Capacitive Feedback Regulator Wake-Up Time

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Voltage regulators experience long wake-up times and output level droops during transitions from standby to active mode due to high RC time constants and high load currents, leading to potential data transfer errors, especially at double data rate speeds.

Innovation Solution

A voltage regulator circuit design that employs a pass transistor and an op-amp with a delayed connection of the second input to a resistive voltage divider during the transition from standby to active mode, utilizing capacitive feedback to speed up the loop response and reduce wake-up time without increasing power consumption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If the regulator uses a high RC time constant feedback loop for stability, then the voltage regulation is stable, but the wake-up time becomes long

Engineering Contradiction:

Improvevoltage regulation stabilityVSAvoidwake-up time

Core Design Contradiction:

Stability of the object's compositionVSLoss of time

Solution Approach 1:

The feedback loop configuration is dynamically changed during wake-up transition. Initially, the feedback loop is disconnected or configured with different parameters to enable fast wake-up, then switched to the stable configuration once wake-up is complete. This dynamic reconfiguration resolves the contradiction between fast response and stable regulation.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The regulator performs preliminary wake-up action using a simplified or accelerated feedback path before engaging the full stable feedback loop. This preliminary action allows the system to quickly transition from standby to active state, after which the complete feedback loop is engaged for stable regulation.

Inventive Principle:

Principle #10Preliminary action

2Use of energy by moving object

If the regulator operates in standby mode with minimal power consumption, then power efficiency is improved, but the output voltage level droops under high load current during active mode transition

Engineering Contradiction:

Improvepower consumption in standbyVSAvoidoutput voltage stability during transition

Core Design Contradiction:

Use of energy by moving objectVSReliability

Solution Approach 1:

Before transitioning to active mode, the regulator performs preliminary actions such as pre-charging output capacitors or activating power pre-conditioning circuits. This preliminary action ensures that when high load current is applied, the output voltage does not droop excessively, while still maintaining low standby power consumption.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The regulator applies preliminary counter-actions to prevent the harmful effect of voltage droop. This may involve pre-adjusting operating points, activating auxiliary power paths, or setting up compensation mechanisms before the high load current is applied, thereby preventing voltage instability during transition.

Inventive Principle:

Principle #9Preliminary anti-action

3Device complexity

If the regulator uses traditional resistive feedback for wake-up, then the circuit is simple, but the loop response is delayed and wake-up time is extended

Engineering Contradiction:

Improvefeedback circuit complexityVSAvoidloop response speed

Core Design Contradiction:

Device complexityVSSpeed

Solution Approach 1:

The feedback circuit parameters are changed during wake-up transition. The regulator switches from using high-value resistors (which consume less power but respond slowly) to using lower-value resistors or alternative feedback paths (which respond faster but consume more power). This parameter change enables fast loop response during wake-up while maintaining power efficiency during standby.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The feedback circuit dynamically switches between different configurations - a simple high-impedance configuration during standby and a low-impedance high-speed configuration during wake-up. This dynamic switching resolves the contradiction between circuit simplicity and response speed.

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 reduces wake-up time and prevents output level overshoot, ensuring stable voltage regulation and accurate data transfer by maintaining the final regulation voltage during the transition, independent of process variations.

Implementation Method 1

First and second capacitors are connected in series between the op-amp's output node and the second input of the op-amp

Methodology Applied

Scientific EffectCapacitive feedback: Capacitance

Implementation Method 2

the output node of the voltage regulator circuit is connected to ground through a resistive voltage divider

Methodology Applied

Scientific EffectResistive voltage division: Electrical Resistance

Data Source

PatentUS8981750B1Active regulator wake-up time improvement by capacitive regulation

Publication Date: 2015.03.17 SANDISK TECHNOLOGIES LLC

AI summary

An active voltage regulator circuit having improved wake-up response is presented. The circuit includes an op-amp whose output is connected to a pass device for supplying the output level, and has both capacitive and resistive parts in its feedback loop. When the regulator is enabled, the capacitive elements are initially connected, followed after a delay by the resistive elements of the feedback loop.