Switching Voltage Regulator Hysteretic Comparator Dynamic Scaling

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Solution Overview

Problem

Existing switching voltage regulators face inefficiencies in dynamic voltage scaling due to noise and peak current issues when measuring critical path gate speed using ring oscillators, particularly in discontinuous buck mode voltage regulators.

Innovation Solution

The implementation of a ring oscillator with adjustable delay elements and a comparator that introduces hysteresis by toggling between different divider values and delay element configurations, allowing for precise control of oscillator frequency relative to a reference signal, thereby optimizing power consumption and reducing noise.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If a ring oscillator is used to measure critical path gate speed for dynamic voltage scaling, then power consumption can be optimized, but noise and peak current issues arise

Engineering Contradiction:

Improvepower consumptionVSAvoidnoise and peak current

Core Design Contradiction:

Use of energy by moving objectVSObject-affected harmful factors

Solution Approach 1:

The patent implements dynamic voltage scaling by adjusting the voltage regulator output based on real-time critical path gate speed measurements from the ring oscillator. The system dynamically changes operating voltage to optimize power consumption while maintaining acceptable performance, directly addressing the power consumption benefit while managing associated noise through controlled adjustment rather than extreme voltage changes

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The system uses the ring oscillator frequency as feedback to control the voltage regulator. The measured gate speed feeds back to adjust the voltage output, creating a closed-loop control system that optimizes power consumption while preventing excessive noise and peak current by using the measured feedback signal to modulate the regulator in a controlled manner

Inventive Principle:

Principle #23Feedback

2Loss of energy

If discontinuous buck mode voltage regulation is used, then efficiency can be improved, but measurement precision of gate speed deteriorates

Engineering Contradiction:

ImproveefficiencyVSAvoidgate speed measurement

Core Design Contradiction:

Loss of energyVSMeasurement precision

Solution Approach 1:

The patent captures the ring oscillator frequency at specific predetermined times during the switching cycle (such as at the beginning or end of the charge cycle). This preliminary sampling approach allows the system to obtain gate speed measurements at critical moments without requiring continuous measurement, maintaining measurement precision while enabling efficient discontinuous buck mode operation

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The system performs gate speed measurements periodically at specific intervals within the switching cycle rather than continuously. This periodic sampling approach maintains sufficient measurement precision for control purposes while allowing the voltage regulator to operate in efficient discontinuous buck mode with reduced switching activity

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 enhances the efficiency of dynamic voltage scaling by reducing peak current and noise, improving transient response and power management in voltage regulators, particularly in applications like microprocessors and disk drives.

Implementation Method 1

a ring oscillator that generates an oscillator signal with a frequency proportional to the gate speed of the critical path circuit (where the gate speed is inversely proportional to the propagation delay of the critical path circuit)

Methodology Applied

Scientific EffectPropagation delay:

Implementation Method 2

A comparator compares the oscillator signal to a reference signal, and switching circuitry charges a charging element in response to the comparison. Control circuitry adjusts the number of delay elements in the ring oscillator and the divider value of the frequency generator to generate hysteresis in the comparison.

Methodology Applied

Scientific EffectHysteresis: Hysteresis

Data Source

PatentUS8085020B1Switching voltage regulator employing dynamic voltage scaling with hysteretic comparator

Publication Date: 2011.12.27 WESTERN DIGITAL TECHNOLOGIES INC

AI summary

A switching voltage regulator is disclosed operable to regulate a voltage supplied to system circuitry. A comparator compares an oscillator signal generated by a ring oscillator to a reference signal generated by a frequency generator. Switching circuitry charges a charging element in response to the comparison, and control circuitry adjusts a number of delay elements in the ring oscillator and a divider value of the frequency generator to generate hysteresis in the comparison. In one embodiment, the charging element is charged while a frequency of the reference signal is above a frequency of the oscillator signal.