Voltage Regulator with Clipping Circuit for Overvoltage Protection
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Solution Overview
Problem
Voltage regulator integrated circuits lack effective protection against overvoltage and undervoltage conditions, which can lead to damage or faulty operation of connected loads due to unregulated output voltages when external resistors fail or become disconnected.
Innovation Solution
Incorporating a voltage clipping circuit that sets a reference voltage within predetermined limits, ensuring the output voltage remains within a safe range by clipping voltages below a minimum or above a maximum limit, thereby protecting circuitry from overvoltage or undervoltage conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a voltage regulator integrated circuit uses an external resistor to set the output voltage, then the output voltage can be adjusted to desired values, but the circuit becomes vulnerable to overvoltage and undervoltage conditions when the external resistor fails or becomes disconnected
Solution Approach 1:
The patent applies preliminary anti-action by incorporating a voltage clipping circuit that proactively limits the reference voltage to predetermined minimum and maximum values (V1 and V2). This pre-established protection mechanism prevents overvoltage and undervoltage conditions before they can occur, even when external resistors fail or become disconnected. The clipping circuit acts in advance to counteract potential harmful voltage excursions.
Solution Approach 2:
The voltage clipping circuit serves as an intermediary between the external resistor and the voltage regulator circuit. It mediates the reference voltage signal by clipping it to predetermined limits, thereby protecting the downstream circuitry from extreme voltage conditions while still allowing the external resistor to function for voltage adjustment. This intermediary component isolates the vulnerability of the external resistor from the critical regulator circuit.
2Power
If the external resistor resistance is increased to achieve higher output voltage, then the output voltage magnitude increases, but the circuit becomes more susceptible to damage from resistor disconnection or failure
Solution Approach 1:
The voltage clipping circuit implements preliminary anti-action by establishing predetermined voltage limits (V1 and V2) that cap the maximum reference voltage regardless of external resistor conditions. This pre-established protection ensures that even if the external resistor fails open or becomes disconnected, the reference voltage cannot exceed V2, preventing overvoltage damage to the regulator circuit and connected loads.
Solution Approach 2:
The clipping circuit provides beforehand cushioning by creating a safety buffer zone through the predetermined voltage limits. The clipping diodes or transistors are positioned to activate before dangerous voltage levels can reach the regulator, absorbing the shock of resistor failure and preventing harmful voltage excursions from propagating through the circuit.
Data Source
AI summary
An integrated circuit includes a voltage set input terminal, a current source, a voltage clipping circuit, and a voltage regulator. The clipping circuit receives a voltage from the terminal and supplies a voltage onto a reference voltage input of the regulator. The magnitude of an output voltage VOUT output by the regulator is the voltage on reference voltage input multiplied by the voltage gain of the regulator. The user sets VOUT by attaching an external resistor to the terminal. Current from the current source flows out of the terminal, and through the external resistor, thereby setting the voltage on the terminal. If the voltage on the terminal is between V1 and V2, then VOUT is a fixed multiple of the voltage. If the voltage is less than V1, then VOUT is a predetermined VOUTMIN value. If the voltage is greater than V2, then VOUT is a predetermined VOUTMAX value.