Filtered Analog Voltage Regulation for Capacitor-Free LDO Stability
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Solution Overview
Problem
Designing a low dropout regulator without an external capacitor poses challenges in achieving rapid voltage regulation stability across a wide range of operating states, as existing solutions require multiple limit values that can lead to fluctuations and increased current consumption, especially in technologies with feature sizes less than 1 micrometer.
Innovation Solution
The solution involves deriving the regulation variable from a duty cycle for overvoltage protection, reducing the number of limit values from three to two, and using either the upper or lower voltage limit to determine the regulation variable, thereby eliminating the need for a predefined target voltage based on feedback signals from resistors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple limit values (three limit values: VDDnom, Vdrop, Vclip) are used for voltage regulation, then voltage stability is improved, but current consumption increases and fluctuations in limit values occur
Solution Approach 1:
The patent extracts and eliminates one of the three limit values (VDDnom) from the voltage regulation system. Instead of using three separate limit values (VDDnom, Vdrop, Vclip), the invention uses only two limit values (Vdrop, Vclip) by deriving the regulation variable from the duty cycle for overvoltage protection rather than from a predefined target voltage. This reduction in the number of limit values directly reduces current consumption while maintaining voltage stability through the duty cycle-based regulation mechanism.
2Reliability
If multiple limit values are used for voltage regulation, then voltage stability is improved, but the complexity of the circuit increases
Solution Approach 1:
The patent removes the complexity associated with maintaining three separate limit values and their corresponding comparison circuits. By deriving the regulation variable from the duty cycle for overvoltage protection and using only two limit values (Vdrop, Vclip), the circuit complexity is reduced. The invention simplifies the voltage regulation architecture while maintaining stability through the duty cycle-based control mechanism.
Solution Approach 2:
The duty cycle for overvoltage protection serves multiple functions: it acts as both the overvoltage protection signal and the regulation variable for the voltage regulator. This multi-functionality eliminates the need for separate circuits to generate and compare the VDDnom limit value, thereby reducing circuit complexity while maintaining regulation capability.
3Use of energy by moving object
If the number of limit values is reduced from three to two, then current consumption is reduced, but the tolerable voltage fluctuation range decreases
Solution Approach 1:
The patent introduces dynamics by using a duty cycle-based regulation variable that can adaptively respond to voltage conditions. Instead of relying on fixed limit values, the regulation variable is dynamically derived from the duty cycle for overvoltage protection. This dynamic approach allows the system to maintain an appropriate voltage fluctuation range with fewer limit values, as the duty cycle continuously adjusts to maintain stability.
Solution Approach 2:
The invention implements feedback by deriving the regulation variable from the duty cycle for overvoltage protection, which inherently contains information about the voltage state. This feedback mechanism allows the system to maintain voltage stability within an appropriate fluctuation range using only two limit values, compensating for the reduced number of reference points through continuous monitoring and adjustment.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach increases the tolerable voltage fluctuation range and decreases the output voltage range without significantly reducing the fluctuation ranges of individual circuit elements, enhancing the performance and reliability of the voltage regulating circuit.
Implementation Method 1
a conversion circuit (106) is provided, said conversion circuit being configured to convert a voltage pulse sequence into a filtered analog voltage
Data Source
AI summary
A voltage regulating circuit including a conversion circuit configured to convert a voltage pulse sequence into a filtered analog voltage, wherein the voltage pulse sequence represents a predefined operating limiting voltage, and a regulator configured to receive the filtered analog voltage as regulation variable and to regulate an output voltage of the voltage regulating circuit to a predefined desired voltage.