Dynamic Bias Control in LDO Regulators for Fast Load Transients
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Solution Overview
Problem
Conventional LDO voltage regulator circuits face challenges in responding quickly to rapid changes in load current, particularly at ultra-low power consumption levels, leading to unstable output voltage and potential damage to connected devices due to high reaction times and leakage currents.
Innovation Solution
The introduction of a regulation adjustment circuit with a watchdog loop and over-voltage protection loop, operating outside the main feedback loop, dynamically adjusts the biasing current to maintain stable output voltage by detecting deviations and triggering boost or pull-down mechanisms as needed, ensuring fast transient response without impacting the main feedback loop's stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the biasing current of the LDO is reduced to ultra-low power levels, then power consumption is minimized, but the reaction time increases and output voltage stability deteriorates
Solution Approach 1:
The patent implements dynamic biasing control where the biasing current of the error amplifier is adjusted in real-time based on operating conditions. During transient events, the biasing current is increased to improve response speed, while during steady-state operation, it is reduced to minimize power consumption. This dynamic adjustment resolves the contradiction between low power consumption and fast response time.
Solution Approach 2:
The patent changes the biasing current parameter of the error amplifier based on detected transient conditions. When a transient event is detected (such as sudden load changes), the biasing current is switched to a higher value to improve reaction time. During normal operation, the biasing current maintains an ultra-low value to minimize power consumption, thus resolving the contradiction between power consumption and response speed.
2Use of energy by moving object
If the LDO uses ultra-low biasing currents, then power consumption is minimized, but the bandwidth becomes too small to respond to sudden load current increases
Solution Approach 1:
The patent dynamically adjusts the biasing current of the error amplifier based on transient detection. During steady-state operation, the biasing current is maintained at an ultra-low level to minimize power consumption. When a transient event is detected (such as sudden load current changes), the biasing current is increased to expand the bandwidth and improve reaction time, thus resolving the contradiction between low power consumption and fast response speed.
Solution Approach 2:
The patent implements a transient detection mechanism that anticipates load current changes before they significantly impact the output voltage. Upon detecting a transient condition, the system proactively increases the biasing current to prepare for the upcoming voltage regulation demand, ensuring fast response without continuously maintaining high power consumption.
3Area of moving object
If digital cells use GO1 devices with nominal voltage, then device size is reduced, but leakage current increases significantly
Solution Approach 1:
The patent reduces the supply voltage to the digital cells below the nominal voltage level during deep power down mode. This voltage reduction significantly decreases the leakage current of GO1-based digital cells while maintaining acceptable functionality for state retention. The voltage parameter is dynamically adjusted based on operational mode to balance device size benefits with leakage current reduction.
4Use of energy by moving object
If the LDO reaction time is increased to compensate for low biasing current, then power consumption is reduced, but output voltage drops significantly during load transitions
Solution Approach 1:
The patent implements dynamic biasing control where the error amplifier's biasing current is adjusted in real-time based on transient detection. During steady-state operation, the biasing current is maintained at an ultra-low level to minimize power consumption. When a transient event is detected, the biasing current is increased to improve response speed and maintain output voltage regulation, thus resolving the contradiction between low power consumption and output voltage stability during load transitions.
Solution Approach 2:
The patent employs a feedback mechanism that continuously monitors the output voltage and load current conditions. When voltage drops or transient conditions are detected, the feedback loop triggers an increase in the error amplifier's biasing current to restore proper voltage regulation. This feedback-based dynamic adjustment ensures output voltage reliability during load transitions while maintaining ultra-low power consumption during normal operation.
Data Source
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AI summary
A low drop out, LDO, voltage regulator circuit (200, 300) is that includes a high gain amplifier (205, 305) configured to receive a current biasing signal and arranged to regulate the voltage supply signal and output a regulated voltage supply signal (225, 325). A regulation adjustment circuit (222) is operably coupled to an output of the high gain amplifier (205, 305) and includes a comparator (235, 245) configured to compare the output regulated voltage supply signal (225, 325) with a threshold, wherein an output of the comparator (235, 245) is configured to perform one of: (i) supply a dynamic current boost (212, 242) to the LDO current biasing signal, in response to the regulated voltage supply signal voltage dropping below the threshold; (ii) activate a dynamic current pull down circuit to reduce an over voltage output of the LDO voltage regulator circuit in response to the regulated voltage supply signal voltage exceeding the threshold.