Source Follower Regulator DAC Feedback for Stable Output Voltage

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Solution Overview

Problem

Low dropout (LDO) voltage regulators with emitter followers face challenges due to high power consumption and area requirements, limiting their integration in semiconductor devices, and output voltage variations due to process and temperature fluctuations.

Innovation Solution

Implementing an ADC or window comparator to measure the output voltage of a source follower, coupled with a DAC to adjust the reference voltage, forming a feedback loop that maintains the output within a desired range by compensating for deviations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If an error amplifier and resistive feedback network are used to regulate output voltage, then output voltage stability is improved, but power consumption and area requirements increase

Engineering Contradiction:
Improveoutput voltage stabilityVSAvoidpower consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent implements a digital feedback mechanism where an ADC measures the output voltage and feeds back to a DAC that adjusts the reference voltage. This closed-loop feedback system maintains output voltage stability while using less power than traditional analog error amplifiers, as the feedback operates at lower power levels and can be optimized for specific voltage ranges.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent replaces the traditional analog error amplifier and resistive feedback network with a digital control system comprising ADC, digital control logic, and DAC. This substitution of analog components with digital equivalents reduces power consumption and area while maintaining voltage regulation functionality through digital signal processing.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If an error amplifier and resistive feedback network are used to regulate output voltage, then output voltage stability is improved, but device area increases

Engineering Contradiction:
Improveoutput voltage stabilityVSAvoidcircuit area
Core Design Contradiction:
ReliabilityVSArea of stationary object

Solution Approach 1:

The patent replaces the traditional analog error amplifier and resistive feedback network with a digital control system comprising ADC, digital control logic, and DAC. This substitution of analog components with digital equivalents reduces power consumption and area while maintaining voltage regulation functionality through digital signal processing.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The digital control system can be designed to perform multiple functions including voltage measurement, comparison, and correction through the same ADC and DAC components. This multi-functionality reduces the overall area requirement compared to dedicated analog components that would be needed for each function separately.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Ease of manufacture

If a traditional LDO regulator is used, then design simplicity is maintained, but power consumption and area requirements increase

Engineering Contradiction:
Improvedesign simplicityVSAvoidpower consumption
Core Design Contradiction:
Ease of manufactureVSUse of energy by moving object

Solution Approach 1:

The patent replaces the traditional analog error amplifier and resistive feedback network with a digital control system comprising ADC, digital control logic, and DAC. This substitution of analog components with digital equivalents reduces power consumption and area while maintaining voltage regulation functionality through digital signal processing.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

4Use of energy by moving object

If ADC and DAC are used to create a feedback loop, then power consumption and area requirements are reduced, but circuit complexity increases

Engineering Contradiction:
Improvepower consumptionVSAvoidcircuit complexity
Core Design Contradiction:
Use of energy by moving objectVSDevice complexity

Solution Approach 1:

The patent implements a digital feedback mechanism where an ADC measures the output voltage and feeds back to a DAC that adjusts the reference voltage. This closed-loop feedback system maintains output voltage stability while using less power than traditional analog error amplifiers, as the feedback operates at lower power levels and can be optimized for specific voltage ranges.

Inventive Principle:
Principle #23Feedback

Data Source

PatentUS20250244783A1Source Follower Type Regulator with DAC feedback
Publication Date: 2025.07.31 INFINEON TECHNOLOGIES AMERICAS CORP
  • US20250244783A1 patent drawing
  • US20250244783A1 patent drawing
  • US20250244783A1 patent drawing

AI summary

Systems and methods are disclosed to measure output voltage of a source follower to control the reference voltage provided to the source follower to compensate for deviations of the output voltage from a desired operating range. Disclosed techniques include using an ADC or a window comparator to sample an output of a source follower type voltage regulator whose regulated voltage is set by a reference voltage. The sampled output voltage is compared against a desired range. The ADC or the window comparator generates an indication in response to the comparison. A processor or a sequencer may determine an adjustment amount to the reference voltage based on the indication and May 10 adjust the reference voltage based on the adjustment amount to maintain the output of the source follower type voltage regulator within the desired range. An ADC may apply the adjusted reference voltage to the source follower.