Voltage Regulator Stability Compensation Circuit
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Solution Overview
Problem
Existing low drop-out (LDO) voltage regulators face challenges in achieving stable operation with fast response times and reduced silicon area requirements, often necessitating large capacitive elements that increase power consumption and introduce parasitic components, while also being limited by the need for external discrete components.
Innovation Solution
A voltage regulator design incorporating a primary current mirror stage and independent voltage-to-current converters to control currents in separate paths, allowing for balanced operation without external capacitors and enabling LDO or non-LDO operation with reduced capacitive load, thus minimizing silicon area and power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a feedback capacitor CF is used to ensure stability, then the voltage regulator operates stably, but the feedback capacitor requires a large silicon area and reduces the speed of operation
Solution Approach 1:
The patent extracts the stability function from the feedback capacitor by introducing a dedicated stability compensation circuit that operates independently. This allows the feedback capacitor to be minimized or eliminated while maintaining stability through the separate compensation mechanism, thereby reducing silicon area and improving speed without sacrificing stability.
Solution Approach 2:
The patent introduces a stability compensation circuit as an intermediary element that mediates between the feedback network and the output stage. This intermediary provides the necessary phase compensation and stability without requiring large feedback capacitors, thus resolving the contradiction between stability and speed of operation.
2Object-generated harmful factors
If a large load capacitive element CL is used to filter fast changes in output voltage, then fast changes are reduced, but the load capacitive element requires a large silicon area and can reduce stability causing oscillation
Solution Approach 1:
The stability compensation circuit acts as an intermediary that provides the necessary filtering and damping effects without requiring large load capacitors. It compensates for the effects of fast load changes through active control, eliminating the need for large passive capacitive elements while maintaining stability.
Solution Approach 2:
The patent replaces the passive mechanical filtering approach (large load capacitors) with an active electronic control approach (stability compensation circuit). This substitution allows for effective filtering of fast voltage changes without the drawbacks of large capacitive elements, resolving the contradiction between filtering performance and stability.
3Adaptability or versatility
If external discrete components are used to provide load capacitance, then the voltage regulator can operate, but additional space is required and parasitic components are introduced
Solution Approach 1:
The patent merges the load capacitance function and stability compensation function into integrated circuits within the voltage regulator itself. By combining these functions internally rather than using external discrete components, the design reduces overall device complexity and eliminates parasitic interconnection components while maintaining operational flexibility.
Solution Approach 2:
The stability compensation circuit is designed to perform multiple functions simultaneously: providing stability compensation, filtering output voltage variations, and replacing the need for external load capacitors. This multi-functionality reduces the overall component count and device complexity while maintaining adaptability.
Data Source
AI summary
A voltage regulator includes a current bridge and first and second current paths coupling a current mirror to respective first and second voltage-to-current converters. The current mirror controls a second current dependent on a first current. The first voltage-to-current converter controls the first current dependent on either a reference voltage or a feedback voltage derived from the regulator's output voltage, and the second voltage-to-current converter controls the second current dependent on the other of the feedback and reference voltages. Voltage-to-current conversion by the first converter is independent of voltage-to-current conversion by the second converter. An output transistor stage coupled to the second current path controls the output voltage dependent on the voltage in the second current path indicative of a deviation of the second current from a target current value dependent on the reference voltage.