Power Supply Sequencer Circuit for Customizable Delay
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Solution Overview
Problem
Existing power supply control systems for electronic devices lack efficient and customizable power sequencing, leading to issues like inrush current and reliance on costly power good pins, and do not ensure safe operation.
Innovation Solution
A power supply control apparatus with a power supply sequencer circuit and control element that uses a cascade arrangement of stages with IGBTs and an n-channel MOSFET to provide a stable and customizable delay between power supplies, generating signals to connect/disconnect voltage rails independently of voltage ramp rates and avoiding accidental triggering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a power supply sequencer circuit is used to control power supply sequencing, then the reliability of power sequencing is improved, but the device complexity increases
Solution Approach 1:
The power supply sequencer circuit is divided into multiple independent sequencer stages, where each stage controls a specific power rail. This segmentation allows the complex power sequencing function to be broken down into manageable, modular units that can be independently designed and tested, reducing overall system complexity while maintaining reliability.
Solution Approach 2:
The circuit employs dynamic signal inversion where the first circuit element generates a negative intermediate signal in response to a positive input signal, which then triggers the second circuit element to generate a positive output signal. This dynamic signal transformation enables flexible control of power sequencing timing without requiring complex hardwired logic.
2Object-affected harmful factors
If power supply sequencing is implemented without customizable delay, then the device complexity is reduced, but the harmful effects of inrush current increase
Solution Approach 1:
The power supply sequencer circuit performs preliminary actions by generating delayed control signals before actually enabling power to each rail. The first circuit element anticipates the power transition and generates an intermediate signal with built-in delay, which then triggers the second circuit element to enable the power rail at the optimal moment, preventing inrush current before it occurs.
Solution Approach 2:
The circuit enables customizable delay by changing the timing parameters of the intermediate signal generation. By adjusting the characteristics of the first and second circuit elements (such as RC time constants or transistor switching characteristics), the delay duration can be customized for each power rail, allowing optimization of inrush current protection for different load requirements.
3Reliability
If power good pins are used in voltage regulators, then the power sequencing safety is improved, but the cost of the system increases
Solution Approach 1:
The invention extracts and removes the requirement for power good pins from the voltage regulator components. Instead of relying on these expensive external indicators, the power supply sequencer circuit internally generates its own control signals based on the actual power rail voltage levels, eliminating the need for additional costly components while maintaining sequencing safety.
Solution Approach 2:
The power supply sequencer circuit makes the system self-sufficient by using its own internal signal generation capability. The first circuit element monitors the power rail voltage and automatically generates the appropriate intermediate and output signals without requiring external power good indicators, enabling the system to manage its own power sequencing safely and cost-effectively.
4Reliability
If a simple power control circuit is used, then the device complexity is reduced, but the ability to provide stable delay independent of voltage ramp rate is lost
Solution Approach 1:
The circuit employs dynamic signal inversion where the first circuit element generates a negative intermediate signal in response to a positive input signal, which then triggers the second circuit element to generate a positive output signal. This dynamic signal transformation enables flexible control of power sequencing timing without requiring complex hardwired logic.
Data Source
AI summary
There is provided a power supply control apparatus for connection to electrical inputs of an electronic device wherein each electrical input is operatively connected to a power source having a sequencer circuit and a control element, the sequencer circuit including sequencer stage(s). The sequencer circuit selectively receives an indication signal, the sequencer circuit selectively receives a positive indication signal indicative of a voltage supplied to a first of the electrical inputs reaching or passing a predefined voltage threshold, and the sequencer circuit selectively provides a control signal to the control element, the control element triggerable by a positive control signal. Each sequencer stage includes circuit elements, the first selectively receives an input signal and selectively provides an intermediate signal to the second, the second selectively provides an output signal.