PLP Capacitor Charging Control Under SSD Peak Current Limits

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Solution Overview

Problem

In memory systems with power loss protection (PLP) functions, it is challenging to balance peak current requirements and performance, as charging the backup capacitor increases current consumption, potentially exceeding allowable limits and reducing SSD performance.

Innovation Solution

A memory system that includes a controller to preferentially charge the PLP capacitor when current consumption is below a certain threshold, using throttling control to manage command issuance and adjust power consumption, thereby reducing peak current demands without compromising performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the PLP capacitor is charged regularly to maintain power loss protection function, then the capacitor energy is sufficient for backup power supply, but the current consumption increases and peak current may exceed allowable limits

Engineering Contradiction:

Improvepower loss protection functionVSAvoidcurrent consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The patent implements dynamic charging control where the charging timing and frequency of the PLP capacitor are adjusted based on real-time current consumption conditions. The controller monitors current levels and schedules capacitor charging during periods when current consumption is below threshold values, making the charging process adaptive rather than static or fixed-period.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The system changes operational parameters by adjusting the charging schedule based on current consumption thresholds. When current consumption is low, the capacitor is charged; when current consumption is high, charging is deferred. This parameter-based control allows the system to maintain reliability while managing peak current demands.

Inventive Principle:

Principle #35Parameter changes

2Use of energy by moving object

If the capacitor charging is delayed to reduce peak current, then current consumption is managed within limits, but the power loss protection function may be compromised

Engineering Contradiction:

Improvecurrent consumptionVSAvoidpower loss protection function

Core Design Contradiction:

Use of energy by moving objectVSReliability

Solution Approach 1:

The controller continuously monitors current consumption levels and uses this feedback to make real-time decisions about capacitor charging. The system measures actual current conditions and adjusts charging operations accordingly, ensuring that charging occurs when it won't cause peak current violations while still maintaining adequate capacitor charge levels for power loss protection.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The system performs preliminary assessment of current consumption conditions before initiating capacitor charging. By evaluating whether current levels are below threshold values in advance, the controller can safely schedule charging operations without risking peak current exceedance, thus preventing both current violations and power loss protection failures.

Inventive Principle:

Principle #10Preliminary action

3Use of energy by moving object

If throttling control is applied to reduce current consumption during capacitor charging, then peak current is prevented from exceeding limits, but SSD performance is reduced

Engineering Contradiction:

Improvecurrent consumptionVSAvoidSSD performance

Core Design Contradiction:

Use of energy by moving objectVSProductivity

Solution Approach 1:

The patent employs periodic charging operations scheduled during low-current periods rather than continuous charging or charging during high-performance periods. By using periodic action aligned with natural low-current intervals, the system maintains capacitor charge levels without requiring sustained throttling that would degrade SSD performance.

Inventive Principle:

Principle #19Periodic 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 allows for both effective power loss protection and maintaining performance by managing current consumption, preventing peak current exceedance while ensuring the PLP capacitor is adequately charged.

Implementation Method 1

a capacitor for power loss protection functions or the like. The power supply circuit supplies power to the non-volatile memory and the controller from an external power supply during normal operations and supplies power to the non-volatile memory and the controller from the capacitor if the external power supply is interrupted

Methodology Applied

Scientific EffectCapacitance: Capacitance

Data Source

PatentUS11875042B2Memory system and control method for controlling charging capacitor of a power supply circuit

Publication Date: 2024.01.16 KIOXIA CORP

AI summary

According to one embodiment, a memory system includes a non-volatile memory, a controller for writing data to the non-volatile memory and reading data from the non-volatile memory, and a power supply circuit. The power supply circuit includes a capacitor. The power supply circuit supplies power to the non-volatile memory and the controller from an external power supply and supplies power to the non-volatile memory and the controller from the capacitor if the external power supply is interrupted. The controller controls the power supply circuit to charge the capacitor when current consumption of the non-volatile memory is less than some first current level.