Synchronous Discharge Circuit for Capacitive Loads

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Solution Overview

Problem

Distributive systems with multiple capacitive loads face issues such as power overload and data corruption during power up or power down, leading to potential structural damage if capacitive loads are not properly discharged, especially when voltage regulators with different power supplies are shut down simultaneously.

Innovation Solution

A synchronous discharge circuit is introduced to synchronously discharge multiple capacitive loads to a target end voltage, ensuring that all loads are discharged at proportional rates, thereby preventing damage and ensuring a controlled power down process, even in systems with linear and nonlinear capacitive loads.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of time

If multiple voltage regulators are powered down simultaneously, then power down time is reduced, but structural damage may occur due to uncontrolled capacitive discharge

Engineering Contradiction:
Improvepower down timeVSAvoidstructural damage
Core Design Contradiction:
Loss of timeVSObject-affected harmful factors

Solution Approach 1:

The patent applies preliminary action by initiating controlled discharge of capacitive loads before the voltage regulators are fully powered down. The discharge circuit is activated in advance to ensure capacitors are safely discharged before the power down sequence completes, preventing damage while maintaining fast shutdown capability

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent introduces a discharge circuit as an intermediary component between the capacitive loads and ground. This mediator circuit controls the discharge process through current sources and switching elements, enabling safe energy dissipation without directly affecting the voltage regulators during power down

Inventive Principle:
Principle #24Intermediary (Mediator)

2Speed

If capacitive loads are discharged quickly, then power down speed is improved, but voltage imbalance may cause damage to voltage regulators

Engineering Contradiction:
Improvepower down speedVSAvoidvoltage regulator damage
Core Design Contradiction:
SpeedVSObject-affected harmful factors

Solution Approach 1:

The patent implements feedback by using comparator circuits that continuously monitor the voltages across different capacitive loads. The comparators provide feedback signals to control switches, adjusting the discharge current dynamically to maintain voltage balance and prevent damage during fast power down operations

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent applies dynamics by making the discharge circuit adjustable and adaptive. The discharge current is not fixed but is dynamically controlled through switching elements and current sources that respond to real-time voltage conditions, enabling both fast and safe discharge across varying load conditions

Inventive Principle:
Principle #15Dynamics

3Manufacturing precision

If a complex control circuit is used to manage capacitive discharge, then discharge control precision is improved, but device complexity increases

Engineering Contradiction:
Improvedischarge control precisionVSAvoidcontrol circuit complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent applies segmentation by dividing the discharge control into modular functional blocks: comparator circuits for voltage monitoring, control switches for individual capacitor control, and current sources for discharge. This segmentation enables precise control while maintaining modularity and reducing overall system complexity

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent implements universality by designing control circuit elements that serve multiple functions. For example, the comparator circuits not only monitor voltages but also generate control signals for switching elements, and the switching elements simultaneously control discharge paths and provide feedback signals, reducing the need for separate dedicated components

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 synchronous discharge circuit effectively prevents structural damage and data loss by ensuring that all capacitive loads reach zero voltage simultaneously, maintaining system integrity and stability during power down operations.

Implementation Method 1

A capacitor is a passive two-terminal electronic component that stores electrical energy in an electric field. The effect of a capacitor is known as capacitance.

Methodology Applied
Scientific EffectCapacitance: Capacitance

Data Source

PatentEP3739738B1System for synchronously discharging multiple capacitive loads
Publication Date: 2021.12.08 NXP USA INC
  • EP3739738B1 patent drawingFigure 1~2
  • EP3739738B1 patent drawingFigure 3~4
  • EP3739738B1 patent drawingFigure 5

AI summary

An apparatus and method for synchronously discharging multiple capacitive loads. In one embodiment, the apparatus includes first and second discharge circuits for discharging first and second capacitive loads, respectively. The apparatus also includes a control circuit coupled to the first and second discharge circuits and configured to control the second discharge circuit. The control circuit includes a first scaler circuit configured to generate a first scaled voltage based on a first voltage on the first capacitive load, a second scaler circuit configured to generate a second scaled voltage based on a second voltage on the second capacitive load, and a comparator circuit for comparing the first and second scaled voltages. The comparator circuit asserts a control signal when the second scaled voltage exceeds the first scaled voltage. The second discharge circuit discharges the second capacitive load when the comparator circuit asserts its control signal.