Voltage Regulator Driver Stage Segmentation for Transient Response
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Solution Overview
Problem
Voltage regulators face challenges in providing a fast and stable reaction to load transients due to the substantial current carried by the driver stage, which degrades reaction speed and stability, especially at high load currents.
Innovation Solution
The implementation of a driver stage with a two-stage current mode amplifier and current mode feedback, forming current mirrors to amplify the drive current and reduce the size of the drive transistor, thereby decreasing gate capacitance and enhancing reaction speed and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the driver stage carries substantial current to provide sufficient drive capability, then the drive strength is improved, but the reaction speed and stability deteriorate
Solution Approach 1:
The driver stage is segmented into two parallel paths: a first drive transistor providing substantial current for drive strength, and a second drive transistor with smaller size providing fast reaction speed. Both paths independently control the pass transistor gate, combining the advantages of both current capability and speed response.
Solution Approach 2:
The patent transitions from a single-dimensional drive approach (one transistor) to a two-dimensional approach by adding parallel drive paths with different characteristics. This dimensional expansion allows simultaneous optimization of both current capability and response speed without compromise.
2Power
If the drive transistor size is increased to provide sufficient drive current, then the drive capability is improved, but the gate capacitance increases and reaction speed deteriorates
Solution Approach 1:
The drive function is segmented between two transistors of different sizes. The first drive transistor is sized for substantial current capability while the second drive transistor is sized for fast response. This segmentation allows each transistor to be optimized for its specific function rather than requiring one oversized transistor to handle both requirements.
Solution Approach 2:
The patent uses a copy approach where the second drive transistor replicates the control function of the first drive transistor but with different sizing characteristics. This allows the system to leverage both the current capability of the larger transistor and the speed response of the smaller transistor for the same control objective.
3Device complexity
If the driver stage is simplified to reduce complexity, then the device complexity is reduced, but the ability to provide fast and stable reaction to load transients deteriorates
Solution Approach 1:
The driver stage is segmented into two parallel simple transistor paths rather than one complex path. This segmentation maintains relative simplicity while improving reliability through redundancy and differentiated functionality, where each path contributes a specific strength to the overall response.
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 results in a 50% performance improvement in load transient response and significant gain-bandwidth improvement, maintaining stability and reducing current consumption while addressing the limitations of existing voltage regulators.
Implementation Method 1
the diode transistor forms a current mirror with the pass transistor
Data Source
AI summary
A voltage regulator to provide a load current at an output node is presented. The voltage regulator has a pass transistor for providing the load current at the output node from an input node. The voltage regulator contains a driver stage to set a gate voltage at a gate of the pass transistor based on a drive voltage at a gate of a drive transistor. The voltage regulator has voltage regulation means to set the drive voltage in dependence of an indication of the output voltage at the output node and in dependence of a reference voltage for the output voltage. The driver stage has the drive transistor and a diode transistor, wherein the diode transistor forms a current mirror with the pass transistor. The driver stage has a current amplifier amplifies a drive current through the drive transistor to provide an amplified current through the diode transistor.