Linear Voltage Regulator Undershoot Minimization
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Solution Overview
Problem
Conventional voltage regulators suffer from undershoot issues during rapid load transitions due to loop bandwidth limitations, leading to voltage overload and inefficient recovery from unregulated conditions, which can hinder load device operation.
Innovation Solution
A linear voltage regulating circuit with a capacitive device and current mirror modules that convert pass voltage into currents to manage charging and discharging periods, ensuring quick recovery from overshoot conditions and maintaining regulated output voltage during load transitions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If loop bandwidth is increased to improve transient response speed, then recovery time from load transitions is reduced, but circuit complexity and stability requirements increase
Solution Approach 1:
The patent segments the voltage regulation function into two independent paths: a fast transient response path using the capacitive device and current mirror modules for immediate load transition handling, and a standard regulator loop for steady-state voltage regulation. This segmentation allows the fast path to operate with high bandwidth without compromising the stability of the main regulation loop, thereby improving transient response speed without proportionally increasing overall circuit complexity.
Solution Approach 2:
The capacitive device serves as an intermediary energy storage element that mediates between the load and the regulator during transient conditions. It provides immediate charge/discharge current to compensate for load changes, acting as a buffer that reduces the burden on the main regulator loop and enables faster response without requiring the entire regulation system to operate at high bandwidth.
2Speed
If pass transistor gate capacitance is reduced to improve switching speed, then transient response improves, but voltage control precision and stability may deteriorate
Solution Approach 1:
The capacitive device performs preliminary action by pre-storing charge energy before load transitions occur. During heavy-to-light load transitions, this pre-stored charge is immediately discharged to maintain output voltage, preventing the need for rapid pass transistor switching. This preliminary energy preparation enables fast transient response without requiring the pass transistor to switch rapidly, thereby maintaining voltage control precision.
3Stability of the object's composition
If loop bandwidth is limited to maintain stability, then circuit stability is maintained, but transient response speed and undershoot recovery deteriorate
Solution Approach 1:
The patent divides the regulation system into two functional segments: a stable main regulator loop with limited bandwidth for reliable steady-state operation, and a fast transient response segment using the capacitive device and current mirror modules. This segmentation allows each segment to be optimized independently - the main loop maintains stability with limited bandwidth while the transient segment provides fast response, thereby resolving the contradiction between stability and transient response speed.
Solution Approach 2:
The capacitive device performs multiple functions: it acts as an energy storage element for transient compensation, a current source for fast response, and a stabilizing element for the overall system. This multi-functionality allows a single component to simultaneously improve transient response speed while maintaining circuit stability, eliminating the need to trade off between these conflicting requirements.
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
The solution effectively minimizes undershoot and ensures proper voltage regulation by maintaining current mirror modules active during charging or discharging periods, allowing the output voltage to recover quickly from overshoot conditions to under regulation states.
Implementation Method 1
a capacitive device coupled to a first converting node and capable of maintaining a first current mirror module for a charging/discharging period
Data Source
AI summary
A voltage regulating circuit for providing a regulated output voltage. The voltage regulating circuit includes a voltage regulator, a converting circuit, a capacitive device, a first current mirror module, and a second current mirror module. The voltage regulator has a first output producing the regulated output voltage and a second output producing a pass voltage. The converting circuit converts the pass voltage into a first current and a second current passing through a first converting node and a second converting node respectively, where the first current charges/discharges the capacitive device. The first current mirror module has a first current mirror path coupled to the first converting node and a second current mirror path coupled to the second converting node. The second current mirror module has a first current mirror path coupled to the second converting node and a second current mirror path coupled to the first output.