Oscillator Voltage Sensing for Fast On-Chip Droop Detection

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Solution Overview

Problem

Reducing power supply voltage in mobile devices leads to voltage droop and noise issues, potentially causing logic failures and unexpected shutdowns, which existing voltage sensors struggle to effectively monitor and manage.

Innovation Solution

A voltage sensor system comprising a voltage-controlled oscillator and multiple transition detectors, which count transitions at different locations on the oscillator and generate an output value proportional to the voltage, allowing for accurate voltage estimation and adaptive clock frequency adjustment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If power supply voltage is reduced to decrease power consumption, then energy efficiency is improved, but voltage droop and noise increase causing logic failures

Engineering Contradiction:
Improvepower consumptionVSAvoidlogic failure risk
Core Design Contradiction:
Use of energy by moving objectVSReliability

Solution Approach 1:

The voltage sensor performs preliminary detection of voltage droop conditions before they cause logic failures. By continuously monitoring voltage at critical locations and generating early warnings, the system can take preventive actions (such as adjusting power delivery or clock gating) before voltage drops reach failure thresholds, thus maintaining reliability while operating at reduced voltages

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The voltage sensor provides real-time feedback about voltage conditions to power management circuits. This feedback loop enables dynamic adjustment of power delivery and operational parameters based on actual voltage measurements, allowing the system to maintain stable operation at lower voltages by compensating for droop conditions as they occur

Inventive Principle:
Principle #23Feedback

2Measurement precision

If existing voltage sensors are used to monitor voltage, then voltage detection is achieved, but time resolution and accuracy are insufficient for capturing fast voltage droop events

Engineering Contradiction:
Improvevoltage measurement accuracyVSAvoidtime resolution
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The voltage sensor divides the voltage monitoring function into multiple parallel detection paths with different measurement ranges and resolutions. By segmenting the measurement task across multiple detectors operating simultaneously, the system achieves both high time resolution (for capturing fast droop events) and high voltage precision (for accurate threshold detection), overcoming the limitations of single-channel sensors

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The voltage sensor employs dynamic measurement techniques that adapt the measurement bandwidth and integration time based on the detected voltage conditions. During fast transient events, the sensor switches to high-speed sampling mode to capture rapid changes, while during steady-state operation, it uses higher-resolution measurement modes, thus optimizing both time and voltage resolution across different operating conditions

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

The system provides high voltage resolution and time resolution, enabling effective monitoring of voltage waveforms and preventing voltage drops by adjusting clock frequencies, thus ensuring stable device operation.

Implementation Method 1

a voltage sensor comprises a voltage-controlled oscillator coupled to a voltage being sensed

Methodology Applied
Scientific EffectVoltage-controlled oscillation:

Data Source

PatentEP3180626B1Low power high resolution oscillator based voltage sensor
Publication Date: 2020.04.01 QUALCOMM INC
  • EP3180626B1 patent drawingFigure 1
  • EP3180626B1 patent drawingFigure 2
  • EP3180626B1 patent drawingFigure 3

AI summary

Systems and methods for sensing voltage on a chip are described herein. In one embodiment, a voltage sensor comprises a voltage-controlled oscillator coupled to a voltage being sensed, and a plurality of transition detectors, wherein each of the transition detectors is coupled to a different location on the oscillator, and wherein each of the transition detectors is configured to count a number of transitions at the respective location over a time period. The voltage sensor also comprises an adder configured to add the numbers of transitions from the transition detectors to generate an output value that is approximately proportional to the voltage.