Start-Up Circuit With PTAT Threshold Compensation

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Existing electronic devices face challenges in ensuring that the power supply voltage reaches a stable operating threshold before activating components, particularly due to temperature variations, which can affect the accuracy and reliability of voltage comparison in starting circuits.

Innovation Solution

A starting circuit is designed with a current proportional to temperature, utilizing MOS transistors and current mirrors to compare the power supply voltage with a threshold, incorporating source degeneration resistors to compensate for temperature influences, ensuring accurate voltage threshold detection and minimizing power consumption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a starting circuit compares power supply voltage with a threshold using conventional methods, then the voltage comparison function is achieved, but temperature variations cause inaccuracies in the threshold detection

Engineering Contradiction:

Improvevoltage threshold detection accuracyVSAvoidtemperature variations

Core Design Contradiction:

Measurement precisionVSTemperature

Solution Approach 1:

The patent changes the parameter of threshold voltage by making it proportional to temperature through a PTAT current generator. The threshold voltage is generated by multiplying a temperature-proportional current with a resistance, ensuring that the threshold automatically adjusts with temperature variations, thereby maintaining accurate detection across different temperature conditions.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The circuit incorporates feedback mechanisms where the temperature-proportional current is used to dynamically adjust the threshold voltage level. This feedback ensures that the comparison circuit adapts to temperature changes, compensating for thermal effects and maintaining measurement precision without requiring external temperature sensing or adjustment.

Inventive Principle:

Principle #23Feedback

2Reliability

If the power supply voltage rises slowly from zero, then component activation is controlled, but excessive power consumption occurs during the voltage ramp-up period

Engineering Contradiction:

Improvecomponent activation controlVSAvoidpower consumption during voltage ramp-up

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The starting circuit performs preliminary actions by continuously monitoring the power supply voltage and preparing the threshold comparison mechanism in advance. The PTAT current generator and threshold voltage circuit are pre-configured to immediately compare and control component activation as soon as voltage rises, eliminating the need for prolonged voltage ramp-up and reducing energy consumption during the startup phase.

Inventive Principle:

Principle #10Preliminary action

3Reliability

If conventional voltage comparison circuits are used, then the circuit structure is simple, but the reliability of operation is compromised due to temperature sensitivity

Engineering Contradiction:

Improveoperation reliabilityVSAvoidcircuit structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent implements a universal starting circuit design where the PTAT current generator serves multiple functions: it generates the threshold voltage, provides temperature compensation, and enables reliable component activation control. This multi-functional approach integrates temperature sensing and threshold adjustment into a single cohesive circuit block, maintaining structural simplicity while significantly improving operation reliability across temperature variations.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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

The solution provides a precise and efficient method to determine the power supply voltage threshold, effectively compensating for temperature variations and ensuring reliable operation of electronic device components while maintaining low power consumption and a compact design.

Implementation Method 1

a generator of a current proportional to temperature

Methodology Applied

Scientific EffectTemperature-proportional current generation:

Implementation Method 2

source degeneration resistance values are selected to compensate for the influence of temperature variations on the threshold value

Methodology Applied

Scientific EffectSource degeneration compensation:

Data Source

PatentUS11137786B2Device comprising a start-up circuit, and method of manufacturing thereof

Publication Date: 2021.10.05 STMICROELECTRONICS (ROUSSET) SAS

AI summary

An electronic device includes a starting circuit configured to compare a value representative of the power supply voltage with a threshold, wherein the circuit includes a generator of a current proportional to temperature.