Voltage Regulator Overcurrent Protection Using Passive Components
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Solution Overview
Problem
Existing voltage regulators for in-vehicle systems face complexity in circuit design due to the need for operational amplifiers and comparators to detect overcurrents, making it challenging to forcibly stop the output when the output current exceeds a reference without increasing circuit complexity.
Innovation Solution
A voltage regulator configuration using a switch, resistors, transistors, and a Zener diode, where the control unit applies an operating voltage to manage currents through these components to set the output voltage and stop the output when it falls below a threshold, primarily utilizing passive elements to simplify the circuit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If operational amplifiers and comparators are used to detect overcurrents and forcibly stop output, then overcurrent protection function is improved, but circuit complexity increases
Solution Approach 1:
The patent changes the detection parameter from voltage comparison (using comparators) to direct current sensing through strategically placed resistors. By monitoring voltage drops across these resistors, the circuit detects overcurrent conditions and triggers shutdown without requiring operational amplifiers or comparators, thus maintaining protection function while reducing complexity
Solution Approach 2:
The patent extracts and removes the operational amplifier and comparator components from the traditional overcurrent protection circuit. By using only passive elements (resistors, transistors, Zener diode) to achieve the same protection function, the design eliminates unnecessary complex components while maintaining reliability
2Device complexity
If a simplified circuit configuration is used, then circuit complexity is reduced, but overcurrent detection and protection capability may be compromised
Solution Approach 1:
The patent implements a self-service protection mechanism where the circuit uses its own operational components (transistors, resistors, Zener diode) to automatically detect and respond to overcurrent conditions. The simplification does not compromise protection capability because the circuit self-regulates through inherent component characteristics and feedback mechanisms
Solution Approach 2:
The patent incorporates feedback mechanisms through the transistor biasing networks and Zener diode voltage regulation. The circuit continuously monitors operational parameters and automatically adjusts or shuts down when overcurrent conditions are detected, ensuring protection capability is maintained despite the simplified component structure
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 the voltage regulator to forcibly stop the output when the output current exceeds a reference, maintaining a simplified circuit design and reducing complexity, while effectively managing overcurrent conditions.
Implementation Method 1
a Zener diode having an anode electrically connected to a conductive path between the emitter of the second transistor and the ground-side resistor portion, and a cathode electrically connected to the second conductive path; and the Zener diode sets, in the operating state, a voltage of the second conductive path to a voltage corresponding to a voltage across the Zener diode
Data Source
AI summary
A voltage regulator is provided wherein electricity flows through a second transistor in an operating state in which a control unit) applies an operating voltage to a base of the second transistor. A Zener diode sets, in the operating state, a voltage of a second conductive path to a voltage corresponding to a voltage across the Zener diode. A current corresponding to an addition value obtained by adding a value of a current flowing through a second resistor portion in the operating state, a value of a current flowing through a third resistor portion in the operating state, and a value of a current flowing through the Zener diode in the operating state flows through a ground-side resistor portion. A control unit stops the output of the operating voltage when a voltage of the second conductive path is lower than or equal to a threshold value.