Microcomputer Power Supply Control for Capacitor Discharge

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Solution Overview

Problem

Existing electronic control devices face challenges in reliably controlling the power supply voltage to ensure normal termination and re-activation of microcomputers, particularly due to issues with voltage level and sequence discrepancies, leading to incomplete power-down and activation sequences.

Innovation Solution

An electronic control device is designed with a power supply control unit that includes a power supply unit, a reset control unit, and a discharge control unit, which manages the power supply voltage by turning it ON and OFF, generates a Low reset signal to discharge capacitor charges, and ensures complete discharge before re-activation, using a capacitor between the power supply control unit and the microcomputer.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the power supply voltage is quickly discharged at power-down, then the microcomputer can complete normal shutdown process and follow desired activation sequence, but the discharge time becomes too short for the microcomputer to execute normal shutdown process

Engineering Contradiction:

Improvenormal shutdown process completionVSAvoiddischarge time

Core Design Contradiction:

ReliabilityVSDuration of action of moving object

Solution Approach 1:

The discharge control unit initiates capacitor discharge immediately upon detecting power-down, performing the discharge action in advance before the microcomputer finishes its shutdown process. This preliminary discharge action ensures that the capacitor is fully discharged by the time the microcomputer attempts to re-activate, preventing voltage conflicts and ensuring proper shutdown sequence completion.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The discharge control unit acts as an intermediary between the power supply control unit and the microcomputer. It manages the capacitor discharge process independently, allowing the microcomputer to complete its shutdown procedures while ensuring the power supply voltage is ready for the next activation sequence without interfering with the microcomputer's internal shutdown timing.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Productivity

If the microcomputer is re-activated before power supply voltage sufficiently decreases, then the activation sequence can be faster, but the microcomputer cannot execute normal shutdown process or may not activate normally

Engineering Contradiction:

Improvere-activation speedVSAvoidnormal activation

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The discharge control unit continuously monitors the power supply voltage level and the operational state of the microcomputer. Based on this feedback, it dynamically adjusts the discharge process and controls the timing of power supply restoration, ensuring that re-activation only occurs after the capacitor is fully discharged and the microcomputer is ready, thus maintaining both speed and reliability.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The system performs preliminary discharge of the capacitor and prepares the power supply voltage in advance before the microcomputer needs to re-activate. This preliminary preparation ensures that when the microcomputer finishes its shutdown process and attempts to re-activate, the power supply is already ready, enabling fast and reliable activation without waiting for gradual voltage decay.

Inventive Principle:

Principle #10Preliminary action

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

This solution enables reliable normal termination and re-activation of microcomputers by quickly and completely discharging power supply voltages, ensuring proper power-down and activation sequences are followed, thereby improving the reliability of electronic control devices.

Implementation Method 1

a capacitor for stabilizing the power supply voltage is generally attached to an output terminal that outputs the power supply voltage. The power supply voltage is gradually discharged depending on a value of the connected capacitor

Methodology Applied

Scientific EffectCapacitance: Capacitance

Implementation Method 2

The power supply voltage is gradually discharged depending on a value of the connected capacitor and a connected resistor

Methodology Applied

Scientific EffectJoule heating: Joule Heating

Data Source

PatentUS11726794B2Preventing supply of power to a microcomputer of an electronic control device until capacitors are discharged

Publication Date: 2023.08.15 ASTEMO LTD

AI summary

To obtain a highly reliable electronic control device capable of reliably causing a microcomputer to perform normal termination and normal re-activation by controlling a power supply voltage. According to the present invention, an electronic control device 25 includes a microcomputer 18, a power supply control unit 20 that controls a power supply voltage of the microcomputer, and a capacitor 19 provided between the power supply control unit and the microcomputer. The power supply control unit 20 includes a power supply unit 24 that supplies a first power supply voltage V1 to the microcomputer by turning ON an activation signal for activating the microcomputer, and stops the supply of the power supply voltage by turning the activation signal OFF, a reset control unit 14 that generates a Low reset signal by turning the activation signal OFF, and a discharge control unit 12 that discharges electric charges of the capacitor when acquiring the Low reset signal.