Power Distribution Switch Fast Short-Circuit Response
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Solution Overview
Problem
Conventional power distribution switches are unable to respond quickly enough to hard short-circuit conditions, leading to potential damage and system instability due to excessive current flow before feedback loops can increase resistance.
Innovation Solution
Incorporating a digital voltage feedback loop in conjunction with an analog current feedback loop to rapidly increase the resistance of the power distribution switch when a hard short-circuit is detected, using a comparator to monitor output voltage and generate a digital signal to shut down conduction paths and raise series resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an analog current feedback loop is used to monitor and control current draw, then the power distribution switch can limit excessive current, but the response time is too slow to prevent damage during hard short-circuit conditions
Solution Approach 1:
The feedback control is segmented into two independent loops: an analog current feedback loop for normal operation and a digital voltage feedback loop for hard short-circuit detection. Each loop operates independently with optimized response characteristics for its specific function, allowing fast protection without compromising normal current limiting performance
Solution Approach 2:
The output voltage serves as an intermediary signal that indirectly indicates hard short-circuit conditions. By monitoring voltage drop across the switch rather than directly measuring current, the system achieves faster detection of catastrophic failures while the analog loop continues to handle normal current regulation
2Object-affected harmful factors
If the power distribution switch increases resistance to limit current, then excessive current draw is prevented, but large currents may still flow during hard short-circuits before the feedback loop responds
Solution Approach 1:
The digital voltage feedback loop is continuously monitoring output voltage in advance, ready to detect hard short-circuit conditions immediately when they occur. This preliminary monitoring state allows the system to react instantaneously to catastrophic failures without the delay associated with analog loop response time
Solution Approach 2:
The system changes the monitoring parameter from direct current measurement (analog loop) to voltage drop measurement (digital loop). This parameter change enables faster detection of hard short-circuits because voltage collapse occurs more rapidly and is easier to detect digitally than current surge
3Ease of operation
If a sense resistor and amplifier are used for current monitoring, then current draw can be controlled, but the system cannot respond quickly enough to hard short-circuits
Solution Approach 1:
The analog current feedback mechanism (sense resistor and amplifier) is supplemented with a digital voltage monitoring system. The digital system replaces the need for fast analog response by using voltage drop as a proxy indicator, which can be detected and processed digitally with much faster response times
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
This solution enables faster limitation of excessive currents during hard short-circuits, reducing the risk of damage and system instability, while also relaxing decoupling capacitor requirements and minimizing energy surges.
Implementation Method 1
a voltage feedback loop having a digital output voltage to increase the resistance of the switching device in response to a short-circuit based on the output voltage
Implementation Method 2
an analog current feedback loop to increase the resistance of the switching device based on a current through the switching device and a reference current
Data Source
AI summary
Methods and apparatus to provide power distribution switch circuits with fast responses to hard short-circuits are disclosed. In one example, a power distribution switch to detect a hard short-circuit condition is described, comprising a switching device having a resistance between an input terminal and an output terminal, to conduct a current from an input power source having an input voltage to an output terminal having an output voltage, a voltage feedback loop having a digital output voltage to increase the resistance of the switching device in response to a short-circuit based on the output voltage, and an analog current feedback loop to increase the resistance of the switching device based on a current through the switching device and a reference current.