Soft Switching Circuit for Stable Power-Up Without Decoupling Caps

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Solution Overview

Problem

Electronic systems-on-chip face challenges in maintaining continuous voltage levels due to sudden transient drops during power switching, which can cause system resets and require external decoupling capacitors, hindering miniaturization and increasing manufacturing costs.

Innovation Solution

A soft-switching device with a MOS transistor and a filter capacitor is used to progressively supply voltage to electronic units, avoiding sudden charge transfers and allowing controlled activation of units with a defined voltage ramp, eliminating the need for external decoupling capacitors.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a simple switch is used to activate electronic units directly on the VDD supply voltage, then the device complexity is reduced, but transient voltage drops occur causing system resets

Engineering Contradiction:

Improveswitching device complexityVSAvoidsystem operation stability

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The patent introduces a soft switching device as an intermediary component between the power supply and electronic units. This device includes a switch and a filter element (capacitor) that work together to provide smooth voltage transitions, preventing direct connection issues while maintaining system reliability.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The filter element (capacitor) in the soft switching device provides beforehand cushioning by storing energy and releasing it during switching transitions. This prevents voltage dips before they can cause system resets, ensuring stable operation during power supply transitions.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

2Stability of the object's composition

If external decoupling capacitors are used to prevent voltage dips, then the voltage stability is improved, but the manufacturing cost increases and miniaturization is hindered

Engineering Contradiction:

Improvevoltage stabilityVSAvoidmanufacturing cost and miniaturization

Core Design Contradiction:

Stability of the object's compositionVSEase of manufacture

Solution Approach 1:

The patent merges the decoupling function with the switching function by integrating a filter element directly into the soft switching device. This eliminates the need for separate external decoupling capacitors, reducing component count, manufacturing cost, and enabling miniaturization while maintaining voltage stability.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The soft switching device performs multiple functions simultaneously: it acts as both a switching device for activating electronic units and a decoupling device for stabilizing voltage. This multi-functionality reduces the overall system complexity and eliminates the need for additional external components.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Productivity

If voltage is supplied immediately to all electronic units, then the productivity is improved, but transient charge transfers cause excessive voltage variations

Engineering Contradiction:

Improvesystem activation speedVSAvoidvoltage variation magnitude

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The soft switching device dynamically controls the voltage transition by using a switch to activate electronic units while a filter element (capacitor) smooths the voltage ramp. This dynamic approach allows fast activation while preventing excessive voltage variations during the transition period.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The filter element in the soft switching device performs preliminary action by pre-charging and smoothing the voltage before it reaches the electronic units. This prepares the voltage waveform in advance to avoid sudden jumps and harmful transients during activation.

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 approach ensures stable voltage transitions, preventing system resets and enabling miniaturization by maintaining continuous voltage levels without external decoupling capacitors, thus optimizing power supply and reducing manufacturing costs.

Implementation Method 1

a filter element, preferably a capacitor, is provided between the drain and the gate terminal in order to make the MOS transistor gently conductive when activated

Methodology Applied

Scientific EffectCapacitance: Capacitance

Data Source

PatentEP4304088A1Soft switching device, electronic system with soft switching device with an electrical power source

Publication Date: 2024.01.10 EM MICROELECTRONIC-MARIN

Figure 1a~3
Figure 2a~2b
Figure 4a

AI summary

The soft switching device (sw) is provided for connecting a power supply to at least one large electronic unit of an electronic system (1), so as to be activated via the soft switching device to the power supply. The device comprises a switch component (M1) with a control terminal and a current source (13) connected to the control terminal to control the switch component closure when the current source is activated. The soft switching device also includes a soft transition element (C1) of capacitive type between the output terminal (12) and the control terminal of the switch component (M1) so as to gradually close the switch for connection to a power supply.