Overcurrent Protection Circuit With Adjustable Threshold Voltage
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Solution Overview
Problem
Existing overcurrent protection devices in power conversion systems face challenges in accurately setting and maintaining an overcurrent detection threshold voltage due to temperature deviations and voltage errors, particularly when using multiple diodes or Zener diodes.
Innovation Solution
A simplified overcurrent protection device configuration utilizing a shunt regulator with resistors and diodes in series, allowing for easy adjustment of the overcurrent detection threshold voltage, reducing errors from external factors like temperature.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple diodes are connected in series to reduce cut-off detection threshold voltage, then the voltage threshold value is reduced, but temperature deviation increases affecting circuit reliability
Solution Approach 1:
The patent introduces a dedicated overcurrent limit circuit as an intermediary component between the controller and switching element. This circuit uses a shunt regulator and resistor network to generate the threshold voltage, isolating the threshold generation function from the main control path and reducing temperature-induced deviations that affect circuit reliability.
Solution Approach 2:
The patent changes the approach from using multiple diodes (fixed voltage drop) to using a shunt regulator with resistor network (adjustable voltage division). This allows precise control of the threshold voltage parameter while maintaining stability, as the shunt regulator compensates for temperature variations that would otherwise cause drift in the threshold value.
2Adaptability or versatility
If a complex monitoring circuit with multiple diodes and Zener diodes is used, then the voltage threshold can be adjusted, but device complexity increases
Solution Approach 1:
The patent extracts the threshold voltage generation function into a separate, dedicated overcurrent limit circuit module. This modular approach simplifies the overall system by concentrating the complexity in a single functional block that can be independently designed and adjusted, rather than distributing complex diode/Zener networks throughout the control circuitry.
Solution Approach 2:
The patent uses a shunt regulator with resistor network to provide adjustable threshold voltage with fewer components compared to multiple diodes or Zener diodes. The adjustability is achieved through resistor ratio selection rather than component multiplication, reducing device complexity while maintaining versatility.
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
Enables accurate and adjustable overcurrent detection threshold voltage settings, minimizing temperature-related deviations and ensuring precise voltage control, even with small current flows.
Implementation Method 1
The overcurrent protection device may include a shunt regulator
Implementation Method 2
a voltage is dropped by the plurality of diodes, and thus a voltage threshold value of the switching element is changed
Implementation Method 3
a voltage is dropped by the diode and the Zener diode, and thus a voltage threshold value of the switching element is changed
Data Source
AI summary
Disclosed are an overcurrent protection device and a power conversion device using same. A power conversion device according to an embodiment of the present disclosure comprises: a control unit for providing a collector-emitter voltage to a switching element by means of a first output node; and an overcurrent protection circuit connected in a line between the first output node and the switching element and for limiting the overcurrent of the switching element.