Power Controller Short-Circuit Protection via High-Pass Filter
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Solution Overview
Problem
Conventional power supplies lack effective protection mechanisms to prevent explosions or fires when the current sense resistor is short-circuited, leading to uncontrolled current flow and potential damage.
Innovation Solution
A power controller with a short-circuited protection circuit that includes a high-pass filter and state detection circuit, which filters the current sense signal and generates a protection signal to prevent the power switch from turning on when a short-circuit is detected, thereby preventing excessive current flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional power supply protection mechanisms are used, then output over-voltage, over-current, and over-temperature protection are provided, but short-circuit protection of the current sense resistor is not effectively detected or responded to
Solution Approach 1:
The patent introduces a high-pass filter as an intermediary component in the protection circuit. This filter processes the current sense signal to extract short-circuit conditions, enabling effective detection without requiring complete redesign of the entire protection system. The high-pass filter acts as a mediator between the current sense resistor and the protection logic, selectively responding to short-circuit events while maintaining existing protection mechanisms.
Solution Approach 2:
The protection circuit performs preliminary detection and response to short-circuit conditions before they can cause damage. By continuously monitoring the current sense signal through the high-pass filter and state detection circuit, the system identifies short-circuit events immediately when they occur and disables the power switch proactively, preventing magnetic saturation, explosions, or fires before they can develop.
2Reliability
If the current sense resistor is short-circuited and not detected timely, then the power supply operates normally according to control signals, but excessive current flows through the power switch causing explosions or fires
Solution Approach 1:
The protection circuit is designed to detect short-circuit conditions immediately when they occur, performing the detection action before excessive current can cause damage. The high-pass filter continuously processes the current sense signal during normal operation, and the state detection circuit is ready to immediately respond when a short-circuit condition is detected, disabling the power switch proactively within one or two switch cycles to prevent explosions or fires.
Solution Approach 2:
The protection circuit implements continuous feedback monitoring of the current sense signal. The high-pass filter processes this signal in real-time, and the state detection circuit uses the filtered signal to determine whether a short-circuit condition exists. This feedback mechanism ensures that the system responds immediately to short-circuit events by disabling the power switch, preventing excessive current flow and potential catastrophic failures.
3Reliability
If a high-pass filter and state detection circuit are added to detect short-circuit conditions, then short-circuit protection is achieved, but the circuit complexity increases
Solution Approach 1:
The patent introduces a high-pass filter as an intermediary component in the protection circuit. This filter processes the current sense signal to extract short-circuit conditions, enabling effective detection without requiring complete redesign of the entire protection system. The high-pass filter acts as a mediator between the current sense resistor and the protection logic, selectively responding to short-circuit events while maintaining existing protection mechanisms.
Solution Approach 2:
The protection circuit is designed to handle multiple protection functions using a unified approach. The high-pass filter and state detection circuit work together to detect various abnormal conditions (short-circuit, over-current, over-temperature) through a single monitoring pathway, reducing the need for separate dedicated circuits for each protection function and thereby limiting the increase in overall circuit complexity.
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 prevents the power switch from turning on during a short-circuit condition, thereby preventing magnetic saturation and potential explosions or fires, ensuring safe operation of the power supply.
Implementation Method 1
The high-pass filter filters the current sense signal in a high-pass manner to generate a filtered signal
Data Source
AI summary
A power controller with short-circuit protection is disclosed to control a power switch, which is connected in series with a current-sense resistor and an inductive device between two power lines. The current-sense resistor provides a current-sense signal. The power controller includes a PWM signal generator and a short-circuit protection circuit. The PWM signal generator generates a PWM signal to the power switch to create switching cycles, each consisting of an ON time and an OFF time. The short-circuit protection circuit has a high-pass filter and a condition detector. The high-pass filter high-pass filters the current-sense signal to provide a filtered signal to the condition detector, which determines whether the filtered signal fits a predetermined condition during the ON time to generate a short-circuit protection signal and to prevent the power switch being turned on.