Load-Adaptive LDO Regulator for Low-Voltage Droop Response
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Solution Overview
Problem
Current LDO regulators struggle to predict and quickly respond to load current fluctuations, leading to voltage droop issues, especially at low input voltages below 0.6 V, which affects the stability of power management in battery-powered edge devices.
Innovation Solution
The LDO regulator incorporates an error amplifier, load adaptive bias generator, and voltage droop predictor to adjust bias voltage and input voltage dynamically, using a class AB configuration to quickly stabilize output voltage and prevent droop through a Look-Ahead Droop Reduction (LADR) function.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a conventional LDO regulator is used, then the circuit structure is simple, but it cannot quickly respond to voltage droop due to load current fluctuation
Solution Approach 1:
The voltage droop predictor detects potential voltage droop conditions in advance (before they actually occur) by monitoring wake-up signals and predicting load current fluctuations. This preliminary detection allows the LDO regulator to prepare and respond proactively, improving response speed without requiring complex real-time control mechanisms
2Adaptability or versatility
If the minimum input voltage is set at 0.6 V for stable operation, then the LDO regulator operates stably, but it cannot operate at low input voltages such as 0.4 V
Solution Approach 1:
The LDO regulator dynamically adjusts its operating parameters based on the input voltage level. The error amplifier and control circuitry adapt their behavior to maintain stability whether the input voltage is 0.6 V or as low as 0.4 V, allowing the device to operate across a wider voltage range while maintaining reliability
Solution Approach 2:
The regulator changes its internal operating parameters (such as bias currents, gain settings, or control loop characteristics) depending on the input voltage level. This parameter adaptation enables stable operation at low input voltages like 0.4 V while maintaining the ability to operate at higher voltages
3Reliability
If the LDO regulator responds quickly to load current fluctuation, then voltage droop is prevented, but power consumption increases
Solution Approach 1:
Instead of continuously operating at full power, the LDO regulator uses periodic or event-driven monitoring of voltage droop conditions. The error amplifier and voltage droop predictor are activated only when needed (e.g., upon detecting a wake-up signal or potential droop condition), reducing average power consumption while maintaining voltage stability when required
Solution Approach 2:
The voltage droop predictor and error amplifier monitor the system's own operating conditions and automatically adjust control signals to maintain stability. This self-regulating mechanism responds only when actual or potential droop conditions exist, avoiding unnecessary power consumption during normal stable operation
Data Source
AI summary
The present invention relates to an LDO regulator, and more specifically, to an LDO regulator that can quickly respond to voltage droop due to load current fluctuation and operate stably even at a low input voltage, a driving method thereof, and a power management apparatus including the same.