt sensing circuit and a DC overvoltage sensing circuit to quickly shut down the half-bridge switching components during a surge event, allowing switches Q1 and Q2 to block twice the voltage when powered off, and ensuring the integrated circuit is in shutdown mode when the rail voltage exceeds the maximum rated voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If switches Q1 and Q2 are designed for steady-state voltage operation, then the circuit operates efficiently under normal conditions, but the switches cannot withstand high voltage surges from lightning strikes
Solution Approach 1:
The dv/dt sensing circuit detects voltage surges in advance by monitoring the rate of change of voltage across the switches. When a surge is detected, the circuit triggers a shutdown signal to the half-bridge driver before the surge voltage reaches dangerous levels, allowing the switches to block the surge voltage in their off state without damage
Solution Approach 2:
The patent introduces a dv/dt sensing circuit as an intermediary component that senses voltage changes and triggers a shutdown mechanism. This intermediary protection circuit acts as a mediator between the surge event and the switches, enabling the switches to withstand surges they were not originally designed for
2Reliability
If the circuit operates with switches in steady-state mode, then power conversion efficiency is maintained, but the switches are vulnerable to damage during surge events
Solution Approach 1:
The dv/dt sensing circuit applies preliminary anti-action by detecting the onset of a voltage surge and immediately triggering a shutdown of the half-bridge switches. This preemptive shutdown prevents the surge from damaging the switches, countering the harmful effect before it can occur
Solution Approach 2:
The patent replaces traditional mechanical or slow-responding surge protection mechanisms with an electronic dv/dt sensing system that provides fast electronic detection and response. The sensing circuit monitors voltage changes electronically and triggers shutdown through electronic control signals, achieving much faster response times than mechanical alternatives
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
The solution effectively protects half-bridge switching components by turning them off during input line surges, preventing damage from high voltage surges and ensuring the circuit can withstand twice the voltage rating of the switches, thereby enhancing the reliability of the power supply system.
Implementation Method 1
A fast triggering surge protection circuit that includes a dv/dt sensing circuit and a DC overvoltage sensing circuit to quickly shut down the half-bridge switching components during a surge event
Implementation Method 2
A fast triggering surge protection circuit that includes a dv/dt sensing circuit and a DC overvoltage sensing circuit to quickly shut down the half-bridge switching components during a surge event
Implementation Method 3
allowing switches Q1 and Q2 to block twice the voltage when powered off
Data Source
AI summary
A protection system for an LED driver includes a voltage rail, an input voltage source, and a surge protector connected between the input voltage source and the voltage rail. The voltage change sensing block detects a change in a voltage associated with the input voltage source. The protection system further includes a voltage sensing block connected to the voltage change sensor. A half-bridge switching circuit may include a switch controller, a first switching element, and a second switching element. The switch controller controls an operating state of each of the first switching element and the second switching element. A reset block disables at least one of the switch controller, the first sensing element, and the second switching element, responsive to a control signal associated with at least one of the voltage change sensing block and the voltage sensing block.