Self-Timed Level Shifter Circuit for Fast Safe Voltage Transfer

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Solution Overview

Problem

Integrated circuit level shifters introduce bottlenecks in operation speed and can cause circuitry damage due to voltage overshoots when transitioning signals between different voltage domains, particularly when using transistors with ratings lower than the required voltage width.

Innovation Solution

Implementing self-timed level shifters with self-timing modules that provide voltage transition accelerator signals to speed up the pull-up operations of specific nodes within the level shifter, minimizing voltage overshoots and protecting transistors from damage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If conventional level shifters are used to transition signals between voltage domains, then signal level shifting is achieved, but operation speed is limited due to bottlenecks in the level shifting process

Engineering Contradiction:

Improvelevel shifting operation speedVSAvoidlevel shifter transaction lag

Core Design Contradiction:

SpeedVSLoss of time

Solution Approach 1:

The self-timing circuit generates accelerator signals in advance to pre-charge or pre-discharge specific nodes before the main level shifting operation completes. This preliminary action reduces the overall transition time by preparing the circuit state ahead of time, thereby speeding up the level shifting operation without causing voltage overshoots.

Inventive Principle:

Principle #10Preliminary action

2Use of energy by moving object

If transistors with lower voltage ratings are used in the level shifter, then power performance is improved and battery life is prolonged, but voltage overshoots can occur causing circuitry damage

Engineering Contradiction:

Improvepower performanceVSAvoidvoltage overshoot damage

Core Design Contradiction:

Use of energy by moving objectVSObject-affected harmful factors

Solution Approach 1:

The self-timing circuit monitors the state of internal nodes and generates accelerator signals based on feedback from these node states. This feedback mechanism ensures that acceleration is applied only when safe and necessary, preventing voltage overshoots that could damage the low-voltage-rated transistors while still achieving fast transition times.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The self-timing circuit acts as an intermediary between the input signal and the transistor switching operation. It generates intermediate accelerator signals that carefully control the charging/discharging process, mediating between the need for fast switching and the vulnerability of low-voltage transistors to overshoot damage.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Productivity

If faster level shifting is implemented to reduce transaction lag, then operation speed improves, but voltage overshoots increase causing potential transistor damage

Engineering Contradiction:

Improvelevel shifting throughputVSAvoidtransistor safety

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The level shifter includes a self-timing circuit that automatically generates the appropriate accelerator signals based on its own internal state. This self-service mechanism eliminates the need for external timing control while ensuring that acceleration is applied safely and efficiently, maintaining both high productivity and transistor reliability.

Inventive Principle:

Principle #25Self-service

Data Source

PatentUS12483246B2Self timed level shifter circuit

Publication Date: 2025.11.25 TAIWAN SEMICONDUCTOR MANUFACTURING CO LTD

AI summary

Systems and methods are provided for a level shifter. A level shifter includes a network of transistors configured to receive a signal at a first node in a first voltage domain and to generate a corresponding signal at a second node in a second voltage domain during a transition period of time. A self timing circuit is configured to receive an initiation signal based on the signal at the first node and to generate a voltage transition accelerator signal that is used to pull up the second node prior to the expiration of the transition period of time.