Dual LDO Regulator Circuit for Stable Output Under Load Transients
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional LDO regulator circuits face issues with maintaining a constant output voltage during rapid load fluctuations, leading to increased load current and potential overshoot or undershoot due to added switching circuits.
Innovation Solution
A regulator circuit employing two LDO regulators that supply different output voltages, with one regulator operating alone when load is small and both regulators operating together when load increases, using error amplifiers and voltage dividers to maintain stable output.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a switching circuit is added to compensate for voltage drop during load fluctuations, then the output voltage stability is improved, but overshoot or undershoot occurs causing reliability problems
Solution Approach 1:
The regulator circuit is divided into two separate LDO regulators instead of using one regulator with a switching circuit. Each regulator independently regulates the output voltage, avoiding the switching operations that cause overshoot or undershoot. This segmentation allows the system to maintain stability without introducing harmful transient effects.
Solution Approach 2:
A capacitor is introduced as an intermediary energy storage element between the two LDO regulators and the load. This capacitor smooths out any rapid voltage changes and provides additional energy during load transients, preventing overshoot and undershoot while maintaining output voltage stability.
2Device complexity
If a single LDO regulator is used, then the circuit structure is simple, but the output voltage cannot maintain constant level when load fluctuations exceed certain limit
Solution Approach 1:
The single LDO regulator is segmented into two parallel LDO regulators. This division allows each regulator to handle a portion of the load current, improving the overall current driving capability and voltage regulation performance during load fluctuations while maintaining a relatively simple circuit structure.
Solution Approach 2:
Two LDO regulators are merged in parallel configuration to work together. Their combined current output capability exceeds that of a single regulator, enabling the system to maintain stable output voltage even when load fluctuations are large, while avoiding the complexity of switching circuits.
3Device complexity
If one LDO regulator supplies all current during load fluctuations, then the regulation is simple, but the voltage drop increases and regulation performance deteriorates
Solution Approach 1:
The current supply task is segmented between two LDO regulators. Instead of one regulator bearing the full burden of compensating for voltage drop during load fluctuations, both regulators share the current supply responsibility, reducing the voltage drop across each regulator and improving overall regulation performance.
Solution Approach 2:
A second LDO regulator is introduced as a copy of the first, with identical regulation functionality. This duplicate regulator provides additional current supply capability, reducing the voltage drop and improving regulation performance without requiring a fundamentally different regulation mechanism.
Data Source
AI summary
A regulator circuit includes a first regulator configured to supply a first current to a VDD pad connected to a power line based on a first output voltage, and a second regulator configured to supply a second current to the VDD pad based on a second output voltage. The second output voltage has dropped by a predetermined delta voltage from the first output voltage.