Analog Power Sequencer for Customizable Voltage Rail Control

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Solution Overview

Problem

Existing supply voltage sequencers are either complex and costly or prone to noise-induced logic errors, lacking the ability to provide customizable power-up and power-down sequences for multiple supply voltage rails while monitoring threshold levels effectively.

Innovation Solution

A simple, analog single-channel supply voltage sequencer that monitors upper and lower threshold levels, enabling customizable power-up and power-down sequences by interconnecting multiple single-channel sequencers, avoiding the use of state machines to prevent noise-induced errors.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If complex digital supply voltage sequencers are used to sequence multiple supply voltage rails, then sequencing capability is improved, but cost and device complexity increase significantly

Engineering Contradiction:
Improvesequencing capabilityVSAvoiddevice complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent divides a complex multi-channel sequencing function into multiple simple single-channel supervisor modules. Each supervisor monitors one supply voltage rail and generates enable signals independently. By interconnecting these simple modules, a flexible multi-channel sequencing system is formed without requiring complex digital processing circuitry in each unit.

Inventive Principle:
Principle #1Segmentation

2Adaptability or versatility

If digital processing circuitry is used in supply voltage sequencers, then sequencing functionality is improved, but susceptibility to noise-induced logic errors increases

Engineering Contradiction:
Improvesequencing functionalityVSAvoidnoise immunity
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent replaces digital electronic processing (prone to noise) with analog voltage comparison and simple logic circuitry. Supervisors use analog voltage threshold detection and basic logic gates instead of digital microprocessors or state machines, making the system immune to noise-induced logic errors while maintaining sequencing functionality.

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

3Device complexity

If simple voltage monitor circuits are used, then cost and simplicity are improved, but ability to control power-down sequencing is lost

Engineering Contradiction:
Improvecircuit simplicityVSAvoidpower-down control capability
Core Design Contradiction:
Device complexityVSAdaptability or versatility

Solution Approach 1:

The patent combines the functions of voltage monitoring, threshold detection, and enable signal generation into integrated supervisor modules. Each supervisor not only monitors its designated supply voltage rail but also actively generates control signals for both power-up and power-down sequencing, enabling bidirectional control capability while maintaining circuit simplicity.

Inventive Principle:
Principle #5Merging (Combining)

4Ease of operation

If conventional voltage supervisors with delay circuits are used, then power-up sequencing is achieved, but power-down sequencing capability is lost

Engineering Contradiction:
Improvepower-up sequencingVSAvoidpower-down sequencing
Core Design Contradiction:
Ease of operationVSAdaptability or versatility

Solution Approach 1:

The patent makes the supervisor modules dynamic by enabling them to operate in different modes depending on the system state. The same supervisor circuit that provides delayed enable signals during power-up can also detect voltage drops and generate power-down sequencing signals, allowing the system to adapt its behavior for both power-up and power-down operations.

Inventive Principle:
Principle #15Dynamics

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

Enables efficient, cost-effective management of supply voltage rails with customizable sequencing and noise resilience, reducing the need for complex digital sequencers and minimizing the risk of logic errors due to electrical noise.

Implementation Method 1

a comparator circuit having a positive input, a negative input and an output; the positive input being coupled to receive the divided supply voltage signal, the negative input being coupled to receive a reference voltage

Methodology Applied
Scientific EffectVoltage comparison:

Data Source

PatentUS8680710B2Analog power sequencer and method
Publication Date: 2014.03.25 TEXAS INSTRUMENTS INC
  • US8680710B2 patent drawing
  • US8680710B2 patent drawing
  • US8680710B2 patent drawing

AI summary

Supply voltage sequencing circuitry includes a first sequencer (10-1) that produces an active level of a Power Good signal PG if a first supply voltage VOUT1 exceeds an upper threshold V90% while a control signal EN_PG is active, and produces an inactive level of PG if EN_PG is inactive. The PG level is latched when a control signal EN is inactive. A Power Down signal PD is produced if VOUT1 is less than a lower threshold V10% while EN is inactive. An active level of PD is produced when EN is active. A power-up sequence of supply voltages VOUT1, VOUT2, and VOUT3 monitored by the first sequencer and similar second (10-2) and third (10-3) sequencers, respectively, is determined by connection of PG of each of the first and second sequencers to control the supply voltage monitored by the next sequencer. A desired power-down sequence of the supply voltages is determined by connections of the PDs of the first and second sequencers in the power-down sequence to EN_PG inputs and EN inputs of other sequencers, respectively, in accordance with a predetermined power-down algorithm.