LDO Regulator Dynamic Bias Control for Transient Response
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Solution Overview
Problem
Low-dropout voltage regulators (LDOs) in portable electronic devices face challenges in balancing static power consumption and load transient response characteristics, leading to either short battery life or system failures during state transitions.
Innovation Solution
An LDO design incorporating a power transistor, driving stage circuit, feedback circuit, bias power source, and auxiliary reference current generation circuit that dynamically adjusts drive capability based on output current sampling and mapping, allowing for low static power consumption and improved load transient response.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the LDO is designed for large-current application with higher static power consumption (0.5-2 mA), then the load transient response characteristics are improved, but the battery life is reduced
Solution Approach 1:
The patent implements dynamic adjustment of the driving stage circuit's drive capability based on the output current magnitude. The bias current is dynamically controlled to match the load requirements, allowing the LDO to operate with low static power consumption during standby while providing sufficient drive capability during operation, thus resolving the contradiction between speed and energy use
Solution Approach 2:
The patent changes the bias current parameter dynamically based on output current conditions. By adjusting the bias current from a low standby value to a higher operational value, the system achieves both low static power consumption and adequate load transient response characteristics at different operating states
2Use of energy by moving object
If the hardware parameters of the LDO are adjusted to lower the static state power consumption (e.g., down to about 0.1 mA), then the battery life is prolonged, but the load transient response characteristics deteriorate
Solution Approach 1:
The system dynamically adjusts the drive capability of the driving stage circuit based on the sampled output current. During standby state, the drive capability is reduced to minimize static power consumption, while during operation state, the drive capability is increased to ensure adequate load transient response, thus resolving the contradiction between energy efficiency and performance
3Use of energy by moving object
If the LDO operates in standby state with low bias current, then the static power consumption is reduced, but the system may experience unrecoverable failure during transition to operation state
Solution Approach 1:
The patent implements preliminary detection of output current conditions and proactively adjusts the bias current before the transition to operation state occurs. This preliminary action ensures that the driving stage circuit has sufficient drive capability when needed, preventing unrecoverable failures while maintaining low static power consumption during standby
Solution Approach 2:
The patent uses feedback from the output current sampling to dynamically control the bias current. The feedback mechanism detects when the system needs to transition from standby to operation state and adjusts the bias current accordingly, ensuring reliable operation while minimizing static power consumption during standby state
Data Source
AI summary
The invention is directed to a low-dropout voltage regulator (LDO), including a power transistor, a driving stage circuit, a feedback circuit, a bias power source and an auxiliary reference current generation circuit. The power transistor is controlled by a driving signal to convert an input voltage into an output voltage. The feedback circuit generates a feedback voltage according to the output voltage. The driving stage circuit generates the driving signal according to the feedback voltage and the reference voltage. The bias power source provides a bias current. The auxiliary reference current generation circuit is configured to sample an output current, adjust the sampled output current to generate an adjustment current by means of mapping and superpose the adjustment current onto the bias current to generate a reference current to control drive capability of the driving stage circuit.