SSD Super-Capacitor Inrush Current Control Circuit

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

The integration of super-capacitors as backup power supplies in solid-state drives (SSDs) leads to high inrush currents when main power is applied, necessitating additional current limiting measures to prevent data loss and ensure system stability during power failures.

Innovation Solution

A system and method that utilize a power control circuit with switches to manage the connection of super-capacitors to the power supply and capacitive loads, incorporating a current limiting circuit to regulate the initial current rush, allowing the super-capacitors to charge and then supply power to the DC-DC converter, thereby reducing inrush currents.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If super-capacitors are integrated as backup power supplies in SSDs, then backup power capability and data protection are improved, but inrush current increases causing system stability issues

Engineering Contradiction:

Improvebackup power capabilityVSAvoidinrush current

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The power control circuit performs preliminary action by detecting power failure conditions and activating the super-capacitor backup power supply before the main power is completely lost. This ensures continuous power supply to protect data integrity while managing the inrush current through controlled switching sequences.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The power control circuit acts as an intermediary between the main power supply and the super-capacitor backup power supply. It manages the transition and current flow, controlling the inrush current by regulating when and how the super-capacitor connects to the system, thus resolving the contradiction between providing backup power and limiting inrush current.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Stability of the object's composition

If current limiting circuits are added to limit inrush current, then system stability is improved, but device complexity increases

Engineering Contradiction:

Improvesystem stabilityVSAvoidcircuit complexity

Core Design Contradiction:

Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The power control circuit combines multiple functions into a single integrated device: it detects power failures, controls switching between power sources, manages super-capacitor charging/discharging, and limits inrush current. This merging approach maintains system stability without adding separate dedicated current limiting circuits, thus avoiding increased device complexity.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The power control circuit is designed as a universal component that performs multiple functions: power failure detection, backup power activation, current limiting, and switching control. This multi-functionality resolves the contradiction by providing current limiting capability without requiring additional specialized circuitry.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Volume of moving object

If super-capacitors are used instead of batteries for backup power, then size and power delivery speed are improved, but inrush current and power dissipation increase

Engineering Contradiction:

Improvebackup power component sizeVSAvoidpower dissipation

Core Design Contradiction:

Volume of moving objectVSLoss of energy

Solution Approach 1:

The power control circuit implements dynamic control of the super-capacitor connection, adjusting the switching timing and duration based on real-time power conditions. By dynamically managing when the super-capacitor is connected and disconnected, the circuit limits inrush current and reduces power dissipation while maintaining the size advantages of super-capacitors over batteries.

Inventive Principle:

Principle #15Dynamics

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 effectively limits inrush currents in SSDs with super-capacitor backup power, ensuring stable operation and data integrity by pre-charging the DC-DC converter's input capacitors, eliminating the need for separate current limiting circuits and reducing power dissipation.

Implementation Method 1

A super-capacitor is configured for charging by the power supply and powering the capacitive load

Methodology Applied

Scientific EffectCapacitance: Capacitance

Implementation Method 2

A current limiting circuit between the super-capacitor and the power supply is provided

Methodology Applied

Scientific EffectElectrical Resistance: Electrical Resistance

Data Source

PatentUS9553483B2System and method for limiting inrush current in solid state drives

Publication Date: 2017.01.24 KIOXIA CORP

AI summary

A system and method thereof to regulate a current to a capacitive load from a power supply connected to the capacitive load. The system includes a first switch between the power supply and the capacitive load, a super-capacitor configured for charging by the power supply and powering the capacitive load, a current limiting circuit between the super-capacitor and the power supply, a second switch between the super-capacitor and the capacitive load, and a power control circuit configured to control opening and closing of the first switch and the second switch independently, sense a voltage of the power supply, and sense a voltage of the super-capacitor.