Current Mirror Circuit for Overvoltage Protection
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Solution Overview
Problem
Existing protective circuits that include Zener diodes struggle to pass large currents due to the high cost of Zener diodes with large allowable dissipation, and parallel connections of Zener diodes do not effectively increase dissipation due to variations in breakdown voltage, leading to ineffective protection against overvoltages.
Innovation Solution
An electronic circuit with a first consumption part, a second consumption part, and a current mirror circuit, where the current mirror circuit passes a current to the second consumption part corresponding to the current flowing through the first consumption part, allowing for simultaneous current flow through both parts when a voltage exceeding a certain threshold is applied, thereby consuming electricity and protecting against overvoltages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a Zener diode with large allowable dissipation is used to protect against large currents, then the protective capability is improved, but the cost increases
Solution Approach 1:
The protective circuit is divided into two separate consumption parts (first consumption part and second consumption part) instead of using a single Zener diode. Each part handles a portion of the current, allowing the use of lower-cost components with smaller allowable dissipation ratings while collectively providing protection against large currents.
2Reliability
If multiple Zener diodes are connected in parallel to increase allowable dissipation, then the current handling capacity is improved, but the effectiveness is reduced due to breakdown voltage variations
Solution Approach 1:
A current mirror circuit is introduced as an intermediary mechanism between the first consumption part and the second consumption part. This current mirror circuit ensures that when the first consumption part breaks down, a corresponding current is automatically directed through the second consumption part, overcoming the breakdown voltage variations that would otherwise prevent effective parallel operation.
3Device complexity
If a simple parallel connection of Zener diodes is used, then the device complexity is reduced, but the allowable dissipation is not effectively increased
Solution Approach 1:
The current mirror circuit provides a feedback mechanism that monitors the current through the first consumption part and automatically adjusts the current distribution to the second consumption part. This feedback ensures that both consumption parts effectively share the total current and dissipation load, achieving increased allowable dissipation without excessive 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
This configuration enables the protective circuit to consume electricity efficiently and pass large currents with a simple setup, effectively protecting against overvoltages by utilizing two Zener diodes in parallel, which are designed to consume electricity when the voltage exceeds a certain threshold.
Implementation Method 1
a current mirror circuit, which passes, to the second consumption part, a current corresponding to a current flowing through the first consumption part
Implementation Method 2
a first consumption part, which passes a current to consume electricity when a voltage exceeding a first voltage is applied
Data Source
AI summary
An electronic circuit includes a first consumption part, at least one second consumption part, and a current mirror circuit. The first consumption part passes a current to consume electricity when a voltage exceeding a first voltage is applied. At least one second consumption part is disposed in parallel with the first consumption part and passes a current to consume electricity. The current mirror circuit passes, to the second consumption part, a current corresponding to a current that flows through the first consumption part.