Power Control Device Short Circuit Detection
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Solution Overview
Problem
Existing power control devices fail to detect a short-circuited sensing resistor, leading to continuous high current output and potential damage to electronic components due to the inability to perform over-current protection.
Innovation Solution
The power control device incorporates a switch control circuit, resistors, comparators, and a transformation circuit to filter current sample voltages and generate control signals, allowing for timely shutdown of the primary switch even if the sensing resistor is short-circuited, using a second comparator to compare filtered and current sample voltages to ensure over-current protection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the power control device operates continuously with high currents, then it can meet the power supply requirements, but it dissipates excessive heat that can damage electronic components
Solution Approach 1:
The patent implements preliminary protective action by detecting abnormal conditions before they lead to catastrophic failure. The detection circuit continuously monitors the sensing resistor's status and the current conditions. When over-current conditions are detected (either through the sensing resistor or when its failure is detected), the protection circuit activates beforehand to shut down the power switch, preventing excessive heat accumulation and component damage. This preliminary action ensures that the device can operate at high power levels safely by preventing thermal runout before it occurs.
2Ease of operation
If the sensing resistor is short-circuited, then the current detection function fails, but the output switch remains turned on causing damage to electronic components
Solution Approach 1:
The patent implements a feedback mechanism that monitors the health of the sensing resistor and provides feedback signals to the control circuit. The detection transistor and detection capacitor form a feedback path that continuously checks the sensing resistor's status. When the sensing resistor becomes short-circuited, the voltage across the detection capacitor changes, generating a feedback signal that indicates the failure condition. This feedback enables the control circuit to detect the short circuit condition and activate protection, thus preventing component damage even though the sensing resistor has failed and the device was operating continuously.
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 the power control device to effectively prevent overheating and damage by ensuring the primary switch is turned off in case of a short-circuited sensing resistor, maintaining the stability and reliability of the power supply.
Implementation Method 1
The transformation circuit is coupled to the sense node, and filters the current sample voltage to output a short detection voltage
Data Source
AI summary
A power control device includes a switch control circuit, a first resistor, a second resistor, a third resistor, a sense node, a first comparator, a second comparator, a transformation circuit, and a logic control circuit. The switch control circuit outputs a driving signal according to a set signal and a reset signal. The first resistor, the second resistor, and the third resistor generate a reference voltage according to a feedback current. The sense node receives a current sample voltage. The first comparator outputs a first control signal according to the current sample voltage and the reference voltage. The transformation circuit outputs a short detection voltage according to the current sample voltage. The second comparator outputs the second control signal according to the current sample voltage and the short detection voltage. The logic control circuit gate outputs the reset signal according to the first control signal and the second control signal.