Step-Up Charge Pump Soft-Start for Switching Current Control

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Solution Overview

Problem

Existing charge pump power conversion circuits face issues with high switching currents during startup, which can exceed component ratings and cause damage, particularly in high-power applications like data centers and AI hardware processors, and existing solutions may not work when switch or capacitor characteristics are unknown.

Innovation Solution

Implement a multi-phase, bootstrapping soft-start process that gradually increases the gate voltage of power switches, limiting current during startup, and uses control circuitry to manage switching configurations without prior knowledge of switch or capacitor characteristics.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If charge pump circuit is started up with fully enhanced switches, then power conversion efficiency is improved, but switching currents exceed component ratings and cause damage

Engineering Contradiction:

Improvepower conversion efficiencyVSAvoidswitching currents

Core Design Contradiction:

Loss of energyVSObject-affected harmful factors

Solution Approach 1:

The patent applies preliminary action by implementing a soft-start sequence that gradually enhances switch conduction before full operation. The controller initially operates switches in a partially enhanced state to pre-charge capacitors and limit inrush currents, then progressively transitions to full enhancement mode, preventing component damage while maintaining eventual efficiency

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent applies dynamics by making switch enhancement levels variable rather than static. The controller dynamically adjusts gate voltages during startup, transitioning switches from partially enhanced to fully enhanced states based on real-time circuit conditions, allowing current limiting during startup while achieving optimal efficiency during steady-state operation

Inventive Principle:

Principle #15Dynamics

2Reliability

If soft-start process is implemented to reduce switching currents, then component damage is prevented, but startup time is increased

Engineering Contradiction:

Improvecomponent safetyVSAvoidstartup time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The patent applies periodic action through multi-phase startup sequences where switches are enhanced in staged intervals. The controller cycles through different enhancement phases, alternating between charging different capacitor groups and progressively enabling more switches, which limits currents while maintaining reasonable startup timing through structured periodic operation

Inventive Principle:

Principle #19Periodic action

Solution Approach 2:

The patent applies segmentation by dividing the startup process into distinct phases targeting different circuit components. Instead of uniformly enhancing all switches simultaneously, the controller segments the startup sequence to progressively enable specific switch groups (e.g., first high-side switches, then low-side switches), distributing the current stress over time and components

Inventive Principle:

Principle #1Segmentation

3Adaptability or versatility

If existing startup solutions are used, then simple circuits are protected, but they fail when switch or capacitor characteristics are unknown

Engineering Contradiction:

Improvecircuit compatibilityVSAvoidoperation safety

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The patent applies self-service by implementing a control method that automatically adapts to unknown component characteristics. The controller monitors actual circuit behavior during startup and dynamically adjusts enhancement levels based on measured currents and voltages, allowing the system to self-calibrate and safely operate with components of varying characteristics without requiring pre-programmed component data

Inventive Principle:

Principle #25Self-service

4Loss of energy

If gate voltage is increased to improve switching performance, then switching losses are reduced, but switching currents increase and damage components

Engineering Contradiction:

Improveswitching lossesVSAvoidswitching currents

Core Design Contradiction:

Loss of energyVSObject-affected harmful factors

Solution Approach 1:

The patent applies dynamics by making gate voltage levels time-dependent and condition-based. During startup, the controller applies reduced gate voltages to limit currents, then progressively increases them to full enhancement levels as capacitors charge and currents stabilize, dynamically optimizing the balance between switching performance and current limitation throughout the startup transient

Inventive Principle:

Principle #15Dynamics

Data Source

PatentUS20260051815A1Step-up charge pump power up systems and methods

Publication Date: 2026.02.19 MURATA MFG CO LTD

AI summary

The present disclosure relates to charge pumps, and more particularly, to apparatuses, integrated circuits, and methods for powering up a step-up charge pump circuit. The charge pump circuit is capable of operating as a step-up converter and comprises a network of interconnected switches and fly capacitors, each switch operable between ON and OFF states to cycle the network between at least two switching configurations, wherein a first switch of the switches is connected to a fly capacitor terminal and a step-up input node of the charge pump circuit. The method comprises increasing over a period of time a voltage achieved at the fly capacitor terminal during the ON state of the first switch by controlling the first switch, while operating the switches to transition the network between the at least two switching configurations.