LDO Regulator Switching Between Closed-Loop and Open-Loop Control
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Solution Overview
Problem
Low-dropout (LDO) regulators in flash memory devices face challenges in efficiently controlling voltage at a node, particularly in maintaining a specified regulator output voltage across varying currents and voltages, which can lead to instability and inefficiency.
Innovation Solution
The LDO regulator is configured with a circuit that includes a switch, capacitor, and operational amplifier to control voltage at a node by adjusting current flow and using closed-loop and open-loop control systems to maintain the specified regulator output voltage, with additional switches and capacitors to manage voltage changes and charging states.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional LDO regulator is used to control voltage at a node, then the regulator can maintain a specified output voltage, but the regulator becomes unstable and inefficient when currents and voltages vary
Solution Approach 1:
The patent implements dynamic control by switching between closed-loop and open-loop modes based on operating conditions. The regulator transitions from closed-loop control during steady-state operation to open-loop control during transient conditions, allowing the system to adapt dynamically to varying currents and voltages while maintaining stability
Solution Approach 2:
The patent changes control parameters by switching between different control modes (closed-loop and open-loop) depending on the operational state. This parameter change allows the regulator to optimize performance across different operating conditions, improving both stability and adaptability
2Measurement precision
If the LDO regulator uses closed-loop control to maintain precise voltage, then voltage precision is improved, but the response speed during transient changes decreases
Solution Approach 1:
The patent employs periodic switching between closed-loop and open-loop control modes. During transient events, the system switches to open-loop mode for fast response, then returns to closed-loop mode for precise voltage maintenance. This periodic action between different control modes optimizes both response speed and voltage precision
Solution Approach 2:
The patent detects transient conditions in advance and switches to open-loop control mode before the full transient effect occurs. This preliminary action allows the regulator to prepare for upcoming changes, improving response speed while maintaining voltage precision through subsequent closed-loop control
Data Source
AI summary
A low-dropout (LDO) regulator is provided. The LDO regulator comprises a first circuit operating as a closed loop control system. The first circuit is configured to control a voltage at a first node such that the voltage at the first node is substantially equal to a specified regulator output voltage. The LDO regulator comprises a second circuit operating as an open loop control system. The second circuit is configured to increase the voltage at the first node when a current flowing through a load changes from a first current to a second current. The first current is substantially equal to 0 amperes.