Voltage Regulator Spike Rejection via Dual Filter Paths
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Solution Overview
Problem
Conventional voltage regulators fail to reject large positive and negative voltage spikes, leading to circuit malfunctions in load circuits due to the propagation of spikes in the regulated voltage.
Innovation Solution
A voltage regulator design comprising a master circuit, a bias filter, and a supply filter, where the bias filter rejects positive spikes and the supply filter rejects negative spikes, ensuring the regulated voltage remains stable by using NMOS transistors and capacitors to create filtered reference and supply voltages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional linear voltage regulator is used, then the circuit is simple, but it fails to reject large positive and negative voltage spikes
Solution Approach 1:
The voltage regulator is divided into two independent filtering paths: a bias filter path that processes the reference voltage and a supply filter path that processes the supply voltage. Each path uses dedicated filter circuits with capacitors and transistors to reject spikes of opposite polarities, allowing complex spike rejection functionality to be achieved through modular segmentation of the regulator circuit.
2Reliability
If an RC filter is added to reject positive spikes, then positive spike rejection is improved, but negative spikes are still passed through
Solution Approach 1:
Different filtering characteristics are applied to different parts of the circuit: the bias filter uses an RC circuit configured to reject positive spikes on the reference voltage line, while the supply filter uses a different RC configuration to reject negative spikes on the supply voltage line. Each filter is optimized for its specific location and polarity requirement, achieving bidirectional spike rejection through localized filtering solutions.
3Device complexity
If the regulator passes large voltage spikes to the output, then the regulator structure remains simple, but circuit malfunctions occur in load circuits
Solution Approach 1:
Two filter circuits act as intermediary elements between the input voltages and the regulated output: the bias filter mediates the reference voltage from the bias generator, and the supply filter mediates the supply voltage to the pass transistor. These intermediary filters remove harmful spike components before they can affect the regulated output, protecting the load circuit while maintaining regulator functionality.
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
Effectively rejects both positive and negative voltage spikes, preventing them from appearing in the regulated voltage and thus preventing circuit malfunctions, as demonstrated by the filtered voltage plots.
Implementation Method 1
a first filter configured to provide a filtered second reference voltage based on the second reference voltage, and to reject positive spikes in the second reference voltage
Implementation Method 2
a second filter configured to provide a filtered supply voltage based on the supply voltage, and to reject negative spikes in the supply voltage
Data Source
AI summary
A voltage regulator includes a supply filter, a bias filter, and first and second circuits. The supply filter is configured to operate from a supply voltage, and to generate a filtered supply voltage at a first node. The supply filter includes a transistor and a capacitor. First and control terminals of the transistor receive the supply voltage. A second terminal of the transistor and a first terminal of the capacitor are connected to the first node. The first circuit is configured to operate from both the supply voltage and the filtered supply voltage, and to generate a second reference voltage based on an input reference voltage. The bias filter is configured to generate a filtered second reference voltage based on the second reference voltage. The second circuit is configured to operate from the filtered supply voltage, and to generate a regulated voltage based on the filtered second reference voltage.