Analog Power Sequencer for Multi-Rail Threshold-Based Sequencing
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Solution Overview
Problem
Existing supply voltage sequencers are either costly and complex, or they lack the ability to manage power-up and power-down sequences effectively, particularly in scenarios requiring precise voltage threshold monitoring and noise resilience.
Innovation Solution
A simple, inexpensive single-channel analog sequencer that monitors supply voltage rails for pre-determined upper and lower threshold levels, enabling various power-up and power-down sequences without the need for complex digital circuitry or state machines, allowing interconnection with other similar sequencers to form multi-channel systems.
Engineering Contradictions & Design Principles
Engineering 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
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.
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
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.
3Device complexity
If simple voltage monitor circuits are used, then cost and simplicity are improved, but ability to control power-down sequencing is lost
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.
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
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.
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 cost-effective, noise-resistant management of supply voltage rails with precise sequencing, avoiding the limitations of complex digital sequencers and ensuring reliable operation across varying electrical conditions.
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
Data Source
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.