Preconditioned Voltage Level Shifters for Faster Cross-Domain Switching

Solution Overview

Problem

Voltage level shifters face challenges in preventing concurrent activation of components as the difference in supply voltages between domains increases, leading to increased area requirements and slower transition times.

Innovation Solution

Incorporating preconditioning circuits that generate and provide shifted voltage signals to complement outputs, allowing for faster transition rates by configuring pull-up and pull-down circuits to operate within specific voltage domains without concurrent activation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the pull-down circuit is configured to be stronger than the pull-up circuit to prevent concurrent activation, then reliability is improved, but area increases due to larger pull-down circuit size

Engineering Contradiction:

Improveprevention of concurrent activationVSAvoidarea of voltage level shifter

Core Design Contradiction:

ReliabilityVSArea of moving object

Solution Approach 1:

The voltage level shifter is divided into separate pull-up and pull-down circuits with distinct control mechanisms. The preconditioning circuit segments the control signal path, providing early activation of the pull-up circuit before the pull-down circuit activates, thereby preventing concurrent operation without requiring the pull-down circuit to be oversized.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The preconditioning circuit performs preliminary action by early activating the pull-up circuit in response to the input signal transition before the main pull-down circuit operates. This timing arrangement ensures that the output node is already prepared with the appropriate voltage level, preventing concurrent activation issues without increasing the pull-down circuit size.

Inventive Principle:

Principle #10Preliminary action

2Area of moving object

If conventional voltage level shifters are used without preconditioning, then area is reduced, but transition time increases leading to slower operation

Engineering Contradiction:

Improvearea of voltage level shifterVSAvoidtransition time of output signal

Core Design Contradiction:

Area of moving objectVSLoss of time

Solution Approach 1:

The preconditioning circuit performs preliminary action by early activating the pull-up circuit in response to the input signal transition before the main pull-down circuit operates. This timing arrangement ensures that the output node is already prepared with the appropriate voltage level, preventing concurrent activation issues without increasing the pull-down circuit size.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The preconditioning circuit acts as an intermediary between the input signal and the main pull-up/pull-down circuits. It conditions the control signals by providing early activation cues to the pull-up circuit, thereby reducing transition time without requiring larger circuit components that would increase area.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Use of energy by moving object

If the voltage difference between domains increases, then power efficiency is improved by using lower voltage for idle operations, but concurrent activation risk increases requiring larger pull-down circuit

Engineering Contradiction:

Improvepower consumption during idle modeVSAvoidarea of pull-down circuit

Core Design Contradiction:

Use of energy by moving objectVSArea of moving object

Solution Approach 1:

The preconditioning circuit performs preliminary action by early activating the pull-up circuit in response to the input signal transition before the main pull-down circuit operates. This timing arrangement ensures that the output node is already prepared with the appropriate voltage level, preventing concurrent activation issues without increasing the pull-down circuit size.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The preconditioning circuit uses small, transient control signals to achieve the desired effect of preventing concurrent activation. Rather than relying on permanently oversized pull-down circuit transistors, the system uses brief preconditioning pulses that activate the pull-up circuit in advance, effectively using small, short-duration control elements instead of large permanent structures.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

Data Source

PatentEP3304736B1Voltage level shifters employing preconditioning circuits, and related systems and methods

Publication Date: 2019.05.01 QUALCOMM INC

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AI summary

Voltage level shifters (100) employing preconditioning circuits (102) are disclosed. Related systems and methods are also disclosed. In one aspect, voltage level shifter (100) is configured to generate a voltage level shifted non-complement output signal and complement output signal corresponding to non-complement input signal (110) and complement input signal (108), respectively. First pull-up circuit (112) is configured to generate complement output signal (104) in response to non-complement input signal (106) transitioning to logic low voltage. First pull-down circuit (116) is configured to generate non-complement output signal (110) in response to complement input signal (108) transitioning to logic high voltage. First preconditioning circuit (102) is configured to receive non-complement (110) and complement output signals (104) and generate and provide shifted voltage signal to complement output (104) in response to non-complement output signal (110) transitioning to logic low voltage. This allows the complement output signal (104) to transition to the shifted voltage more quickly.